Cyproheptadine is an antihistamine, although it also acts as an anticholinergic and local anesthetic.It works by displacing neurotransmitters on several types of nerve receptors.
It is usually used to treat allergies, but is also used to treat nightmares caused by post-traumatic stress disorder, serotonin syndrome, migraine and anorexia.
Side effects are typical of antihistamines and include drowsiness and dizziness.