Tamfast 0.4 mg Tamsulosin Hydrochloride Finasteride
ModerateLab tests on liver enzyme preparations (the cytochrome P450 system, which the liver uses to break down medicines) found no interaction between Tamsulosin and finasteride. The same tests found none with amitriptyline, salbutamol or glibenclamide either. So in the liver, Tamsulosin does not seem to disturb how finasteride is broken down.
These medicines are often taken together with some care. Your doctor may change a dose, space them apart or check on you more often. Make sure your doctor and pharmacist know you take both.