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 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.
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