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Drug Interactions between dihydrocodeine / guaifenesin / phenylephrine and Vaprisol

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

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Interactions between your drugs

Moderate

dihydrocodeine conivaptan

Applies to: dihydrocodeine / guaifenesin / phenylephrine and Vaprisol (conivaptan)

MONITOR: Coadministration with conivaptan may increase the plasma concentrations of drugs that are substrates of the CYP450 3A4 isoenzyme. The mechanism is decreased clearance due to inhibition of CYP450 3A4 activity by conivaptan. In pharmacokinetic studies with drugs that are primarily metabolized by CYP450 3A4 such as midazolam, simvastatin, and amlodipine, conivaptan has increased systemic exposure (AUC) by 2- to 3-fold.

MANAGEMENT: Caution is advised if conivaptan must be used concurrently with medications that undergo metabolism by CYP450 3A4, particularly those with a narrow therapeutic range. Dosage adjustments as well as clinical and laboratory monitoring may be appropriate for some drugs whenever conivaptan is added to or withdrawn from therapy, or the combination avoided altogether. If a clinical decision is made to discontinue concomitant medications at recommended doses, clinicians should allow an appropriate amount of time following the end of conivaptan administration before resuming these medications.

References

  1. (2006) "Product Information. Vaprisol (conivaptan)." Cumberland Pharmaceuticals Inc

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Drug and food interactions

Moderate

phenylephrine food

Applies to: dihydrocodeine / guaifenesin / phenylephrine

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

  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
View all 7 references

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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.