Generic Periactin contains an allergy drug called cyproheptadine, which has been found to be highly effective when it comes to treating allergies. It is safe to use Generic Periactin 4mg tablets after talking to your medical provider. PharmaExpressRx is an online pharmacy that looks after meeting the pharmacy needs of people at a cheaper price. Generic Periactin is indeed worth buying from PharmaExpressRx because you get it at a very affordable price. Plus, the store offers free bonus pills on every purchase.