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Drug Interactions between ospemifene and phenobarbital

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

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Interactions between your drugs

Moderate

PHENobarbital ospemifene

Applies to: phenobarbital and ospemifene

MONITOR: Coadministration with potent inducers of CYP450 3A4, 2C9, and/or 2C19 may decrease the plasma concentrations of ospemifene, which is metabolized by these isoenzymes. The interaction has been studied with rifampin, a potent CYP450 3A4/moderate CYP450 2C9/moderate CYP450 2C19 inducer. In 12 postmenopausal women pretreated with rifampin 600 mg once daily for 5 days, administration of ospemifene 60 mg after breakfast on day 6 resulted in 51% and 58% decreases in ospemifene peak plasma concentration (Cmax) and systemic exposure (AUC), respectively, compared to administration of ospemifene alone.

MANAGEMENT: The potential for reduced therapeutic effects of ospemifene should be considered when used in combination with potent inducers of CYP450 3A4, 2C9, and/or 2C19.

References

  1. "Product Information. Osphena (ospemifene)." Shionogi USA Inc (2013):

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Drug and food interactions

Major

PHENobarbital food

Applies to: phenobarbital

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

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

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Moderate

ospemifene food

Applies to: ospemifene

ADJUST DOSING INTERVAL: Food significantly enhances the oral bioavailability of ospemifene. In a cross-study comparison, administration of a single 60 mg dose of ospemifene with a high-fat/high-calorie meal (860 kcal) in postmenopausal women increased ospemifene peak plasma concentration (Cmax) and systemic exposure (AUC) by 2.3- and 1.7-fold, respectively, compared to administration under fasted condition. Elimination half-life and time to maximum concentration (Tmax) were not altered. In two separate food effect studies where different ospemifene tablet formulations were given to healthy male volunteers, ospemifene Cmax and AUC increased by 2.3- and 1.8-fold, respectively, with a low-fat/low-calorie meal (300 kcal) and 3.6- and 2.7-fold, respectively, with a high-fat/high-calorie meal (860 kcal) relative to fasting.

MANAGEMENT: Ospemifene should be taken once daily with food.

References

  1. "Product Information. Osphena (ospemifene)." Shionogi USA Inc (2013):

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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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