Periactin 4mg tablets contain Cyproheptadine HCl, an antihistamine medication used to treat allergic reactions, itching, and other conditions as prescribed by healthcare providers. Each pack contains 20 tablets manufactured by Algorithm. Each tablet contains 4mg of Cyproheptadine HCl as the active ingredient. The medication comes in a white box with red and blue branding. The product code A6774 is printed on the packaging. As this is a prescription medication, it should only be taken under medical supervision and according to the prescribed dosage. Store in a cool, dry place away from direct sunlight.