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Acetaminophen
GENERIC
NAME: acetaminophen
BRAND NAME: Tylenol
and many other
DRUG CLASS AND MECHANISM:
Acetaminophen belongs to a class of drugs called
analgesics (pain relievers) and antipyretics (fever
reducers). The exact mechanism of action of
acetaminophen is not known. Acetaminophen relieves pain
by elevating the pain threshold, that is, by requiring a
greater amount of pain to develop before it is felt by a
person. It reduces fever through its action on the
heat-regulating center of the brain. Specifically, it
tells the center to lower the body's temperature when
the temperature is elevated. Acetaminophen was approved
by the FDA in 1951.
PRESCRIPTION:
no
GENERIC AVAILABLE:
yes
PREPARATIONS: Liquid suspension,
chewable tablets, coated caplets, gelcaps, geltabs, and
suppositories. Common dosages are 325, 500 and 650
mg.
STORAGE: Store tablets and
solutions at room temperature 15-30°C (59-86°F).
Suppositories should be refrigerated below 27°C (80°F
).
PRESCRIBED FOR: Acetaminophen is
used for the relief of fever as well as aches and pains
associated with many conditions. Acetaminophen relieves
pain in mild arthritis but has no effect on the
underlying inflammation, redness and swelling of the
joint. If the pain is not due to inflammation,
acetaminophen is as effective as aspirin. It is as
effective as the non-steroidal anti-inflammatory drug
ibuprofen (Motrin) in relieving the pain of
osteoarthritis of the knee.
DOSING: The oral dose for adults is
325 to 650 mg every 4-6 hours. The maximum daily dose is
4 grams. The oral dose for a child is based on the
child's age, and the range is 40-650 mg every 4 hours.
When
administered as a suppository, the adult dose is 650 mg
every 4-6 hours. For children, the dose is 80-325 mg
every 4-6 hours depending on age.
DRUG INTERACTIONS: Acetaminophen is
metabolized (eliminated by conversion to other
chemicals) by the liver. Therefore drugs that increase
the action of liver enzymes that metabolize
acetaminophen (e.g. carbamazepine, isoniazid, rifampin)
may decrease the action of acetaminophen. The potential
for acetaminophen to harm the liver is increased when it
is combined with alcohol or drugs that also harm the
liver.
PREGNANCY: Acetaminophen is used in
all stages of pregnancy.
NURSING MOTHERS: Acetaminophen is
excreted in breast milk in small quantities. However,
acetaminophen use by the nursing mother appears to be
safe.
SIDE EFFECTS: When used appropriately,
side effects are rare. The most serious side effect is
liver damage due to large doses, chronic use or
concomitant use with alcohol or other drugs that also
damage the liver.
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