Drug Interactions between moxifloxacin / triamcinolone and rifabutin

MONITOR CLOSELY: Concomitant administration of corticosteroids may potentiate the risk of tendinitis and tendon rupture associated with fluoroquinolone treatment. The mechanism is unknown. Tendinitis and tendon rupture have most frequently involved the Achilles tendon, although cases involving the rotator cuff (the shoulder), the hand, the biceps, and the thumb have also been reported. Some have required surgical repair or resulted in prolonged disability. Tendon rupture can occur during or up to several months after completion of fluoroquinolone therapy.

MANAGEMENT: Caution is recommended if fluoroquinolones are prescribed in combination with corticosteroids, particularly in patients with other concomitant risk factors (e.g., age over 60 years; recipient of kidney, heart, and/or lung transplant). Patients should be advised to stop taking the fluoroquinolone, avoid exercise and use of the affected area, and promptly contact their physician if they experience pain, swelling, or inflammation of a tendon. In general, fluoroquinolones should only be used to treat conditions that are proven or strongly suspected to be caused by bacteria and only if the benefits outweigh the risks.

MONITOR: Rifampin may induce the hepatic metabolism of corticosteroids, possibly reducing their therapeutic effect. The elimination half-life of corticosteroids has been shown to be reduced by up to 45% when rifampin is coadministered. Theoretically, rifabutin could interact with corticosteroids in a similar manner.

MANAGEMENT: Patients should be monitored for altered corticosteroid effects. Dosage increases may be necessary. Two- to threefold increases in prednisolone dosage have been recommended.