clarithromicine

Clarithromycin is a semi-synthetic macrolide antibiotic derived from erythromycin, used primarily to treat bacterial infections. It functions by inhibiting bacterial protein synthesis through binding to the 50S subunit of the ribosome, thereby halting the elongation of peptide chains. This mechanism disrupts essential cellular processes in susceptible bacteria, leading to their death or inhibition of growth.

Commonly prescribed for respiratory tract infections such as pneumonia, bronchitis, and sinusitis, clarithromycin is also effective against skin and soft tissue infections, including those caused by *Streptococcus* and *Staphylococcus* species. It may be used in combination with other antibiotics for Helicobacter pylori eradication in peptic ulcer disease. The drug is available in oral formulations, including tablets and extended-release forms, as well as intravenous administration in hospital settings.

Like other macrolides, clarithromycin exhibits activity against Gram-positive bacteria, some Gram-negative organisms, and atypical pathogens like *Mycoplasma* and *Chlamydia*. However, resistance due to ribosomal mutations or efflux pumps has been observed in certain bacterial strains, limiting its efficacy in some cases.

Adverse effects may include gastrointestinal disturbances such as nausea, diarrhea, or abdominal pain, as well as potential hepatotoxicity at higher doses. Clarithromycin interacts with several medications, particularly those metabolized by the cytochrome P450 enzyme system, which can lead to altered drug levels and increased side effects. Contraindications include hypersensitivity to macrolides and concurrent use with certain drugs like pimozide or ergot alkaloids.

Dosage varies depending on the infection and patient factors, with extended-release formulations designed to reduce dosing frequency. Clarithromycin is generally well-tolerated, but monitoring is recommended in patients with hepatic impairment or those taking interacting medications. As with all antibiotics, its use should be guided by susceptibility testing to ensure optimal therapeutic outcomes.