There is no evidence of any significant drug interactions with Propecia. Clinically established interactions between Propecia and other drugs are of no special importance.
Medicines that have been tested with Finasteride include: antipyrine, digoxin, propranolol, theophylline, and warfarin. No important drug interactions were observed.
Finasteride has been used concomitantly with other medicines commonly used by patients for headaches, hypertension, pain and other purposes.
However, it is recommended to avoid certain drugs with Finasteride. The list of these drugs includes: acetaminophen, acetylsalicylic acid, α-blockers, analgesics, angiotensin-converting enzyme (ACE) inhibitors, anticonvulsants, benzodiazepines, beta blockers, calcium-channel blockers, cardiac nitrates, diuretics, H2 antagonists, HMG-CoA reductase inhibitors, prostaglandin synthetase inhibitors.
Before using Finasteride it is recommended to clarify if the medicine, you currently use, may interact with Propecia.