ABSTRACT
Long-term adverse effects of sildenafil citrate [Viagra] have not been properly assessed. Consequently, this study aimed at evaluating the long-term alterations in different organs according to the dose and frequency of administration. To fulfill this aim, [132] male Wistar albino rats were studied for [18] weeks, and divided into [5]groups. Group [1] [n[=]12]: is the negative control group, Group [2] [n=12]: received distilled water; Group [3] [n=36]: received sildenafil [0.002 mg/g] and was subdivided into [3] subgroups: [a] received the dose daily=[b] received it day after day-[c] received it once weekly; Group [4] [n=36]; received sildenafil [0.004 mg/g] and was subdivided into [3] subgroups as group [3]; Group [5] n=36]; received sildenafil [0.008 mg/g] and was subdivided into 3 subgroups as groups [3] and [4]. Histological esamination of brain, retina, heart, lung, liver, kidney, prostate, seminal vesicles, epididymis and testis was performed using light microscopy for all the aforementioned organs. It was concluded that the testis and epididymis were the most affected organs. The retina then follows with disintegration of photoreceptors. The brain also showed congestion and increased astrocytic activity. As for the heart, it showed disarray and edema; while the lungs showed thickening of alveolar walls. The liver showed histological alterations, while the kidneys did not. All these histo-pathological alterations were observed to be dose-dependent and directly correlated to the frequency of sildenafil administration