Lipoic Acid in the Treatment of Smell Dysfunction Following Viral Infection of the Upper Respiratory Tract
- 1 November 2002
- journal article
- clinical trial
- Published by Wiley in The Laryngoscope
- Vol. 112 (11), 2076-2080
- https://doi.org/10.1097/00005537-200211000-00031
Abstract
The study aimed to investigate the potential therapeutic effects of alpha-lipoic acid in olfactory loss following infections of the upper respiratory tract. Possible mechanisms of actions include the release of nerve growth factor and antioxidative effects, both of which may be helpful in the regeneration of olfactory receptor neurons. Unblinded, prospective clinical trial. A total of 23 patients participated (13 women, 10 men; mean age 57 y, age range 22-79 y; mean duration of olfactory loss, 14 mo; range, 4 to 33 mo); 19 of them were hyposmic and 4 had functional anosmia. Alpha-lipoic acid was used orally at a dose of 600 mg/day; it was prescribed for an average period of 4.5 months. Olfactory function was assessed using olfactory tests for phenyl ethyl alcohol odor threshold, odor discrimination, and odor identification. Seven patients (30%) showed no change in olfactory function. Two patients (9%) exhibited a moderate decrease in olfactory function; in contrast, six patients (26%) showed moderate and eight patients (35%) remarkable increase in olfactory function. Two of the 4 patients with functional anosmia reached hyposmia; 5 of 19 hyposmic patients became normosmic. Overall, this resulted in a significant improvement in olfactory function following treatment (P =.002). At the end of treatment parosmias were less frequent (22%) than at the beginning of therapy (48%). Interestingly, recovery of olfactory function appeared to be more pronounced in younger patients than in patients above the age of 60 years (P =.018). The results indicate that alpha-lipoic acid may be helpful in patients with olfactory loss after upper respiratory tract infection. However, to judge the true potential of this treatment, the outcome of double-blind, placebo-controlled studies in large groups of patients must be awaited, especially when considering the relatively high rate of spontaneous recovery in olfactory loss after upper respiratory tract infection.Keywords
This publication has 33 references indexed in Scilit:
- Effect of DL-α-lipoic acid on mitochondrial enzymes in aged ratsChemico-Biological Interactions, 2001
- TGF-α and olfactory marker protein enhance mitosis in rat olfactory epithelium in vivoNeuroReport, 2000
- Evaluation and treatment of anosmiaCurrent Opinion in Otolaryngology & Head and Neck Surgery, 2000
- Treatment of diabetic polyneuropathy with the antioxidant thioctic acid (α-lipoic acid): A two year multicenter randomized double-blind placebo-controlled trial (ALADIN II)Free Radical Research, 1999
- Clinical Study of Olfactory DisturbanceActa Oto-Laryngologica, 1998
- Prevalence and Assessment of Qualitative Olfactory Dysfunction in Different Age GroupsThe Laryngoscope, 1996
- Patterns of adrenergic and peptidergic innervation in human olfactory mucosa: Age‐related trendsJournal of Comparative Neurology, 1993
- Ultrastructural histopathology of human olfactory dysfunctionMicroscopy Research and Technique, 1992
- Evaluation of olfactory dysfunction in the connecticut chemosensory clinical research centerThe Laryngoscope, 1988
- HYPOSMIA IN ACUTE VIRAL HEPATITISThe Lancet, 1971