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Drug Interactions between Seroquel and Unipen

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

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Interactions between your drugs

Moderate

nafcillin QUEtiapine

Applies to: Unipen (nafcillin) and Seroquel (quetiapine)

MONITOR: Coadministration with inducers of CYP450 3A4 may decrease the plasma concentrations of quetiapine, which is primarily metabolized by the isoenzyme. In 18 psychiatric patients receiving quetiapine 300 mg twice daily, addition of the potent CYP450 3A4 inducer carbamazepine (200 mg three times daily) decreased mean quetiapine peak plasma concentration (Cmax) and systemic exposure (AUC) by 80% and 87%, respectively, and increased oral clearance (Cl/F) by 7.5-fold compared to quetiapine administered alone. The interaction has also been reported with phenytoin, another potent CYP450 3A4 inducer. In ten subjects with various affective disorders, coadministration of quetiapine (250 mg orally three times a day) with phenytoin (100 mg orally three times a day) decreased the mean steady-state Cmax, trough plasma concentration (Cmin) and AUC of quetiapine by 66%, 89% and 80%, respectively. The mean oral clearance increased by 5.5-fold. No data are available for other, less potent CYP450 3A4 inducers.

MANAGEMENT: Pharmacologic response to quetiapine should be monitored more closely whenever a CYP450 3A4 inducer is added to or withdrawn from therapy, and the quetiapine dosage adjusted as necessary. Patients should be advised to notify their physician if their symptoms worsen or their condition changes.

References

  1. "Product Information. Seroquel (quetiapine)." Astra-Zeneca Pharmaceuticals PROD (2001):
  2. "Quetiapine for schizophrenia." Med Lett Drugs Ther 39 (1997): 117-8
  3. Wong YWJ, Yeh C, Thyrum PT "The effects of concomitant phenytoin administration on the steady-state pharmacokinetics of quetiapine." J Clin Psychopharmacol 21 (2001): 89-93
  4. Grimm SW, Richtand NM, Winter HR, Stams KR, Reele SB "Effects of cytochrome P450 3A modulators ketoconazole and carbamazepine on quetiapine pharmacokinetics." Br J Clin Pharmacol 61 (2006): 58-69
  5. Cerner Multum, Inc. "Australian Product Information." O 0
View all 5 references

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Drug and food interactions

Moderate

nafcillin food

Applies to: Unipen (nafcillin)

ADJUST DOSING INTERVAL: Certain penicillins may exhibit reduced gastrointestinal absorption in the presence of food. The therapeutic effect of the antimicrobial may be reduced.

MANAGEMENT: The interacting penicillin should be administered one hour before or two hours after meals. Penicillin V and amoxicillin are not affected by food and may be given without regard to meals.

References

  1. Neu HC "Antimicrobial activity and human pharmacology of amoxicillin." J Infect Dis 129 (1974): s123-31
  2. Welling PG, Huang H, Koch PA, Madsen PO "Bioavailability of ampicillin and amoxicillin in fasted and nonfasted subjects." J Pharm Sci 66 (1977): 549-52
  3. McCarthy CG, Finland M "Absorption and excretion of four penicillins." N Engl J Med 263 (1960): 315-26
  4. Cronk GA, Wheatley WB, Fellers GF, Albright H "The relationship of food intake to the absorption of potassium alpha-phenoxyethyl penicillin and potassium phenoxymethyl penicillin from the gastrointestinal tract." Am J Med Sci 240 (1960): 219-25
  5. Klein JO, Sabath LD, Finland M "Laboratory studies on oxacillin. I: in vitro activity against staphylococci and some other bacterial pathogens. II: absorption and urinary excretion in normal young." Am J Med Sci 245 (1963): 399-411
  6. Neuvonen PJ, Elonen E, Pentikainen PJ "Comparative effect of food on absorption of ampicillin and pivampicillin." J Int Med Res 5 (1977): 71-6
View all 6 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.


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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.