Which medications are safe to take before mastectomy surgery?

Varies. This is best covered at your anesthesia preop interview. Usually, pain meds are ok except for nsaids like ibuprofen. Antacids are good, though do not eat Tums (calcium carbonate) while fasting as this counts as food. BP meds generally ok, especially beta blockers like metoprolol. Long-acting Insulin held or reduced, short-acting held. It really should be spelled out for you exactly before your surgery.
ALLhavetobe reviewed. The safe answer none all meds over the counter and rx have to be reviewed with your surgeon or the preop. Anesthesia team... Certain anticoagulants have to stopped in advance -- aspirin, plavix, coumadin, (warfarin) Lovenox . But you just can't stop them on your own - some have to be bridged before surgery to something faster acting /and leaving ie. Heparin or you may clot a heart valve/pe/ stroke.