Chemotherapy Of Tuberculosis and Leprosy Question And Answers

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

Read And Learn More: Pharmacology Question and Answers

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.

• 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: