Learn about Cyproheptadine (Generic Periactin), dosing, proper use and what to know before beginning treatment Cyproheptadine 4mg (Periactin generic) for cats and dogs is used as an antihistamine to treat allergy symptoms such as swelling and itching. Cyproheptadine, sold under the brand name Periactin among others, is a first-generation antihistamine with additional anticholinergic, antiserotonergic, and local anesthetic properties. It was patented in 1959 and came into medical use in 1961. Cyproheptadine is a type of drug called an antihistamine. These drugs are used to relieve allergy symptoms. Cyproheptadine overdose occurs when someone takes more than the normal or recommended amount of this medicine. Periactin is the brand name for cyproheptadine for an antihistamine that is used to treat allergic reactions, including skin reactions, by blocking histamines. It also is used to prevent migraine headaches. There are a variety of side effects of this drug, for example, itching, nausea, and vomiting. Cyproheptadine comes as a tablet and a solution (liquid) to take by mouth. It is usually taken two or three times a day. Take cyproheptadine at around the same time(s) every day. Find information about which conditions Periactin Oral is commonly used to treat. Selected from data included with permission and copyrighted by First Databank, Inc. This copyrighted material has been downloaded from a licensed data provider and is not for distribution, expect. Periactin tablets are white round bevel-edged tablets marked ‘MSD 62’ on one side with a single scoreline on the other. Periactin are supplied in blister packs of 30 tablets. What other drugs will affect Periactin (cyproheptadine)? Cold or allergy medicine, sedatives, narcotic pain medicine, sleeping pills, muscle relaxers, and medicine for seizures, depression or anxiety can add to sleepiness caused by cyproheptadine.