Paroxetine sexual function

Fluoxetine, along with sertraline, fluvoxamine, and paroxetine, belongs to the more recently developed group of SSRI. The clinical efficacy of SSRI is considered comparable to that of established antidepressants. Added advantages include absence of cardiotoxicity, fewer autonomic nervous side effects, and relative safety with overdosage. Fluoxetine causes loss of appetite and weight reduction. Its main adverse effects include overarousal, insomnia, tremor, akathisia, anxiety, and disturbances of sexual function. 

Fluoxetine was the first SSRI to reach general clinical use. Paroxetine and sertraline differ mainly in having shorter half-lives and different potencies as inhibitors of specific P450 isoenzymes. While the SSRIs have not been shown to be more effective overall than prior drugs, they lack many of the toxicities of the tricyclic and heterocyclic antidepressants. Thus, patient acceptance has been high despite adverse effects such as nausea, decreased libido, and even decreased sexual function. 

These data suggest that antidepressant-induced sexual dysfunction is more likely to be associated with agents that greatly potentiate 5HT neurotransmission. This notion is supported by the results of a 6-week doubleblind study of 24 men with premature ejaculation, in which paroxetine (20 mg/day) increased latency to ejaculation six-fold while mirtazapine (30 mg/day) had minimal effect (4). In a randomized, 8-week, double-blind, placebo-controlled study in 450 patients with major depression, fluoxetine (20 -0 mg/day) significantly impaired sexual function, while the noradrenaline re-uptake inhibitor reboxetine had no effect (5). 

The adverse sexual effects of SSRIs have been reviewed (58). The use of SSRIs is most often associated with delayed ejaculation and absent or delayed orgasm, but reduced desire and arousal have also been reported. Estimates of the prevalence of sexual dysfunction with SSRIs vary from a small percentage to over 80%. Prospective studies that enquire specifically about sexual function have reported the highest figures. Similar sexual disturbances are seen in patients taking SSRIs for the treatment of anxiety disorders (59), showing that SSRI-induced sexual dysfunction is not limited to patients with depression. It is not clear whether the relative incidence of sexual dysfunction differs between the SSRIs, but it is possible that paroxetine carries the highest risk (58). 

Sexual function SSRIs can cause sexual dysfunction, particularly reduced libido, impaired orgasm in women, and inhibition of ejaculation or erectile difficulties in men. There have been two reports of unusual male sexual dysfunction. In two cases of spermatorrhea (excessive emission of semen without orgasm or erection) in men taking fluvoxamine, the problem resolved on drug withdrawal [IS ]. Spontaneous ejaculations occurred daily in a 27-year-old man after he had taken citalopram for 2 weeks [16 ]. They were unrelated to sexual fantasies, arousal, erection, or any sensation of orgasm and resolved on drug withdrawal. They did not recur when he took paroxetine. 

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