Klacid Sr (Clarithromycin)

Klacid Sr is a macrolide antibiotic used to treat a range of bacterial infections affecting the respiratory tract, skin and gastrointestinal system.

• Community‑acquired pneumonia: eliminates the causative bacteria and improves respiratory function.
• Acute bacterial sinusitis: reduces sinus inflammation and clears infection.
• Acute exacerbations of chronic bronchitis: controls bacterial overgrowth and eases symptoms.
• Skin and soft‑tissue infections: eradicates susceptible organisms and promotes wound healing.
• Helicobacter pylori eradication (in combination therapy): contributes to bacterial clearance as part of a multi‑drug regimen.

• Clarithromycin binds to the 50S subunit of bacterial ribosomes, inhibiting the translocation step of protein synthesis. This action blocks the elongation of peptide chains, exerting a bacteriostatic effect against susceptible Gram‑positive and some Gram‑negative organisms, and thereby limiting bacterial growth and replication.

Clarithromycin may cause a range of adverse reactions, from mild to severe. Awareness of common and serious events helps guide monitoring.

Common Side Effects

• Nausea: mild to moderate upset stomach.
• Diarrhea: frequent loose stools.
• Abdominal pain: cramping or discomfort.
• Taste disturbance: altered or metallic taste.
• Headache: mild to moderate intensity.
• Vomiting: occasional episodes.

Serious or Rare Side Effects

• Severe allergic reactions: rash, swelling, anaphylaxis.
• QT interval prolongation: risk of cardiac arrhythmias.
• Hepatic dysfunction: elevated liver enzymes or hepatitis.
• Clostridioides difficile infection: severe colitis.
• Arrhythmias: ventricular tachycardia or fibrillation.
• Anaphylaxis: life‑threatening hypersensitivity.

Before prescribing Klacid Sr, clinicians should evaluate patient-specific factors and monitor for potential complications.

• Assess renal and hepatic function: adjust therapy if impairment is present.
• Monitor cardiac status: avoid in patients with known QT prolongation.
• Avoid in individuals with documented macrolide hypersensitivity.
• Use caution during pregnancy and lactation: benefits must outweigh potential risks.
• Review concomitant medications for interaction potential.
• Store at below 25°C: keep in the original pack, protect from moisture.

Clarithromycin interacts with several drug classes; awareness of interaction severity guides clinical decisions.

Major Interactions (Avoid)

• Cisapride and pimozide: risk of serious cardiac arrhythmias.
• Simvastatin and lovastatin: increased risk of myopathy.
• Ergot alkaloids: potential for ergotism.
• Colchicine: heightened toxicity, especially in renal impairment.
• Warfarin: enhanced anticoagulant effect.

Moderate Interactions (Monitor Closely)

• Antacids containing aluminum or magnesium: may reduce absorption.
• Oral contraceptives: possible reduction in efficacy.
• Digoxin: increased serum concentrations.
• Carbamazepine and phenytoin: reduced clarithromycin levels.
• Rifampin: decreased clarithromycin exposure.