ACETAMINOPHEN AND CODEINE PHOSPHATE TABLETS, USP CIII
Rx only
Acetaminophen and codeine are supplied in tablet form for oral administration.
Acetaminophen, USP, 4'-hydroxyacetanilide, a slightly bitter, white, odorless, crystalline powder, is a
non-opiate, non-salicylate analgesic and antipyretic. It has the following structural formula:
C H NO M.W. 151.16
Codeine phosphate, USP, 7,8-didehydro-4,5α-epoxy-3-methoxy-17-methylmorphinan-6α-ol phosphate
(1:1) (salt) hemihydrate, a white crystalline powder, is a narcotic analgesic and antitussive. It has the
following structural formula:
8 9 2
C H NO •H PO •1/2H O M.W. 406.37
Each tablet contains:
acetaminophen, USP...........................300 mg
codeine phosphate, USP.......................15 mg
(Warning: May be habit forming)
OR
acetaminophen, USP...........................300 mg
codeine phosphate, USP....................... 30 mg
(Warning: May be habit forming)
OR
acetaminophen, USP...........................300 mg
codeine phosphate, USP....................... 60 mg
(Warning: May be habit forming)
In addition, each tablet contains the following inactive ingredients: corn starch, colloidal silicon
dioxide, croscarmellose sodium, magnesium stearate, and microcrystalline cellulose. The 300 mg/60
mg strength tablets also contain crospovidone, povidone, pregelatinized starch, and stearic acid.
CLINICAL PHARMACOLOGY
This product combines the analgesic effects of a centrally acting analgesic, codeine, with a
peripherally acting analgesic, acetaminophen.
Pharmacokinetics
The behavior of the individual components is described below.
Codeine
Codeine is readily absorbed from the gastrointestinal tract. It is rapidly distributed from the
intravascular spaces to the various body tissues, with preferential uptake by parenchymatous organs
such as the liver, spleen and kidney. Codeine crosses the blood-brain barrier, and is found in fetal tissue
and breast milk. The plasma concentration does not correlate with brain concentration or relief of pain;
however, codeine is not bound to plasma proteins and does not accumulate in body tissues.
The plasma half-life is about 2.9 hours. The elimination of codeine is primarily via the kidneys, and
about 90% of an oral dose is excreted by the kidneys within 24 hours of dosing. The urinary secretion
products consist of free and glucuronide conjugated codeine (about 70%), free and conjugated
norcodeine (about 10%), free and conjugated morphine (about 10%), normorphine (4%), and
hydrocodone (1%). The remainder of the dose is excreted in the feces.
18 21 3 3 4 2
At therapeutic doses, the analgesic effect reaches a peak within 2 hours and persists between 4 and 6
hours.
See OVERDOSAGE for toxicity information.
Acetaminophen
Acetaminophen is rapidly absorbed from the gastrointestinal tract and is distributed throughout most
body tissues. The plasma half-life is 1.25 to 3 hours, but may be increased by liver damage and
following overdosage. Elimination of acetaminophen is principally by liver metabolism (conjugation)
and subsequent renal excretion of metabolites. Approximately 85% of an oral dose appears in the urine
within 24 hours of administration, most as the glucuronide conjugate, with small amounts of other
conjugates and unchanged drug.
See OVERDOSAGE for toxicity information.
INDICATIONS AND USAGE
Acetaminophen and codeine phosphate tablets are indicated for the relief of mild to moderately severe
pain.