Clarithromycin: Price, Dosage & Where to Buy

Clarithromycin is a macrolide antibiotic used to treat bacterial infections, particularly respiratory tract infections caused by bacteria susceptible to it. It requires a prescription in the United Kingdom and is available as tablets and an oral suspension. Treatment is intended for infections proven or strongly suspected to be bacterial, helping to limit the development of antibiotic resistance.

Clarithromycin belongs to the macrolide group of antibiotics. These medicines act on bacterial ribosomes, the structures bacteria use to make proteins. By interfering with protein production, clarithromycin limits the ability of susceptible bacteria to grow and multiply.

This helps the body's immune system control the infection. Its effectiveness depends on the bacteria being sensitive to the medicine; resistant bacteria can continue to survive despite treatment. Antibiotics of this class act against bacteria rather than viruses.

Clarithromycin treats mild to moderate infections caused by susceptible bacteria. Its listed uses include bacterial flare-ups of chronic bronchitis in adults, sinusitis, community-acquired pneumonia, and uncomplicated skin infections. It is also used for bacterial throat or tonsil infections when first-line treatment cannot be used, and for acute middle-ear infections in children.

In people with advanced HIV infection, it can treat or prevent disseminated mycobacterial infections, meaning infections that have spread through the body. In adults with Helicobacter pylori infection and duodenal ulcer disease, clarithromycin is used with other medicines to eradicate the bacteria and reduce ulcer recurrence. Clarithromycin-containing treatment should not be used when the bacteria are known or suspected to be resistant to it.

The label lists oral suspension strengths of 125 mg/5 mL and 250 mg/5 mL, oral tablets and film-coated tablets of 250 mg and 500 mg, and extended-release film-coated tablets of 500 mg. The label lists adult treatment doses of 250 mg or 500 mg every 12 hours for 7-14 days, depending on the infection. The label lists clarithromycin 500 mg every 8 or 12 hours for 10-14 days in combination regimens for H. pylori eradication.

The label lists a children's daily dosage of 15 mg/kg/day divided every 12 hours for 10 days, up to the adult dose. The label lists adult mycobacterial infection dosing of 500 mg every 12 hours. These are label facts, not an individual treatment plan.

Dose reductions are specified for severe kidney impairment and for certain combinations involving atazanavir or ritonavir in people with kidney impairment. The appropriate regimen depends on the infection, kidney function and other medicines. The label states that clarithromycin tablets may be given with or without food.

The label specifies storage of clarithromycin tablets at controlled room temperature, 20° to 25°C, in a well-closed container. Storage requirements for the oral suspension should be checked on its dispensing label.

A missed dose can interrupt the regular antibiotic schedule. General pharmacy advice is to resume the prescribed schedule when remembered, unless the next dose is nearly due; in that case, the missed dose is omitted.

A double dose should not be used to make up for it. A pharmacist can clarify uncertainties about the prescribed schedule.

Based on animal findings, clarithromycin is not recommended during pregnancy unless no appropriate alternative therapy exists. Human pregnancy studies are too limited to establish risks of birth defects, miscarriage or other adverse outcomes. Pregnancy during treatment should prompt discussion with the prescriber about potential fetal hazards.

Limited human data show that clarithromycin and its active metabolite enter breast milk at less than 2% of the maternal weight-adjusted dose. Reported effects in breastfed children included rash, diarrhoea, loss of appetite and sleepiness, comparable to those reported with amoxicillin. Effects on milk production have not been assessed.