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Drug Interactions between Terbinex and Tussgen Expectorant

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

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Interactions between your drugs

Moderate

HYDROcodone terbinafine

Applies to: Tussgen Expectorant (guaifenesin / hydrocodone / pseudoephedrine) and Terbinex (terbinafine)

MONITOR: Coadministration with terbinafine may increase the plasma concentrations of drugs that are substrates of the CYP450 2D6 isoenzyme. The mechanism is decreased clearance due to inhibition of CYP450 2D6 activity by terbinafine, which is expected to occur in patients who are CYP450 2D6 extensive metabolizers (approximately 93% of Caucasians and more than 98% of Asians and individuals of African descent). A case of nortriptyline (a CYP450 2D6 substrate) intoxication corresponding to significantly increased serum drug concentrations was reported in a patient shortly after the addition of terbinafine. Rechallenge in the patient produced similar results.

MANAGEMENT: Caution is advised if terbinafine must be used concurrently with medications that undergo metabolism by CYP450 2D6, particularly those with a narrow therapeutic range. Dosage adjustments as well as clinical and laboratory monitoring may be appropriate for some drugs whenever terbinafine is added to or withdrawn from therapy. Due to the long elimination half-life of terbinafine, especially following prolonged use, such interactions may be observed for several months after discontinuation of terbinafine therapy.

References

  1. "Product Information. Lamisil (terbinafine)." Sandoz Pharmaceuticals Corporation PROD (2001):
  2. Van der Kuy PH, Hooymans PM, Verkaaik AJ "Nortriptyline intoxication induced by terbinafine." BMJ 316 (1998): 441
  3. AbdelRahman SM, Gotschall RR, Kauffman RE, Leeder JS, Kearns GL "Investigation of terbinafine as a CYP2D6 inhibitor in vivo." Clin Pharmacol Ther 65 (1999): 465-72
  4. Gupta AK, Katz HI, Shear NH "Terbinafine and potential drug interactions - Reply." J Am Acad Dermatol 43 (2000): 883-4
View all 4 references

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Drug and food interactions

Major

HYDROcodone food

Applies to: Tussgen Expectorant (guaifenesin / hydrocodone / pseudoephedrine)

GENERALLY AVOID: Alcohol may potentiate the central nervous system (CNS) depressant effects of opioid analgesics including hydrocodone. Concomitant use may result in additive CNS depression and impairment of judgment, thinking, and psychomotor skills. In more severe cases, hypotension, respiratory depression, profound sedation, coma, or even death may occur.

GENERALLY AVOID: Consumption of alcohol while taking some sustained-release formulations of hydrocodone may cause rapid release of the drug, resulting in high systemic levels of hydrocodone that may be potentially lethal. Alcohol apparently can disrupt the release mechanism of some sustained-release formulations. In study subjects, the rate of absorption of hydrocodone from an extended-release formulation was found to be affected by coadministration with 40% alcohol in the fasted state, as demonstrated by an average 2.4-fold (up to 3.9-fold in one subject) increase in hydrocodone peak plasma concentration and a decrease in the time to peak concentration. Alcohol also increased the extent of absorption by an average of 1.2-fold (up to 1.7-fold in one subject).

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of hydrocodone. The proposed mechanism is inhibition of CYP450 3A4-mediated metabolism of hydrocodone by certain compounds present in grapefruit. Increased hydrocodone concentrations could conceivably increase or prolong adverse drug effects and may cause potentially fatal respiratory depression.

MANAGEMENT: Patients taking sustained-release formulations of hydrocodone should not consume alcohol or use medications that contain alcohol. In general, potent narcotics such as hydrocodone should not be combined with alcohol. Patients should also avoid consumption of grapefruit or grapefruit juice during treatment with hydrocodone.

References

  1. "Product Information. Zohydro ER (hydrocodone)." Zogenix, Inc (2013):

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Moderate

pseudoephedrine food

Applies to: Tussgen Expectorant (guaifenesin / hydrocodone / pseudoephedrine)

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