Many medicines are suspected of interfering with sexual function, although it is unusual for them to be the sole cause of sexual problems.
It is relatively difficult to determine whether a particular medicine is causing erectile dysfunction (impotence) or disrupting sexual function because:
- many diseases affect sexual function, so it can be difficult to establish if the dysfunction is a result of the disease or the medicine used to treat it.
- side-effects that involve sexual problems are often not reported to doctors because of embarrassment. This means the actual rate of sexual dysfunction caused by medicines may be higher than reported.
How can medicines affect sexual function?
The mechanism of sexual function is not fully understood.
It involves a complex coordination of hormones, chemical messengers in the brain (neurotransmitters such as dopamine and serotonin) and the sexual organs. In general:
- dopamine increases sexual function
- serotonin inhibits sexual function
- the hormone testosterone is important, as are the blood vessels involved in producing an erection.
A medicine can therefore affect sexual function in several ways.
Libido or sex drive
Sex drive is influenced by reproductive hormones, particularly testosterone, which is required for sexual arousal.
Medicines that reduce the testosterone level or block its effects are likely to reduce sex drive.
Libido is also affected by your general emotional and physical health. Medicines that affect any of these aspects, even indirectly by causing drowsiness, lethargy, weight gain or confusion, have the potential to reduce your sex drive.
Arousal and erection
An erection is the result of a coordination between nerves, hormones, blood vessels and psychological factors. This means there are many areas where things can go wrong.
Medicines that have a physical effect on the blood vessels in the penis, those that act on the brain or interfere with hormone levels (particularly testosterone) or affect the transmission of nerve messages, can all cause impotence.
Ejaculation is a complex reflex process that involves the activation of alpha receptors in the prostate gland and seminal vesicles.
Medicines that block alpha receptors can interfere with ejaculation.
During ejaculation, increased alpha receptor activation closes the bladder neck, facilitating the normal flow of semen out of the penis.
If this mechanism is disrupted, it results in retrograde ejaculation, with semen flowing along the path of least resistance from the urethra up into the bladder.
Various chemicals in the brain are also involved in orgasm and ejaculation, and medicines that affect these chemicals can also cause ejaculatory disturbances.
The most widely prescribed centrally-acting agents that affect ejaculation are selective serotonin re-uptake inhibitor (SSRI) antidepressants.
Medicines that can affect sexual function
Antidepressants are the medicines most frequently implicated in causing sexual dysfunction. This is because they work by altering levels of chemicals in the brain. In particular, SSRIs increase serotonin levels, which inhibits sexual function.
Blood pressure lowering (antihypertensive) medicines are also implicated, although the mechanism by which they cause sexual problems will vary from medicine to medicine.
The table of medicines below lists the sexual side effects that some people have reported during their use. This list is not exhaustive.
Remember, not everyone experiences side effects with medicines and your sexual difficulties may be completely unrelated to your medication, even if it does appear in this list.
|Antidepressants||Main use||Possible effect on sexual function|
|MAOI antidepressants (eg moclobemide, phenelzine)||Depression||Decreased sex drive, impotence, delayed orgasm, ejaculatory disturbances|
|SSRI antidepressants (eg fluoxetine)||Depression||Decreased sex drive, impotence, delayed or absent orgasm, ejaculatory disturbances|
|Tricyclic antidepressants (eg amitryptiline)||Depression||Decreased sex drive, impotence, delayed or absent orgasm, ejaculatory disturbances|
|Antiepileptics||Main use||Possible effect on sexual function|
|Antihypertensives||Main use||Possible effect on sexual function|
|ACE inhibitors (eg enalapril, lisinopril)||High blood pressure, heart failure||Impotence|
|Alpha-blockers (eg prazosin, doxazosin)||High blood pressure, enlarged prostate||Impotence, ejaculatory disturbances|
|Beta-blockers (eg atenolol, propranolol and including timolol eye drops)||High blood pressure, angina, glaucoma||Impotence|
|Calcium channel blockers (eg verapamil, nifedipine)||High blood pressure, angina||Impotence|
|Clonidine||High blood pressure||Impotence, decreased sex drive, delayed or failure of ejaculation|
|Methyldopa||High blood pressure||Impotence, decreased sex drive, ejaculatory failure|
|Thiazide diuretics (eg bendroflumethiazide)||High blood pressure||Impotence|
|Antipsychotics||Main use||Possible effect on sexual function|
|Phenothiazines (eg chlorpromazine, thioridazine)||Psychotic illness||Ejaculatory disturbances, decreased sex drive, impotence|
|Risperidone||Psychotic illness||Impotence, ejaculatory disturbances|
|Cholesterol lowering medicines||Main use||Possible effect on sexual function|
|Fibrates (eg clofibrate, gemfibrozil)||High cholesterol||Impotence|
|Statins (eg simvastatin)||High cholesterol||Impotence|
|Other||Main use||Possible effect on sexual function|
|Benzodiazepines||Anxiety and insomnia||Decreased sex drive|
|Cimetidine||Peptic ulcers, acid reflux disease||Decreased sex drive, impotence|
|Cyproterone acetate||Prostate cancer||Decreased libido, impotence, reduced volume of ejaculation|
|Disulfiram||Alcohol withdrawal||Decreased sex drive|
|Finasteride||Enlarged prostate||Impotence, decreased sex drive, ejaculation disorders, reduced volume of ejaculation|
|Metoclopramide||Nausea and vomiting||Decreased sex drive, impotence|
|Omeprazole||Peptic ulcers, acid reflux disease||Impotence|
|Opioid painkillers (eg morphine)||Severe pain||Decreased sex drive, impotence|
|Prochlorperazine||Nausea and vomiting||Impotence|
|Spironolactone||Heart failure, fluid retention||Impotence, decreased sex drive|
What if I think my medicine is affecting my sex life?
- If you are at all worried that your medicine may be affecting your ability to have sex, see your GP.
- Do not stop taking your medicine without first talking to your doctor.
- Do not be put off seeking help. Your quality of life is important, particularly if you are being treated for something like high blood pressure, which often has no symptoms and can require lifelong treatment.
What can my doctor do?
Your doctor may switch you to another medicine in the same class, ie that acts in a similar way, in the hope that the new one will not cause the same side effects.
Alternatively, your doctor may try a different type (class) of medicine altogether, providing it is suitable for you to take.
Some examples of erection-friendly medicines are listed below, but there may be no alternative for your condition.
Treatment of high blood pressure
- Impotence seems to be less of a problem with ACE inhibitors such as enalapril.
- Calcium channel blockers and alpha-blockers cause fewer sexual problems than diuretics (water tablets) or beta-blockers.
- Loop diuretics such as furosemide have a lower risk of impotence than thiazide diuretics.
Treatment of depression
- SSRIs cause the highest frequency of sexual dysfunction, followed by MAOIs (monoamine oxidase inhibitors) and then tricyclic antidepressants.
Treatment of high cholesterol levels
- Not all statins are associated with sexual problems. Even in those that are, the risk of developing such problems is very low.
- Statins may be less likely to cause impotence than fibrates.
ED medicines are not recommended in the treatment of sexual dysfunction due to other medication, unless there is no suitable alternative that can be offered to treat your condition.
This is because taking multiple medicines increases the likelihood of further side effects and drug interactions.