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Drug Interactions between metyrosine and Promethazine VC Plain

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

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Interactions between your drugs

Moderate

metyroSINE promethazine

Applies to: metyrosine and Promethazine VC Plain (phenylephrine / promethazine)

MONITOR: Coadministration of metyrosine in combination with haloperidol, phenothiazines, or other dopamine antagonists may increase the risk of extrapyramidal disorders. Extrapyramidal effects have been reported during metyrosine therapy. The mechanism is inhibition of catecholamine synthesis by metyrosine. In addition, sedative effects of both drugs may be increased.

MANAGEMENT: When concurrent use is required, patients should be monitored for extrapyramidal symptoms and instructed to notify their physician if they experience symptoms such as bradykinesia, hypertonia, rigidity, restlessness, and dysphagia. Patients should also avoid driving or operating hazardous machinery until they know how the medications affect them.

References (1)
  1. (2001) "Product Information. Demser (metyrosine)." Merck & Co., Inc

Drug and food interactions

Moderate

metyroSINE food

Applies to: metyrosine

MONITOR: Metyrosine, when coadministered with other CNS depressants including alcoholic beverages, may lead to excessive somnolence and other forms of nervous system depression.

MANAGEMENT: The patient should be informed to use caution if these agents are coadministered, especially if performing hazardous tasks such as driving or operating machinery.

References (1)
  1. (2001) "Product Information. Demser (metyrosine)." Merck & Co., Inc
Moderate

promethazine food

Applies to: Promethazine VC Plain (phenylephrine / promethazine)

GENERALLY AVOID: Concurrent use of ethanol and phenothiazines may result in additive CNS depression and psychomotor impairment. Also, ethanol may precipitate dystonic reactions in patients who are taking phenothiazines. The two drugs probably act on different sites in the brain, although the exact mechanism of the interaction is not known.

MANAGEMENT: Patients should be advised to avoid alcohol during phenothiazine therapy.

References (2)
  1. Lutz EG (1976) "Neuroleptic-induced akathisia and dystonia triggered by alcohol." JAMA, 236, p. 2422-3
  2. Freed E (1981) "Alcohol-triggered-neuroleptic-induced tremor, rigidity and dystonia." Med J Aust, 2, p. 44-5
Moderate

phenylephrine food

Applies to: Promethazine VC Plain (phenylephrine / promethazine)

MONITOR: Coadministration of two or more sympathomimetic agents may increase the risk of adverse effects such as nervousness, irritability, and increased heart rate. Central nervous system (CNS) stimulants, particularly amphetamines, can potentiate the adrenergic response to vasopressors and other sympathomimetic agents. Additive increases in blood pressure and heart rate may occur due to enhanced peripheral sympathetic activity.

MANAGEMENT: Caution is advised if two or more sympathomimetic agents are coadministered. Pulse and blood pressure should be closely monitored.

References (7)
  1. Rosenblatt JE, Lake CR, van Kammen DP, Ziegler MG, Bunney WE Jr (1979) "Interactions of amphetamine, pimozide, and lithium on plasma norepineophrine and dopamine-beta-hydroxylase in schizophrenic patients." Psychiatry Res, 1, p. 45-52
  2. Cavanaugh JH, Griffith JD, Oates JA (1970) "Effect of amphetamine on the pressor response to tyramine: formation of p-hydroxynorephedrine from amphetamine in man." Clin Pharmacol Ther, 11, p. 656
  3. (2001) "Product Information. Adderall (amphetamine-dextroamphetamine)." Shire Richwood Pharmaceutical Company Inc
  4. (2001) "Product Information. Tenuate (diethylpropion)." Aventis Pharmaceuticals
  5. (2001) "Product Information. Sanorex (mazindol)." Novartis Pharmaceuticals
  6. (2001) "Product Information. Focalin (dexmethylphenidate)." Mikart Inc
  7. (2002) "Product Information. Strattera (atomoxetine)." Lilly, Eli and Company

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.

See also

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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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