We are not confident that cross-over studies are appropriate for this participant group as they are best for conditions that are stable and for interventions with no physiological and psychological carry-over. Sildenafil may be a useful option in the treatment of antipsychotic-induced sexual dysfunction in men with schizophrenia, but this conclusion is based only on one small short trial. Switching to olanzapine may improve sexual functioning in men and women, but the trial assessing this was a small, open label trial. Further well designed randomised control trials that are blinded and well conducted and reported, which investigate the effects of dose reduction, drug holidays, symptomatic therapy and switching antipsychotic on sexual function in people with antipsychotic-induced sexual dysfunction are urgently needed.
Sildenafil in the treatment of antipsychotic-induced erectile dysfunction: a randomized, double-blind, placebo-controlled, flexible-dose, two-way crossover trial.
Antipsychotic-induced erectile dysfunction is a significant clinical problem and is a common reason for poor medication compliance. This report studied the efficacy and tolerability of sildenafil citrate in patients with antipsychotic-induced erectile dysfunction.
                The study design was a randomized, double-blind, placebo-controlled, flexible-dose, two-way crossover trial carried out at a tertiary referral center. Thirty-two married male outpatients with schizophrenia or delusional disorder and antipsychotic-induced erectile dysfunction were recruited for the trial. Sexual function was assessed from patient logs of sexual activity.
                Thirty-two subjects and their spouses, who agreed to take part in the study, were included in the crossover trial. Thirty-one (96.9%) completed the trial. There was no significant period effect or treatment-period interaction. Patients reported significant improvement while taking sildenafil in the number of adequate erections, satisfaction with sexual intercourse, and the duration of erections over 2 weeks. The odds ratios for adequate erections and for satisfactory sexual intercourse with sildenafil were 4.07 and 3.77, respectively. The effect of sildenafil remained significant even after adjustment for period and week effects and treatment-period interaction with Poisson regression analysis. There were no major side effects or adverse drug interactions.
                Sildenafil citrate is safe and effective in the treatment of antipsychotic-induced erectile dysfunction. It is also well tolerated.