Therapeutic Potential of Valproic Acid for Postviral Olfactory Dysfunction: A Single-Arm Pilot Study

Area of Science:

• Neurology
• Otolaryngology
• Pharmacology

Background:

• Postviral olfactory dysfunction (PVOD) significantly impacts quality of life, with limited treatment options.
• Spontaneous recovery occurs in some PVOD cases, but many experience persistent smell loss.
• Valproic acid (VPA), an epilepsy drug, demonstrates neuroregenerative potential in preclinical studies.

Purpose of the Study:

• To investigate the efficacy and safety of Valproic acid (VPA) in treating patients with postviral olfactory dysfunction (PVOD).
• This is the first clinical study exploring VPA as a treatment for PVOD.

Main Methods:

• An open-label, single-arm, phase II study involving 11 PVOD patients.
• Patients received oral Valproic acid (VPA) 200 mg twice daily for 24 weeks.
• Olfactory function was assessed using odor detection and recognition thresholds (T&T olfactometer) and a visual analog scale.

Main Results:

• Significant improvements in odor detection and recognition scores were observed within 4 weeks of VPA treatment.
• Olfactory recovery rates reached 77.8% at both 12 and 24 weeks, with cure rates of 33.3% and 44.4% respectively.
• Valproic acid (VPA) demonstrated a favorable safety profile, with no serious adverse events reported.

Conclusions:

• Valproic acid (VPA) appears to be a safe and effective treatment for postviral olfactory dysfunction (PVOD).
• The observed olfactory improvements suggest VPA's potential neuroregenerative effects in PVOD patients.
• Further controlled studies are warranted to confirm these findings and establish VPA as a standard PVOD treatment.