acetaminophen (oral, rectal)

Contraindicated in:

Previous hypersensitivity;
Products containing alcohol, aspartame, saccharin, sugar, or tartrazine (FDC yellow dye #5) should be avoided in patients who have hypersensitivity or intolerance to these compounds;
Severe hepatic impairment/active liver disease.

Use Cautiously in:

Hepatic disease/renal disease (lower chronic doses recommended);
Alcoholism, chronic malnutrition, severe hypovolemia or severe renal impairment (CCr <30 mL/min, ↑ dosing interval and ↓ daily dose may be necessary);
Chronic alcohol use/abuse;
Malnutrition;
OB: Use in pregnancy only if clearly needed (for IV);
Lactation: Use cautiously (for IV).

Adv. Reactions/Side Effects ⬆ ⬇

CV: hypertension (IV), hypotension (IV)

Derm: ACUTE GENERALIZED EXANTHEMATOUS PUSTULOSIS, rash, STEVENS-JOHNSON SYNDROME, TOXIC EPIDERMAL NECROLYSIS, urticaria

F and E: hypokalemia (IV)

GI: ↑liver enzymes, constipation (↑ in children) (IV), HEPATOTOXICITY (↑ DOSES), nausea (IV), vomiting (IV)

GU: renal failure (high doses/chronic use)

Hemat: neutropenia, pancytopenia

MS: muscle spasms (IV), trismus (IV)

Neuro: agitation (↑ in children) (IV), anxiety (IV), fatigue (IV), headache (IV), insomnia (IV)

Resp: atelectasis (↑ in children) (IV), dyspnea (IV)

Interactions ⬆ ⬇

Drug-drug:

Chronic high-dose acetaminophen (>2 g/day) may ↑ risk of bleeding with warfarin (INR should not exceed 4).
Hepatotoxicity is additive with other hepatotoxic substances, including alcohol.
Concurrent use of isoniazid, rifampin, rifabutin, phenytoin, barbiturates, and carbamazepine may ↑ the risk of acetaminophen-induced liver damage (limit self-medication); these agents will also ↓ therapeutic effects of acetaminophen.
Concurrent use of NSAIDs may ↑ the risk of adverse renal effects (avoid chronic concurrent use).
Propranolol↓ metabolism and may ↑ effects.
May ↓ effects of lamotrigine and zidovudine.

Availability ⬆ ⬇

(Generic available)

Chewable tablets fruit, bubblegum, or grape flavor: 80 mg^OTC; 160 mg^OTC
Tablets: 160 mg^OTC; 325 mg^OTC
Caplets: 325 mg^OTC
Solution berry, fruit, and grape flavor: 100 mg/mL^OTC
Liquid mint: 160 mg/5 mL^OTC
Elixir grape and cherry flavor: 160 mg/5 mL^OTC
Drops: 160 mg/ 5 mL ^OTC
Suspension: 100 mg/mL^OTC; 160 mg/5 mL^OTC
Syrup: 160 mg/5 mL^OTC
Suppositories: 80 mg^OTC; 120 mg^OTC; 325 mg^OTC
Solution for injection: 10 mg/mL
In combination with: many other medications. See Appendix [not included in this PDA edition].

Route/Dosage ⬆ ⬇

Children ≤12 yr should not receive >5 PO or rectal doses/24 hr without notifying physician or other health care professional. No dose adjustment needed when converting between IV and PO acetaminophen in adults and children ≥50 kg
PO (Adults and Children >12 yr): 325–650 mg every 6 hr or 1 g 3–4 times daily or 1300 mg every 8 hr (not to exceed 3 g or 2 g/24 hr in patients with hepatic/renal impairment).
PO (Children 1–12 yr): 10–15 mg/kg/dose every 6 hr as needed (not to exceed 5 doses/24 hr).
PO (Infants ): 10–15 mg/kg/dose every 6 hr as needed (not to exceed 5 doses/24 hr).
PO (Neonates ): 10–15 mg/kg/dose every 6–8 hr as needed.
IV (Adults and Children ≥13 yr and ≥50 kg): 1000 mg every 6 hr or 650 mg every 4 hr (not to exceed 1000 mg/dose, 4 g/day [by all routes], and less than 4 hr dosing interval).
IV (Adults and Children ≥13 yr and <50 kg): 15 mg/kg every 6 hr or 12.5 mg/kg every 4 hr (not to exceed 15 mg/kg/dose [up to 750 mg/dose], 75 mg/kg/day [up to 3750 mg/day] [by all routes], and less than 4 hr dosing interval).
IV (Children 2–12 yr): 15 mg/kg every 6 hr or 12.5 mg/kg every 4 hr (not to exceed 15 mg/kg/dose [up to 750 mg/dose], 75 mg/kg/day [up to 3750 mg/day] [by all routes], and less than 4 hr dosing interval).
IV (Infants 29 days-2 yr): 15 mg/kg every 6 hr (not to exceed 60 mg/kg/day [by all routes]).
IV (Neonates Birth–28 days): 12.5 mg/kg every 6 hr (not to exceed 50 mg/kg [by all routes]).
Rect (Adults and Children >12 yr): 325–650 mg every 4–6 hr as needed or 1 g 3–4 times/day (not to exceed 4 g/24 hr).
Rect (Children 1–12 yr): 10–20 mg/kg/dose every 4–6 hr as needed.
Rect (Infants ): 10–20 mg/kg/dose every 4–6 hr as needed.
Rect (Neonates ): 10–15 mg/kg/dose every 6–8 hr as needed.

US Brand Names ⬆ ⬇

acetaminophen (oral, rectal): Acephen, Infant's Feverall, Tylenol,

acetaminophen (intravenous): ~~Ofirmev~~

Action ⬆ ⬇

Inhibits synthesis of prostaglandins that may serve as mediators of pain and fever, primarily in the CNS.
Has no significant anti-inflammatory properties or GI toxicity.

Therapeutic effects:

Analgesia.
Antipyresis.

Classifications ⬆ ⬇

Therapeutic Classification: antipyretics, nonopioid analgesics

Pharmacokinetics ⬆ ⬇

Absorption: Well absorbed following oral administration. Rectal absorption is variable. Intravenous administration results in complete bioavailability.

Distribution: Widely distributed. Crosses the placenta; enters breast milk in low concentrations.

Metabolism/Excretion: 85–95% metabolized by the liver (CYP2E1 enzyme system). Metabolites may be toxic in overdose situation. Metabolites excreted by the kidneys.

Half-Life: Neonates: 7 hr; Infants and Children: 3–4 hr; Adults: 1–3 hr.

Canadian Brand Names ⬆ ⬇

acetaminophen (oral, rectal): Abenol, Acet, Children Feverhalt, Fortolin, Pediaphen, Pediatrix, Taminol, Tempra

Time/Action Profile ⬆ ⬇

(analgesia and antipyresis)

ROUTE	ONSET	PEAK	DURATION
PO	0.5–1 hr	1–3 hr	3–8 hr‡
Rect	0.5–1 hr	1–3 hr	3–4 hr
IV‡	within 30 min	30 min	4–6 hr

‡Depends on dose.

‡Antipyretic effects.

Patient/Family Teaching ⬆ ⬇

Advise patient to take medication exactly as directed and not to take more than the recommended amount. Chronic excessive use of >4 g/day (2 g in chronic alcoholics) may lead to hepatotoxicity, renal, or cardiac damage. Adults should not take acetaminophen longer than 10 days and children not longer than 5 days unless directed by health care professional. Short-term doses of acetaminophen with salicylates or NSAIDs should not exceed recommended daily dose of either drug alone.
Advise patient to avoid alcohol (3 or more glasses per day increase the risk of liver damage) if taking more than an occasional 1–2 doses and to avoid taking concurrently with salicylates or NSAIDs for more than a few days, unless directed by health care professional.
Advise patient to discontinue acetaminophen and notify health care professional if rash occurs
Inform patients with diabetes that acetaminophen may alter results of blood glucose monitoring. Advise patient to notify health care professional if changes are noted.
Caution patient to check labels on all OTC products. Advise patients to avoid taking more than one product containing acetaminophen at a time to prevent toxicity.
Advise patient to consult health care professional if discomfort or fever is not relieved by routine doses of this drug or if fever is greater than 39.5°C (103°F) or lasts longer than 3 days.
Pedi: Advise parents or caregivers to check concentrations of liquid preparations. All OTC single ingredient acetaminophen liquid products now come in a single concentration of 160 mg/5 mL. Errors have resulted in serious liver damage. Have parents or caregivers determine the correct formulation and dose for their child (based on the child's age/weight), and demonstrate how to measure it using an appropriate measuring device.

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Indications ⬇

Contraind./Precautions ⬆ ⬇