Kristensmith

Drugs And Cough And Bronchial Asthma Important Notes

1. Drugs used in bronchial asthma

• Bronchodilators
  • Sympathomimetics
    • Selective β2 agonists
  • Short-acting – salbutamol, Terbutaline
  • Longer acting – salmeterol
    • Non-selective agents – adrenaline, aminophylline
  • Methylxanthines – Heophylline, aminophylline
  • Anticholinergics – ipratropium bromide, atropine
• Anti-inflammatory
  • Systemic – glucocorticoids, hydrocortisone, prednisolone
  • Inhalational – beclomethasone, triamcinolone
• Mast cell stabilizer – disodium cromoglycate
• Leukotriene receptor antagonists – Montelukast
• Anti – IgE antibody – Omalizumab

2. Drugs causing bronchospasm

• ACE inhibitors
• Aspirin and other NSAIDs
• Beta-blockers
• Cholinergic drugs
• Bulk-forming laxatives
• Quinine
• Morphine

3. Ipratropium bromide

• It is an anticholinergic drug
• Produces slower response
• Used for regular prophylactic use

4. Mechanism of adrenergic as a bronchodilator

• Stimulation of β2 receptor
• Increased cAMP formation in bronchi muscle cells
• Relaxation of bronchi

5. Salbutamol

• It is β2 receptor agonist
• Safer than adrenaline and isoprenaline in the treatment of asthma
• Uses
  • In acute exacerbation of asthma
  • COPD
  • For short-term relief of bronchoconstrictor

Drugs And Cough And Bronchial Asthma Short Essays

Question 1. Mention two drugs used to suppress dry cough
Answer:

Drugs Used To Suppress Dry Cough:

1. Pharyngeal demulcents

• Lozenges
• Cough drops
• Glycerine

2. Expectorants

• Bronchial secretion enhancers
  • Sodium or potassium citrate
  • Potassium iodide
  • Balsum of tolu
• Mucolytic
  • Bromhexine
  • Acetylcysteine

3. Antitussives

• Opioids
  • Codeine
  • Pholcodine
• Non Opioids
  • Noscapine
  • Dextromethorphan
• Antihistamines
  • Chlorpheniramine
  • Diphenhydramine
  • Promethazine

4. Adjuvant Antitussives

• Bronchodilators- Salbutamol, terbutalin

Read And Learn More: Pharmacology Question and Answers

Question 2. Noscapine
Answer:

• Noscapine is a natural opium alkaloid
• It is a potent Antitussive
• It is highly effective and safe
• It may cause bronchoconstriction due to the release of histamine
• It acts by inhibiting the cough center In the medulla

Noscapine Use:

• Cough suppressant

Noscapine Adverse Effects:

• Nausea
• Headache

Noscapine Dose:

• 15-30 mg 6 hourly

Question 3. Disodium cromoglycate
Answer:

• Disodium cromoglycate is a synthetic derivative
• It belongs to a group of antiasthmatic drugs
• It is administered as an aerosol through metered dose inhaler

Disodium cromoglycate Mechanism of Action:

• Inhibits degranulation of mast cells
• Inhibits the release of inflammatory mediators
• Inhibits the release of cytokines
• Depresses neuronal reflexes

Disodium cromoglycate Adverse Effects:

• Throat irritation
• Cough
• Rarely bronchospasm and allergic reactions

Disodium cromoglycate Uses:

1. Prophylactic in bronchial asthma

• It is used for longer periods in mild to moderate asthma
• 2 puffs, 3-4 times daily

2. Allergic rhinitis

• Used as a nasal spray to produce symptomatic improvement

3. Allergic conjunctivitis

• Used as eyedrops
• 1-2 drops, 3-4 times daily

Question 4. Salbutamol
Answer:

• Salbutamol is a sympathomimetic drug
• It is fast acting bronchodilator
• The onset of action-1-5 min
• Duration of action- short

Salbutamol Actions:

• Bronchodilator
• Relaxation of the pregnant uterus
• Dilatation of blood vessels supplying the skeletal muscles
• Promote peptic glycogenolysis and uptake of potassium

Salbutamol Uses:

• In bronchial asthma- 100-200 meg every 6 hours through metered dose inhaler
• To delay premature labor
• In hyperkalemia

Salbutamol Adverse Effects:

• Tachycardia, palpitation
• Muscle tremors
• Tolerance
• Restlessness, nervousness
• Throat irritation
• Ankle edema
• Hyperglycaemia, hypokalaemia

Question 5. Pharmacotherapy of status asthmatics
Answer:

Treatment of status asthmaticus is as follows:

Question 6. Mention three groups of drugs used in bronchial asthma with an example.
Answer:

Drugs Used in Bronchial Asthma:

Question 7. Write the rationale for using any one drug for asthma.
Answer:

The Rationale of Using Sympathomimetic Drugs in Bronchial Asthma:

• Sympathomimetic drugs like adrenaline have the following mechanism

• It has a rapid onset and a short duration of action
• Hence it is used in acute asthmatic attacks as aerosol

Drugs And Cough And Bronchial Asthma Short Question And Answers

Question 1. Aminophylline
Answer:

• Aminophylline is one of the methylxanthines

Aminophylline Mechanism of Action:

• Enhances cAMP levels
• Causes bronchodilatation
• Inhibits the release of inflammatory mediators

Aminophylline Actions:

• CNS stimulant
• CVS stimulant
• Relaxes smooth muscles
• Mild diuretic
• Enhances secretion of acid and pepsin in the stomach
• Inhibits the release of inflammatory mediators

Aminophylline Uses:

• Bronchial asthma and COPD
• Apnea in the premature infant

Aminophylline Adverse Effects:

• Dyspepsia, vomiting, nervousness, tremor, delirium, hypotension, arrhythmia, and convulsions

Question 2. Nasal decongestants.
Answer:

• Nasal decongestants stimulate the alpha receptors and cause vasoconstriction in the nasal mucous membrane and relieve nasal congestion

Drugs Used As Nasal Decongestants:

• Naphazoline
• Pseudoephedrine
• Phenylephrine
• Imidazole

Nasal decongestants Use:

• Allergic rhinitis
• Common cold
• Sinusitis

Nasal decongestants Adverse Effects:

• Atrophic rhinitis
• Anosmia
• Local irritation

Question 3. The rationale for using Salbutamol in bronchial asthma
Answer:

• Salbutamol is used in asthma to reduce cardiac side effects
• Inhaled Salbutamol produces bronchodilatation within 5 min
• Its action lasts for 2-4 hours
• It is the most effective, convenient, and relatively safe
• Hence it is used to terminate the attacks of asthma.

Question 4. Beclomethasone
Answer:

• Beclomethasone is long acting glucocorticoid

Beclomethasone Mechanism of Action:

• Suppresses inflammatory response to antigen-antibody reaction
• Reduces mucosal edema and hyper irritability

Beclomethasone Uses:

• Prophylactic use to prevent acute attacks of asthma
• Prevent bronchial hypersensitivity
• Controls the symptoms

Beclomethasone Available As:

• Nasal spray- For allergic rhinitis
• Ointment- For skin and mucous membrane

Beclomethasone Dose:

• Beclate inhaler- 50,100,200 microgram
• Metered dose-1-2 puffs 3-4 times a day

Beclomethasone Adverse Effects:

• Hoarseness of voice
• Sore throat
• Oropharyngeal Candidiasis

Question 5. Ipratropium.
Answer:

• It is a semi-synthetic anticholinergic drug
• Given by inhalation

Ipratropium Uses:

• Bronchial asthma
• COPD
• Inhaled ipratropium – used as a prophylactic agent
• Nebulized ipratropium mixed with salbutamol – used in refractory asthma

Question 5. Name four bronchodilators.
Answer:

• Sympathomimetics – adrenaline, isoprenaline, salbutamol
• Methyl xanthine – theophylline, aminophylline
• Anticholinergic – ipratropium bromide, tiotropium bromide

Anti Cancer Drugs Important Notes

1. Methotrexate

• It is the folic acid antagonist
• Has antineoplastic activity
• Extensively used as a chemotherapeutic agent

Anti Cancer Drugs Short Essays

Question 1. Toxic effects of alkylating agents.
Answer:

Alkylating agents produce highly reactive carbonium ion intermediates which transfer alkyl groups to cellular macromolecules by forming covalent bonds.
They are:

1. Nitrogen mustards.

• Cyclophosphamide
• Ifosfamide.
• Chlorambucil.
• Melphalan.

2. Alkyl sulfonate-busulfan.

3. Nitrosoureas – lomustine.

4. Triazine – dacarbazine.

Toxic effects of alkylating agents:

1. Bone marrow depression.

• It results in granulocytopenia, agranulocytosis, thrombocytopenia, and aplastic anemia.

2. Immunosuppression.

• Lymphocytopenia and inhibition of lymphocyte function result in suppression of immunity.

3. GIT disturbances.

• Stomatitis, diarrhea, shedding of mucosa, and hemorrhages occur.
• Nausea and vomiting are prominent

4. Skin and hair.

• Alopecia – loss of hair and dermatitis occurs.

5. Gonads.

• Inhibition of gonadal cells causes.
  • Oligozoospermia and impotence – in males.
  • Inhibition of ovulation and amenorrhoea in females.

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6. Foetus.

• Damages foetus.
• Leads to abortion, fetal death, and teratogenesis.

7. Carcinogenicity.

• Secondary cancers appear frequently due to immunosuppression.

8. Hyperuricaemia.

• Massive cell destruction produces uric acid.
• Gout and urate stones in the urinary tract may develop.

Question 2. Vinca alkaloids.
Answer:

• Vinca alkaloids are spindle poison.
• They are mitotic inhibitors.

Vinca alkaloids Mechanism of action:

Vinca alkaloids: are

• Vincristine
• Vinblastine
• Vinorelbine.

Question 3. Two antimetabolites are used in cancer therapy.
Answer:

Antimetabolites are analogs related to the normal components of DNA. Involved in nucleic acid synthesis.

• They competitively inhibit the utilization of normal substrate.

1. Folate antagonist – methotrexate.

Folate antagonist- methotrexate Action:

• Cytotoxic actions on bone marrow, skin, gastrointestinal m synthesis.

Folate antagonist- methotrexate Uses:

• Choriocarcinoma.
• Acute leukemia.
• Carcinoma of tongue/pharynx/lung.
• Rheumatoid arthritis.
• Psoriasis.
• Organ transplantation.

Folate antagonist- methotrexate Treatment of toxicity:

• Methotrexate toxicity is treated with folinic acid.
• It reverses the effects of methotrexate.

2. Purine antagonists – mercaptopurine.

Treatment of toxicity mercaptopurine Mechanism of action:

Treatment of toxicity Uses:

• Acute leukemia in children.
• Choriocarcinoma.
• Some solid tumors.

Treatment of toxicity Adverse effects:

• Bone marrow depression.
• Anorexia.
• Nausea, vomiting.
• Stomatitis.
• Jaundice.
• Dermatitis.

Question 4. Methods to ameliorate the toxicity of anticancer drugs.
Answer:

Question 5. Methotrexate.
Answer:

• It is an anticancer drug
• It is a folate antagonist

Methotrexate Mechanism:

• Binds to dihydrofolate reductase
• Prevents the formation of tetrahydrofolate

Methotrexate Action:

• Cytotoxic actions on bone marrow, skin, GIT, and synthesis

Methotrexate Dose:

• Initial 7.5 mg once weekly
• Increased by 2.5 mg weekly
• Maximum weekly dose – 30 mg

Methotrexate Uses:

• Choriocarcinoma
• Acute leukemia
• Carcinoma of tongue/ pharynx/ lung
• Rheumatoid arthritis
• Psoriasis
• Organ transplantation

Methotrexate Adverse Effects:

• Nausea
• Vomiting
• Mucosal ulcers
• Hepatotoxicity
• Treatment of Toxicity:
• Methotrexate toxicity is treated with folinic acid
• It reverses the effects of methotrexate

Anti Cancer Drugs Short Question And Answers

Question 1. Nitrogen mustards.
Answer:

Nitrogen mustards are alkylating agents.

Question 2. Name antibiotics used in cancer therapy.
Answer:

Antibiotics used in cancer therapy are.

1. Actinomycin D.
2. Daunorubicin.
3. Doxorubicin.
4. Bleomycin.

Question 3. Name vinca alkaloids.
Answer:

Vinca alkaloids are mitotic inhibitors.

• They are.

1. Vincristine
2. Vinblastine
3. Vinorelbine.

Question 4. Antimetabolites.
Answer:

Antimetabolites are analogs related to the normal components of DNA involved in nucleic acid synthesis.

They are:

1. Folate antagonist.

• Methotrexate.

2. Purine antagonist

• Mercaptopurine.
• Thioguanine.
• Azathioprine.

3. Pyrimidine antagonists.

• Fluorouracil.
• Cytarabine.

Question 5. Cyclophosphamide.
Answer:

• Cyclophosphamide is an alkylating agent
• It is converted to its active metabolite aldophosphamide in the body.
• It is more effective on B cells than T cells.

Cyclophosphamide Uses:

• Bone marrow transplantation.
• Hodgkin’s lymphoma.
• Leukemia.
• Maintenance therapy in pemphigus, systemic lupus erythematosus, and idiopathic thrombocytopenic purpura.

Cyclophosphamide Toxic effects:

• It causes cystitis due to its active metabolite caroline.
• Prevent by.

1. IV mesna.
2. Irrigating bladder with acetylcysteine.
3. Intake of excessive fluids.

Question 6. Oxythiamine.
Answer:

• It is an irreversible inhibitor of transketolase
• It is an antivitamin derivative of thiamine which after phosphorylation to oxy thiamine pyrophosphate can bind to the active centers of thiamine-dependent enzymes

Oxythiamine Action:

• It is analog to antimetabolite
• Suppresses the nonoxidative synthesis of ribose
• Induces cell apoptosis

Oxythiamine Mechanism of Action:

Inhibits transketolase
↓
Suppresses pentose phosphate pathway
↓
Interrupts the synthesis of coenzymes, RNA, and DNA in
cancer cells

Anti Helminitics Short Essays

Question 1. Treatment of hookworm infestations.
Answer:

Hookworm infections are more common in developing countries.

• It is seen in people with poor hygiene.
• It is caused by ancylostoma duodenale and necator americanus.

Hookworm infections Drugs used:

• Mebendazole and albendazole are used in hookworm infections.

1. Mebendazole:

• It is broad spectrum antihelmintic.
• Bioavailability-20 %.
• Given orally 100 mg BD for 3 days.

Mebendazole Mechanism of action:

• Binds to b-tubulin with high affinity
• Inhibits glucose uptake in parasites

Mebendazole Uses:

• Hookworm infections.
• Roundworm infections.
• Trichuriasis.
• Trichinella spiralis.
• Hydatid disease.

Read And Learn More: Pharmacology Question and Answers

Mebendazole Adverse effects:

• Nausea, diarrhea, abdominal pain.
• Prolonged use causes headaches, fever, alopecia, jaundice, and neutropenia.

2. Albendazole:

• It is congener of mebendazole.
• Absorption is Moderate.
• It is widely distributed in the body.

Albendazole Uses:

• Trichuriasis.
• Trichinosis.
• Tapeworms and strongyloidosis.
• Neurocysticercosis.
• Hydatid disease.
• Filariasis.

Albendazole Adverse effects:

• Nausea, diarrhea, abdominal pain.
• Prolonged Use Causes Headache, Fever, Alopecia, Jaundice And Neutropenia.

Anti Helminitics Short Question And Answers

Question 1. Advantages of albendazole over mebendazole.
Answer:

• Albendazole is well tolerated.
• Effective in a single dose
• Superior to mebendazole in hookworm infections.
• The active metabolite of albendazole achieves a higher concentration than mebendazole.
• It also has some activity against T. vaginalis, giardia, lamblia, and Wuchereria bancrofti.

Question 2. Peprlzine citrate.
Answer:

Paperizine citrate is narrow-spectrum antihelmintic.

Peprlzine citrate Mechanism:

Peprlzine citrate Uses:

• Roundworm infestation.
• Pinworm infestations.

Peprlzine citrate Adverse effects:

• Nausea, vomiting, abdominal discomfort, urticaria.
• At high doses-dizziness, excitement.
• At toxic doses – produces – convulsions.

Question 3. Uses and adverse effects of Albendazole.
Answer:

Albendazole Uses:

• Ascaris
• Hookworm infections
• Trichuriasis
• Tapeworm and strongyloidiasis
• Neurocysticercosis
• Hydatid disease
• Filariasis

Albendazole Adverse effects:

• Nausea, diarrhea, abdominal pain
• Prolonged use causes a headache, fever, alopecia, jaundice, and neutropenia

Anti Fungal Drugs Important Notes

1. Antifungal drugs

• Topically applied
  • Nystatin
  • Trichomycin
• Systemically employed
  • Griseofulvin
  • Amphotericin B
  • Ketoconazole
  • Fluconazole
  • Miconazole

2. Nystatin- 5 lakh units are used in the treatment of

• Local candidiasis of the mouth, skin, vagina, and gut

Read And Learn More: Pharmacology Question and Answers

3. Griseofulvin

• It is used to treat ringworm infections of the scalp, groin, and feet and fungal infections of the nails
• It causes antabuse like action in the presence of alcohol

4. Ketoconazole

• It produces serious hepatotoxicity.
• Contraindicated in pregnancy
• Maximum endocrinal side effects are seen

Anti Fungal Drugs Short Essays

Question 1. Antifungal drugs
Answer:

Antifungal drugs are drugs used for superficial and deep fungal infections.

Antifungal drugs Classification:

1. Antibiotics:

• Polyenes – amphotericin B, nystatin, natamycin.
• Heterocyclic benzofuran – griseofulvin.

2. Antimetaboljte – flucytosine.

3. Azoles.

• Imidazoles – clotrimazole, econazole.
• Triazoles – fluconazole, itraconazole.

4. Alkylamine – terbinafine.

5. Topical agents.

• Tolnaftate, undecylenic acid, Benzoic acid, butenafine, sod. Thiosulfate.

Antifungal drugs Site of action:

• Antifungal drugs may act on
  • Fungal cell wall
  • Cell membrane
  • On the nucleus

Question 2. Amphotericin B.
Answer:

• Amphotericin B is a polyene antifungal agent
• It is obtained from streptomyces nodosus.

Antifungal spectrum:

• Amphotericin B is active against a wide range of yeast and fungi.
• It is fungicidal at high and fungi-static at low concentrations.

Antifungal spectrum Mechanism of action:

Antifungal spectrum Adverse effects:

1. Acute reactions:

• Fever, chills, aches, pain.
• Nausea, vomiting, dyspnoea.
• Thrombophlebitis of the injected vein.

2. Long-term toxicity.

• Nephrotoxicity – reduced GFR, acidosis, hypo-kalaemia, inability to concentrate urine.
• Neurotoxicity.
• Anaemia due to decreased production of erythropoietin and bone marrow depression.

Antifungal Spectrum Uses:

• Amphotericin B-used topically for oral, vaginal, and cutaneous candidiasis and otomycosis.
• To prevent relapse of cryptococcosis and histoplasmosis in patients with AIDS.
• Leishmaniasis.
• Orally in fungal infections of the gut.

Question 3. Griseofulvin.
Answer:

• Griseofulvin is antifungal antibiotic.
• It is fungistatic.
• It is derived from penicillium griseofulvum.

Griseofulvin Mechanism of action:

Griseofulvin Uses:

• It is used orally in superficial dermatophytosis
• Dose – 1 g daily.
• Duration of treatment – varies from 3 weeks to 1 year.

Griseofulvin Adverse effects:

• Headache.
• Git disturbances.
• Neurotoxicity – peripheral neuritis.
• Allergic reactions.
• Hepatitis.

Question 4. Ketoconazole.
Answer:

• It is the first orally effective broad-spectrum antifungal drug
• It is more soluble at lower pH in the blood
• Food and low gastric pH enhance its absorption
• In blood, it is largely bound to albumin and RBC
• Metabolites are excreted in urine and feces
• Plasma half-life -1 %-6 hours
• Penetration into CSF is poor

Ketoconazole Uses:

• Dermatophytosis
• Superficial candidiasis
• Deep mycosis
• High doses have been used in Cushing’s syndrome

Ketoconazole Adverse Effects:

• Nausea, vomiting, gastric irritation, loss of apatite
• Headache, paraesthesia
• Rashes
• Hair loss
• Allergic reaction
• Decreases androgen production – Gynaecomastia, loss of libido, azoospermia, menstrual irregularities

Ketoconazole Drug Interactions:

• H2 blockers. Proton pump inhibitors and antacids – decrease the oral absorption of ketoconazole
• Rifampicin, phenobarbitone, carbazepine and phenytoin – induces ketoconazole metabolism and reduces its efficacy

Anti Fungal Drugs Short Question And Answers

Question 1. Name two broad-spectrum antifungal drugs.
Answer:

Broad-spectrum antifungal drugs are used against a large variety of fungi and yeasts like C. Albican, H. Capsulation, and Cryptococcus. Neoformans, Blastomyces dermatitis, coccidiosis immits, coreopsis, rhodotorula, aspergillus, deep mycosis, trichophyton.

• They are:

1. Polyenes – amphotericin – B, nystatin, natamycin.
2. Heterocyclic benzofuran – griseofulvin.

Question 2. Amphotericin B.
Answer:

• Nystatin is a polyene antifungal agent
• It is obtained from the streptomyces course
• It is not absorbed when given orally, so used topically.

Amphotericin B Uses:

1. Local candidiasis

• 5 ml oral suspension should be swished in the mouth and then swallowed 4 times a day.

2. Vaginal candidiasis.

• 1 lac unit tab inserted twice daily.

3. Used as an ointment for corneal, conjunctival, and cutaneous candidiasis.

Amphotericin B Adverse effects:

• Bitter foul taste
• Nausea.

Question 4. Griseofulvin.
Answer.

Griseofulvin Uses:

• Dermatophytosis
• Superficial candidiasis
• Deep mycosis
• High doses have been used in Cushing’s syndrome

Griseofulvin Adverse Effects:

• Nausea, vomiting, gastric irritation, loss of apatite
• Headache, paraesthesia
• Rashes
• Hair loss
• Allergic reaction
• Decreases androgen production – Gynaecomastia, loss of libido, azoospermia, menstrual irregularities

Question 5. Ketoconazole.
Answer:

• Ketoconazole is the first orally effective broad-spectrum antifungal drug.
• It is more soluble at lower pH in the blood.
• Metabolites are excreted in urine and feces.
• Plasma t ½ varies from 1½ to 6 hours.

Ketoconazole Uses:

• Dermatophytosis.
• Superficial candidiasis.
• Deep mycosis.

Ketoconazole Adverse effects:

• Nausea, vomiting, gastric irritation, loss of appetite.
• Headache, paresthesia.
• Rashes, hair loss.
• Allergic reactions.
• Decreases androgen production – gynecomastia, loss of libido, azoospermia, menstrual irregularities.

Chemotherapy Of Tuberculosis and Leprosy Important Notes

1. Anti-tuberculous drugs

• First-line drugs are highly effective with low toxicity
• Second-line drugs have low efficacy with high toxicity

2. Drug regimen for tuberculosis

• INH 300 mg + Rifampicin 600 mg + Pyrazinamide 2 g or Ethambutol 15 mg/kg taken daily for 2 months
• Followed by INH 300 mg + Rifampicin 600 mg daily for 4 months

Chemotherapy of Tuberculosis

3. Peripheral neuritis

• It is caused by isoniazid
• Can be prevented by taking pyridoxine 10 mg/day prophylactically
• Can be treated by taking pyridoxine 100 mg/day
• Drugs causing peripheral neuritis are:
  • Griseofulvin
  • Nitrofurantoin.
  • Vincristine

4. Lepra reaction

• It is seen in lepromatous chemotherapy
• Occurs due to the release of antigens from bacilli
• Drugs used to control it are:
  • Clofazimine
  • Chloroquine
  • Thalidomide

Chemotherapy Of Tuberculosis and Leprosy Long Essays

Question 1. Classify drugs used in tuberculosis. Write the pharmacology of any two commonly used drugs.
Answer:

Tuberculosis:

• Tuberculosis is a chronic granulomatous disease.

Tuberculosis Anti-tubercular drugs:

• According to their clinical utility, the anti-tuberculosis drugs are divided into.

1. First-line drugs.

• They have high antitubercular efficacy.
• Have low toxicity.
• They are:
  1. Isoniazid (H)
  2. Rifampicin (R)
  3. Pyrazinamide (Z)
  4. Ethambutol (E)
  5. Streptomycin (S)

2. Second-line drugs.

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• They have low antitubercular efficacy.
• Have high toxicity.
• They are:
  1. Thiacetone (Tzn)
  2. Para-aminosalicylic acid (PAS)
  3. Ethionamide (Etm)
  4. Kanamycin (Kmc)
  5. Amikacin (Am)
• Newer drugs are:
• Ciprofloxacin, ofloxacin, clarithromycin, azithromycin.

Chemotherapy of Tuberculosis

Isoniazid: (INH):

• It is the most effective and cheapest primary antitubercular drug.
• It is effective against both intra and extracellular organisms.

Isoniazid Mechanism of action:

Isoniazid Pharmacokinetics:

• Completely absorbed orally.
• Penetrates all tissues.
• Metabolized by acetylation.
• Metabolites are excreted in the urine.

Isoniazid Adverse effects:

1. Peripheral neuritis.

• Occurs due to increased excretion of pyridoxine.
• Characterized by paraesthesia, numbness, mental disturbances, and convulsions.
• Avoided by prophylactic uses of pyridoxine with INH.

2. Hepatitis.

• Occurs due to dose-related damage to liver cells.
• More common in alcoholics and elders.

3. CNS effects – psychosis, seizures.

4. Hemolysis. In GePD deficiency patients.

5. Other effects.

• Anorexia, GIT disturbances, fever, rashes, acne, arthralgia.

Chemotherapy of Tuberculosis

Rifampicin:

• It is a semisynthetic derivative of rifamycin B.
• It is highly effective.
• Acts on both intracellular and extracellular organisms.

Rifampicin Mechanism of action:

Rifampicin Pharmacokinetics:

• Well-absorbed orally.
• Has good tissue penetrability.
• Metabolized in the liver, excreted in bile.
• It is a microsomal enzyme inducer.
• Appears in saliva, tears, and sweat.

Rifampicin Adverse effects:

1. Hepatotoxicity.

• Causes hepatitis in patients With pre-existing liver disease.

2. Respiratory syndrome.

• Breathlessness, shock, collapse.

3. Purpura, hemolysis, renal failure.

4. GIT disturbances.

• Epigastric distress, nausea, Vomiting, Abdominal cramps, diarrhea.

5. Flu-hike synthesis drome.

• Fever, body ache, chills; hemolytic anemia.

6. CNS effects.

• Headache, drowsiness, dizziness ataxia.

7. Cutaneous syndrome.

• Flushing, pruritis, rash, redness, watering of eyes.

Rifampicin Other Uses:

• Leprosy.
• Prophylaxis Of H.influenza And Meningitis.
• Resistantstephylococcal infections.
• Brucellosis.
• To eradicate the nasal carrier state of meningitis.

Chemotherapy Of Tuberculosis and Leprosy Short Essays

Question 1. DOTS chemotherapy in tuberculosis.
Answer:

• DOTS in directly observed treatment short course.
• It was recommended by WHO in 1995.
• It is found to be effective.
• It involves providing the most effective medicine and confirming that it is taken.
• Antitubercular drugs during the intensive phase are administered under the direct supervision of peripheral health staff or through voluntary workers.
• It ensures a high cure rate through its following components.

1. Appropriate medical treatment.
2. Supervision and Motivation by health and non-health workers.
3. Monitoring of disease status by health services.

DOTS chemotherapy in tuberculosis Category:

• According to DOTS, patients are grouped into two categories

1. Category -1 – new patients

• New sputum smear positive.
• New sputum smear negative.
• New extrapulmonary.
• New others.

2. Category – II – previously treated patients.

• Smear positive relapse.
• Smear positive failure.
• SmeOr positive treatment after default.

Question 2. Mention six drugs for tuberculosis.
Answer:

1. First-line drugs.

• Isoniazid.
• Rifampicin
• Pyrazinamide
• Streptomycin.

2. Second-line drugs

• Thiacetazoue.
• Paia-aminosalicylic acid
• Ethionamide
• Cycloserine
• Kanamycin
• Amikacin

3. Newer Drugs.

• Ciprofloxacin.
• Ofloxacin.
• Clarithromycin.
• Azithromycin.
• Rifabutin.

Question 3. Explain why multidrug therapy is used in the treatment of tuberculosis.
Answer:

Tuberculosis is one of the most difficult infections to curve.

• Its treatment is problematic due to

1. Slow division of mycobacteria.
2. Development of resistance.
3. Ability to remain as persisters for years.
4. Intracellular location of barley.
5. Presence of caseous material.
6. Long term therapy
7. Expensive treatment
8. Drug toxicity.
9. Drug toxicity.

Tuberculosis Aim of treatment:

1. Kill dividing bacilli – to make sputum negative
2. To destroy persisters – to prevent relapse.

Tuberculosis Combination of Drugs:

• Drugs are combined to

1. Delay development of resistance.
2. Reduce toxicity.
3. Shorten the course of treatment

Chemotherapy of Tuberculosis

Question 4. Dapsone (DDS).
Answer:

• Dapsone is diamino diphenyl sulfone (DDS)
• It is a simple, old, cheap, and active antileprotic drug.

Dapsone Mechanism of action:

• Dapsone is chemically related to sulphonamide.
• It is a structural analog of PABA.
• It competitively inhibits bacterial folate synthetase.
• It also inhibits the union of PABA with pteridine residue to form dihydropetroic acid.

Dapsone Pharmacokinetics:

• Dapsone is completely absorbed orally.
• It is widely distributed.
• It is metabolized in the liver and excreted in bile.
• It is acetylated.
• It is leprostatic.

Dapsone Uses:

• Leprosy – a primary drug for leprosy.
• Used in combination with pyrimethamine for chloroquine-resistant malaria.
• Dermatitis is herpetiform.
• Used along with trimethoprim in P.jiroveci infections in patients with AIDS.

Question 5. Treatment schedule for leprosy.
Answer:

• Treated by multidrug therapy regime introduced by WHO in 1981.
• Drugs used are dapsone, rifampicin, and clofazime.
• All are administered orally.

Leprosy Duration:

• 2- years – for multibacillary/infectious leprosy.
• 6 months – for paucibacillary/non-infectious leprosy.

Leprosy Schedule:

Leprosy Alternative regimen:

1. Clofazimine 50 mg with any two newer drugs daily for 6 months.

• Followed by clofazimine 50 mg with anyone new drug daily for 18 months.

2. In single lesion paucibacillary leprosy,

• Single dose of
  • Rifampicin – 600mg.
  • Ofloxacin-400 mg.
  • Minocycline – 100 mg.

Chemotherapy of Tuberculosis

Question 6. Lepra reactions.
Answer:

Lepra reactions are immunologically-mediated reactions that occur during the course of the disease.

Types:

1. Type I reaction – reversal reaction.

• Seen in tuberculoid leprosy.
• They are cell-mediated, delayed hypersensitivity reactions.
• Characterized by cutaneous ulceration, multiple nerve involvement with pain and tenderness.

Type I reaction – reversal reaction Treatment:

• Treated with corticosteroids or clofazimine.

2. Type II reactions – lepra reaction.

• Seen in lepromatous leprosy.
• It is Jarischherxheimertypeofireaction.
• It is a type III hypersensitivity reaction due to the release of antigens from killed bacilli.
• It is abrupt in onset.
• Old lesion – enlarges, becomes red, swollen, and painful.
• New lesions also appear.
• Fever, malaise, lymphadenitis, myositis, and neuralgia occur.

Type II reactions – lepra reaction Treatment:

• Temporary discontinuation of dapsone in severe cases.
• Administration of analgesics, antipyretics, and antibiotics.
• Clofazimine – 200 mg daily in most severe cases.
• Corticosteroids are used in severe cases.

Chemotherapy Of Tuberculosis And Leprosy Short Question And Answers

Question 1. Adverse effects of rifampicin.
Answer:

• Hepatitis.
• Respiratory syndrome.
• Purpura, hemolysis, shock, renal failure.
• Cutaneous syndrome.
• Flu-like syndrome.
• GIT disturbances.
• Staining of secretions.
• Hypersensitivity reactions.

Question 2. Pyridoxine should be administered with INH.
Answer:

• Isoniazid (INH) is anti-tubercular drug.
• It causes peripheral neuritis due to interference with utilization and increased excretion of pyridoxine.
• It is characterized by paresthesia, numbness, mental disturbances, and convulsions.
• It is avoided by prophylactic use of pyridoxine 10-50 mg.
• Hence, pyridoxine should be administered with INH to prevent peripheral neuritis.

Question 3. Streptomycin.
Answer:

• Streptomycin is an anti-tuberCuter drug.
• It is tuberculocidal.
• It acts only against extracellular organisms.
• It does not cross CSF.
• When used alone resistance develops rapidly.

Streptomycin Disadvantages:

• The rapid development of resistance.
• Has to be given IM.
• Causes ototoxicity and nephrotoxicity.
• Thus, streptomycin is the least preferred.

Chemotherapy of Tuberculosis

Question 4. Pyrazinamide.
Answer:

• Pyrazinamide is tuberculocidal.
• It is more active at acidic pH.
• Has good sterilizing activity.
• Highly effective during the first 2 months of therapy.
• It is well-absorbed orally.
• Metabolized in the liver, excreted in urine.

Pyrazinamide Adverse effects:

• Hepatotoxicity.
• Hyperuricaemia.
• Arthralgia.
• Anorexia, vomiting.
• Rashes.
• Fever, flushing.
• Loss of diabetes control.

Question 5. Isoniazid acetylation status in tuberculosis chemotherapy.
Answer:

• Isoniazid is metabolized by acetylation.
• Depending on the genetic variations, patients can be fast or slow acetylation.

• metabolites are excreted in the urine.

Question 6. Drugs used in the treatment of leprosy.
Answer:

1. Sulfone-dapsone.
2. Phenazine derivative – clofazimine.
3. Antitubercular drugs – rifampin, ethionamide.
4. Other antibiotics-Oflaxacin, minocycline.

Question 7. Dapsone.
Answer:

• Dapsopne is diamino dlpheyl sulfone (DDS).
• It is a simple, cheap, old, and more active anti-leprotic drug.

Question 8. Treatment of lepra reactions.
Answer:

Antiviral Drugs Important Notes

1. Antiviral drugs

• Amantadine
• Acyclovir
• Vidarabine
• Zidovudine
• Idoxuridine

2. Classification of anti-retroviral drugs

• Nucleoside reverse transcriptase inhibitors
  • Zidovudine
  • Didanosine
  • Lamivudine
• Non-nucleoside reverse transcriptase inhibitors
  • Nevirapine
  • Efavirenz
• Protease inhibitors
  • Ritonavir
  • Saquinavir

3. Acyclovir

• It is available as IV, oral and topical application
• Used in the treatment of
  • Genital herpes
  • Herpes zoster infection

4. Zidovudine and Didanosine

• Used in the treatment of AIDS
• They block the action of reverse transcriptase in HIV infection 5

Antiviral Drugs Short Essays

Question 1. Antiviral drugs.
Answer:

Viruses are intracellular parasites which depend on the host cells for their food, growth and multiplication.

• Antiviral drugs interfere with the steps of the viral reproduction cycle within host cells.

Antiviral drugs Classification:

1. Anti-herpesvirus.

• Idoxuridine, acyclovir, valacyclovir.

2. Anti-retrovirus.

• Nucleoside reverse transcriptase inhibitors.
  • Zidovudine, Didanosie, abacavir
• Non-nucleoside reverse transcriptase inhibitors.
  • Nevirapine, efavirenz.
• Protease inhibitors.
  • Ritonavir, indinavir, nelfinavir.

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3. Anti-influenza virus.

• Amantadine, rimantadine.

4. Nonselective antiviral drugs.

• Ribavirin, lamivudine.

Antiviral Drugs Short Question And Answers

Question 1. Acyclovir.
Answer:

Acyclovir is antiviral agent.

The spectrum of activity:

• Herpes simplex virus – type 1 and type 2.
• Varicella zoster virus.
• Epstein – Barr virus.

Mechanism of action:

Acyclovir Uses:

• Mucocutaneous herpes simplex – type I
• Genital herpes.
• H. Simplex encephalitis.
• H. Simplex keratitis.
• Herpes zoster.
• Chickenpox.

Acyclovir Adverse effects:

1. Oral use.

• Headache, nausea, malaise, diarrhoea.

2. Topical use.

• Stinging and burning sensation.

3. Intravenous use.

• Rashes, sweating, emesis, fall in BP

Question 2. Zidovueline.
Answer:

• It is the first drug to be used in the treatment of HIV infection.

Zidovueline Mechanism of Action:

Zidovueline Uses:

• Used in HIV – infected patients along with other antiretroviral drugs.
• Its effects are
  • Reduces HIV – RNA titre.
  • Increases CD4 count
  • Improves immune status.
  • Reduces chances of opportunistic infections.

Zidovueline Adverse effects:

• Bone marrow depression – anaemia neutropenia.
• Headache.
• Nausea.
• Myalgia, fatigue.
• Insomnia.
• Myopathy.
• Neurotoxicity.

Question 3. Mention the drugs used in Typhoid fever.
Answer:

• First choice of drugs
  • Ciprofloxacin
  • Ceftriaxone
• Alternative drugs
  • Chloramphenicol
  • Ampicillin
  • Cotrimoxazole

Chemotherapy Of Malaria Important Notes

1. Chloroquine

• Antimalarial drug
• Causes chloroquine retinopathy characterized by
  • Visual disturbances
  • Blurred vision
  • Diplopia
  • Lenticular opacities

Chemotherapy Of Malaria Long Essays

Question 1. Classify the drugs used in malaria and briefly outline the mechanism of actions, uses, and toxicity of chloroquine.
Answer:

Malaria:

• Malaria is caused by 4 species of plasmodium.

Drugs used in malaria – antimalarial drugs:

• These drugs are used for prophylaxis, treatment, and prevention of relapse of malaria.

Antimalarial Drugs Classification:

1. 4-aminoquinolones – chloroquine, amodiaquine.
2. Quinoline – methanol – mefloquine.
3. Cinchona alkaloid – quinine, quinidine.
4. Biguanide – proguanil.
5. Diaminopyrimidine – pyrimethamine.
6. 8-aminoquinolones – primaquine.
7. Sulfonamides – sulfadoxine, dapsone.
8. Tetracyclines – tetracycline, doxycycline.
9. Sesquiterpine – lactones – artesunate, arthemether.
10. Aminoalcohols – halofantrine, lumefantrine.
11. Naphthoquinone – atovaquone.

Chloroquine:

• Chloroquine is a synthetic 4-aminoquinolone.

Chloroquine Mechanism of action:

• The mechanism of action of chloroquine is not clear.

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Chloroquine Uses:

1. Malaria.
   • Used for clinical cure and suppressive prophylaxis of all types of malaria.
2. Extraintestinal amoebiasis.
3. Rheumatoid arthritis.
4. Discoid lupus erythematosus.
5. Lepra reactions.
6. Photogenic reactions.

Chloroquine Adverse effects:

• GIT disturbances – nausea, vomiting, anorexia, epigastric pain.
• Pruritis, headache, visual disturbances, insomnia, skin rashes.
• Cardiomyopathy, peripheral neuropathy.
• Long-term therapy causes blurring of vision, loss of hearing, rashes, photoallergy mental disturbances, myopathy, and graying of hair.

Sulfonamides Cotrimoxazole And Quinolones Important Notes

1. Sulfonamides

• hey have a structural resemblance to PABA
• They compete with PABA for incorporation into folic acid
• They act by inhibiting the enzyme folic acid synthetase which is essential for bacterial growth

Sulfonamides, Cotrimoxazole And Quinolones Uses:

• Nocardial infection
• Leprosy
• Toxoplasmosis
• Ulcerative colitis

Sulfonamides, Cotrimoxazole And Quinolones Adverse Effects:

• Crystalluria
• Haematuria, anuria
• Kernicterus in newborns
• Fixed drug eruption by sulfadiazine
• Steven Johnson syndrome

2. Cotrimoxazole

• It is a combination of Sulfamethoxazole and trimethoprim
• It has a synergistic bacteriocidal effect
• Dose: trimethoprim 80 mg + Sulfamethoxazole 400 mg
• Uses:
• Uncomplicated UTI
  • Respiratory infections
  • Gonorrhoea
  • Otitis media

3. Fluoroquinolones

• Ciprofloxacin, ofloxacin, norfloxacin are fluoroquinolones
• They are contraindicated in children as they cause Arthropathy and damage to developing cartilage
• They are effective against facultative anaerobes
• They inhibit the bacterial enzyme DNA gyrase

Sulfonamides Cotrimoxazole And Quinolones Long Essays

Question 1. Classify sulphonamides. Discuss the mechanism of action, adverse effects, And uses of cotrimoxazole.
Answer:

Sulfonamides Classification:

1. Short-acting – sulfadiazine.
2. Intermediate-acting – sulfamethoxazole.
3. Long-acting – sulfadoxine.
4. Special purpose sulphonamide – Sulfasalazine, Silver sulfadiazine.

Cotrimoxazole:

• A combination of trimethoprim And sulfamethoxazole is called cotrimoxazole.

Cotrimoxazole Mechanism of action:

• Cotrimoxazole causes sequential blockage of folic acid synthesis.

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Cotrimoxazole Uses:

• Respiratory tract infections – tonsillitis, pharyngitis, sinusitis, bronchitis.
• Urinary tract infections – acute And chronic.
• Diarrhea And dysentery.
• Typhoid, chancroid, granuloma inguinale.
• Pneumocystis jiroveci pneumonia in AIDS patients.
• Orodental infections.

Cotrimoxazole Adverse effects:

• Nausea, vomiting, headache, stomatitis, rashes.
• Precipitate megaloblastic anemia.
• Blood disorders – anemia, granulocytopenia.
• Uremia in patients with renal diseases.
• Neonatal hemolysis And methemoglobinemia. When administered to pregnant women.

Question 2. Enumerate fluoroquinolones. Mention their antimicrobial spectrum, uses, And adverse effects.
Answer:

Fluoroquinolones:

• These are quinolones antimicrobials having one or more fluorine substitutes.

Fluoroquinolones Classification:

Antimicrobial spectrum:

1. Gram-positive organisms like

• Staphylococci, chlamydiae, mycoplasma, And mycobacterium.

2. Gram-negative organisms like

• Gonococci, meningococci, E-coli, salmonella, shigella, H. Pylori.

3. Some anaerobic organisms.

Antimicrobial spectrum Uses:

Antimicrobial spectrum Adverse effects:

• Nausea, vomiting, abdominal discomfort, diarrhea, rashes.
• Tendinitis.
• Damage to growing cartilage
• Headache, dizziness.
• Precipitate seizures in epileptic patients.

Question 3. Classify drugs used in the treatment of infections caused by gram-negative organisms. Mention the mechanism of action of fluoroquinolones.
Answer:

Fluoroquinolones Classification:

• Drugs used in the treatment of infections caused by gram-negative organisms are:

1. B-lactam antibiotics

• Penicillin, cephalosporin.

2. Tetracyclines – Doxycycline.

3. Aminoglycosides – Gentamicin, streptomycin.

4. Macrolides – erythromycin, Azithromycin.

5. Nitroimidazoles – Metronidazole.

6. Quinolones – Norfloxacin, Ciprofloxacin.

Fluorozuinolones (FQ):

Fluoroquinolones Mechanism of action:

• DNA gyrase enzyme is required for DNA replication.
• This enzyme has subunits A And B

2. At low doses.

Sulfonamides Cotrimoxazole And Quinolones Short Essays

Question 1. Write important side effects of sulphonamides.
Answer:

Sulphonamides:

• Sulfonamides were the first effective antibacterial agents to be used systemically in man.
• It contains a sulphonamide group.

Sulphonamides Adverse Effects:

1. GIT effects.

• Nausea, vomiting, anorexia, abdominal pain.

2. Renal effects.

• Renal irritation, hematuria, albuminuria. Crystalluria.
• It occurs due to the precipitation of the drug in acidic urine.
• Avoided by:
  • Intake of plenty of fluids.
  • Alkalinizing the urine with sodium bicarbonate.

3. Hypersensitivity reactions.

• Fever, rashes, anaphylaxis, urticaria, and photosensitivity – occur rarely.
• Stevens-Johnson syndrome And exfoliative dermatitis – occurs commonly.

4. Contact sensitization on topical application.

5. Hemolysis.

• Occurs in patients with G6PD deficiency.

6. Kernicterus.

• Occurs in newborns.
• Sulfonamides displace bilirubin from binding sites.
• This then crosses BBB And causes kernicterus.

Question 2. Sulfonamides are not very effective in the presence of pus. Explain.
Answer:

Some bacteria synthesize their own folic acid which consists of p-amino benzoic acid (PABA).

• Sulfonamide is structurally similar to PABA.
• Thus it competitively inhibits the formation of folic acid.
• Pus contains.
  • Purines And thymidine – which decreases the bacterial requirement for folic acid.
  • Antagonizes sulphonamide action.
  • It is rich in PABA.
  • Thus, sulphonamides are not very effective in the presence of pus.

Question 3. Explain the mechanism of action of co-trimoxazole.
Answer:

The combination of trimethoprim And sulfamethoxazole is cotrimoxazole.

Co-trimoxazole Mechanism of action:

• Individual drugs are bacteriostatic.
• While combination causes bacteriocidal action.
• Through their combined effect sequential blockade of folic acid synthesis occurs.

Sulfonamides Cotrimoxazole And Quinolones Short Question And Answers

Question 1. Long-acting sulphonamides.
Answer:

Long-acting sulphonamides are sulfadoxine And sul- famethopyrazine.

• The action lasts for more than 1 week because of
  • High plasma protein binding.
  • Slow renal excretion.
• They attain low plasma concentration so they are not suitable for the treatment of acute pyogenic infectious.

Long-acting sulphonamide Uses:

• In malaria in combination with pyrimethamine.
• Pneumocystis jiroveci pneumonia in AIDS patients.
• Toxoplasmosis.

Long-acting sulphonamide Adverse Reaction:

• Serious cutaneous reactions.

Question 2. The rationale of a combination of sulfamethoxazole with trimethoprim.
Answer:

Sulfamethoxazole And trimethoprim are individually bacteriostatic

• Sulfamethoxazole inhibits the conversion of PABA to dishy-dro folic acid while trimethoprim inhibits and prevents the reduction of dihydrofolate to tetrahydrofolate.
• Thus, combining sulfamethoxazole And trimethoprim causes sequential blockade of folic acid synthesis And has bacteriocidal action.

Question 3. Ciprofloxacin.
Answer:

Ciprofloxacin is first generation fluroquinolones.

• It has a wide spectrum of activity
• Has rapid bacteriocidal activity And high potency.
• It is less active at acidic pH
• It is rapidly absorbed orally.

Ciprofloxacin Uses:

• Systemic infections.
• Typhoid
• Gonorrhoea.
• Gastroenteritis.

Ciprofloxacin Adverse Reactions:

• GIT effects – nausea, vomiting, anorexia.
• CNS effects – Dizziness, headache, anxiety, insomnia, tremors.
• Hypersensitivity reactions – rash, pruritis, photosensitivity, urticaria.
• Tendonitis.

Question 4. Ciprofloxacin is contraindicated in children. Why?
Answer:

Ciprofloxacin is fluoroquinolone.

• It causes damage to the growing cartilage of weight-bearing joints.
• This results in arthropathy.
• Thus, it is contraindicated in children.

General Considerations Important Notes

1. Antibiotics

• Antibiotics are biological substances elaborated by micro-organisms that suppress the growth of other microorganisms or destroy them in high dilution

2. Classification of antibiotics

• Based on the mechanism of action

• Based on antibacterial activity

• Based on the spectrum of activity

3. Superinfection

• It refers to the appearance of a new infection as a result of antimicrobial therapy
• Drugs that cause superinfection are
  • Tetracyclines
  • Chloramphenicol
  • Ampicillin
  • Amoxycillin

4. Methods to prevent drug resistance

• Indiscriminate inadequate prolonged use of antibiotics should be avoided
• The drug should be given after a culture sensitivity test
• If antibiotics are to be given for a prolonged period, combination therapy should be instituted

5. Uses of a combination of drugs

• To achieve synergism
• To reduce the severity or incidence of adverse effects
• To prevent the emergence of resistance
• To broaden the spectrum of antimicrobial action

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6. Examples of combination of drugs

• Combination of two bacteriostatic drugs that are often additive and rarely synergetic
  • Tetracycline + chloramphenicol/ erythromycin
  • Sulfonamide + trimethoprim
  • Clavulanic acid + amoxicillin
• Combination of two bacteriocidal drugs that are frequently additive and sometimes synergetic
  • Penicillin/ ampicillin + streptomycin/ gentamycin
  • Carbenicillin + gentamycin
  • Ceftazidine + ciprofloxacin
  • Rifampicin + tuberculosis
• Combination of bacteriostatic and bacteriocidal drug
  • Penicillin + erythromycin
  • Penicillin + tetracycline/ chloramphenicol
  • Penicillin + sulfonamide
  • Streptomycin + tetracycline
  • Rifampicin + dapsone

General Considerations Long Essays

Question 1. Mention some examples of antibodies And describe the mechanism of action And side effects of two commonly used antibiotics.
Answer:

Antibiotics:

• Antibiotics are produced by microorganisms that selectively suppresses the growth or kill other microorganisms at very low concentration.

Antibiotics Classification:

1. Based on chemical structure.

• Sulfonamides – sulfones, dapsone.
• Diaminopyrimidies – trimethoprim.
• Quinolones – nalidixic acid, norfloxacin.
• p-lactam antibiotics – penicillin, cephalosporin.
• Tetracyclines – Oxytetracyclines.
• Aminoglycosides – streptomycin, gentamicin.
• Macrolide – erythromycin, Azithromycin.
• Polyene antibiotics – Nystatin.
• Azole derivatives – clotrimazole, ketoconazole.

2. Based on the mechanism of action.

• Inhibit cell wall synthesis.
  • Penicillin, cephalosporins.
• Cause leakage from the cell membrane.
  • Polypeptides – polymyxins, colistin.
• Inhibit protein synthesis.
  • Tetracyclines, chloramphenicol.
• Cause misreading of m-RNA
  • Aminoglycosides.
• Inhibit DNA gyrase – fluoroquinolones.
• Interfere with DNA function – Rifampicin.
• Interfere with DNA synthase – Acyclovir.
• Interfere with intermediary metabolism.
  • Sulfonamides, trimethoprim.

3. Based on the type of organisms against which it acts.

• Antibacterial – Penicillin, aminoglycosides.
• Antifungal – Griseofulvin, Amphotericin B.
• Antiviral – Acyclovir, Amantadine.
• Antiprotozoal – Cloroquine metronidazole, chloroquine .
• Anti helmintic – Mebendazole.

4. Based on the spectrum of activity.

• Narrow spectrum – Penicillin G, streptomycin.
• Broad spectrum – Tetracyclines.

5. Based on the type of action.

• Bacteriostatic – sulphonamides, tetracyclines.
• Bacteriocidal – Penicillins, Aminoglycosides.

Antibiotics Penicillins:

Penicillins Mechanism of action:

Penicillins Adverse effects:

1. Hypersensitivity reactions.

• Skin rashes, urticaria, fever, bronchospasm, serum sickness, anaphylaxis.

2. Paint the site of injection.

3. CNS effects.

• Confusion, muscle twitching, convulsions, coma.

4. Suprainfection.

5. Jarisch Herxheimer reaction.

• Occurs when penicillin is injected into the syphilitic patient
• It is characterized by the sudden destruction of spiro chapters And the release of its lytic products.

Antibiotics Sulfonamides:

Sulfonamides Mechanism of action:

• Many bacteria synthesize their own folic acid from p- amino benzoic acid (PABA) by enzyme folic acid synthetase.
• Sulfonamides is structurally similar to PABA.

• Thus sulphonamide is bacteriostatic in action.

Sulfonamides Adverse effects:

• Nausea, vomiting, epigastric pain.
• Renal Irritation, hematuria, albuminuria, And crystalluria.
• Hypersensitivity reactions.
• Kernicterus.
• Hemolysis in G-6 PD deficiency patients.
• Hepatitis.
• Stomatitis, conjunctivitis, And Arthritis

Question 2. Explain four advantages of the combined use of antimicrobials with examples.
Answer:

Advantages of a combination of antimicrobials:

1. To achieve synergism.

• The same drugs may be synergistic for one organism but antagonistic for another.

2. To reduce adverse effects.

• Combining two antimicrobials may reduce the dose of each agent.
• This may thereby reduce the toxicity of drugs.
• Example: Streptomycin + penicillin G for subacute bacterial endocarditis.

3. To prevent the emergence of resistance.

• It is used primarily for chronic infections needing prolonged therapy like tuberculosis, and leprosy.
• Rifampin + ciprofloxacin – prevents S.aureus resistance.

4. To broaden the spectrum of antimicrobial action.

General Considerations Short Essays

Question 1. What is superinfection? Give two examples.
Answer:

Superinfection:

• It refers to the appearance of a new infection as a result of antimicrobial therapy.

Superinfection Reason:

• Antimicrobial agents cause alteration in the normal flora of the intestine respiratory And genitor-urinary tracts.
• Normal microbial flora contributes to host defense.
• In it, the pathogen has to compete with the normal commensals for nutrition.
• But by the use of antimicrobial agents, there is a lack of competition.
• As a result, infection is caused easily.
• Broader the antimicrobial spectrum, the more the chances of superinfection.

Conditions Predisposing to Superinfection:

• Corticosteroid therapy.
• Leukemia.
• AIDS.
• Agranulocytosis.
• Diabetes.
• Disseminated lupus erythematous.

Superinfection Examples:

Androgens And Anabolic Steroids Short Essays

Question 1. Anabolic steroids.
Answer:

Anabolic steroids are synthetic androgen with higher anabolic and low androgenic activity.

• It enhances protein synthesis and increases muscle mass.

Anabolic steroids Uses:

• In catabolic states – to correct negative nitrogen balance.
• Senile osteoporosis – in elderly males.
• Growth stimulation in children – used for short periods.
• Chronic renal failure.
• In refractory anemia.
• Abuse in athletics

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Anabolic steroids Contraindications:

• Pregnancy.
• Carcinoma of the prostrate or breast in males.

Anabolic steroids Drugs used are:

• Nandrolone.
• Oxymetholone
• Stanozolol.
• Methandienone.

Anabolic steroids Adverse effects:

• Masculinization and acne in females.
• Hepatotoxicity.
• Increased libido.
• Precocious puberty.
• Salt and water retention.
• Suppression of spermatogenesis.