THE EXTENSIVE USE of phenothiazine drugs in the treatment of emotional disorders and their usefulness in such areas as anesthesiology, obstetrics, geriatrics, and neurology make a knowledge of their side effects, and the treatment of these, important. The most common side effects are of a neurological nature, namely, extrapyramidal effects. An incidence of almost 40% of such drug-induced reactions was reported in a series of several thousand patients being treated with phenothiazines for emotional disturbances. Some of the factors which may play a role relative to this sensitivity are gradually being outlined. Numerous clinical investigations have demonstrated that the drug-induced extrapyramidal-like syndromes are only different from those clinically seen following naturally occurring diseases, such as paralysis agitans ( parkinsonism ) and postencephalitic varieties of basal ganglia disturbances, in that the drug-induced reactions are generally considerd reversible and respond readily to treatment with antiparkinsonian drugs.
The recognition and the careful evaluation
Carlos Medina, Morton D. Kramer, Albert A. Kurland. Biperiden in the Treatment of Phenothiazine-Induced Extrapyramidal Reactions. JAMA. 1962;182(11):1127–1129. doi:10.1001/jama.1962.03050500059015d