Dapoxetine, a drug developed for the treatment of premature ejaculation, may have a protective effect against testosterone-induced benign prostatic hyperplasia (BPH), according to study, conducted using rats, by scientists in Egypt.

The study, “Dapoxetine attenuates testosterone-induced prostatic hyperplasia in rats by the regulation of inflammatory and apoptotic proteins,” was published in the journal Toxicology and Applied Pharmacology.

Researchers led by Dr. Ayman El-Sahar, with the Department of Pharmacology and Toxicology at Cairo University, first analyzed the effect of dapoxetine on prostate weight in rats with BPH, induced by injecting a daily dose of testosterone under their skin.

The rats were then divided into four groups. The animals in the first group did not receive any other treatment, while those in the other three groups received 1 mg/kg, 5 mg/kg and 10 mg/kg of dapoxetine, respectively. The animals were then sacrificed and the weight of their prostates measured.

Results showed that there was a clear relationship between the dose of dapoxetine and the prostate weight of the animals, with prostate weight decreasing with increasing dapoxetine dose levels. However, there was no difference in prostate weight of rats treated with either 5 mg/kg or 10 mg/kg of dapoxetine. Interestingly, the 10 mg/kg and 1 mg/kg doses of dapoxetine had the same effect on relative prostate weight, which is the weight of the prostate over total body weight. Therefore, 5 mg/kg of dapoxetine was determined as the optimal dose to be used for further experiments.

Next, the researchers conducted a mechanistic analysis where rats were again divided into four groups. The animals in the first group did not receive any treatment and constituted the control group. BPH was induced in the animals in the remaining three groups, again using daily testosterone injections. Animals in the second group did not receive any other treatment, those in the third group received 5 mg/kg of dapoxetine, and those in the forth group received 5 mg/kg of finasteride, which is often used to treat BPH. The prostates of the animals were then, again, removed and weighed.

Here, results showed that testosterone injection caused prostate weight to increase by around 250%. Although neither drug was able to return the prostate to its weight prior to testosterone injection, finasteride reduced the relative prostate weight by 44% and dapoxetine by 45% in testosterone-treated rats. These findings suggest that dapoxetine might be as effective as finasteride in reducing prostate weight in testosterone-induced rats.

“However, more clinical research on this topic needs to be undertaken before the association between dapoxetine and the prevention of prostatic hyperplasia be more clearly understood and practically used,” the authors wrote.

The researchers also noted that both finasteride and dapoxetine reverted most of the changes that occurred in the body of the rats by testosterone injection, such as the expression of androgen receptor, and pathologic changes in the prostate tissue. The researchers suggested that dapoxetine might improve prostatic growth induced by testosterone by inhibiting cell proliferation and inflammation and by inducing programmed cell death.

Dapoxetine is not a U.S. Food and Drug Administration (FDA)-approved treatment for any indication, and the FDA states in a release that its safety or efficacy has not been determined.