Effects of losartan on the sexual behavior of male rats

Many commonly used antihypertensive drugs such as diuretics and beta-blockers can interfere with sexual function in both sexes, causing loss of libido, impairment of erectile function and ejaculation in men, and delay or prevent orgasm in women. Newly developed antihypertensive drugs should ideally not interfere with the patients' quality of life including sexual function. This study examined the effects of losartan, a nonpeptide, specific antagonist for type I angiotensin II receptors, on the male sexual behavior of rats. Spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto (WKY) rats were treated with losartan 30 mg/kg/day or saline control for 7, 30 and 90 days. Dark-cycle video recording was used to analyze the male sexual activities of the rats. No significant alteration in male sexual performance was observed after 7 and 30 days of treatment with losartan. In contrast, SHRs treated with propranolol 5 mg/kg/day showed increases in intromission latency, ejaculation latency and postejaculatory period indicating decreased libido and erectile and ejaculatory function. Upon completion of 90 days of losartan administration, the mount latency of the SHR was significantly increased, suggesting a decrease in libido although other parameters were unchanged and there was no effect in WKY rats. It is therefore concluded that losartan may have an advantage in preservation of sexual function when used clinically for the treatment of hypertensive disorders.