Macrolides: Overview

Definition

• Class of antibiotics used to treat a variety of infections caused by Gram-positive and Gram-negative bacteria.

Common Macrolides

• Azithromycin (Aziy)
• Clarithromycin
• Erythromycin

Administration

• All can be administered orally for mild to moderate bacterial infections of:
  • Respiratory tract
  • Gastrointestinal tract
  • Genitourinary tract
• Erythromycin can be given intravenously.
• Azithromycin has an ophthalmic formulation for bacterial conjunctivitis.

Mechanism of Action

• Target the bacterial 50S ribosomal subunit to inhibit protein synthesis.
• Have a bacteriostatic effect, meaning they stop bacterial growth.
• Considered broad-spectrum antibiotics, effective against most Gram-positive bacteria and moderately against some Gram-negative bacteria.

Side Effects

Common Side Effects

• Headaches
• Skin rash
• Gastrointestinal disturbances:
  • Diarrhea
  • Abdominal pain
  • Nausea
  • Vomiting

Rare but Serious Side Effects

• Disruption of normal intestinal flora leading to Clostridium difficile infection (CDI).
• Vaginitis and candidiasis.
• Ototoxicity and hearing loss if used long-term.

Other Serious Risks

• Prolonged QT interval
• Ventricular arrhythmias (e.g., Torsades de Pointes)
• Hepatotoxicity (can lead to hepatitis)
• Seizures
• Hypersensitivity reactions (e.g., Angioedema, Stevens-Johnson syndrome, Toxic epidermal necrolysis)

Specific Macrolide Side Effects

• Erythromycin: Can cause esophagitis.
• Azithromycin: Rarely causes thrombocytopenia.
• Clarithromycin: Can cause abnormal taste and pancreatitis.

Contraindications

• Contraindicated in patients with hepatic disease.
• Use cautiously in pregnant and breastfeeding women, elderly clients, and those with cardiovascular disease.

Drug Interactions

• Avoid combining with medications that prolong the QT interval (e.g., quinines, amiodarone).
• Avoid with CYP3A4 inhibitors due to risk of sudden cardiac death.
• Avoid with ergot derivatives or statins, as it can affect their metabolism and increase toxicity.

Nursing Considerations

1. Assessment:

   • Vital signs
   • Symptoms of infection (e.g., dysuria, burning sensation, urethral discharge)
   • Review laboratory results (CBC, renal and hepatic function tests, Gram stain, culture & sensitivity, NAT, urinalysis).
   • Confirm no known cardiac arrhythmias or prescriptions for strong CYP3A4 inhibitors.

2. Client Education:

   • Explain how the medication helps resolve the infection.
   • Dosage instructions (e.g., one tablet with or without food).
   • Discuss potential side effects and which symptoms to report (e.g., CDI, hepatotoxicity, ototoxicity, QT prolongation).
   • Stress the importance of abstaining from sexual activity during and for 7 days after therapy.

3. Monitoring:

   • Monitor for side effects.
   • Assess for desired therapeutic effect (resolution of infection and absence of symptoms).

Summary

• Macrolides are effective antibiotics for treating Gram-positive and Gram-negative bacterial infections.
• Work by inhibiting protein synthesis.
• Generally well tolerated but can have serious side effects, necessitating careful nursing considerations and patient education.