. DRUG INTERACTIONS
Focalin XR should not be used in patients being treated (currently or within the preceding two weeks) with MAO Inhibitors [ see Contraindications (4. 5 ) ].
Because of possible effects on blood pressure, Focalin XR should be used cautiously with pressor agents.
Methylphenidate may decrease the effectiveness of drugs used to treat hypertension.
Dexmethylphenidate is metabolized primarily to d -ritalinic acid by de-esterification and not through oxidative pathways.
The effects of gastrointestinal pH alterations on the absorption of dexmethylphenidate from Focalin XR have not been studied. Since the modified release characteristics of Focalin XR are pH dependent, the coadministration of antacids or acid suppressants could alter the release of dexmethylphenidate.
Human pharmacologic studies have shown that racemic methylphenidate may inhibit the metabolism of coumarin anticoagulants, anticonvulsants (e.g., phenobarbital, phenytoin, primidone), and tricyclic drugs (e.g., imipramine, clomipramine, desipramine). Downward dose adjustments of these drugs may be required when given concomitantly with methylphenidate. It may be necessary to adjust the dosage and monitor plasma drug concentration (or, in the case of coumarin, coagulation times), when initiating or discontinuing methylphenidate.
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 systematically evaluated.
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. OVERDOSAGE
Signs and Symptoms
Signs and symptoms of acute methylphenidate overdosage, resulting principally from overstimulation of the CNS and from excessive sympathomimetic effects, may include the following: 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.
Poison Control Center
The physician may wish to consider contacting a poison control center for up-to-date information on the management of overdosage with methylphenidate.
Recommended Treatment
As with the management of all overdosage, the possibility of multiple drug ingestion should be considered.
When treating overdose, practitioners should bear in mind that there is a prolonged release of dexmethylphenidate from Focalin XR.
Treatment consists of appropriate supportive measures. The patient must be protected against self-injury and against external stimuli that would aggravate overstimulation already present. Gastric contents may be evacuated by gastric lavage as indicated. Before performing gastric lavage, control agitation and seizures if present and protect the airway. Other measures to detoxify the gut include administration of activated charcoal and a cathartic. Intensive care must be provided to maintain adequate circulation and respiratory exchange; external cooling procedures may be required for hyperpyrexia.
Efficacy of peritoneal dialysis for Focalin overdosage has not been established.
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. CONTRAINDICATIONS
Agitation
Focalin XR is contraindicated in patients with marked anxiety, tension, and agitation, since the drug may aggravate these symptoms.
Hypersensitivity to Methylphenidate
Focalin XR is contraindicated in patients known to be hypersensitive to methylphenidate, or other components of the product.
Glaucoma
Focalin XR is contraindicated in patients with glaucoma.
Tics
Focalin XR is contraindicated in patients with motor tics or with a family history or diagnosis of Tourette’s syndrome [ see Adverse Reactions (6.1) ].
Monoamine Oxidase Inhibitors
Focalin XR is contraindicated during treatment with monoamine oxidase inhibitors, and also within a minimum of 14 days following discontinuation of treatment with a monoamine oxidase inhibitor (hypertensive crises may result).
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