Methylphinidate, un stimulant psychomoteur a faible action sympathomime'tique, supprime completement la spasticite' musculaire ct le tremblement, qui peuvent se manifester au cours du rttablissement d'une anesthesie a liialothane. Lcs auteurs croient que la spasticuS est due au re'tablissement de l'activirf spinale reftexe, qui precede celfc dcs neurones moteurs supirieurs, de l'inhibitkm par l...

Self administered questionnaires completed by 69 out of 100 consecutive drug addicts attending two drug dependence clinics suggested that some private general practitioners were easily persuaded to prescribe controlled drugs. These drugs were usually methadone, dipipanone-cyclizine (Diconal), and methylphenidate (Ritalin). Numbers of new narcotic addicts notified to the Home Office confirmed th...

Methylphenidate (MP) (Ritalin) is widely used for the treatment of attention deficit hyperactivity disorder (ADHD). It is a chiral drug, marketed as the racemic mixture of d- and l-threo enantiomers. Our previous studies (PET and microdialysis) in humans, baboons, and rats confirm the notion that pharmacological specificity of MP resides predominantly in the d-isomer. A recent report that intra...

Previous observations have indicated lamellated ultrastructural lesions in the myocardium of a patient treated with methylphenidate (Ritalin) hydrochloride (MPH). A causal relationship between MPH exposure and these membranous changes was tested in the myocardium of rats and mice. Following injection of varying doses of MPH for different periods, myocardial ultrastructure was examined and lesio...

We describe a "high performance" liquid chromatographic method for quantitating methylphenidate in serum. The internal standard, 4,5-diphenylimidazole, and serum or plasma sample are extracted in chloroform, evaporated, and redissolved in 20 mmol/L potassium phosphate (pH 3.5)/high-purity acetonitrile, 80/20 by vol. A centrifuged aliquot is chromatographed on mu-Bondapak C-18 with the phosphat...

Methylphenidate, a psychomotor stimulant with a weak sympathomimetic action, completely suppresses the muscular spasticity and tremor which may occur during the recovery from halothane anaesthesia. It is suggested that the spasticity is due to the recovery of spinal reflex activity before the upper motor neurones have recovered from the inhibition of anaesthesia and that methylphenidate acts by...

Despite a growing interest in the use of methylphenidate (Ritalin) to treat attention deficit/hyperactivity disorders, prevalence data has been scarce in Canada. A probability school survey conducted in 1997 among Ontario students in grades 7, 9, 11 and 13 is used to collect data on such use. Overall, 3.4% of students (5.3% of males, 1.7% of females) used methylphenidate in the previous year. R...