According to a report from Bloomberg, it cites a study that was posted onto pre-print website operated by Cold Spring Harbor Laboratory in which based on the testing of the drug on mice, it was found that the drug caused an unintended side-effect in which the sperm count on the mice was found to have been lowered.
The study claims that in the trial which involved 28 mice, it was found that sperm count and motility showed a downwards trend, along with a number of abnormalities in the sperm. Of course, how this affects humans is unclear, but obviously the lowered sperm count is definitely not something that the makers of the drug want.
In the past we have seen how some older drugs have been repurposed in the treatment of the COVID-19 virus. For example, a drug meant to treat erectile dysfunction was found to have helped patients who are in the critical stages of the infection.