Dosing & Uses
Dosage Forms & Strengths
tablet
- 325mg
- 500mg
caplet
- 325mg
- 500mg
- 650mg
capsule
- 325mg
- 500mg
caplet, extended-release
- 650mg
tablet, oral-disintegrating
- 80mg
- 160mg
tablet chewable
- 80mg
solution or suspension, oral
- 160mg/5mL
liquid oral
- 160mg/5mL
- 500mg/5mL
syrup oral
- 160mg/5mL
Analgesia & Fever
immediate-release
- Regular strength: 325-650 mg PO/PR q4hr PRN; not to exceed 3250 mg/day; under supervision of healthcare professional, daily doses of up to 4 g/day may be used
- Extra Strength: 1000 mg PO q6-8hr PRN; not to exceed 3000 mg/day; under supervision of healthcare professional, daily doses of up to 4 g/day may be used:
extended-release
- 2 capsules (1300 mg) PO q8hr PRN; not to exceed 3.9 g/day
maximum dose
- Acetaminophen containing products: Not to exceed a cumulative dose of 3.25 g/day of acetaminophen; under supervision of healthcare professional, daily doses of up to 4 g/day may be used
- Tylenol Extra-Strength (ie, 500 mg/tab or cap): Not to exceed 3 g/day (6 tabs or caps); under supervision of healthcare professional, daily doses of up to 4 g/day may be used
Dosing Considerations
When calculating the maximum daily dose, consider all sources of acetaminophen, including OTC, and routes of administration not to exceed the maximum recommended daily dosing
Renal Impairment
GFR≥50 mL/min: No dosage adjustment necessary
GFR 10-50 mL/min: Administer q6hr
GFR<10mL/min: Administer q8hr
Continuous renal replacement therapy: Administer q6hr
Hepatic Impairment
Use extreme caution; avoid use as much as possible; limit therapy to short-term use at doses not to exceed 2 g/day
Dosage Forms & Strengths
tablet
- 325mg
- 500mg
caplet
- 325mg
- 500mg
- 650mg
capsule
- 325mg
- 500mg
caplet, extended-release
- 650mg
tablet, oral-disintegrating
- 80mg
- 160mg
tablet chewable
- 80mg
solution or suspension, oral
- 160mg/5mL
liquid oral
- 160mg/5mL
- 500mg/5mL
syrup oral
- 160mg5mL
Pain & Fever Relief
Weight-based dosing
- Oral solution
- Neonates 28-31 weeks gestation: 10-15 mg/kg/dose PO q12hr prn; may administer an initial load of 20 mg/kg PO; not to exceed 40 mg/kg/day or 48 hr (consecutive) of maximum dose
- Neonates 32-37 weeks gestation: 10-15 mg/kg/dose PO q8hr prn; may administer an initial load of 20 mg/kg PO; not to exceed 60 mg/kg/day or 48 hr (consecutive) of maximum dose
- Neonates 0-9 days: 10-15 mg/kg/dose PO q6-8hr prn; may administer an initial load of 20 mg/kg PO; not to exceed 60 mg/kg/day; or 48 hr (consecutive) of maximum dose
- Neonates 10-29 days: 10-15 mg/kg/dose PO q4-8hr prn; may administer an initial load of 20 mg/kg PO; not to exceed 90 mg/kg/day; or 48 hr (consecutive) of maximum dose
- Infants: 10-15 mg/kg/dose PO q4-6hr prn; not to exceed 15 mg/kg/dose or 75 mg/kg/day
- Children and adolescents <60 kg: 10-15 mg/kg/dose PO q4-6hr prn; not to exceed 15 mg/kg/dose or 1,000 mg/dose, whichever is less or 75 mg/kg/day or 4,000 mg/day, whichever is less
Fixed dosing
- <6 years: Ask a healthcare provider
- 6-12 years: 325-650 mg PO q4-6hr; not to exceed 1.625 g/day for not more than 5 days unless directed by healthcare provider
- >12 years
- Regular strength: 325-650 mg q4-6hr; not to exceed 3.25 g/day; under supervision of healthcare professional, doses of up to 4 g/day may be used
- Extra strength: 1000 mg q6hr; not to exceed 3 g/24hr; under supervision of healthcare professional, doses of up to 4 g/day may be used
- Extended release: 1.3 g q8hr; not to exceed 3.9 g/24hr
Dosing Considerations
When calculating the maximum daily dose, consider all sources of acetaminophen, including OTC, and routes of administration not to exceed the maximum recommended daily dosing
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Adverse Effects
Frequency Not Defined
Angioedema
Disorientation
Dizziness
Pruritic maculopapular rash
Rash
Hyperammonemia
Stevens-Johnson syndrome
Toxic epidermal necrolysis
Urticaria
Gastrointestinal hemorrhage
Laryngeal edema
Agranulocytosis
Leukopenia
Neutropenia
Pancytopenia
Thrombocytopenia
Thrombocytopenic purpura
Hepatotoxicity
Liver failure
Nephrotoxicity
Pneumonitis
Anaphylactoid
Warnings
Contraindications
Hypersensitivity
Severe active liver disease
Cautions
Hypersensitivity and anaphylactic reactions reported; discontinue immediately if symptoms of allergic or hypersensitivity reactions occur
Acetaminophen is available in many dosage forms and products, check label carefully to avoid overdose
Use caution in patients with hepatic impairment or active liver disease
Risk of hepatotoxicity is higher in patients taking chronic high dose, or use of more than one acetaminophen-containing product
Use caution in patients with severe renal impairment; consider dosage adjustments
Consumption of 3 or more alcoholic drinks/day may increase risk of liver damage
Use with caution in patients with G6PD deficiency
Use caution in patients with chronic malnutrition
Risk for rare, but serious skin reactions that can be fatal; these reactions include Stevens-Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN), and acute generalized exanthematous pustulosis (AGEP); symptoms may include skin redness, blisters and rash
Limit acetaminophen dose from all sources and routes to <4 g/day in adults
Pregnancy & Lactation
Pregnancy
Drug crosses placenta and can be detected in cord blood, newborn serum, and urine immediately after delivery
Increased risk of teratogenic effects not reported following maternal use of drug during pregnancy
Use of normal doses during pregnancy not associated with increased risk of miscarriage or still birth; however, increase in fetal death or spontaneous abortion may be seen with maternal overdose if treatment delayed
Wheezing and asthma in early childhood associated with frequent maternal use of drug during pregnancy
Lactation
Drug is excreted in milk; in general, breastfeeding is generally acceptable if relative infant dose (RID) is <10%; avoid breastfeeding when RID>25%
Pregnancy Categories
A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA:Information not available.
Pharmacology
Mechanism of Action
Acts on hypothalamus to produce antipyresis
May work peripherally to block pain impulse generation; may also inhibit prostaglandin synthesis in CNS
Pharmacokinetics
Peak Plasma Time: 10-60 min (PO immediate-release); 60-120 min (PO extended-release); 6 hr (PO 500 mg, conventional tablet); 8 hr (PO 650 mg, extended-release tablet)
Peak Plasma Concentration: 2.1 mcg/mL (PO 500 mg, conventional tablet); 1.8 mcg/mL (PO 650 mg, extended-release tablet)
Onset: 1 hr
Distribution: 1 L/kg
Protein Bound: 10 to 25%
Metabolism: Liver (microsomal enzyme systems); conjugation (glucuronic/sulfuric acid)
Metabolites: N-acetyl-p-benzoquinoneimine, N-acetylimidoquinone, NAPQI; further metabolized via conjugation with glutathione
Half-life elimination: 1.25-3 hr (adolescents); 2-5 hr (children); 4 hr (infants); 7 hr (neonates); 2-3 hr (adults)
Excretion: urine (principally as acetaminophen glucuronide with acetaminophen sulfate/mercaptate)
