GENERIC NAME: propoxyphene and acetaminophen
BRAND NAMES: Darvocet; Darvocet A500; Wygesic
DRUG CLASS AND MECHANISM: Propoxyphene is a medication
for
treating pain. It is an opioid analgesic (related to opium)
chemically
similar to methadone. The use of opium is at least 2300 years
old. In
1806, the first alkaloid of opium was isolated by Serturner. He
called it
morphine, after the Greek god of dreams, Morpheus. Codeine,
another opioid
analgesic was identified in 1832. Propoxyphene is half to two-
thirds as
potent as codeine, meaning that 90 to 120mg of propoxyphene
provides as
much pain relief as 60mg of codeine. This is comparable to the
pain relief
achieved by 600mg of aspirin. Opioid analgesics, including
propoxyphene,
reduce pain by blocking the receptors in the brain that are
involved in
the perception (sensing) of pain.
Acetaminophen is a non-narcotic analgesic (pain reliever) and
antipyretic (fever reducer). Acetaminophen relieves pain by
elevating the
threshold for pain. 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 drug
taken alone.
For more information please see acetaminophen.
PRESCRIPTION: yes
GENERIC AVAILABLE: yes
PREPARATIONS: Capsules: 65 mg propoxyphene and 325 mg
acetaminophen; 32 mg propoxyphene and 325 mg acetaminophen; Darvocet A500 capsules: 100 mg propoxyphene and 500 mg acetaminophen.
STORAGE: Capsules should be stored at room temperature,
between
15° (59°F) and 30°C (86°F).
PRESCRIBED FOR: Propoxyphene and acetaminophen is used
for the
treatment of mild to moderate pain.
DOSING: Propoxyphene and acetaminophen usually are
given every 4
hours as needed for the relief of pain.
DRUG INTERACTIONS: Opioids such as propoxyphene can
reduce the
activity of intestinal muscles. When combined with medications
that
possess anticholinergic activity, this effect on intestinal
muscles may be
accentuated leading to constipation. Such drugs include
dicyclomine
(Bentyl), some antihistamines [carbinoxamine (Rondec),
clemastine
(Tavist), diphenhydramine (Benadryl), promethazine
(Phenergan)], some
phenothiazines [e.g. thioridazine (Mellaril), triflupromazine
(Stelazine)], some tricyclic antidepressants [e.g.
amitriptyline (Elavil),
amoxapine (Asendin), clomipramine (Anafranil), protriptyline
(Vivactil)],
clozapine (Clozaril), cyclobenzaprine (Flexeril), and
disopyramide
(Norpace).
Propoxyphene adds to the sedating effects of alcohol and other
drugs
that can cause sedation such as the benzodiazepine class of
anti-anxiety
drugs (e.g., Valium, Ativan, Klonopin, Xanax), the tricyclic
class of
antidepressants (e.g., Elavil, Tofranil, Norpramin),
dicyclomine (Bentyl),
certain antihistamines (Benadryl, Vistaril, Atarax, Tavist),
and certain
antihypertensive medications (e.g., Catapres, Inderal).
For drug interactions of acetaminophen, please see acetaminophen.
PREGNANCY: There is very little information about the
effects on
the fetus of propoxyphene given to pregnant women. Physicians
may use it
if they consider its benefits to outweigh potential (and
unknown) risks.
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.
SIDE EFFECTS: The most frequent adverse reactions of
propoxyphene include lightheadedness, dizziness, sedation,
nausea, and
vomiting. Other side effects include drowsiness, constipation,
and spasm
of the ureter, which can lead to difficulty in urinating.
Propoxyphene can depress breathing and, therefore, is used
with caution
in elderly, debilitated patients and in patients with serious
lung
disease. Propoxyphene can impair thinking and the physical
abilities
required for driving or operating machinery. Propoxyphene may
be habit
forming. Mental and physical dependence can occur but are
unlikely when it
is used short-term.
For more information on acetaminophen, please see acetaminophen
.
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From the Doctors at MedicineNet.com  |
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Back to Medications IndexLast Editorial Review: 3/26/1998 2:30:00 PM
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