Klacid Od (Clarithromycin)

• Clarithromycin is used to treat bacterial infections across several organ systems.
• Community‑acquired pneumonia: eradicates the causative bacteria, leading to clinical recovery.
• Acute bacterial sinusitis: reduces sinus inflammation by eliminating the infecting organisms.
• Skin and soft‑tissue infections: clears Staphylococcus and Streptococcus species to promote wound healing.
• Helicobacter pylori eradication regimens: acts as part of combination therapy to achieve bacterial eradication and ulcer healing.

• Clarithromycin binds to the 50S subunit of bacterial ribosomes, blocking the translocation step of protein synthesis. This inhibition prevents elongation of the peptide chain, exerting a bacteriostatic effect against susceptible Gram‑positive and some Gram‑negative organisms. By halting bacterial growth, the immune system can more effectively clear the infection.

Clarithromycin may cause a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Nausea
• Diarrhea
• Abdominal pain or discomfort
• Altered taste sensation
• Headache
• Vomiting

Serious or Rare Side Effects

• Severe allergic reactions such as anaphylaxis
• QT‑interval prolongation leading to cardiac arrhythmias
• Hepatic dysfunction or jaundice
• Clostridioides difficile‑associated colitis
• Stevens‑Johnson syndrome or toxic epidermal necrolysis

• When prescribing Clarithromycin, clinicians should consider several precautionary measures to ensure safe use.
• Assess liver function: evaluate hepatic enzymes before initiating therapy.
• Monitor cardiac QT interval: avoid use in patients with known QT prolongation or concurrent QT‑prolonging drugs.
• Use caution in renal impairment: adjust therapy based on renal function where necessary.
• Avoid in known macrolide hypersensitivity: discontinue immediately if allergic reaction occurs.
• Pregnancy and lactation: safety data are limited; prescribe only if benefit outweighs risk.
• Store below 25°C: keep in the original pack, protect from moisture and light.

Clarithromycin interacts with several medicines, requiring attention to avoid clinically significant effects.

Major Interactions (Avoid)

• Concomitant use with other QT‑prolonging agents (e.g., cisapride, certain antiarrhythmics).
• Co‑administration with drugs metabolized by CYP3A4 that have narrow therapeutic windows (e.g., simvastatin, lovastatin).
• Use with pimozide or terfenadine: may cause serious cardiac events.

Moderate Interactions (Monitor Closely)

• Warfarin: may increase INR; monitor coagulation parameters.
• Oral hypoglycemics (e.g., sulfonylureas): may enhance hypoglycaemia; check blood glucose.
• Theophylline and carbamazepine: may increase plasma concentrations; adjust dose if needed.