Does mirtazapine cause erectile dysfunction? This is an important question for men prescribed this antidepressant. Mirtazapine, a noradrenergic and specific serotonergic antidepressant (NaSSA) licensed in the UK for major depressive disorder, is generally associated with a lower risk of sexual side effects compared to many other antidepressants. Whilst erectile dysfunction is listed as an uncommon adverse reaction in the UK Summary of Product Characteristics, affecting between 1 in 100 and 1 in 1,000 people, individual responses vary. Understanding the evidence, risk factors, and management options helps patients and clinicians make informed treatment decisions.
Summary: Mirtazapine is associated with a lower risk of erectile dysfunction compared to many other antidepressants, with sexual dysfunction listed as an uncommon side effect affecting between 1 in 100 and 1 in 1,000 people.
- Mirtazapine is a noradrenergic and specific serotonergic antidepressant (NaSSA) licensed in the UK for major depressive disorder.
- Its unique mechanism—blocking specific serotonin receptors whilst enhancing noradrenaline transmission—reduces the likelihood of sexual side effects compared to SSRIs.
- Clinical studies suggest sexual dysfunction occurs in approximately 5–15% of mirtazapine users, compared to 25–70% with SSRIs.
- Depression itself frequently causes erectile dysfunction, making it difficult to determine whether symptoms are medication-related or part of the underlying condition.
- If erectile dysfunction develops, management options include dose adjustment, switching antidepressants, PDE5 inhibitors, or lifestyle modifications under medical supervision.
- Seek urgent medical attention if you experience an erection lasting more than 4 hours (priapism), a rare but serious side effect requiring immediate treatment.
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Does Mirtazapine Cause Erectile Dysfunction?
Mirtazapine is an antidepressant medication licensed in the UK for the treatment of major depressive disorder. It belongs to a class of medicines known as noradrenergic and specific serotonergic antidepressants (NaSSAs), which work differently from selective serotonin reuptake inhibitors (SSRIs). Whilst mirtazapine is sometimes prescribed off-label for anxiety disorders, this use should be under specialist guidance. Understanding its potential impact on sexual function is important for patients and healthcare professionals alike.
Sexual dysfunction and mirtazapine: what the evidence shows
Compared to many other antidepressants, mirtazapine is generally associated with a lower risk of sexual side effects, including erectile dysfunction (ED). The UK Summary of Product Characteristics (SmPC) lists sexual dysfunction—including decreased libido and erectile dysfunction—as an uncommon adverse reaction (affecting between 1 in 100 and 1 in 1,000 people). Clinical studies and systematic reviews suggest that sexual dysfunction occurs less frequently with mirtazapine than with SSRIs, though reported rates vary widely depending on study design and assessment methods. Estimates for mirtazapine range from approximately 5–15%, whilst SSRIs may be associated with rates of 25–70% in different studies.
The mechanism behind mirtazapine's relatively favourable sexual side effect profile relates to its unique pharmacology. Unlike SSRIs, which increase serotonin levels throughout the brain (including areas that can inhibit sexual function), mirtazapine blocks specific serotonin receptors (5-HT₂ and 5-HT₃) whilst enhancing noradrenaline and serotonin transmission through other pathways. This selective action appears to reduce the likelihood of sexual adverse effects.
Individual variation matters
Whilst mirtazapine carries a lower risk, it is important to acknowledge that some men do experience erectile dysfunction whilst taking this medication. Individual responses to antidepressants vary considerably, and factors such as dosage, duration of treatment, underlying health conditions, and psychological factors all play a role. Depression itself is strongly associated with sexual dysfunction, which can make it challenging to determine whether symptoms are medication-related or part of the underlying condition.
Important safety information
If you experience an erection lasting more than 4 hours (priapism), seek urgent medical attention. This is a rare but serious side effect that requires immediate treatment. You should report any suspected side effects via the MHRA Yellow Card Scheme at yellowcard.mhra.gov.uk or through the Yellow Card app.
Comparing Mirtazapine to Other Antidepressants
When considering antidepressant treatment, understanding the comparative risk of sexual side effects across different medication classes helps inform shared decision-making between patients and clinicians. NICE guideline NG222 recommends SSRIs as first-line treatment for depression, alongside discussion of potential side effects including sexual dysfunction.
SSRIs and SNRIs: higher sexual dysfunction rates
Selective serotonin reuptake inhibitors (SSRIs) such as sertraline, citalopram, and fluoxetine are commonly prescribed for depression. However, they are associated with higher rates of sexual dysfunction among antidepressants. Systematic reviews and meta-analyses indicate that sexual side effects—including erectile dysfunction, reduced libido, and delayed ejaculation—may affect a substantial proportion of patients taking SSRIs, with reported rates varying from approximately 25% to over 70% depending on the study and assessment method. Serotonin-noradrenaline reuptake inhibitors (SNRIs) such as venlafaxine and duloxetine show similar patterns, with sexual dysfunction reported in a significant proportion of users.
The mechanism involves excessive serotonin stimulation of 5-HT₂ receptors, which inhibits dopamine and noradrenaline pathways crucial for sexual arousal and function. This widespread serotonergic effect explains why sexual side effects are common with these medications.
Antidepressants with lower sexual side effect profiles
Beyond mirtazapine, several other antidepressants may have more favourable sexual side effect profiles, though availability and licensing vary:
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Bupropion: Not licensed for depression in the UK and only available for off-label use under specialist supervision. Associated with lower rates of sexual dysfunction due to its dopaminergic and noradrenergic activity.
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Agomelatine: A melatonergic antidepressant that is not recommended by NICE. It requires regular liver function test (LFT) monitoring due to the risk of hepatotoxicity, and NHS availability may be limited.
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Moclobemide: A reversible monoamine oxidase inhibitor (MAOI) with lower sexual side effect rates than SSRIs, though dietary and drug interaction cautions apply.
Clinical implications
For patients particularly concerned about sexual function, or those who have experienced problematic sexual side effects with SSRIs, mirtazapine may represent a reasonable alternative. The choice of antidepressant should balance efficacy, side effect profile, individual patient factors (including comorbidities and previous treatment response), and NICE guidance. Shared decision-making, including discussion of potential side effects such as sexual dysfunction, is essential when initiating antidepressant therapy.
Managing Erectile Dysfunction While Taking Mirtazapine
If erectile dysfunction develops during mirtazapine treatment, several evidence-based management strategies can help whilst maintaining effective treatment for depression.
Initial assessment and timing considerations
Before attributing erectile dysfunction to mirtazapine, a thorough assessment is essential. Depression itself frequently causes sexual dysfunction, and symptoms may improve as mood stabilises with treatment. Your GP will typically review your antidepressant within 2–4 weeks of starting or adjusting the dose, and earlier if side effects are troublesome. Some sexual symptoms may resolve spontaneously as depression improves.
It is also important to exclude other contributing factors:
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Physical health conditions: Diabetes, cardiovascular disease, hypertension, and hormonal imbalances (such as low testosterone)
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Other medications: Antihypertensives, antihistamines, and certain prostate medications
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Lifestyle factors: Excessive alcohol consumption, smoking, obesity, and lack of physical activity
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Psychological factors: Relationship difficulties, performance anxiety, or stress
Medication management strategies
If erectile dysfunction persists and is clearly related to mirtazapine, several options exist:
Dose adjustment: Some patients experience improvement with dose reduction, though this must be balanced against maintaining therapeutic efficacy for depression. This should only be done under medical supervision.
Medication switching: If sexual dysfunction significantly impacts quality of life, switching to an antidepressant with a lower risk profile may be considered in consultation with your GP or psychiatrist. However, switching carries risks including withdrawal symptoms and potential relapse of depression, so this decision requires careful clinical judgement.
Adjunctive treatments: Phosphodiesterase-5 (PDE5) inhibitors such as sildenafil, tadalafil, or vardenafil are effective treatments for erectile dysfunction. Generic sildenafil and tadalafil are commonly prescribed on the NHS, and sildenafil 50 mg is also available over the counter from pharmacies as Viagra Connect. These medications can be safely used alongside mirtazapine in most cases, but your GP or pharmacist must assess suitability and exclude contraindications.
Important safety information for PDE5 inhibitors:
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Absolute contraindications: Do not use if you take nitrates (e.g. glyceryl trinitrate for angina) or riociguat, as the combination can cause a dangerous drop in blood pressure.
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Cautions: Use with care if you take alpha-blockers or have significant cardiovascular disease. Your GP will assess your cardiovascular risk before prescribing.
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Rare serious side effects: Seek urgent medical attention if you experience sudden vision or hearing loss, or an erection lasting more than 4 hours (priapism).
Non-pharmacological approaches
Lifestyle modifications can significantly improve erectile function:
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Regular physical exercise (at least 150 minutes of moderate activity weekly)
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Maintaining a healthy weight
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Reducing alcohol intake and stopping smoking
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Stress management techniques
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Relationship counselling or psychosexual therapy where appropriate
Psychosexual therapy services may be available via NHS Talking Therapies or GP referral, though local provision varies. These services can address both psychological and relationship factors contributing to sexual dysfunction.
When to Speak to Your GP About Sexual Side Effects
Open communication with healthcare professionals about sexual side effects is crucial for optimising both mental health treatment and quality of life. Many patients feel embarrassed discussing sexual problems, but GPs are accustomed to these conversations and can offer practical solutions.
When to seek medical advice
You should contact your GP if:
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Erectile dysfunction develops or worsens after starting mirtazapine or increasing the dose
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Sexual side effects significantly impact your quality of life, relationships, or willingness to continue treatment
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You are considering stopping your antidepressant due to sexual side effects (never stop suddenly without medical advice, as this can cause withdrawal symptoms and depression relapse)
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You experience persistent erectile dysfunction lasting more than a few weeks, regardless of potential cause
Seek urgent medical attention if:
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You experience an erection lasting more than 4 hours (priapism)
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You develop chest pain, breathlessness, or other cardiovascular symptoms during sexual activity
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You experience sudden vision or hearing loss after using a PDE5 inhibitor
What to expect during your consultation
Your GP will take a comprehensive history, including:
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Timeline of erectile dysfunction in relation to medication
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Severity and impact on quality of life
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Other medications and health conditions
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Lifestyle factors and relationship context
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Mental health status and depression symptoms
Physical examination may include blood pressure measurement. Your GP may arrange blood tests when clinically indicated, which could include HbA1c or fasting glucose (to check for diabetes), fasting lipid profile, morning total testosterone (if hypogonadism is suspected), and thyroid function tests (if thyroid disorder is suspected). These investigations help identify treatable underlying causes.
Treatment options your GP can offer
Depending on the assessment, your GP may:
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Adjust your mirtazapine dose or timing
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Consider switching to an alternative antidepressant with a more favourable sexual side effect profile, in line with NICE guidance
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Prescribe PDE5 inhibitors if appropriate and not contraindicated, following cardiovascular risk assessment
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Refer you to specialist services such as psychosexual therapy (where available locally), endocrinology (for confirmed hypogonadism), urology (for refractory ED or structural concerns), or cardiology (for high cardiovascular risk)
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Address modifiable risk factors through lifestyle advice
The importance of continuing depression treatment
Whilst sexual side effects are distressing, untreated depression carries significant health risks and profoundly affects quality of life. Working collaboratively with your GP to find a solution that addresses both depression and sexual function is essential. Most cases of antidepressant-related erectile dysfunction can be successfully managed without compromising mental health treatment. Remember that effective depression treatment often improves sexual function overall, as depression itself is a major cause of sexual dysfunction.
Reporting side effects
You can report any suspected side effects from mirtazapine or other medicines via the MHRA Yellow Card Scheme at yellowcard.mhra.gov.uk or through the Yellow Card app. Reporting helps improve the safety of medicines for everyone.
Frequently Asked Questions
Is mirtazapine less likely to cause erectile dysfunction than other antidepressants?
Yes, mirtazapine is generally associated with a lower risk of erectile dysfunction compared to SSRIs and SNRIs. Clinical studies suggest sexual dysfunction occurs in approximately 5–15% of mirtazapine users, whilst SSRIs may affect 25–70% of patients depending on the study.
Can I take Viagra or other erectile dysfunction tablets with mirtazapine?
PDE5 inhibitors such as sildenafil (Viagra), tadalafil, and vardenafil can usually be safely used alongside mirtazapine. However, your GP or pharmacist must assess suitability and exclude contraindications, particularly if you take nitrates for angina or have significant cardiovascular disease.
Will erectile dysfunction from mirtazapine go away on its own?
Some sexual symptoms may resolve spontaneously as depression improves with treatment, as depression itself frequently causes erectile dysfunction. If symptoms persist beyond a few weeks or significantly impact quality of life, speak to your GP about management options including dose adjustment or adjunctive treatments.
What's the difference between mirtazapine and SSRIs for sexual side effects?
Mirtazapine blocks specific serotonin receptors that inhibit sexual function, whilst SSRIs increase serotonin levels throughout the brain including areas that can impair sexual response. This difference in mechanism explains why mirtazapine typically causes fewer sexual side effects than SSRIs like sertraline, citalopram, or fluoxetine.
Should I stop taking mirtazapine if I develop erectile dysfunction?
Never stop mirtazapine suddenly without medical advice, as this can cause withdrawal symptoms and depression relapse. Speak to your GP about management strategies including dose adjustment, switching to an alternative antidepressant, or using PDE5 inhibitors whilst continuing effective depression treatment.
How do I get help for erectile dysfunction caused by antidepressants?
Contact your GP to discuss your symptoms and treatment options. Your GP can assess whether erectile dysfunction is medication-related, adjust your antidepressant regimen, prescribe PDE5 inhibitors if appropriate, or refer you to specialist services such as psychosexual therapy or urology depending on your individual circumstances.
The health-related content published on this site is based on credible scientific sources and is periodically reviewed to ensure accuracy and relevance. Although we aim to reflect the most current medical knowledge, the material is meant for general education and awareness only.
The information on this site is not a substitute for professional medical advice. For any health concerns, please speak with a qualified medical professional. By using this information, you acknowledge responsibility for any decisions made and understand we are not liable for any consequences that may result.
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