Acetaminofeni

Acetaminofeni, also known as acetaminophen or paracetamol, is a widely used non-opioid analgesic and antipyretic. It is employed to relieve mild to moderate pain such as headaches, toothache, and musculoskeletal pain, and to reduce fever. It is available in various forms, including tablets, capsules, liquids, and suppositories, and is commonly sold over the counter.

Pharmacology and mechanism of action are centered on the central nervous system. Acetaminofeni reduces pain and fever primarily by inhibiting prostaglandin synthesis in the brain. It has little anti-inflammatory activity at typical doses, unlike many nonsteroidal anti-inflammatory drugs. After oral administration, it is well absorbed and mainly metabolized in the liver through conjugation to glucuronide and sulfate. A small portion is oxidized to a reactive metabolite (NAPQI) that is normally detoxified by glutathione; in overdose or in liver disease, NAPQI can accumulate and cause liver injury.

Dosing and safety considerations: in adults, the usual dose is 500-1000 mg every 4-6 hours as needed, with a maximum daily limit commonly set at 4 grams (some guidelines allow up to 3-4 grams). Lower maximums are advised for those with liver impairment, chronic alcohol use, or fasting states. Pediatric dosing is weight-based. Contraindications include significant liver disease and known hypersensitivity. Adverse effects are generally rare but can include rash; hepatotoxicity is the major safety concern at high doses.

Overdose and interactions: acetaminofeni overdose is a leading cause of acute liver failure. Early symptoms may be mild, with liver injury potentially developing later. The antidote N-acetylcysteine is most effective when given promptly. Interactions with alcohol, certain enzyme inducers, or warfarin can influence safety and efficacy and should be considered in treatment decisions.