Paracetamoli

Paracetamoli, known internationally as paracetamol and in the United States and Canada as acetaminophen, is a widely used over-the-counter analgesic and antipyretic. It is commonly taken to relieve mild to moderate pain such as headaches, toothache, menstrual cramps, and musculoskeletal pain, and to reduce fever. It is typically available in tablets, capsules, suspensions for children, and as an intravenous formulation for hospital use.

Pharmacology and mechanism of action

Paracetamol has strong antipyretic properties and is effective for pain relief, but it has little anti-inflammatory activity compared with nonsteroidal anti-inflammatory drugs. The precise mechanism is not fully understood; it is believed to involve central inhibition of certain cyclooxygenase enzymes in the brain and modulation of endogenous pain pathways. After absorption, it is extensively metabolized in the liver and excreted in the urine. Most metabolism occurs via glucuronidation and sulfation; a smaller amount is oxidized by cytochrome P450 enzymes to a reactive metabolite that is detoxified by glutathione.

Safety, dosing, and risks

The typical adult maximum daily dose is about 4 grams, with lower limits for older adults, those with liver impairment, or chronic alcohol use. Overdose can cause severe liver injury and is a leading cause of acute liver failure in some countries. Caution is advised with concomitant use of alcoholic beverages and in patients taking multiple products that contain paracetamol. In cases of overdose, treatment with N-acetylcysteine within a specific time window can be lifesaving. Rare but serious skin reactions have been reported in some individuals.

Regulatory and usage notes

Paracetamol is widely available as a single-ingredient medicine and as an ingredient in many combination products. It is generally considered safe for use during pregnancy when used at recommended doses, and it remains a first-line option for fever and mild pain in many clinical guidelines.