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Drug Interactions between phenobarbital and Quillivant XR

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Minor

PHENobarbital methylphenidate

Applies to: phenobarbital and Quillivant XR (methylphenidate)

According to the manufacturer, methylphenidate may inhibit the metabolism of anticonvulsants including phenobarbital, phenytoin, and primidone. There have been only isolated case reports of phenytoin intoxication during coadministration with methylphenidate and none for the other anticonvulsants. Moreover, two studies found little or no effect of methylphenidate on plasma phenytoin concentrations. Thus, available evidence does not seem to support a clinically significant drug interaction. Nevertheless, it may be appropriate to monitor the pharmacologic response to these anticonvulsants more closely whenever methylphenidate (racemic) or dexmethylphenidate (the more pharmacologically active d-enantiomer) is added to or withdrawn from therapy, and the anticonvulsant dosage adjusted as necessary.

References (6)
  1. Kupferberg HJ, Jeffery W, Hunninghake DB (1972) "Effect of methylphenidate on plasma anticonvulsant levels." Clin Pharmacol Ther, 13, p. 201-4
  2. Garrettson LK, Perel JM, Dayton PG (1969) "Methylphenidate interaction with both anticonvulsants and ethyl biscoumacetate." JAMA, 207, p. 1053-6
  3. Mirkin BL, Wright F (1971) "Drug interactions: effect of methylphenidate on the disposition of diphenylhydantoin in man." Neurology, 21, p. 1123-8
  4. Ghofrani M (1988) "Possible phenytoin-methylphenidate interaction." Dev Med Child Neurol, 30, p. 267
  5. (2001) "Product Information. Ritalin (methylphenidate)." Novartis Pharmaceuticals
  6. (2001) "Product Information. Focalin (dexmethylphenidate)." Mikart Inc

Drug and food interactions

Major

PHENobarbital food

Applies to: phenobarbital

GENERALLY AVOID: Concurrent acute use of barbiturates and ethanol may result in additive CNS effects, including impaired coordination, sedation, and death. Tolerance of these agents may occur with chronic use. The mechanism is related to inhibition of microsomal enzymes acutely and induction of hepatic microsomal enzymes chronically.

MANAGEMENT: The combination of ethanol and barbiturates should be avoided.

References (5)
  1. Gupta RC, Kofoed J (1966) "Toxological statistics for barbiturates, other sedatives, and tranquilizers in Ontario: a 10-year survey." Can Med Assoc J, 94, p. 863-5
  2. Misra PS, Lefevre A, Ishii H, Rubin E, Lieber CS (1971) "Increase of ethanol, meprobamate and pentobarbital metabolism after chronic ethanol administration in man and in rats." Am J Med, 51, p. 346-51
  3. Saario I, Linnoila M (1976) "Effect of subacute treatment with hypnotics, alone or in combination with alcohol, on psychomotor skills related to driving." Acta Pharmacol Toxicol (Copenh), 38, p. 382-92
  4. Stead AH, Moffat AC (1983) "Quantification of the interaction between barbiturates and alcohol and interpretation of fatal blood concentrations." Hum Toxicol, 2, p. 5-14
  5. Seixas FA (1979) "Drug/alcohol interactions: avert potential dangers." Geriatrics, 34, p. 89-102
Moderate

methylphenidate food

Applies to: Quillivant XR (methylphenidate)

GENERALLY AVOID: Alcohol may exacerbate the adverse central nervous system effects of psychoactive drugs, including methylphenidate.

GENERALLY AVOID: Consumption of alcohol while taking certain sustained-release formulations of methylphenidate may cause rapid release of the drug, resulting in increased systemic levels of methylphenidate. In vitro studies have been conducted using Metadate CD 60 mg and Ritalin LA 40 mg capsules, as well as Concerta 18 mg tablet. At an alcohol concentration of 40%, an increase in the release rate of methylphenidate was observed in the first hour for Metadate CD and Ritalin LA, resulting in 84% and 98% of the methylphenidate being released, respectively. In contrast, there was no increased release of methylphenidate in the first hour for Concerta. These results are considered to be representative of the other available strengths of the corresponding product.

MANAGEMENT: Patients treated with methylphenidate should be advised to avoid alcohol or medications that contain alcohol.

References (3)
  1. (2022) "Product Information. Metadate CD (methylphenidate)." Celltech Pharmaceuticals Inc
  2. (2002) "Product Information. Concerta (methylphenidate)." Alza
  3. (2013) "Product Information. Ritalin LA (methylphenidate)." Quality Care Products/Lake Erie Medical

Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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