Macrolides Question And Answers

Macrolides Important Notes

1. Macrolides

  • They have large lactone ring
  • They are used as an alternative to penicillin

Macrolides Classification:

Macrolides Macrolides Classification

2. Macrolides Erythromycin

  • Given in patients allergic to penicillin
  • Effective against all penicillin-sensitive organisms and penicillin-resistant streptococci
  • Inactivated by gastric acid
  • Thus available in enteric-coated tablets
  • It is bacteriostatic at low concentrations and bacteriocidal at high concentrations

Macrolides Long Essays

Question 1. Enumerate macrolide antibiotics. Describe the antimicrobial spectrum and therapeutic uses of erythromycin.

Macrolide antibiotics:

  • These are antibiotics having a macrocyclic lactone ring with attached sugars.
  • They are
  1. Erythromycin.
  2. Roxithromycin.
  3. Clarithromycin.
  4. Azithromycin.


It is isolated from streptomyces erythroid.

Erythromycin Antibacterial spectrum:

  • Erythromycin has a narrow spectrum.
  • It is effective against aerobic gram-positive bacteria and a few gram-negative organisms.
  • Streptococci, pneumococci, staphylococci, gonococci, C.diptheria, B. Pertussis, and some atypical mycobacteria.

Erythromycin Uses:

1. Orodental infections

  • Used in the prevention and treatment of oriental infections including post-extraction infections, periapical abscesses, and other periodontal lesions.
  • Used in patients who are allergic to penicillin.

2. Medical use

  • Atypical pneumonia.
    • Erythromycin – 500 mg 6 hourly oral or IV is used.
  • Legionnaire’s pneumonia.
    • Treated for 10 – 14 days with erythromycin.
  • Whooping cough.
  • Streptococcal infections like pharyngitis tonsillitis and scarlet fever.
  • Staphylococcal infections.
  • Diptheria.
  • Syphilis and gonorrhea.
  • Tetanus, anthrax.

3. Topical use

  • Ointment – for skin infections and boils.
  • Lotions – for acne vulgaris.

4. Prophylactic use

  • In valvular heart disease patients.
  • For rheumatic fever.

Erythromycin Adverse effects:

1. Gastrointestinal disturbances

  • Erythromycin induces gastric contractions, hastens gastric emptying, and promotes intestinal motility.
  • Causes epigastric pain.
  • Rarely diarrhea occurs.

2. Hepatitis with cholestatic jaundice

  • Starts after 2-3 weeks of treatment
  • Symptoms are Nausea, vomiting, abdominal cramps, and mimic acute cholecystitis.

3. Hypersensitivity reactions

Fever, skin rashes.

4. Cardiac arrhythmias in patients with cardiac disease.

5. Reversible hearing impairment

Read And Learn More: Pharmacology Question and Answers

Macrolides Short Essays

Question 1. Difference between amoxicillin and gentamicin.

Macrolides Differences Between Amoxicillin And Gentamicin

Macrolides Short Question And Answers

Question 1. Compare penicillin and erythromycin.

Macrolides Compare Penicillin And Erythromycin

Question 2. Macrolide antibiotics.

Macrolides are antibiotics with a macrocyclic lactone ring to which sugars are attached.

They are:

  1. Erythromycin.
  2. Roxithromycin.
  3. Clarithromycin.
  4. Azithromycin.

They are bacteriostatic at low concentrations and bacteriocidal at high concentrations.

Macrolide antibiotics Mechanism:

Macrolides Macrolide Antibiotics Mechanism

Macrolides Short Question And Answer

Question 1. Azithromycin

  • It is a derivative of erythromycin
  • It is acid stable
  • Rapidly absorbed, absorption is decreased by food
  • Has better tissue permeability
  • Longer-acting
  • Better tolerated
  • Plasma half-life – 3 days
  • Free of drug interactions
  • Azithromycin Uses
    • Prophylactic use
    • Treatment of atypical mycobacterial infections in AIDS patients
    • Respiratory infections
    • Genital and skin infections
    • Pneumonias
    • Orodental infection instead of erythromycin
    • Acute exacerbation of chronic bronchitis
  • Azithromycin Adverse effects
  • Mild gastric upset
  • Abdominal pain
  • Headache
  • Dizziness

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