DrugindexOnline^{2nd edition}

( N-Acetyl-p-Aminophenol ; APAP ) Pronouncation: (ass-cet-ah-MEE-noe-fen)
Class: Analgesic, Antipyretic

Trade Names:
Acephen
- Suppositories 120 mg
- Suppositories 325 mg
- Suppositories 650 mg

Trade Names:
Aspirin Free Anacin Maximum Strength
- Tablets 500 mg
- Caplets 500 mg
- Gelcaps 500 mg

Trade Names:
Aspirin Free Pain Relief
- Tablets 325 mg
- Tablets 500 mg
- Caplets 500 mg

Trade Names:
Children's Feverall
- Suppositories 120 mg
- Tablets, chewable 120 mg
- Capsules, sprinkle 80 mg

Trade Names:
Children's Genapap
- Tablets, chewable 80 mg
- Elixir 160 mg per 5 mL

Trade Names:
Children's Mapap
- Tablets, chewable 80 mg
- Elixir 160 mg per 5 mL

Trade Names:
Children's Silapap
- Elixir 80 mg per 2.5 mL

Trade Names:
Children's Tylenol
- Tablets, chewable 80 mg
- Elixir 160 mg per 5 mL

Trade Names:
Children's Tylenol Soft Chews
- Tablets, chewable 80 mg

Trade Names:
Feverall, Junior Strength
- Suppositories 325 mg
- Capsules, sprinkle 160 mg

Trade Names:
Feverall, Infants
- Suppositories 80 mg

Trade Names:
Genapap
- Tablets 325 mg

Trade Names:
Genapap, Infants' Drops
- Solution 100 mg/mL

Trade Names:
Genapap Extra Strength
- Tablets 500 mg
- Caplets 500 mg

Trade Names:
Genebs
- Tablets 325 mg

Trade Names:
Genebs Extra Strength
- Tablets 500 mg

Trade Names:
Infants' Pain Reliever
- Drops 80 mg per 0.8 mL

Trade Names:
Infants' Silapap
- Solution 100 mg/mL

Trade Names:
Mapap Extra Strength
- Tablets 500 mg

Trade Names:
Mapap Infant Drops
- Solution 100 mg/mL

Trade Names:
Mapap Regular Strength
- Tablets 325 mg

Trade Names:
Tempra 1
- Solution 100 mg/mL

Trade Names:
Tempra 2
- Liquid 160 mg per 5 mL

Trade Names:
Tylenol Arthritis
- Tablets, extended-release 650 mg

Trade Names:
Tylenol Caplets
- Tablets 325 mg

Trade Names:
Tylenol Extended Relief
- Caplets 650 mg

Trade Names:
Tylenol Extra Strength
- Tablets 500 mg
- Gelcaps 500 mg
- Liquid 500 mg per 15 mL

Trade Names:
Tylenol Infants' Drops
- Solution 100 mg/mL

Trade Names:
Tylenol Junior Strength
- Tablets 160 mg

Trade Names:
Tylenol Regular Strength
- Tablets 325 mg

Apo-Acetaminophen (Canada)
Atasol (Canada)
Pediatrix (Canada)

Mechanism of Action

Pharmacology

Inhibits prostaglandins in CNS but lacks anti-inflammatory effects in periphery; reduces fever through direct action on hypothalamic heat-regulating center.

Pharmacokinetics

Absorption

Rapid and complete from the GI tract. T _max is 0.5 to 2 h; 4 h after overdosage.

Distribution

Distributed throughout most body fluids. Binding to plasma proteins is variable.

Metabolism

Primarily metabolized by hepatic conjugation (94%), and about 4% is metabolized by CYP-450 oxidase to toxic metabolite.

Elimination

T _½ is about 2 h. 90% to 100% is recovered in the urine within the first day, primarily as inactive metabolites. 2% is excreted as unchanged drug.

Special Populations

Neonates and cirrhotic patients

Half-life is slightly prolonged.

Indications and Usage

Relief of mild to moderate pain; treatment of fever.

Unlabeled Uses

Pain and fever prophylaxis after vaccination.

Contraindications

Standard considerations.

Dosage and Administration

Oral
Adults

PO 325 to 650 mg as needed every 4 to 6 h or 1 g 3 to 4 times/day. Do not exceed 4 g/day.

Children

PO 10 to 15 mg/kg dose as needed every 4 to 6 h; do not exceed 5 doses per 24 h.

Suppositories
Adults

PR 650 mg every 4 to 6 h; do not exceed 6 suppositories per 24 h.

Children 3 to 6 yr of age

PR 120 mg every 4 to 6 h; do not exceed 720 mg per 24 h.

Children 6 to 12 yr of age

PR 325 mg every 4 to 6 h; do not exceed 2.6 g per 24 h.

Storage/Stability

Store tablets and capsules at room temperature in tightly closed container. Refrigerate suppositories. Refrigeration of elixir improves palatability.

Drug Interactions

Ethanol

Chronic excessive use may increase risk of hepatotoxicity.

Hydantoins, sulfinpyrazone

May decrease therapeutic effect of acetaminophen; concomitant long-term use may increase risk of hepatotoxicity.

Laboratory Test Interactions

With Chemstrip bG , Dextrostix , Visidex II home blood glucose measurement systems, drug may cause more than 20% decrease in mean glucose.

Adverse Reactions

Hematologic

Hemolytic anemia; neutropenia; leukopenia; pancytopenia; thrombocytopenia.

Hepatic

Jaundice.

Miscellaneous

Hypoglycemia; allergic skin eruptions or fever.

Precautions

Pregnancy

Category B .

Lactation

Excreted in breast milk.

Hepatic Function

Chronic alcoholics should not exceed 2 g/day.

Persistent pain or fever

May indicate serious illness. Consult health care provider.

Overdosage

Symptoms

Nausea, vomiting, abdominal pain, diarrhea, anorexia, malaise, diaphoresis, confusion, low BP, cardiac arrhythmias, jaundice, acute renal failure, liver failure.

Patient Information

• Instruct family to consult health care provider for use in children younger than 3 yr of age and not to continue taking drug more than 5 days unless advised by health care provider.
• Instruct adult patients not to continue taking drug more than 10 days for pain or 3 days for fever.
• Instruct patient/family to contact health care provider if pain or fever (above 103°F) persists for more than 3 days.
• Advise diabetic patients to use sugar-free form of drug.