Klaritromicin Krka (Clarithromycin)

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

• Community‑acquired pneumonia: eradicates susceptible pathogens, improving breathing and preventing complications.
• Acute bacterial sinusitis: relieves sinus inflammation by eliminating the causative bacteria.
• Acute bacterial bronchitis: reduces cough and bacterial load in the lower airways.
• Skin and soft‑tissue infections: clears susceptible skin pathogens and promotes healing.
• Helicobacter pylori eradication: part of combination therapy to eliminate H. pylori and heal gastric ulcers.

• 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, from mild to severe.

Common Side Effects

• Nausea: transient upset stomach.
• Diarrhea: loose stools, often mild.
• Abdominal pain: cramping or discomfort.
• Altered taste: metallic or bitter sensation.
• Headache: mild to moderate.
• Vomiting: occasional episodes.

Serious or Rare Side Effects

• Severe allergic reactions (anaphylaxis): rash, swelling, difficulty breathing.
• QT interval prolongation: risk of cardiac arrhythmias.
• Hepatic dysfunction: elevated liver enzymes or jaundice.
• Clostridioides difficile‑associated diarrhea: severe colitis.
• Stevens‑Johnson syndrome/toxic epidermal necrolysis: extensive skin blistering.
• Cardiac arrhythmias: irregular heartbeats beyond QT prolongation.

When prescribing clarithromycin, clinicians should consider several safety measures.

• Assess renal and hepatic function: dose adjustment may be required in impairment.
• Avoid use in patients with known macrolide hypersensitivity: discontinue if reaction occurs.
• Monitor ECG in patients with cardiac risk factors: risk of QT prolongation.
• Use caution in pregnancy: limited data, weigh benefits against potential risks.
• Avoid concomitant use with other QT‑prolonging agents: increased cardiac risk.
• Store at ambient temperature below 25°C: keep in the original pack, protect from moisture.

Clarithromycin interacts with several medicines; some require avoidance, others close monitoring.

Major Interactions (Avoid)

• Erythromycin or other macrolides: additive toxicity and increased risk of QT prolongation.
• Cisapride or domperidone: heightened risk of serious cardiac events.
• HIV protease inhibitors (e.g., ritonavir): markedly increased clarithromycin plasma levels.
• Theophylline: elevated theophylline concentrations leading to toxicity.

Moderate Interactions (Monitor Closely)

• Warfarin: enhanced anticoagulant effect, monitor INR.
• Statins such as simvastatin or lovastatin: increased risk of myopathy.
• Carbamazepine: reduced clarithromycin exposure, may diminish efficacy.
• Digoxin: modest increase in serum levels, monitor for toxicity.