Products
Clarithromycin is commercially available as film-coated tablets, sustained-release tablets, oral suspension, and powder for solution for infusion (Klacid, generics). It has been approved in many countries since 1990. Clarithromycin should not be confused with ciprofloxacin.
Structure and properties
Clarithromycin (C38H69NO13, Mr = 747.96 g/mol) exists as a white crystalline powder that is practically insoluble in water. It is prepared semisynthetically. It is a 6- methyl derivative of erythromycin. Unlike the parent compound, it is gastric acid stable, has a higher bioavailability (55%) and a longer half-life (up to 6 hours including metabolite). Clarithromycin has an active metabolite (4-OH-clarithromycin).
Effects
Clarithromycin (ATC J01FA09) has bacteriostatic to bactericidal properties against Gram-positive and Gram-negative pathogens. The effects are due to inhibition of bacterial protein synthesis by binding to the 50S subunit of ribosomes.
Indications
For treatment of bacterial infectious diseases with susceptible pathogens.
Dosage
According to the SmPC. Tablets are usually taken twice daily (in the morning and evening, 12 hours apart) and independently of meals (sustained-release tablets: once daily with food).
Contraindications
For complete precautions, see the drug label.
Interactions
Clarithromycin has a high potential for drug-drug interactions. It is both a substrate and a potent inhibitor of CYP3A and an inhibitor of P-glycoprotein.
Adverse effects
The most common possible adverse effects include insomnia, headache, drowsiness, taste changes, gastrointestinal distress, pruritus, rash, and weakness. Rarely, serious side effects such as prolongation of the QT interval with cardiac arrhythmias are possible.
