Can Buspar (buspirone) cause loss of smell or anosmia?

Loss of Smell (Anosmia) and Buspirone (Buspar)

Buspirone (Buspar) does not cause loss of smell or anosmia based on available evidence. According to the FDA drug label, altered smell is classified as an infrequent adverse event, occurring in only 1/100 to 1/1,000 patients taking buspirone 1.

Evidence Analysis

FDA Drug Label Information

The FDA-approved drug label for buspirone specifically categorizes adverse effects by frequency:

• Frequent events (occurring in at least 1/100 patients)
• Infrequent events (occurring in 1/100 to 1/1,000 patients)
• Rare events (occurring in less than 1/1,000 patients)

Within the EENT (Eye, Ear, Nose, and Throat) category, "altered smell" is listed as an infrequent adverse event 1. This means that while it has been reported, it occurs relatively uncommonly.

Common Side Effects of Buspirone

The more commonly observed side effects of buspirone include:

• Dizziness
• Nausea
• Headache
• Nervousness
• Lightheadedness
• Excitement

These side effects are more likely to be experienced than loss of smell 1.

Differential Diagnosis for Anosmia

If you're experiencing loss of smell while taking buspirone, it's important to consider other more common causes:

1. Viral infections: The most recent evidence strongly indicates that anosmia is a significant symptom of COVID-19 infection 2. In fact, anosmia may present as a primary or early symptom in COVID-19 positive patients, with some studies showing it has a positive predictive value of 67% for COVID-19 2.

2. Other respiratory infections: Common cold, influenza, and other upper respiratory tract infections can cause temporary loss of smell.

3. Allergies or sinus problems: Nasal congestion and inflammation can block odors from reaching smell receptors.

4. Neurological conditions: Some neurological disorders can affect the sense of smell.

Clinical Approach for Patients with Anosmia

If you're experiencing loss of smell while taking buspirone:

1. Consider COVID-19 testing: Given the strong association between anosmia and COVID-19 2, testing for SARS-CoV-2 should be prioritized, especially if there are other symptoms such as fever, cough, or fatigue.

2. Evaluate timing: If the anosmia began shortly after starting buspirone, it might be medication-related, though this is uncommon.

3. Look for other symptoms: Accompanying symptoms like nasal congestion, runny nose, or facial pain might suggest other causes like sinusitis or allergies.

4. Medication review: Consider other medications that might more commonly cause altered smell.

Prognosis

If anosmia is related to buspirone (which is uncommon), discontinuation of the medication would likely resolve the symptom. However, given the infrequent nature of this side effect, other causes should be thoroughly investigated before attributing loss of smell to buspirone.

For COVID-19-related anosmia, studies show variable recovery rates, with complete resolution seen in 13-44% of patients and partial resolution in 14% of patients, with a mean time to improvement of 7.2 days 2.

Important Considerations

• Buspirone's pharmacological profile primarily involves serotonin 5-HT1A receptors and dopamine D2 autoreceptors 3, with minimal reported effects on olfactory function.
• If experiencing loss of smell, consider COVID-19 testing given the strong association between anosmia and SARS-CoV-2 infection 2.
• Always consult with your healthcare provider before making any changes to your medication regimen.