💊 Paracetamol

Paracetamol is an analgesic and antipyretic agent, often classified as a non-opioid pain reliever. It is widely used for mild to moderate pain and fever reduction.

Its exact mechanism is not fully understood, but it is thought to act primarily in the central nervous system. It inhibits prostaglandin synthesis, possibly by inhibiting cyclooxygenase (COX) enzymes, particularly COX-3, though this is debated. It also has effects on serotonergic descending pathways.

Paracetamol is indicated for the relief of mild to moderate pain, including headache, musculoskeletal pain, and dysmenorrhoea. It is also a first-line agent for the reduction of fever in various conditions. It is often used as an adjunct to stronger analgesics for more severe pain.

The primary contraindication is hypersensitivity to paracetamol. Severe hepatic impairment or active liver disease is a significant contraindication due to the risk of hepatotoxicity. Caution is advised in patients with chronic alcohol abuse, malnutrition, or glutathione depletion.

At therapeutic doses, paracetamol is generally well-tolerated. The most serious adverse effect is hepatotoxicity, which can occur with overdose due to the accumulation of a toxic metabolite (NAPQI). Other rare effects include skin rashes, blood dyscrasias (e.g., thrombocytopenia, leucopenia), and kidney damage with chronic high-dose use.

In cases of suspected overdose, liver function tests (ALT, AST, bilirubin) should be monitored, along with paracetamol levels. In routine therapeutic use, no specific monitoring is typically required. Renal function may be monitored in patients with pre-existing renal impairment or prolonged high-dose use.

When prescribing, always check for paracetamol-containing products already being taken by the patient to avoid accidental overdose. Enquire about liver disease or alcohol history. Counsel patients on the maximum daily dose and the importance of not exceeding it, and to check other medications for paracetamol content.

Paracetamol is a cornerstone of pain management and antipyresis. Its hepatotoxicity in overdose is a critical concept for finals. The management of paracetamol overdose with N-acetylcysteine is a high-yield topic. It is safe in pregnancy and breastfeeding at recommended doses.

SBAs often focus on paracetamol overdose management, particularly the role of N-acetylcysteine and the timing of its administration. Questions may also test knowledge of its hepatotoxicity risk factors and contraindications in liver disease. Differentiating its mechanism from NSAIDs is another common theme.