It is very frequent to find references to sexual disorders related to the medication employed to treat psychiatric alterations, especially with antidepressant and antipsychotics, in addition the psychological alteration by itself can be the source of the dysfunction.
Psychotropic medication can produce sexual disorders through a variety of mechanisms such as:
- Non specific effects over the central nervous system, like the sedation which can lead to a general decrement in sexual interest and performance;
- Specific effects over the central nervous system which affects certain neurotransmitters leading to a diminution of the arousal phase, for instance in the case of antidopaminergic drugs which have an important incidence on the diminution of libido;
- Effects at a peripheral level which can decrease the function of a determined neurotransmitter, which is the case of the priapism produced by an alpha-androgenic blocking which impedes the detumescence due to a local vasoconstriction which never takes place.
Some medicines can share more than one mechanism of those that were mentioned and their effects over the male sexual performance can be multiple and sometimes even contradictory. It is not fully understood yet the biology of a normal sexual response, but the role performed by the neurotransmitters on the sexual response is very well known. Besides the effects related to the excitatory or inhibitory receptors can produce important incidence on sexual performance. Even the interactive effects of the different neurotransmitters can give place to indirect effects on sexual function, for instance the effects on sexual function produce by the serotonergic involvement which also affects the androgenic tone.
The dopaminergic stimulation, which can produce stimulant effects over the sexual performance, can be inhibited by the blockers at a central level; according to this the blockers like the antipsychotics can produce an erectile dysfunction. The norepinephrine plays an important role on both the erection and the ejaculation.
Basically almost all the medicines included on this group have been related to a variety of sexual disorders which include an ejaculatory dysfunction, an erectile dysfunction and a diminution of libido. The antipsychotics have dopamine blocking properties which can produce alterations and diminution of sexual desire. The sedation produced as a direct effect over the central nervous system can also contribute to the decrement of the libido.
The alpha adrenergic blocking of the sympathetic reflex is the responsible of the alterations on the ejaculation, and it also affects the penile detumescence which can give place to the emergence of the priapism. The alterations on the erection seem to emerge as a consequence of an anticholinergic blockade.
Sexual dysfunction produced by antipsychotics can effect to about twenty five percent of the patients and about to sixty percent in the case of the thioridazine which can decrease the levels of testosterone.
It is well known that sexual dysfunction related to antipsychotics affects more men than women. There are contradictory publications regarding the effects produced by the atypical antipsychotics such as the quetiapine, olanzapine, risperidone and clozapine over male sexual performance.