Intramuscular anticholinergics are the treatment of choice for ADRs. Benztropine 2 mg or diphenhydramine 50–100 mg generally will produce complete resolution within 20–30 minutes, with a second dose repeated after 30 minutes if there is not a complete recovery. Benztropine has been shown to resolve ADRs in less time than diphenhydramine (Lee 1979). Starting a standing dose of an antiparkinsonian agent afterward is generally not necessary. ADRs do not recur, unless large doses of high-potency antipsychotics are being used or unless the dose is increased. A more complete discussion of prophylaxis is given below.