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Drug Interactions between Premphase 14/14 and roflumilast

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

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Interactions between your drugs

Moderate

conjugated estrogens roflumilast

Applies to: Premphase 14 / 14 (conjugated estrogens / medroxyprogesterone) and roflumilast

MONITOR: Coadministration with CYP450 1A2 inhibitors or dual CYP450 1A2/3A4 inhibitors may increase the systemic exposure to roflumilast and its pharmacologically active N-oxide metabolite. In drug interaction studies, the total exposure to roflumilast and roflumilast N-oxide increased by 25%, 47% and 59% with the CYP450 1A2 inhibitor enoxacin and the dual CYP450 1A2/3A4 inhibitors cimetidine and fluvoxamine, respectively.

MANAGEMENT: Treatment with roflumilast should be re-evaluated if an interaction is suspected and persistent intolerability occurs. Patients should be advised to contact their physician if they experience increased frequency and/or severity of side effects such as diarrhea, nausea, abdominal pain, weight loss, and headache.

References (3)
  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. (2011) "Product Information. Daxas (roflumilast)." Nycomed Inc
  3. (2011) "Product Information. Daliresp (roflumilast)." Astra-Zeneca Pharmaceuticals

Drug and food interactions

Minor

conjugated estrogens food

Applies to: Premphase 14 / 14 (conjugated estrogens / medroxyprogesterone)

Coadministration with grapefruit juice may increase the bioavailability of oral estrogens. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruits. In a small, randomized, crossover study, the administration of ethinyl estradiol with grapefruit juice (compared to herbal tea) increased peak plasma drug concentration (Cmax) by 37% and area under the concentration-time curve (AUC) by 28%. Based on these findings, grapefruit juice is unlikely to affect the overall safety profile of ethinyl estradiol. However, as with other drug interactions involving grapefruit juice, the pharmacokinetic alterations are subject to a high degree of interpatient variability. Also, the effect on other estrogens has not been studied.

References (2)
  1. Weber A, Jager R, Borner A, et al. (1996) "Can grapefruit juice influence ethinyl estradiol bioavailability?" Contraception, 53, p. 41-7
  2. Schubert W, Eriksson U, Edgar B, Cullberg G, Hedner T (1995) "Flavonoids in grapefruit juice inhibit the in vitro hepatic metabolism of 17B-estradiol." Eur J Drug Metab Pharmacokinet, 20, p. 219-24
Minor

roflumilast food

Applies to: roflumilast

Food intake does not affect the total exposure to roflumilast and its pharmacologically active N-oxide metabolite, but delays the time to maximum concentration (Tmax) of roflumilast by one hour and reduces its peak plasma concentration (Cmax) by approximately 40%. The Tmax and Cmax of
roflumilast N-oxide are unaffected. Roflumilast may be taken with or without food.

References (3)
  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. (2011) "Product Information. Daxas (roflumilast)." Nycomed Inc
  3. (2011) "Product Information. Daliresp (roflumilast)." Astra-Zeneca Pharmaceuticals

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.

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