Skip to main content

Drug Interactions between Femara and letrozole / ribociclib

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

Edit list (add/remove drugs)

Interactions between your drugs

Moderate

letrozole ribociclib

Applies to: Femara (letrozole) and letrozole / ribociclib and letrozole / ribociclib

MONITOR: Coadministration with ribociclib may increase the plasma concentrations and pharmacologic effects of drugs that are substrates of CYP450 3A4. The proposed mechanism is decreased clearance due to ribociclib-mediated inhibition of CYP450 3A4 metabolism. In healthy study subjects, administration of midazolam, a sensitive CYP450 3A4 substrate, with multiple 400 mg daily doses of ribociclib increased the midazolam peak plasma concentration (Cmax) and systemic exposure (AUC) by 2.1-fold and 3.8-fold, respectively, compared to midazolam administered alone. When given at a clinically relevant dose of 600 mg daily, ribociclib is predicted to increase midazolam Cmax and AUC by 2.4-fold and 5.2-fold, respectively.

MANAGEMENT: Caution is advised when ribociclib is used concomitantly with drugs 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as well as clinical and laboratory monitoring may be appropriate for some drugs whenever ribociclib is added to or withdrawn from therapy.

References

  1. Zhou XJ, Zhou-Pan XR, Gauthier T, Placidi M, Maurel P, Rahmani R (1993) "Human liver microsomal cytochrome P450 3A isozymes mediated vindesine biotransformation. Metabolic drug interactions." Biochem Pharmacol, 45, p. 853-61
  2. Trivier JM, Libersa C, Belloc C, Lhermitte M (1993) "Amiodarone N-deethylation in human liver microsomes: involvement of cytochrome P450 3A enzymes (first report)." Life Sci, 52, pl91-6
  3. Rawden HC, Kokwaro GO, Ward SA, Edwards G (2000) "Relative contribution of cytochromes P-450 and flavin-containing monoxygenases to the metabolism of albendazole by human liver microsomes." Br J Clin Pharmacol, 49, p. 313-22
  4. DSouza DL, Levasseur LM, Nezamis J, Robbins DK, Simms L, Koch KM (2001) "Effect of alosetron on the pharmacokinetics of alprazolam." J Clin Pharmacol, 41, p. 452-4
  5. Katoh M, Nakajima M, Yamazaki H, Yokoi T (2001) "Inhibitory effects of CYP3A4 substrates and their metabolites on P-glycoprotein-mediated transport." Eur J Pharm Sci, 12, p. 505-13
  6. Kane GC, Lipsky JJ (2000) "Drug-grapefruit juice interactions." Mayo Clin Proc, 75, p. 933-42
  7. Yu DK (1999) "The contribution of P-glycoprotein to pharmacokinetic drug-drug interactions." J Clin Pharmacol, 39, p. 1203-11
  8. Nagy J, Schipper HG, Koopmans RP, Butter JJ, van Boxtel CJ, Kager PA (2002) "Effect of grapefruit juice or cimetidine coadministration on albendazole bioavailability." Am J Trop Med Hyg, 66, p. 260-3
  9. (2017) "Product Information. Kisqali (ribociclib)." Novartis Pharmaceuticals
View all 9 references

Switch to consumer interaction data

Drug and food interactions

Moderate

ribociclib food

Applies to: letrozole / ribociclib

GENERALLY AVOID: Pomegranates and grapefruit may increase the systemic exposure to ribociclib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in these fruits. Increased exposure to ribociclib may increase the risk of adverse effects such as infections, neutropenia, leukopenia, anemia, thrombocytopenia, anorexia, nausea, vomiting, diarrhea, stomatitis, alopecia, fatigue, headache, and abnormal liver function may be increased.

MANAGEMENT: Patients receiving ribociclib should avoid consumption of pomegranates or pomegranate juice and grapefruit or grapefruit juice during treatment.

References

  1. (2017) "Product Information. Kisqali (ribociclib)." Novartis Pharmaceuticals

Switch to consumer interaction data

Therapeutic duplication warnings

Therapeutic duplication is the use of more than one medicine from the same drug category or therapeutic class to treat the same condition. This can be intentional in cases where drugs with similar actions are used together for demonstrated therapeutic benefit. It can also be unintentional in cases where a patient has been treated by more than one doctor, or had prescriptions filled at more than one pharmacy, and can have potentially adverse consequences.

Duplication

Antineoplastic hormones

Therapeutic duplication

The recommended maximum number of medicines in the 'antineoplastic hormones' category to be taken concurrently is usually one. Your list includes two medicines belonging to the 'antineoplastic hormones' category:

  • Femara (letrozole)
  • letrozole/ribociclib

Note: In certain circumstances, the benefits of taking this combination of drugs may outweigh any risks. Always consult your healthcare provider before making changes to your medications or dosage.

See also

Report options

Loading...
QR code containing a link to this page

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.

Medical Disclaimer