Klerimed (Clarithromycin)

Clarithromycin is used to treat bacterial infections affecting the respiratory tract, sinuses, skin and gastrointestinal system.

• Community‑acquired pneumonia: reduces bacterial load and improves clinical recovery in adults and children.
• Acute bacterial sinusitis: alleviates sinus inflammation and clears infection caused by susceptible organisms.
• Acute bacterial bronchitis: shortens duration of cough and resolves bronchial infection.
• Skin and soft tissue infections: eradicates susceptible Staphylococcus and Streptococcus species in cellulitis and wound infections.
• Helicobacter pylori eradication regimens: contributes to bacterial eradication when combined with other agents in approved triple or quadruple therapy.

• Clarithromycin exerts its antibacterial effect by binding to the 50S subunit of the bacterial ribosome. This interaction blocks the translocation step of protein synthesis, preventing elongation of the peptide chain. By inhibiting bacterial protein production, the drug halts bacterial growth and leads to a bacteriostatic effect against susceptible Gram‑positive, atypical and some Gram‑negative organisms. The resulting inhibition of essential protein synthesis contributes to clinical improvement in infected patients.

Clarithromycin may be associated with a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Nausea: mild to moderate stomach upset.
• Diarrhea: loose stools, occasionally watery.
• Abdominal pain: cramping or discomfort in the abdomen.
• Taste disturbance: altered or metallic taste sensation.
• Headache: mild headache episodes.

Serious or Rare Side Effects

• Hepatotoxicity: elevated liver enzymes or liver injury.
• QT prolongation: cardiac rhythm changes that may lead to arrhythmia.
• Severe allergic reactions: rash, itching, swelling, or anaphylaxis.
• Clostridioides difficile colitis: severe diarrhea due to intestinal flora disruption.

When prescribing clarithromycin, clinicians should consider several precautionary measures to ensure safe use.

• Assess liver function: avoid use in patients with severe hepatic impairment.
• Monitor cardiac status: caution in patients with known QT prolongation or electrolyte disturbances.
• Review drug history: avoid concurrent use with strong CYP3A4 inhibitors.
• Adjust for renal impairment: dose may need modification in severe renal dysfunction.
• Pregnancy and lactation: use only if benefits outweigh potential risks, as safety data are limited.
• Store at ambient temperature: keep below 25 °C, protect from moisture and light in the original container.

Clarithromycin interacts with several medicines through metabolic pathways and additive pharmacodynamic effects.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): may increase clarithromycin levels and toxicity.
• Certain antiarrhythmics (e.g., amiodarone, sotalol): risk of severe QT prolongation.
• Statins metabolized by CYP3A4 (e.g., simvastatin, lovastatin): heightened risk of myopathy.

Moderate Interactions (Monitor Closely)

• Warfarin: may enhance anticoagulant effect, requiring INR monitoring.
• Theophylline: clarithromycin can raise plasma concentrations, monitor for toxicity.
• Carbamazepine: may reduce clarithromycin efficacy and increase carbamazepine levels.