Clarithromycin (Clarosip / Klaricid / Klaricid XL) is an approved antibiotic for use in combination with other drugs for the treatment of Mycobacterium avium intracellulare (MAI)^[1]. In the United States it is also approved as MAI prophylaxis^[2]. It is also approved for treating respiratory tract infections and mild-to-moderate skin and soft tissue infections.

The recommended dose for treating people with MAI is 500mg twice daily on an empty stomach. Doses higher than this have been associated with worse survival in several clinical trials.

Clarithromycin is also being tested alone and in combination with other drugs for the treatment of toxoplasmosis^[3].

Its side-effects include diarrhoea, nausea, abnormal taste, dyspepsia, abdominal pain, and headache.

Clarithromycin should not be taken at the same time as the anti-histamine drugs astemizole or terfenadine due to heart irregularities. Taking clarithromycin decreases levels of AZT (zidovudine, Retrovir) in the blood^[4]. Due to complex interactions, clarithromycin should be avoided by patients taking the protease inhibitors atazanavir (Reyataz), efavirenz (Sustiva) or nevirapine (Viramune)^[5][6][7]. A reduced dose should be used by patients taking ritonavir-boosted lopinavir (Kaletra), while patients taking ritonavir (Norvir) or tipranavir (Aptivus) should use clarithromycin with caution^[8][9].