Product Information
Registration Status: ActiveRITALIN SR TABLET 20mg is approved to be sold in Singapore with effective from 2000-01-06. It is marketed by NOVARTIS (SINGAPORE) PTE LTD, with the registration number of SIN11335P.
This product contains Methylphenidate 20mg in the form of TABLET, FILM-COATED. It is approved for ORAL use.
This product is manufactured by PATHEON WHITBY INC in CANADA.
It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.
Description
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.
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.
Mechanism of Action
Methylphenidate blocks dopamine uptake in central adrenergic neurons by blocking dopamine transport or carrier proteins. Methylphenidate acts at the brain stem arousal system and the cerebral cortex and causes increased sympathomimetic activity in the central nervous system. Alteration of serotonergic pathways via changes in dopamine transport may result.
Pharmacokinetics
- Absorption
- Readily absorbed in a biphasic manner when orally administered (tablets) to children diagnosed with ADHD and to healthy adults. In children and adults males, after administration of a single oral dose of Ritalin LA and Ritalin given in two doses 4 hours apart, peak plasma concentration is reached approximately 2 hours for the first phase and 5-6 hours for the second phase. The absolute oral bioavailability of methylphenidate in children was 22±8% for d-methylphenidate and 5±3% for l-methylphenidate. These low values suggest that methylphenidate is highly metabolized presystemically.
- Distribution
- d-methylphenidate = 2.65 L/kg; l-methylphenidate = 1.80 L/kg;
- Metabolism
- Methylphenidate is hepatically metabolized. More specifically, it is rapidly and extensively metabolized by carboxylesterase CES1A1. Via this enzyme, methylphenidate undergoes de-esterification to ritalinic acid (a-phenyl-2-piperidine acetic acid, PPAA), which has little to no pharmacologic activity.
- Elimination
Clearance
Systemic clearance for Ritalin LA and Ritalin tablets is as follows: d-methylphenidate= 0.40±0.12 L/h/kg; l-methylphenidate = 0.73±0.28 L/h/kg;
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)
Active Ingredient/Synonyms
Methyl phenidylacetate | methyl phenyl(piperidin-2-yl)acetate | methyl α-phenyl-α-(2-piperidyl)acetate | methyl α-phenyl-α-2-piperidinylacetate | Methylphenidan | Methylphenidatum | Metilfenidato | MPH | α-phenyl-2-piperidineacetic acid methyl ester | Methylphenidate |
Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.