PDE5 Inhibitors: Do they have a Role in Treating Female Sexual Dysfunction?
Until recent years therapeutic approaches to female sexual dysfunction (FSD) have relied mainly on cognitive behavioural sex therapy, couple counselling and psychotherapy. The success of the phosphodiesterase type 5 (PDE5) inhibitors in the treatment of erectile dysfunction in men prompted the notion that there may be a similar role for these drugs in thetreatment of female sexual dysfunction.
Triggers of sexual dysfunction in women can be biological, psychological and interpersonal. To be optimally effective, drug therapy should ideally be combined with education and appropriate counselling. During the arousal phase in women blood flow into the genitals increases under the influence of vasoactive chemicals and their second messengers including cyclic guanosine monophosphate.
In women this leads to vasocongestion and engorgement of the clitoris and vagina, the production of a lubricating transudate from the vaginal epithelium and relaxation of vaginal smooth muscle. It was hypothesized that PDE5 inhibitors may have a role in treating FSD and studies assessed a range of parameters such as desire, arousal, lubrication, orgasms and pain in response to treatment. It is not surprising that trial results did not live up to expectations. While PDE5 inhibitor-increased blood flow creates improved erections for men, it does not contribute to male sexual desire, orgasm or pleasure.
In women these peripherally-acting drugs might be expected to increase lubrication and swelling but not to effect the subjective experience of arousal, or of pleasure nor levels of sexual desire which all are central nervous system processes. While the power and quality of some trials in this area were less than adequate, the consensus of opinion at this stage is that there is not enough evidence to recommend PDE5 inhibitors as a standard treatment option in FSD.
