PMS-Methylphenidate - General Information
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]
Pharmacology of PMS-Methylphenidate
PMS-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.
PMS-Methylphenidate for patients
Ritalin should not be used in children under six years, since safety and efficacy in
this age group have not been established.
Sufficient data on safety and efficacy of long-term use of Ritalin in children are
not yet available. Although a causal relationship has not been established, suppression
of growth (i.e., weight gain, and/or height) has been reported with the long-term use of
stimulants in children. Therefore, patients requiring long-term therapy should be carefully
Ritalin should not be used for severe depression of either exogenous or endogenous origin.
Clinical experience suggests that in psychotic children, administration of Ritalin may
exacerbate symptoms of behavior disturbance and thought disorder.
Ritalin should not be used for the prevention or treatment of normal fatigue states.
There is some clinical evidence that Ritalin may lower the convulsive threshold in patients
with prior history of seizures, with prior EEG abnormalities in absence of seizures, and,
very rarely, in absence of history of seizures and no prior EEG evidence of seizures. Safe
concomitant use of anticonvulsants and Ritalin has not been established. In the presence of
seizures, the drug should be discontinued.
Use cautiously in patients with hypertension. Blood pressure should be monitored at appropriate
intervals in all patients taking Ritalin, especially those with hypertension.
Symptoms of visual disturbances have been encountered in rare cases. Difficulties with accommodation
and blurring of vision have been reported.
Usage in Pregnancy
Adequate animal reproduction studies to establish safe use of Ritalin during pregnancy have not been
conducted. However, in a recently conducted study, methylphenidate has been shown to have teratogenic
effects in rabbits when given in doses of 200 mg/kg/day, which is approximately 167 times and 78 times
the maximum recommended human dose on a mg/kg and a mg/m� basis, respectively. In rats, teratogenic
effects were not seen when the drug was given in doses of 75 mg/kg/day, which is approximately 62.5
and 13.5 times the maximum recommended human dose on a mg/kg and a mg/m� basis, respectively. Therefore,
until more information is available, Ritalin should not be prescribed for women of childbearing age
unless, in the opinion of the physician, the potential benefits outweigh the possible risks.
Ritalin may decrease the hypotensive effect of guanethidine. Use cautiously with pressor agents.
Human pharmacologic studies have shown that Ritalin may inhibit the metabolism of coumarin anticoagulants, anticonvulsants (phenobarbital, diphenylhydantoin, primidone), phenylbutazone, and tricyclic drugs (imipramine, clomipramine, desipramine). Downward dosage adjustments of these drugs may be required when given concomitantly with Ritalin.
Serious adverse events have been reported in concomitant use with clonidine, although no causality for the combination has been established. The safety of using methylphenidate in combination with clonidine or other centrally acting alpha-2 agonists has not been systemically evaluated.
Marked anxiety, tension, and agitation are contraindications to Ritalin, since the drug may aggravate these symptoms. Ritalin is contraindicated also in patients known to be hypersensitive to the drug, in patients with glaucoma, and in patients with motor tics or with a family history or diagnosis of Touretteís syndrome.
Ritalin is contraindicated during treatment with monoamine oxidase inhibitors, and also within a minimum of 14 days following discontinuation of a monoamine oxidase inhibitor (hypertensive crises may result).
Additional information about PMS-Methylphenidate
PMS-Methylphenidate 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: PMS-Methylphenidate blocks dopamine uptake in central adrenergic neurons by blocking dopamine transport or carrier proteins. PMS-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.
Drug Interactions: Carbamazepine Carbamazepine could reduce the effect of methylphendiate
Cyclosporine PMS-Methylphenidate increases the effect and toxicity of cyclosporine
Guanethidine The agent decreases the effect of guanethidine
Isocarboxazid Possible hypertensive crisis with this combination
Phenelzine Possible hypertensive crisis with this combination
Rasagiline Possible hypertensive crisis with this combination
Tranylcypromine Possible hypertensive crisis with this combination
Food Interactions: Avoid alcohol.
Take on empty stomach: 1 hour before or 2 hours after meals.
Avoid excessive quantities of coffee or tea (Caffeine).
Generic Name: Methylphenidate
Synonyms: Methyl phenidyl acetate; Methylphenidate HCl; Methylphenidate hydrochloride; Methylphenidatum [Inn-Latin]; Methylphenidylacetate hydrochloride; Metilfenidat hydrochloride; Metilfenidato [Inn-Spanish]; Metilfenidato [Italian]; Phenidylate
Drug Category: Adrenergic Agents; Adrenergic Uptake Inhibitors; Central Nervous System Stimulants; Dopamine Uptake Inhibitors; Sympathomimetics
Drug Type: Small Molecule; Approved; Investigational
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%)
Toxicity (Overdose): 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)
Protein Binding: Low (approximately 15%)
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.
Half Life: 2.4 hours in children and 2.1 hours in adults
Dosage Forms of PMS-Methylphenidate: Tablet, extended release Oral
Capsule, extended release Oral
Chemical IUPAC Name: methyl 2-phenyl-2-piperidin-2-ylacetate
Chemical Formula: C14H19NO2
Methylphenidate on Wikipedia: https://en.wikipedia.org/wiki/Methylphenidate
Organisms Affected: Humans and other mammals