Acetaminophen (Ofirmev, Paracetamol)

Anesthesia Implications

Classification: Analgesic, Antipyretic
Therapeutic Effects: Analgesia, Antipyretic

Contraindications

Absolute: Severe hepatic impairment or severe active liver disease
Relative: hepatic impairment or active hepatic disease, in
cases of alcoholism, chronic malnutrition, severe hypovolemia, or
severe renal impairment (creatinine clearance ≤ 30 mL/min)

Primary Considerations

Neonates and infants – these patients form a reactive intermediate metabolite that causes hepatocellular damage, especially after repeated doses. These patients are more susceptible to toxicity if they are acutely malnourished and/or dehydrated. Also, Neonates possess very little glucuronyl tranferase. Therefore, in these patients, acetaminophen administration is especially risky of toxic effects and administration should err on the side of safety.

No conversions necessary – The maximum daily dose of acetaminophen is based on all routes of administration (i.e. intravenous, oral, and rectal) and all products containing acetaminophen.

Maximum doses in 24 hours:
2-12 years old: 75 mg/kg per day
13+ years old and LESS than 50 kg: 75 mg/kg per day
13+ years old and MORE than 50 kg: 4000 mg per day

IV side effects (most common):
Adult: nausea, vomiting, headache, and insomnia
Pediatric: nausea, vomiting, constipation, pruritus, agitation, and atelectasis

IV push dose

2-12 years of age:

15 mg/kg every 6 hours or 12.5 mg/kg every 4 hours, with a maximum single dose of 15 mg/kg, a minimum dosing interval of 4 hours, and a maximum daily dose of acetaminophen of 75 mg/kg per day.

13 years of age and above:

less than 50 kg: the recommended dosage is 15 mg/kg every 6 hours or 12.5 mg/kg every 4 hours, with a maximum single dose of 15 mg/kg, a minimum dosing interval of 4 hours, and a maximum daily dose of acetaminophen of 75 mg/kg per day.

greater than 50 kg: 1000 mg every 6 hours, or 650 mg every 4 hours, with a maximum single dose of 1000 mg, a minimum dosing interval of 4 hours, and a maximum daily dose of acetaminophen of 4000 mg per day

Metabolism

Metabolized by glucuronyl tranferase (the same enzyme that facilitates conjugation of bilirubin)

Additional Notes
Rectal dosing: 10 – 15 mg/kg