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Drug Interactions between 5-hydroxytryptophan / melatonin / pyridoxine and pralsetinib

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

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Interactions between your drugs

Moderate

melatonin pralsetinib

Applies to: 5-hydroxytryptophan / melatonin / pyridoxine and pralsetinib

MONITOR: Coadministration with pralsetinib may alter the plasma concentrations of drugs that are substrates of CYP450 2C8, 2C9, 3A4, and/or 3A5. In vitro studies indicate that pralsetinib is both an inhibitor as well as an inducer of CYP450 2C8, 2C9, 3A4, and 3A5. Therefore, pralsetinib may decrease clearance via inhibition or increase clearance via induction of these isoenzymes, resulting in increased or decreased plasma concentrations of agents that are metabolized by one or more of these isoenzymes. Clinical and pharmacokinetic data are currently lacking.

MANAGEMENT: Caution is advised if pralsetinib is used concomitantly with drugs that are substrates of CYP450 2C8, 2C9, 3A4, and/or 3A5, particularly sensitive substrates or those with a narrow therapeutic range. Some authorities recommend avoiding coadministration of pralsetinib with CYP450 2C8, 2C9, 3A4, and/or 3A5 substrates for which minimal concentration changes may lead to therapeutic failure or serious toxicities. If coadministration is required, dosage adjustments as well as clinical and laboratory monitoring may be appropriate whenever pralsetinib is added to or withdrawn from therapy. The prescribing information for concomitant medications should be consulted to assess the benefits versus risks of coadministration and for any dosage adjustments that may be required.

References

  1. (2023) "Product Information. Gavreto (pralsetinib)." Roche Products Pty Ltd, GAVRETO 20230406
  2. (2023) "Product Information. Gavreto (pralsetinib)." Roche Products Ltd
  3. (2023) "Product Information. Gavreto (pralsetinib)." Genentech
  4. (2021) "Product Information. Gavreto (pralsetinib)." Hoffmann-La Roche Limited
View all 4 references

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Drug and food interactions

Major

pralsetinib food

Applies to: pralsetinib

ADJUST DOSING INTERVAL: Food significantly increases the oral bioavailability of pralsetinib. According to the product labeling, administration of pralsetinib with a high-fat meal (approximately 800 to 1000 calories; 50% to 60% from fat) increased mean pralsetinib peak plasma concentration (Cmax) and systemic exposure (AUC) by 104% and 122%, respectively. The median time to maximum concentration (Tmax) was delayed from 4 to 8.5 hours.

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of pralsetinib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. 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. Increased exposure to pralsetinib may increase the risk of adverse effects such as musculoskeletal toxicity, fatigue, constipation, hypertension, and pneumonia.

MANAGEMENT: Pralsetinib should be administered on an empty stomach, at least 2 hours after or 1 hour before a meal. Patients should avoid consumption of grapefruit or grapefruit juice during treatment with pralsetinib.

References

  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. (2020) "Product Information. Gavreto (pralsetinib)." Blueprint Medicines Corporation
  3. (2023) "Product Information. Gavreto (pralsetinib)." Roche Products Pty Ltd, GAVRETO 20230406

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Moderate

melatonin food

Applies to: 5-hydroxytryptophan / melatonin / pyridoxine

MONITOR: Oral caffeine may significantly increase the bioavailability of melatonin. The proposed mechanism is inhibition of CYP450 1A2 first-pass metabolism. After administration of melatonin 6 mg and caffeine 200 mg orally (approximately equivalent to 1 large cup of coffee) to 12 healthy subjects, the mean peak plasma concentration (Cmax) of melatonin increased by 137% and the area under the concentration-time curve (AUC) increased by 120%. The metabolic inhibition was greater in nonsmokers (n=6) than in smokers (n=6). The greatest effect was seen in subjects with the *1F/*1F genotype (n=7), whose melatonin Cmax increased by 202%. The half-life did not change significantly. The clinical significance of this interaction is unknown.

According to some authorities, alcohol may reduce the effect of melatonin on sleep. The mechanism of this interaction is not fully understood.

In addition, CYP450 1A2 inducers like cigarette smoking may reduce exogenous melatonin plasma levels. In a small clinical trial (n=8), habitual smokers had their melatonin plasma levels measured two times, each after a single oral dose of 25 mg of melatonin. They had smoked prior to the first measurement but had not smoked for 7 days prior to the second. Cigarette smoking significantly reduced melatonin plasma exposure (AUC) as compared to melatonin levels after 7 days of smoking abstinence (7.34 +/- 1.85 versus 21.07 +/- 7.28 nmol/L*h, respectively).

MANAGEMENT: Caution and monitoring are recommended if melatonin is used with inhibitors of CYP450 1A2 like caffeine or inducers of CYP450 1A2 like cigarette smoking. Consumption of alcohol should be avoided when taking melatonin.

References

  1. Hartter S, Nordmark A, Rose DM, Bertilsson L, Tybring G, Laine K (2003) "Effects of caffeine intake on the pharmacokinetics of melatonin, a probe drug for CYP1A2 activity." Br J Clin Pharmacol, 56, p. 679-682
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  3. Ursing C, Bahr CV, Brismar K, Rojdmark S (2005) "Influence of cigarette smoking on melatonin levels in man" Eur J Clin Pharmacol, 61, p. 197-201

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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.