Treatment of postinfectious olfactory disorders with minocycline: a double-blind, placebo-controlled study.

Abstract

Infection of the upper respiratory tract is one of the most common causes of olfactory loss. One of the possible underlying pathologic pathways is an increase of apoptosis of olfactory receptor neurons. Therefore, treatment with the antibiotic minocycline, which has been shown to act as an antiapoptotic agent, is thought to accelerate improvement of olfactory function. To investigate this idea, 55 patients with postinfectious olfactory dysfunction were tested for their olfactory ability. Randomized, prospective, double-blind, placebo-controlled. Olfactory function was examined by means of a standardized psychophysical method (Sniffin' Sticks) before and 7 months after a 3-week treatment with either minocycline (2 × 50 mg/d) or a placebo. Statistical analyses did not reveal any influence of the treatment on the progress of olfactory function, possibly indicating that pathologic changes other than apoptosis contribute to postinfectious olfactory loss, either on a peripheral level (e.g., scarring/reorganization of the olfactory epithelium) or on a central nervous level. In conclusion, the present results indicate that minocycline in the given dosage has little or no effect on the recovery of human olfactory function following postinfectious olfactory loss. However, spontaneous recovery is found in approximately 20% of the patients over an observation period of 7 months.