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Drug Interactions between glycerol phenylbutyrate and Tambocor

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

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Interactions between your drugs

Moderate

flecainide glycerol phenylbutyrate

Applies to: Tambocor (flecainide) and glycerol phenylbutyrate

MONITOR: Coadministration of glycerol phenylbutyrate may lead to increased concentrations of CYP450 2D6 substrates. The proposed mechanism is inhibition of CYP450 2D6 by phenylbutyrate, the active moiety of glycerol phenylbutyrate, which has been shown to be an in vitro inhibitor of this isoenzyme. In in vitro studies, administration of phenylbutyrate at a concentration of 800 mcg/mL caused greater than 60% reversible inhibition of CYP450 2D6, 2C9, and 3A4/5. The clinical significance of these results has not been established; however, the manufacturer states that a potential interaction with CYP450 2D6 substrates cannot be ruled out.

MANAGEMENT: Caution is recommended if glycerol phenylbutyrate is administered with medicines that are substrates of CYP450 2D6, such as codeine, dextromethorphan, and some beta blockers (including metoprolol, carvedilol, labetalol, propranolol, and nebivolol). Dosage adjustments as well as clinical and laboratory monitoring may be appropriate.

References (2)
  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. (2013) "Product Information. Ravicti (glycerol phenylbutyrate)." Hyperion Therapeutics Inc

Drug and food interactions

Moderate

flecainide food

Applies to: Tambocor (flecainide)

MONITOR: Smoking cessation may lead to elevated plasma concentrations and enhanced pharmacologic effects of drugs that are substrates of CYP450 1A2 (and possibly CYP450 1A1) and/or certain drugs with a narrow therapeutic index (e.g., flecainide, pentazocine). One proposed mechanism is related to the loss of CYP450 1A2 and 1A1 induction by polycyclic aromatic hydrocarbons in tobacco smoke; when smoking cessation agents are initiated and smoking stops, the metabolism of certain drugs may decrease leading to increased plasma concentrations. The mechanism by which smoking cessation affects narrow therapeutic index drugs that are not known substrates of CYP450 1A2 or 1A1 is unknown. The clinical significance of this interaction is unknown as clinical data are lacking.

MANAGEMENT: Until more information is available, caution is advisable if smoking cessation agents are used concomitantly with drugs that are substrates of CYP450 1A2 or 1A1 and/or those with a narrow therapeutic range. Patients receiving smoking cessation agents may require periodic dose adjustments and closer clinical and laboratory monitoring of medications that are substrates of CYP450 1A2 or 1A1.

References (4)
  1. (2024) "Product Information. Cytisine (cytisinicline)." Consilient Health Ltd
  2. jeong sh, Newcombe D, sheridan j, Tingle M (2015) "Pharmacokinetics of cytisine, an a4 b2 nicotinic receptor partial agonist, in healthy smokers following a single dose." Drug Test Anal, 7, p. 475-82
  3. Vaughan DP, Beckett AH, Robbie DS (1976) "The influence of smoking on the intersubject variation in pentazocine elimination." Br J Clin Pharmacol, 3, p. 279-83
  4. Zevin S, Benowitz NL (1999) "Drug interactions with tobacco smoking: an update" Clin Pharmacokinet, 36, p. 425-38

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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