Quetiapine Pharmacokinetics

By Flavio Guzman, MD.

Absorption

  • Absorbed in the gastrointestinal tract
  • Time to reach peak blood levels:
    • Quetiapine IR: 2 hours
    • Quetiapine ER: 6 hours
  • Can be taken with food
  • Half-life:
    • Approximately 6 hours

Metabolism and drug interactions

 

Quetiapine pharmacokinetics

Pharmacokinetics of quetiapine: CYP3A4 metabolism

Quetiapine is metabolized by cytochrome P450 (CYP) 3A4 to inactive metabolites, drug interactions with inhibitors and inducers are likely to be significant.

  • CYP 3A4 inhibitors: these drugs inhibit drug clearance, quetiapine dose may need to be reduced.
    • Ritonavir
    • Erythromycin
    • Ketoconazole
    • Nefazodone
  • CYP 3A4 inducers: these drugs accelerate drug clearance, quetiapine dose may need to be increased.
    • Carbamazepine
    • Phenytoin

Renal insufficiency

The manufacturer does not recommend dose adjustment.

Hepatic Insufficiency

According to the manufacturer, dose adjustment may be needed (because of extensive liver metabolism).

More Information on Quetiapine

References

  1. Schatzberg, AF, Nemeroff, C . The American Psychiatric Publishing Textbook of Psychopharmacology. 4th ed.American Psychiatric Publishing, 2009.
  2. AstraZeneca Pharmaceuticals LP. Seroquel (quetiapine fumarate) prescribing information. Retrieved from http://www1.astrazeneca-us.com/pi/seroquel.pdf
  3. AstraZeneca Pharmaceuticals LP. Seroquel XR( quetiapine fumarate) prescribing information. Retrieved from http://www1.astrazeneca-us.com/pi/seroquelxr.pdf

 

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