Mirtazapine Has Lower Risk of Erectile Dysfunction Than Buspirone
Mirtazapine has a significantly lower risk of causing erectile dysfunction compared to buspirone and should be preferred when sexual dysfunction is a concern. 1, 2
Comparative Sexual Side Effect Profiles
Mirtazapine
- Has a favorable sexual side effect profile with only 24.4% incidence of sexual dysfunction 2
- Acts as an alpha2-adrenoceptor and serotonin-2/3 receptor antagonist, which appears to cause few sexual problems 3
- May actually improve sexual function in depressed patients:
- Studies show patients report fewer sexual problems over time with mirtazapine treatment 5
Buspirone
- Often used as an augmentation strategy for SSRI-induced sexual dysfunction 1
- Has higher rates of sexual side effects compared to mirtazapine 2
- In the STAR*D trial, buspirone augmentation had higher discontinuation rates due to adverse events compared to bupropion augmentation (20.6% vs. 12.5%) 6
Mechanism of Action Related to Sexual Function
- Mirtazapine's antagonism of 5-HT2 and 5-HT3 receptors likely contributes to its lower incidence of sexual dysfunction 3
- Medications that block serotonin-2 (5-HT2) receptors (like mirtazapine) have demonstrated lower rates of sexual dysfunction 2
- Buspirone's mechanism as a partial 5-HT1A agonist does not provide the same protective effect against sexual dysfunction
Clinical Considerations
When to Choose Mirtazapine
- For patients with depression who are concerned about erectile dysfunction
- As a replacement for SSRIs in patients experiencing sexual dysfunction 3
- When treating depression in patients with pre-existing erectile dysfunction
When to Consider Buspirone
- As an augmentation strategy for partial response to antidepressants 6
- In patients who cannot tolerate other side effects of mirtazapine (such as sedation or weight gain)
Important Caveats
- Individual responses to medications may vary
- Mirtazapine may cause other side effects including sedation, irritability, and weight gain 3
- For patients with erectile dysfunction and testosterone deficiency, testosterone therapy should be considered alongside antidepressant treatment 6
- If erectile dysfunction persists despite medication adjustment, PDE5 inhibitors remain the first-line treatment for ED 6, 1
By selecting mirtazapine over buspirone when sexual function is a concern, clinicians can reduce the risk of medication-induced erectile dysfunction while still effectively treating depression.