propoxyphene and acetaminophen, Darvocet A500; Darvocet-N, Wygesic (cont.)
Omudhome Ogbru, PharmD
Omudhome Ogbru, PharmD
Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.
Medical and Pharmacy Editor:
Drugs which both stimulate and block opioid receptors for example pentazocine (Talwin), nalbuphine (Nubain), butorphanol (Stadol), and buprenorphine (Buprenex), may reduce the effect of propoxyphene or may precipitate withdrawal symptoms from propoxyphene. Acetaminophen is metabolized (eliminated by conversion to other chemicals) by the liver. Therefore drugs that increase the action of liver enzymes that metabolize acetaminophen, for example, carbamazepine (Tegretol), isoniazid (INH, Nydrazid, Laniazid), and rifampin (Rifamate, Rifadin, Rimactane), reduce the levels of acetaminophen and therefore may decrease its action. Doses of acetaminophen greater than the recommended doses are toxic to the liver and may result in severe liver damage. The potential for acetaminophen to harm the liver is increased when it is combined with alcohol or drugs that also harm the liver.
Cholestyramine (Questran) reduces the effect of acetaminophen by decreasing its absorption into the body from the intestine. Therefore, acetaminophen should be administered 3 to 4 hours after cholestyramine or one hour before cholestyramine. Acetaminophen doses greater than 2275 mg per day may increase the blood thinning effect of warfarin (Coumadin) by an unknown mechanism. Therefore, prolonged administration or large doses of acetaminophen should be avoided during warfarin therapy.
PREGNANCY: There are no adequate studies in pregnant women.
NURSING MOTHERS: Low concentrations of propoxyphene have been measured in the breast milk of mothers taking propoxyphene. It is not known whether these small amounts can cause side effects in nursing infants.
Medically reviewed by Eni Williams, PharmD
Reference: FDA Prescribing Information
Medically Reviewed by a Doctor on 3/30/2015
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