Overview
Paracetamol (Acetaminophen) is a widely used analgesic and antipyretic medication with minimal anti-inflammatory effects. It is considered first-line therapy for mild to moderate pain and fever management across all age groups. Unlike NSAIDs, it does not significantly affect platelet function or cause gastrointestinal irritation at therapeutic doses.
Mechanism of Action
The exact mechanism is not fully understood but involves central inhibition of prostaglandin synthesis via selective inhibition of cyclooxygenase (COX) enzymes, particularly COX-2 in the central nervous system. It may also involve modulation of the endocannabinoid system and serotonergic pathways. Unlike NSAIDs, it has minimal peripheral anti-inflammatory effects.
Indications
- Mild to moderate pain
- Fever reduction
- Headache
- Muscle aches
- Arthritis pain
- Dental pain
- Post-operative pain
- Dysmenorrhea
Dosage
Adults: 325-1000 mg every 4-6 hours as needed, not to exceed 4000 mg daily. Children: 10-15 mg/kg every 4-6 hours as needed, not to exceed 5 doses in 24 hours. Maximum daily dose varies by age and weight. Hepatic impairment requires dose reduction.
Contraindications
- Severe hepatic impairment
- History of hypersensitivity to acetaminophen
- Alcoholics with active liver disease
- Concurrent use with other acetaminophen-containing products
Side Effects
- Hepatotoxicity (with overdose)
- Rash
- Hypersensitivity reactions
- Blood dyscrasias (rare)
- Renal toxicity (with chronic overdose)
- Nausea
- Headache
Interactions
- Warfarin (increased INR with chronic high doses)
- Alcohol (increased hepatotoxicity risk)
- Isoniazid (increased hepatotoxicity risk)
- Barbiturates (increased hepatotoxicity risk)
- Carbamazepine (increased hepatotoxicity risk)
- Phenytoin (increased hepatotoxicity risk)