Paracétamol

Paracétamol, also known as acetaminophen, is a widely used analgesic and antipyretic. It relieves mild to moderate pain such as headaches, dental pain, and musculoskeletal discomfort, and lowers fever. It is not a significant anti-inflammatory agent in peripheral tissues.

The mechanism is thought to involve inhibition of prostaglandin synthesis in the central nervous system, leading to reduced pain perception and a lowered set point for fever. The drug has minimal anti-inflammatory effects in the periphery. Pharmacokinetics vary by age and liver function: paracétamol is rapidly absorbed from the gastrointestinal tract, with peak plasma levels in about 30 to 60 minutes. It is primarily metabolized in the liver through glucuronidation and sulfation, with a small portion oxidized by cytochrome P450 to a reactive metabolite (NAPQI). NAPQI is normally detoxified by glutathione; excessive doses or liver disease can lead to hepatotoxicity.

Dosing recommendations depend on age and weight. In adults, typical doses are 500 to 1000 mg every 4 to 6 hours as needed, with a maximum daily dose commonly set at 3 to 4 grams, depending on guidelines. It is important not to exceed the labeled dose and to avoid multiple products containing acetaminophen. Overdose can cause severe liver injury and requires prompt medical attention; the antidote N-acetylcysteine is most effective when given early.

Paracétamol is available in many formulations, including tablets, capsules, liquids, and suppositories, and is commonly used during pregnancy and lactation when used as directed. Caution is advised in liver disease and with chronic alcohol use. It may interact with certain medications, notably those that affect liver enzymes or anticoagulants.