Anti-nociceptive and anti-inflammatory properties of 5alpha-reductase inhibitor finasteride in experimental animals.

Finasteride is a potent drug which has been prescribed for the management of benign prostatic hyperplasia (BPH) for more than 20 years. Recent studies indicate that finasteride, as 5alpha-reductase inhibitor, can influence some central effects such as analgesia, neurosteroidogeneses and behavior. The purpose of this study was to investigate the analgesic effect of finasteride, to determine whether finasteride interact with morphine analgesia in tail-flick test and to examine the anti-inflammatory effect of this drug. Adult male Wistar rats (280-330 g) were used for the both of experiments. Tests were assessed on groups of 6 animals. The first control group (O) received water (1 ml/kg, p.o.), the second control group (OO) received the vehicle (olive oil, 1 ml/kg, p.o.) and the third group (F) received finasteride (0.5 mg/kg, p.o.) suspended in olive oil, every morning for 30 days. After 30 days of treatment, tail-flick test and formalin-induced foot paw edema test were performed. Finasteride increased the average latency in seconds in comparison to both controls (10.06 vs. 9.16 and 8.66 s). It was 9.83% higher depression of pain in group F in comparison to O and 16.17% in comparison to OO, but the anti-nociceptive effect of finasteride at applied dose didn't significantly differ compared to both controls (p > 0.05). Chronic pre-treatment with finasteride didn't interact with analgesic effect of morphine compared to O (p > 0.05), but compared to OO finasteride fastened, increased and prolonged the analgesic effect of morphine at all measuring intervals, achiving statistical significance in 60 min (p < 0.01). Finasteride also exhibited significant anti-inflammatory action (p < 0.05) in comparison to OO, but It was not significantly different from the control O. Finasteride didn't exert analgesic action, it increased morphine antinociception and showed chronic anti-inflammatory effect to some extent. This might be a useful contribution to highlight the pathogenesis of BPH. There is the need for further studies in order to confirm these results with more details.