Mirtazapine causes erectile dysfunction in some men and can also affect libido and sexual performance. However, the risk is usually lower than with other antidepressants.
Mirtazapine is an antidepressant used in the treatment of depression, anxiety, panic disorder, and post-traumatic stress disorder. Although sexual effects are less frequent compared to other antidepressants, some men may experience changes in libido and erectile function during mirtazapine use.
The medication can also potentiate erectile difficulties that already existed before starting treatment with mirtazapine. This does not mean that all patients will develop sexual problems.
The response to the medication varies according to factors such as health status, presence of other diseases, use of associated medications, and individual characteristics.
Below, understand how mirtazapine causes erectile dysfunction in some cases, its interference with libido, and what are the treatments for erectile dysfunction caused by antidepressants.
Does Mirtazapine Affect Male Libido?
Mirtazapine can affect male libido in some cases, but presents lower probability of causing sexual side effects when compared to many other antidepressants.
The explanation lies in how the medication works in the brain. Traditional antidepressants tend to significantly increase serotonin levels, which helps control symptoms of depression and anxiety. However, excess of this neurotransmitter can interfere with mechanisms related to sexual desire, arousal, and orgasm.
Mirtazapine works differently. According to studies on antidepressant-induced sexual dysfunction, it does not promote excessive serotonin increase and even blocks some receptors associated with the negative effects of excess serotonin on sexual function.
In some patients, improvement of depressive and anxiety symptoms can even result in increased libido and improved sexual interest.
Sexual Desire and Neurotransmitters
Sexual desire depends on the balance between neurotransmitters, substances responsible for communication between neurons.
The dopamine and noradrenaline are associated with pleasure, motivation, energy, and sexual interest. When imbalance occurs in these systems, libido and sexual function can be affected.
Some antidepressants that cause erectile dysfunction and affect libido, such as duloxetine, work by increasing serotonin levels.
Although this mechanism is important for treating depression and anxiety, it can also reduce the activity of neurotransmitters related to sexual desire, such as dopamine.
The mechanism of action of mirtazapine reduces the activation of receptors associated with unwanted sexual effects of serotonin and increases the activity of noradrenaline.
Therefore, the incidence of sexual side effects is usually lower when compared to that observed with various serotonergic antidepressants.
Does Mirtazapine Cause Erectile Dysfunction?
Mirtazapine can cause erectile dysfunction in some users, but this is an infrequent adverse effect. It can also happen that the medication worsens erectile problems that already existed before starting mirtazapine treatment. 
Is Erectile Dysfunction Caused by Mirtazapine Reversible?
Erectile dysfunction caused by antidepressants can be reversible, and normalization of erectile function can occur in up to 8 weeks after starting treatment, although recovery varies according to the individual.
The doctor responsible for prescribing mirtazapine can adjust the dose, replace the medication, and even refer the patient to a urologist to investigate possible conditions associated with erectile dysfunction.
Why Can Antidepressants Cause Erectile Dysfunction?
Antidepressants can cause erectile dysfunction by excessively stimulating serotonin and, at the same time, reducing the activity of dopamine, a neurotransmitter associated with sexual motivation, arousal, and pleasure.
An article from the Brazilian Journal of Human Sexuality explains that antidepressants associated with erectile dysfunction excessively stimulate serotonin action in brain areas responsible for pleasure and sexual desire.
With this, some men may experience reduced sexual interest, difficulty reaching orgasm, or erectile problems.
In addition to neurochemical changes, mental health problems can decrease libido and contribute to erectile dysfunction, often making it difficult to identify whether changes in sexual function are medication side effects or the patient’s emotional state. 
Which Antidepressants Most Affect Sexual Health?
| Antidepressant | Class | Impact on Libido | Risk of Erectile Dysfunction | Main Characteristics |
|---|---|---|---|---|
| Sertraline | SSRI | High | High | Can reduce libido, impair erection, and delay orgasm. |
| Fluoxetine | SSRI | Medium/High | Medium | Associated with reduced sexual desire and difficulty reaching orgasm. |
| Escitalopram | SSRI | Medium | Medium | Usually more tolerable, but can still affect sexual function. |
| Mirtazapine | Tetracyclic Antidepressant | Low | Low | Lower risk of sexual effects, can be an alternative to SSRIs. |
Treatments for Erectile Dysfunction Related to Antidepressants
Treatment of erectile dysfunction related to antidepressant use varies according to symptom intensity, medication used, and patient’s emotional conditions, and can include erectile medications, hormonal evaluation, and adjustments in depression treatment.
Erectile Medications
Medications such as Sildenafil, Tadalafil, and Vardenafil can improve erection because they increase blood circulation to the penis, a fundamental mechanism for erectile function.
Hormonal Evaluation
Hormonal evaluation is important to diagnose possible hormonal changes. This evaluation can be done through tests such as:
- total and free testosterone;
- prolactin measurement;
- TSH;
- thyroid hormones.
Related: 15 tests for a complete male check-up
Therapeutic Changes
The psychiatrist responsible for prescribing the antidepressant can reduce the dose, replace the medication, or associate other medications to minimize sexual side effects.
When to See a Urologist?
A man should see a urologist if erectile difficulty does not improve after one month of medication use, if he already had erectile dysfunction and noticed worsening of the condition, or if he has risk factors such as sedentary lifestyle, obesity, smoking, high blood pressure, and diabetes.
Fill out the pre-analysis form to schedule your consultation with Dr. Paulo Egydio, a urologist specializing in erectile dysfunction treatments.
