propoxyphene and acetaminophen, Darvocet A500; Darvocet-N, Wygesic (cont.)

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PRESCRIPTION: Yes

GENERIC AVAILABLE: Yes

PREPARATIONS: Tablets: propoxyphene/acetaminophen 50/325, 65/650, 100/325, 100/500, and 100 mg/650 mg

STORAGE: Tablets should be stored at room temperature, 15 C to 30 C (59 F to 86 F).

PRESCRIBED FOR: Propoxyphene/acetaminophen combinations are used for the treatment of mild to moderate pain.

DOSING: The recommended adult dose is 1-2 tablets every 4 hours as needed for relief of pain. The total dose should not exceed six 100/650 mg tablets or twelve 50/325 mg tablets in a 24-hour period.

DRUG INTERACTIONS: Propoxyphene, like other narcotic pain-relievers, increases the effect of drugs that slow brain function, such as alcohol, barbiturates, skeletal muscle relaxants, for example, carisoprodol (Soma) and cyclobenzaprine (Flexeril), and benzodiazepine sedatives, for example, diazepam (Valium) and lorazepam (Ativan). Combined use of muscle relaxants and propoxyphene may lead to greater respiratory depression than either drug alone.

Combining propoxyphene with carbamazepine (Tegretol, Tegretol XR , Equetro, Carbatrol) may have severe effects on the brain including coma. Since propoxyphene causes constipation, the use of antidiarrheals, for example, diphenoxylate (Lomotil) and loperamide (Imodium), in persons taking propoxyphene can lead to severe constipation.

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.

Medically Reviewed by a Doctor on 7/15/2013


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