Cautions
Contraindications
- Known hypersensitivity to acetaminophen or any ingredient in the formulation.
Warnings/Precautions
Warnings
Hepatic Effects
Ingestion of a single toxic dose or multiple excessive doses can result in hepatotoxicity. Following suspected overdosage, evaluate necessity of antidote (acetylcysteine) therapy.
Increased serum ALT concentrations reported in healthy individuals receiving acetaminophen 4 g daily for 14 days in 1 study.
Sensitivity Reactions
Sensitivity reactions reported rarely. If such reactions occur, discontinue the drug.
Sulfite Sensitivity
Some formulations contain sulfites, which may cause allergic-type reactions (including anaphylaxis and life-threatening or less severe asthmatic episodes) in certain susceptible individuals.
General Precautions
Do not use multiple acetaminophen-containing preparations concomitantly.
Phenylketonuria
Children’s Tylenol® and Junior Strength Tylenol® chewable tablets contain aspartame (NutraSweet®), which is metabolized in the GI tract to phenylalanine.
Use of Fixed Combinations
When used in fixed-combination with other agents (e.g., aspirin, caffeine, chlorpheniramine, dextromethorphan, dichloralphenazone, diphenhydramine, doxylamine, guaifenesin, isometheptene, phenylephrine, pseudoephedrine), consider the cautions, precautions, and contraindications associated with the concomitant agent(s).
Specific Populations
Pregnancy
Category B.
Lactation
Distributed into milk; however, AAP considers acetaminophen to be usually compatible with breast-feeding.
Pediatric Use
Severe hepatotoxicity and death reported in children who apparently received acetaminophen dosages exceeding those recommended (10–15 mg/kg per dose with a maximum of 5 doses per day) for children. Contributing factors include improper interpretation of dosing information or failure to read such information, use of adult-strength preparations, use of excessive dosing because of the perception that desired therapeutic effects had not been achieved, and lack of knowledge about the potential toxicity of acetaminophen in excessive dosage.
Risk of overdosage and toxicity (including death) in children <2 years of age receiving preparations containing antihistamines, cough suppressants, expectorants, and nasal decongestants alone or in combination for relief of symptoms of upper respiratory tract infection. Limited evidence of efficacy for these cold and cough preparations in this age group; appropriate dosages not established. Use such preparations in children <2 years of age with caution and only as directed by clinician. Clinicians should ask caregivers about use of OTC cough/cold preparations to avoid overdosage.
Drug Interactions
Specific Drugs
| Drug |
Interaction |
Comments |
| Alcohol |
Increased risk of acetaminophen-induced hepatotoxicity |
Avoid regular or excessive use of acetaminophen; alternatively, avoid chronic ingestion of alcohol (see Prescribing Limits: Adults, under Dosage and Administration) |
| Anticonvulsants (barbiturates, carbamazepine, phenytoin) |
Increased conversion of acetaminophen to hepatotoxic metabolites; increased risk of hepatotoxicity |
Limit acetaminophen self-medication; dosage adjustment not required |
| Anticoagulants, oral |
Possible increased PT |
Clinical importance questioned; monitor anticoagulant activity if large doses of acetaminophen used |
| Aspirin |
No inhibition of antiplatelet effect of aspirin |
|
| Isoniazid |
Possible increased risk of hepatotoxicity |
Limit acetaminophen self-medication |
| Phenothiazines |
Possible increased risk of severe hypothermia |
|
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