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Drug Interactions between carbamazepine and olanzapine

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

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Interactions between your drugs

Moderate

carBAMazepine OLANZapine

Applies to: carbamazepine and olanzapine

MONITOR: Coadministration with inducers of CYP450 1A2 may decrease the plasma concentrations of olanzapine. Data from available studies indicate that olanzapine is primarily metabolized by CYP450 1A2 and, to a lesser extent, by CYP450 2D6 and uridine diphosphate glucuronosyltransferase (UGT) 1A4. When coadministered with rifampin, a moderate CYP450 1A2 inducer that also induces UGT 1A4, olanzapine peak plasma concentration (Cmax) and systemic exposure (AUC) decreased by 11% and 48%, respectively. Coadministration with 200 mg twice daily of carbamazepine, another CYP450 1A2 inducer, caused an approximately 50% increase in the clearance of olanzapine. Higher daily dosages of carbamazepine may cause an even greater increase in olanzapine clearance.

MANAGEMENT: The potential for diminished pharmacologic effects of olanzapine should be considered during coadministration with CYP450 1A2 inducers. Alternative treatments may be required if an interaction is suspected.

References

  1. (2002) "Product Information. Tegretol (carbamazepine)." Novartis Pharmaceuticals
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  3. (2021) "Product Information. Lybalvi (olanzapine-samidorphan)." Alkermes, Inc

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Drug and food interactions

Moderate

carBAMazepine food

Applies to: carbamazepine

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of carbamazepine. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

In a small, randomized, crossover study, the administration of carbamazepine with grapefruit juice (compared to water) increased plasma drug concentrations by approximately 40%. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits.

MANAGEMENT: Patients receiving carbamazepine should be advised to avoid or limit consumption of alcohol. Given the drug's narrow therapeutic index, patients receiving carbamazepine therapy should preferably avoid the regular consumption of grapefruits and grapefruit juice to prevent any undue fluctuations in plasma drug levels. Patients should be advised to report signs of carbamazepine toxicity (nausea, visual disturbances, dizziness, or ataxia) to their physicians.

References

  1. (2002) "Product Information. Tegretol (carbamazepine)." Novartis Pharmaceuticals
  2. Garg SK, Kumar N, Bhargava VK, Prabhakar SK (1998) "Effect of grapefruit juice on carbamazepine bioavailability in patients with epilepsy." Clin Pharmacol Ther, 64, p. 286-8
  3. 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

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Moderate

OLANZapine food

Applies to: olanzapine

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

References

  1. Warrington SJ, Ankier SI, Turner P (1986) "Evaluation of possible interactions between ethanol and trazodone or amitriptyline." Neuropsychobiology, 15, p. 31-7
  2. Gilman AG, eds., Nies AS, Rall TW, Taylor P (1990) "Goodman and Gilman's the Pharmacological Basis of Therapeutics." New York, NY: Pergamon Press Inc.
  3. (2012) "Product Information. Fycompa (perampanel)." Eisai Inc
  4. (2015) "Product Information. Rexulti (brexpiprazole)." Otsuka American Pharmaceuticals Inc
View all 4 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.

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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