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Drug Interactions between letermovir and primidone

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

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Interactions between your drugs

Moderate

primidone letermovir

Applies to: primidone and letermovir

GENERALLY AVOID: Coadministration with inducers of the P-glycoprotein (P-gp) efflux transporter and/or the uridine diphosphate glucuronosyltransferase (UGT) enzymes may decrease the plasma concentrations of letermovir according to the product labeling. Because letermovir is a substrate of P-gp and UGT 1A1 and 1A3, induction of the efflux transporter and metabolic enzymes may theoretically increase the clearance of letermovir. Concomitant use of rifampin initially resulted in a clinically insignificant increase in letermovir plasma concentrations (due to inhibition of organic anion transporting polypeptide [OATP] 1B1/3 and/or P-gp), followed by clinically significant decreases in letermovir plasma concentrations with continued rifampin coadministration (due to induction of P-gp/UGT).

MANAGEMENT: Due to the potential loss of efficacy, use of letermovir with inducers of the P-glycoprotein (P-gp) efflux transporter and/or the uridine diphosphate glucuronosyltransferase (UGT) enzymes is not recommended.

References (4)
  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. Cerner Multum, Inc. "Australian Product Information."
  3. Cerner Multum, Inc. (2015) "Canadian Product Information."
  4. (2017) "Product Information. Prevymis (letermovir)." Merck & Co., Inc

Drug and food interactions

Major

primidone food

Applies to: primidone

GENERALLY AVOID: Concurrent acute use of barbiturates and ethanol may result in additive CNS effects, including impaired coordination, sedation, and death. Tolerance of these agents may occur with chronic use. The mechanism is related to inhibition of microsomal enzymes acutely and induction of hepatic microsomal enzymes chronically.

MANAGEMENT: The combination of ethanol and barbiturates should be avoided.

References (5)
  1. Gupta RC, Kofoed J (1966) "Toxological statistics for barbiturates, other sedatives, and tranquilizers in Ontario: a 10-year survey." Can Med Assoc J, 94, p. 863-5
  2. Misra PS, Lefevre A, Ishii H, Rubin E, Lieber CS (1971) "Increase of ethanol, meprobamate and pentobarbital metabolism after chronic ethanol administration in man and in rats." Am J Med, 51, p. 346-51
  3. Saario I, Linnoila M (1976) "Effect of subacute treatment with hypnotics, alone or in combination with alcohol, on psychomotor skills related to driving." Acta Pharmacol Toxicol (Copenh), 38, p. 382-92
  4. Stead AH, Moffat AC (1983) "Quantification of the interaction between barbiturates and alcohol and interpretation of fatal blood concentrations." Hum Toxicol, 2, p. 5-14
  5. Seixas FA (1979) "Drug/alcohol interactions: avert potential dangers." Geriatrics, 34, p. 89-102

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.