| Item |
Information |
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Drug Groups
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approved; investigational |
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Description
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A central nervous system stimulant used most commonly in the treatment of attention-deficit disorders in children and for narcolepsy. Its mechanisms appear to be similar to those of dextroamphetamine. [PubChem] |
| Indication |
For use as an integral part of a total treatment program which typically includes other remedial measures (psychological, educational, social) for a stabilizing effect in children with a behavioral syndrome characterized by the following group of developmentally inappropriate symptoms: moderate-to-severe distractibility, short attention span, hyperactivity, emotional lability, and impulsivity. |
| Pharmacology |
Methylphenidate is a central nervous system stimulant used most commonly in the treatment of attention-deficit disorders in children and for narcolepsy. Its mechanisms appear to be similar to those of dextroamphetamine. |
| Toxicity |
Symptoms of overdose include vomiting, agitation, tremors, hyperreflexia, muscle twitching, convulsions (may be followed by coma), euphoria, confusion, hallucinations, delirium, sweating, flushing, headache, hyperpyrexia, tachycardia, palpitations, cardiac arrhythmias, hypertension, mydriasis, and dryness of mucous membranes. LD50=190mg/kg (orally in mice) |
| Affected Organisms |
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Humans and other mammals |
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| Biotransformation |
Hepatic, methylphenidate is metabolized primarily by de-esterification to ritalinic acid (α-phenyl-2-piperidine acetic acid, PPAA), which has little to no pharmacologic activity. |
| Absorption |
Readily absorbed in a biphasic manner. It reaches peak absorption at approximately two hours for the first phase and five hours for the second phase. Bioavailability is low (approximately 30%) |
| Half Life |
2.4 hours in children and 2.1 hours in adults |
| Protein Binding |
Low (approximately 15%) |
| References |
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Keating GM, McClellan K, Jarvis B: Methylphenidate (OROS formulation). CNS Drugs. 2001;15(6):495-500; discussion 501-3.
[Pubmed]
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Markowitz JS, DeVane CL, Pestreich LK, Patrick KS, Muniz R: A comprehensive in vitro screening of d-, l-, and dl-threo-methylphenidate: an exploratory study. J Child Adolesc Psychopharmacol. 2006 Dec;16(6):687-98.
[Pubmed]
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Fone KC, Nutt DJ: Stimulants: use and abuse in the treatment of attention deficit hyperactivity disorder. Curr Opin Pharmacol. 2005 Feb;5(1):87-93.
[Pubmed]
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Sharma RP, Javaid JI, Pandey GN, Easton M, Davis JM: Pharmacological effects of methylphenidate on plasma homovanillic acid and growth hormone. Psychiatry Res. 1990 Apr;32(1):9-17.
[Pubmed]
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Shults T, Kownacki AA, Woods WE, Valentine R, Dougherty J, Tobin T: Pharmacokinetics and behavioral effects of methylphenidate in Thoroughbred horses. Am J Vet Res. 1981 May;42(5):722-6.
[Pubmed]
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