Medications and Drugs
Pharmacy Author: Omudhome Ogbru, PharmD
Medical and Pharmacy Editor: Jay W. Marks, MD
GENERIC NAME: propoxyphene and acetaminophen
BRAND NAMES: Darvocet A500; Darvocet-N (Darvocet, Wygesic: These brands no
longer are available in the U.S.)
DRUG CLASS AND MECHANISM:
Propoxyphene is a strong narcotic pain-reliever and
cough suppressant but is weaker than other narcotics such as morphine, codeine,
and hydrocodone. The precise mechanism of action is not known but may involve
stimulation of opioid receptors in the brain. Propoxyphene increases pain
tolerance and decreases discomfort, but the presence of pain is still apparent.
In addition to pain reduction, propoxyphene also causes sedation and respiratory depression. Acetaminophen is a non-narcotic analgesic and antipyretic (fever
reducer). Acetaminophen relieves pain by elevating the pain threshold. It
reduces fever through its action on the heat-regulating center of the brain. The
combination of propoxyphene and acetaminophen achieves greater pain relief than
either taken separately. For more information on acetaminophen, please see
acetaminophen (Tylenol). The FDA first approved propoxyphene/acetaminophen
combinations in October 1972.
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 to 30 C (59 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. Do 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 and 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.
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
- acetaminophen, Tylenol and Others - Describes the medication acetaminophen (Tylenol) a drug used to relieve pain and reduce fever. Article includes descriptions, uses, drug interactions, and side effects.
- Arthritis - Arthritis symptoms include pain, joint inflammation and swelling. Get the facts on arthritis types, causes, research information, statistics and diagnosis.
- Drug Interactions - Learn about potential drug interactions you may be exposed to. Drug interactions can occur with prescription drugs, OTC medication, vitamins, herbs, and supplements.
Latest Medical News
Back to Medications Index
Chronic Pain RSS