Polyarthralgia-arthritis syndrome induced by low doses of rifabutin.

We describe 2 cases of polyarthralgia-arthritis syndrome induced by rifabutin, an effective treatment for infections of Mycobacterium avium intracellulare complex. This syndrome has been reported with doses higher than 1 g per day when rifabutin is given in monotherapy. But our cases were treated with low doses, 300-450 mg per day, in combination with clarithromycin. The plasma concentration of rifabutin has been shown to be increased by clarithromycin, suggesting that co-prescription of clarithromycin could lead to development of rifabutin induced polyarthralgia-arthritis syndrome.