Are your medicines disrupting your sex life?

Reviewed by Dr John Dean, specialist in sexual medicine

Many medicines can have an adverse effect on your sex life.

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

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.

Prescribed medicines	Main use	Possible effect on sexual function
Antidepressants	.	.
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	.	.
Carbamazepine	Epilepsy	Impotence
Antihypertensives	.	.
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	.	.
Phenothiazines (eg chlorpromazine, thioridazine)	Psychotic illness	Ejaculatory disturbances, decreased sex drive, impotence
Risperidone	Psychotic illness	Impotence, ejaculatory disturbances
Cholesterol lowering medicines	.	.
Fibrates (eg clofibrate, gemfibrozil)	High cholesterol	Impotence
Statins (eg simvastatin)	High cholesterol	Impotence
Other	.	.
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
Propantheline	Gut spasm	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.

References
Drug-induced sexual dysfunction and infertility. Pharmaceutical Journal 1999; 262(7047): 780-784.

Impotence and lipid lowering drugs. Pharmaceutical Journal 2000; 264 (7089): 460.

Wagner G, Saenz de Tejada I. Update on male erectile dysfunction. BMJ 1998; 316: 678-682.

Based on a text by Helen Marshall, pharmacist

Last updated 08.12.2010

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