Ageusia, the loss of the sense of taste, is an infrequently reported adverse effect of antimicrobial use. We describe a patient who developed ageusia while receiving rifabutin therapy for Mycobacterium simiae pulmonary infection.

A 71-year-old white woman with cavitary lung disease had a transbronchial biopsy specimen that yielded Nocardia asteroides and M. simiae. She received sulfisoxazole for the former infection and clarithromycin and rifabutin for the latter. Six weeks after starting therapy with clarithromycin and rifabutin, she reported ageusia, arthralgias, and myalgias. Physical examination showed cachexia and mild skin hyperpigmentation. The patient had no edema, tenderness, or decreased range of joint motion. The leukocyte count was 3400 cells/mm³ (with a normal differential); the erythrocyte sedimentation rate was 35 mm/h; the calcium level was 8.4 mg/dL; and the magnesium level was 2.0 mg/dL. The symptoms were attributed to rifabutin, which was then withdrawn. Two weeks later, ageusia had almost completely resolved. Rifabutin therapy was restarted, but within 2 days she reported worsening ageusia, myalgias, and arthralgias. Rifabutin therapy was discontinued and over the next few weeks her ageusia resolved.

Rifabutin is a rifamycin-like antimicrobial that reacts in vitro against M. avium-intracellulare and M. tuberculosis. Adverse effects include painless urine discoloration; flushing erythema of the upper trunk and head; influenza-like episodes characterized by fever, myalgia, and headache; arthritis-arthralgia syndrome; elevated transaminase levels; and renal impairment [1-3]. Ageusia has not been previously reported with rifabutin use.

Previous reports have attributed drug-induced ageusia to phenylbutazone, chlormezanone, baclofen, captopril, amphotericin B, griseofulvin, metronidazole, and lincomycin [4, 5]. Although our patient was also taking sulfisoxazole and clarithromycin, the return of sense of taste followed by recurrence of ageusia after restarting rifabutin indicates that rifabutin was the probable cause. With its recent Food and Drug Administration approval, rifabutin will be increasingly used to treat and suppress M. avium complex infections in patients with the acquired immunodeficiency syndrome (AIDS), and clinicians should be aware of this potential adverse effect.