Paracetamol /Acetaminophen information from DrugsUpdate
FI - Food *
LI - Lab *
Paracetamol is a widely used over-the-counter analgesic (pain reliever) and antipyretic (fever reducer). It is commonly used for the relief of fever, headaches, and other minor aches and pains, and is a major ingredient in numerous cold and flu remedies. In combination with non-steroidal anti-inflammatory drugs (NSAIDs) and opioid analgesics, paracetamol is used also in the management of more severe pain (such as postoperative pain).
Pharmacodynamics
Pharmacokinetics
Paracetamol exhibits analgesic action by peripheral blockage of pain impulse generation. It produces antipyresis by inhibiting the hypothalamic heat-regulating centre. Its weak anti-inflammatory activity is related to inhibition of prostaglandin synthesis in the CNS.
Onset
<1 hour
Duration
4-6 hours
Absorption
Incomplete; depends upon dosage form. Time to peak, serum: oral: 10-60 minutes; may be delayed in acute overdoses. Decreased rate of absorption with food.
Distribution
Present in most body tissues; crosses the placenta and enters the breast milk. Protein binding: 8-43% (at toxic doses).
Metabolism
Hepatic via glucuronic and sulphuric acid conjugation. At normal therapeutic levels, glucuronide metabolites are metabolised to reactive intermediate (acetylimidoquinone) which is conjugated with glutathione and inactivated; at toxic doses, glutathione conjugation is insufficient leading to increased acetylimidoquinone which may cause hepatic cell necrosis.
Excretion
Plasma half-life: 2.7 hours (adults); 1.5-2 hours (infants and children); 3.5 hours (neonates). Neonates, infants and children up ≤10 years excrete less glucuronide than adults. Half-life may be longer after toxic doses. Excreted mainly via urine (2- 5% unchanged; 55% as glucuronide metabolites). Total body clearance: 18 L/hours.
Paracetamol /Acetaminophen Indications / Paracetamol /Acetaminophen Uses
Information Not Available
Paracetamol /Acetaminophen Adverse Reactions / Paracetamol /Acetaminophen Side Effects
Nausea, allergic reactions, skin rashes, acute renal tubular necrosis.
Potentially Fatal: Very rare, blood dyscrasias (e.g. thrombocytopenia, leucopenia, neutropenia, agranulocytosis); liver damage.
Precautions
Information Not Available
Special Precautions
Renal or hepatic impairment; alcohol-dependent patients; G6PD deficiency.
Other Drug Interactions
Reduced absorption of cholestyramine within 1 hr of admin. Accelerated absorption with metoclopramide. Decreased effect with barbiturates, carbamazepine, hydantoins, rifampicin and sulfinpyrazone. Paracetamol may increase effect of warfarin.
Potentially Fatal: Paracetamol increases the risk of liver damage in chronic alcoholics. Increased risk of toxicity with other hepatotoxic drugs or drugs which induce microsomal enzymes e.g. barbiturates, carbamazepine, hydantoins, rifampicin and sulfinpyrazone.
Other Interactions
Food Interaction
St John's Wort may decrease effect.
Dosage
Oral
Mild to moderate pain and fever
Adult: 0.5-1 g 4-6 hourly as necessary. Max: 4 g daily.
Child: Neonate 28-32 weeks post menstrual age: 20 mg/kg as a single dose then 10-15 mg/kg 8-12 hourly (max 30 mg/kg daily in divided doses); neonate >32 weeks post menstrual age: 20 mg/kg as a single dose then 10-15 mg/kg 6-8 hourly (max 60 mg/kg daily in divided doses); child 1-3 months: 30 mg 8 hourly (max 60 mg/kg daily in divided doses); 3 months-1 year: 60-120 mg 4-6 hourly (max 4 doses in 24 hours); 1-5 years: 120-250 mg 4-6 hourly (max 4 doses in 24 hours); 6-12 years: 250-500 mg 4-6 hourly (max 4 doses in 24 hours).
CrCl (ml/min) Dosage Recommendation
10-50 6 hourly.
<10 8 hourly.
Oral
Post-immunisation pyearexia
Child: 2-3 month: Initially, 60 mg repeated 4-6 hourly if necessary.
CrCl (ml/min) Dosage Recommendation
<10 8 hourly.
10-50 6 hourly.
Intravenous
Mild to moderate pain and fever
Adult: Admin over 15 minutes. weight >50 kg: 1 g 4-6 hourly (max 4 g daily); <50 kg: 15 mg/kg 4-6 hourly (max 60 mg/kg daily).
Child: Admin over 15 min. weight <10 kg: 7.5 mg/kg 4-6 hourly (max 30 mg/kg daily); 10-50 kg: 15 mg/kg 4-6 hourly (max 60 mg/kg daily); >50 kg: 1 g 4-6 hourly (max 4 g daily).
CrCl (ml/min) Dosage Recommendation
10-50 6 hourly.
<10 8 hourly.
Rectal
Mild to moderate pain and fever
Adult: 0.5-1 g 4-6 hourly as necessary. Max: 4 g daily.
Child: Neonate 28-32 weeks postmenstrual age: 20 mg/kg as a single doses then 15 mg/kg 12 hourly as necessary (max 30 mg/kg daily in divided doses); neonate >32 weeks postmenstrual age: 30 mg/kg as a single dose then 20 mg/kg 8 hourly as necessary (max 60 mg/kg daily in divided doses); 1-3 month: 30-60 mg 8 hourly (max 60 mg/kg daily in divided doses); 3-12 month: 60-125 mg 4-6 hourly (max 4 doses in 24 hour); 1-5 year: 125-250 mg 4-6 hourly (max 4 doses in 24 hour); 6-12 year: 250-500 mg 4-6 hourly (max 4 doses in 24 hour; >12 year: 500 mg 4-6 hourly (max 4g daily).
CrCl (ml/min) Dosage Recommendation
10-50 6 hourly.
<10 8 hourly.
Reconstitution
Can be diluted in 0.9% sodium chloride or 5% glucose solution up to one 1/10.
Incompatibility
Do not mix with other drugs.
Food(before/after)
May be taken with or without food
List of Contraindications
Paracetamol /Acetaminophen and Pregnancy
Information Not Available
Paracetamol /Acetaminophen and Lactation
Information Not Available
Paracetamol /Acetaminophen and Children
Information Not Available
Paracetamol /Acetaminophen and Geriatic
Information Not Available
Paracetamol /Acetaminophen and Other Contraindications
Information Not Available
Storage
Intravenous
Do not store above 30°C; do not freeze or refrigerate; if parenteral solution is diluted: use within an hour (infusion time included).
Oral
Do not store above 30°C; do not freeze or refrigerate; if parenteral solution is diluted: use within an hour (infusion time included).
Rectal
Do not store above 30°C; do not freeze or refrigerate; if parenteral solution is diluted: use within an hour (infusion time included).
Lab interference
Intravenous
Do not store above 30°C; do not freeze or refrigerate; if parenteral solution is diluted: use within an hour (infusion time included).
Oral
Do not store above 30°C; do not freeze or refrigerate; if parenteral solution is diluted: use within an hour (infusion time included).
Rectal
Do not store above 30°C; do not freeze or refrigerate; if parenteral solution is diluted: use within an hour (infusion time included).
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