Medikinet Drug Interactions

Pharmacokinetic interaction: It is not known how methylphenidate may effect plasma concentrations of concomitantly administered drugs. Therefore, caution is recommended at combining methylphenidate with other drugs, especially those with a narrow therapeutic window.
Methylphenidate is not metabolised by cytochrome P450 to a clinically relevant extent. Inducers or inhibitors of cytochrome P450 are not expected to have any relevant impact on methylphenidate pharmacokinetics. Conversely, the d- and l-enantiomers of methylphenidate do not relevantly inhibit cytochrome P450 1A2, 2C8, 2C9, 2C19, 2D6, 2E1, or 3A.
However, there are reports indicating that methylphenidate may inhibit the metabolism of coumarin anticoagulants, anticonvulsants (e.g. phenobarbital, phenytoin, primidone), phenylbutazone and some antidepressants (tricyclics and selective serotonin reuptake inhibitors). When starting or stopping treatment with methylphenidate, it may be necessary to adjust the dosage of these drugs already being taken and establish drug plasma concentrations (or for coumarin, coagulation times).
Pharmacodynamic interactions: Anti-hypertensive drugs: Methylphenidate may decrease the effectiveness of drugs used to treat hypertension.
Use with drugs that elevate blood pressure: Caution is advised in patients being treated with methylphenidate with any other drug that can also elevate blood pressure (see also Cardiovascular and Cerebrovascular Conditions under Precautions).
Because of possible hypertensive crisis, methylphenidate is contraindicated in patients being treated (currently or within the preceding 2 weeks) with non-selective, irreversible MAO inhibitors (see Contraindications).
Use with alcohol: Alcohol may exacerbate the adverse CNS effects of psychoactive drugs, including methylphenidate. It is therefore advisable for patients to abstain from alcohol during treatment.
Use with halogenated anaesthetics: There is a risk of sudden blood pressure increase during surgery. If surgery is planned, methylphenidate treatment should not be used on the day of surgery.
Use with centrally acting alpha-2 agonists (e.g. clonidine): Serious, adverse events, including sudden death, have been reported in concomitant use with clonidine. The safety of using methylphenidate in combination with clonidine or other centrally acting alpha-2 agonists has not been systematically evaluated.
Use with dopaminergic drugs: Because a predominant action of methylphenidate is to increase extracellular dopamine levels, methylphenidate may be associated with pharmacodynamic interactions when co-administered with direct and indirect dopamine agonists (including DOPA and tricyclic antidepressants) or with dopamine antagonists including antipsychotics.
The coadministration of methylphenidate with antipsychotics is not recommended because of the counteracting mechanism of action.
Use with other drugs: MEDIKINET MR must not be administered together with H₂ receptor blockers or antacids, as this may lead to an accelerated liberation of the total amount of active substance.
Drug/Laboratory Test: Methylphenidate may induce false positive laboratory tests for amphetamines, particularly with immunoassays screen test.