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Drug Interactions between mavacamten and pseudoephedrine / terfenadine

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

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Interactions between your drugs

Moderate

terfenadine mavacamten

Applies to: pseudoephedrine / terfenadine and mavacamten

MONITOR: Coadministration with mavacamten may decrease the plasma concentrations of drugs that are primarily metabolized by CYP450 3A4, 2C9, and/or 2C19. The proposed mechanism is accelerated clearance due to induction of these isoenzymes by mavacamten. The interaction may be particularly important for sensitive substrates or those that demonstrate a narrow therapeutic index. When midazolam, a probe substrate for CYP450 3A4, was coadministered with a 16-day course of mavacamten (25 mg on days 1 and 2, followed by 15 mg for 14 days) in healthy CYP450 2C19 normal metabolizers, midazolam peak plasma concentration (Cmax) decreased by 7% and systemic exposure (AUC) decreased by 13%. Following coadministration of mavacamten once daily in patients with obstructive hypertrophic cardiomyopathy (HCM), midazolam Cmax and AUC are predicted to decrease by 13% to 48% and 21% to 64%, respectively, depending on the dose of mavacamten and CYP450 2C19 phenotype. Additionally, concomitant use of mavacamten once daily in HCM patients is predicted to decrease the Cmax and AUC of repaglinide, a CYP450 2C8 and 3A4 substrate, by 12% to 39%; the Cmax and AUC of tolbutamide, a CYP450 2C9 substrate, by 33% to 65%; and the Cmax and AUC of omeprazole, a CYP450 2C19 substrate, by 48% to 67%, depending on the dose of mavacamten and CYP450 2C19 phenotype.

MANAGEMENT: Caution is advised when mavacamten is used concomitantly with drugs that are substrates of CYP450 3A4, 2C9 and/or 2C19, particularly sensitive substrates or those with a narrow therapeutic range. Dosage adjustments as well as clinical and laboratory monitoring may be appropriate for some drugs whenever mavacamten is added to or withdrawn from therapy. The prescribing information for concomitant medications should be consulted to assess the benefits versus risks of coadministration of a CYP450 inducer like mavacamten and for any dosage adjustments that may be required.

References

  1. (2022) "Product Information. Camzyos (mavacamten)." MyoKardia Inc
  2. (2023) "Product Information. Camzyos (mavacamten)." Bristol-Myers Squibb Australia Pty Ltd, 2

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Drug and food interactions

Major

terfenadine food

Applies to: pseudoephedrine / terfenadine

CONTRAINDICATED: The consumption of grapefruit juice has been associated with significantly increased plasma concentrations of terfenadine. The mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruits. Terfenadine in high serum levels has been associated with prolongation of the QT interval and development of torsade de pointes, a potentially fatal ventricular arrhythmia.

MANAGEMENT: Due to the risk of cardiotoxicity, patients receiving the drug should be advised to avoid consumption of grapefruit products. Loratadine, cetirizine, and fexofenadine may be safer alternatives in patients who may have trouble adhering to the dietary restriction.

References

  1. Honig PK, Woosley RL, Zamani K, Conner DP, Cantilena LR Jr (1992) "Changes in the pharmacokinetics and electrocardiographic pharmacodynamics of terfenadine with concomitant administration of erythromycin." Clin Pharmacol Ther, 52, p. 231-8
  2. Zimmermann M, Duruz H, Guinand O, et al. (1992) "Torsades de Pointes after treatment with terfenadine and ketoconazole." Eur Heart J, 13, p. 1002-3
  3. Mathews DR, McNutt B, Okerholm R, et al. (1991) "Torsades de pointes occurring in association with terfenadine use." JAMA, 266, p. 2375-6
  4. Monahan BP, Ferguson CL, Killeavy ES, et al. (1990) "Torsades de pointes occurring in association with terfenadine use." JAMA, 264, p. 2788-90
  5. Honig PK, Wortham DC, Zamani K, et al. (1993) "Terfenadine-ketoconazole interaction: pharmacokinetic and electrocardiographic consequences." JAMA, 269, p. 1513-8
  6. Pohjola-Sintonen S, Viitasalo M, Toivonene L, Neuvonen P (1993) "Torsades de pointes after terfenadine-itraconazole interaction." BMJ, 306, p. 186
  7. Cortese LM, Bjornson DC (1992) "Potential interaction between terfenadine and macrolide antibiotics." Clin Pharm, 11, p. 675
  8. Paris DG, Parente TF, Bruschetta HR, Guzman E, Niarchos AP (1994) "Torsades-de-pointes induced by erythromycin and terfenadine." Am J Emerg Med, 12, p. 636-8
  9. Zechnich AD, Haxby DG (1996) "Drug interactions associated with terfenadine and related nonsedating antihistamines." West J Med, 164, p. 68-9
  10. Honig PK, Wortham DC, Lazarev A, Cantilena LR (1996) "Grapefruit juice alters the systemic bioavailability and cardiac repolarization of terfenadine in poor metabolizers of terfenadine." J Clin Pharmacol, 36, p. 345-51
  11. Woosley RL (1996) "Cardiac actions of antihistamines." Annu Rev Pharmacol Toxicol, 36, p. 233-52
  12. Benton RE, Honig PK, Zamani K, Cantilena LR, Woosley RL (1996) "Grapefruit juice alters terfenadine pharmacokinetics resulting in prolongation of repolarization on the electrocardiogram." Clin Pharmacol Ther, 59, p. 383-8
  13. Hsieh MH, Chen SA, Chiang CE, et al. (1996) "Drug-induced torsades de pointes in one patient with congenital long QT syndrome." Int J Cardiol, 54, p. 85-8
  14. Clifford CP, Adams DA, Murray S, Taylor GW, Wilkins MR, Boobis AR, Davies DS (1996) "Pharmacokinetic and cardiac effects of terfenadine after inhibition of its metabolism by grapefruit juice." Br J Clin Pharmacol, 42, p662
  15. Rau SE, Bend JR, Arnold JMO, Tran LT, Spence JD, Bailey DG (1997) "Grapefruit juice terfenadine single-dose interaction: Magnitude, mechanism, and relevance." Clin Pharmacol Ther, 61, p. 401-9
  16. Bailey DG, Malcolm J, Arnold O, Spence JD (1998) "Grapefruit juice-drug interactions." Br J Clin Pharmacol, 46, p. 101-10
  17. Bailey DG, Dresser GR, Kreeft JH, Munoz C, Freeman DJ, Bend JR (2000) "Grapefruit-felodipine interaction: Effect of unprocessed fruit and probable active ingredients." Clin Pharmacol Ther, 68, p. 468-77
View all 17 references

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Major

mavacamten food

Applies to: mavacamten

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of mavacamten. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Inhibition of hepatic CYP450 3A4 may also contribute. The interaction has not been studied with grapefruit juice, but has been reported for other CYP450 3A4 inhibitors. According to the prescribing information, mavacamten is primarily metabolized by CYP450 2C19 (74%) and to a lesser extent by CYP450 3A4 (18%) and 2C9 (8%). When mavacamten (25 mg) was coadministered with the moderate CYP450 3A4 inhibitor verapamil (sustained-release 240 mg) in intermediate and normal metabolizers of CYP450 2C19, mavacamten systemic exposure (AUC) increased by 15% and peak plasma concentration (Cmax) increased by 52%. Concomitant use of mavacamten with diltiazem, another moderate CYP450 3A4 inhibitor, in CYP450 2C19 poor metabolizers is predicted to increase mavacamten AUC and Cmax by up to 55% and 42%, respectively. Concomitant use of mavacamten (15 mg) with the potent CYP450 3A4 inhibitor ketoconazole (400 mg once daily) is predicted to increase mavacamten AUC and Cmax by up to 130% and 90%, respectively. Because mavacamten reduces systolic contraction and left ventricular ejection fraction, increased exposure may potentiate the risk of heart failure. In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition.

Food does not affect the extent of absorption of mavacamten. No clinically significant difference in mavacamten exposure was observed following administration with a high-fat meal. However, the time to reach peak plasma concentration (Tmax) was increased by 4 hours.

MANAGEMENT: Mavacamten may be administered with or without food. Patients should avoid consumption of grapefruit and grapefruit juice during treatment with mavacamten.

References

  1. (2022) "Product Information. Camzyos (mavacamten)." MyoKardia Inc
  2. (2023) "Product Information. Camzyos (mavacamten)." Bristol-Myers Squibb Australia Pty Ltd, 2

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Moderate

pseudoephedrine food

Applies to: pseudoephedrine / terfenadine

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

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