Treatment of postinfectious olfactory disorders with minocycline: a double-blind, placebo-controlled study
Jens Reden1, Birgit Herting, Katja Lill
1Smell and Taste Clinic, Department of Otorhinolaryngology, Northwestern University, Chicago, Illinois, USA. jens.reden@uniklinikum-dresden.de
Objectives/Hypothesis:
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.
Study Design:
Randomized, prospective, double-blind, placebo-controlled.
Methods:
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.
Results:
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.
Conclusions:
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.
Insights
Minocycline did not improve olfactory function in patients with postinfectious olfactory loss. Spontaneous recovery occurred in about 20% of patients over seven months, suggesting other factors contribute to olfactory dysfunction.
Area of Science:
- Otolaryngology
- Neuroscience
- Pharmacology
Background:
- Upper respiratory tract infections are a leading cause of olfactory loss.
- Increased apoptosis of olfactory receptor neurons is a potential mechanism.
- Minocycline, an antibiotic with antiapoptotic properties, was investigated for its potential to aid recovery.
Purpose of the Study:
- To evaluate the efficacy of minocycline in improving olfactory function in patients with postinfectious olfactory dysfunction.
- To determine if minocycline accelerates recovery compared to placebo.
Main Methods:
- A randomized, prospective, double-blind, placebo-controlled study.
- 55 patients with postinfectious olfactory dysfunction were enrolled.
- Olfactory function was assessed using the standardized "Sniffin' Sticks" test before and 7 months after a 3-week treatment with minocycline or placebo.
Main Results:
- No statistically significant difference in olfactory function improvement was observed between the minocycline and placebo groups.
- This suggests that factors beyond apoptosis, such as peripheral scarring or central nervous system changes, may contribute to persistent olfactory loss.
Conclusions:
- Minocycline, at the tested dosage, demonstrated minimal to no effect on the recovery of olfactory function after infection.
- Spontaneous olfactory recovery was observed in approximately 20% of patients within a 7-month period.
- The findings indicate that non-apoptotic pathways are likely involved in post-infectious olfactory dysfunction.
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