Ritalin (methylphenidate): clinical experiences.

METHYLPHENIDATE is a white, water-soluble crystalline compound. It is a piperidine derivative which can be administered orally, subcutaneously, intramuscularly or intravenously and is marketed under the name of "Ritalin" by Ciba Pharmaceuticals. It is a behaviour-alteirmg drug which is often included in the classification of tranquillizer or ataractic compounds (9). In contradistinction to the tranquillizers, however, its mam pharmacologic action is stimulation of the mesencephalic reticular formations and accentuation of the arousal or alerting mechanism (8) This psychic stimulation of Ritalin has interested many investigators and it has been uthzed to counteract barbiturate depression (1), "(5), (6), (7), barbiturate (7) and non-barbiturate (3) poisoning and chlorpromazine (1), (4) and rauwolfia (2), (4) lethargy in psychiatric patients. Gale (6) measured the effect of Ritalin on the recovery time of 272 patients who had a utdrme dilatation and curettage performed under light pentothal and nitrous oxide anaesthesia. He reported that the optimum dose appeared to be between 0.1 and 0 2 mg /lb. This dosage was effective in shortening the recovery time to about one-half as compared to the controls. In a subsequent publication (5), he reaffirmed the above findings and suggested that dosages above 0.1 to 0.2 mg./lb. are less effective. He noted a mild transient rise in blood pressure, and occasional nausea and retchmg and -emesis as the only side-effects of Ritalin therapy. He was favourably impressed with the effects of Ritalin on barbitaateinduced depression in the newborn infant. Carter and Malley (1) studied the effects of Ritalin in 12§ mentally retarded or brain-damaged patients who were classified mto the following categories: (1) shock from chlorpromazine overdosage, (over 300 mg. T.I.D. for several days); (2) barbiturate poisoning and barbiturate anaesthesia, (3) moribund states such as severe pneumonia. They report beneficial results m all of these categories and mentioned that chlorpromazine overdosage responded more slpwly and required higher doses of Ritalin. Their dosage ranged from 20 to 55 mg. intramuscularly and intravenously, repeated as often as every 20 mm. to every 4 hrs. Ferguson (2) administered 20 to 40 mg. of Ritalin orally to depressed psychiatric patients. He inferred that its main action was possibly in the thalamic area