antipyretica

Antipyretics, or antipyretica, are substances that reduce fever (pyrexia). They are used to relieve fever associated with infections, inflammatory conditions, or postoperative states. Fever is driven by pyrogenic cytokines that stimulate the hypothalamic thermoregulatory center to raise the body's set-point, often through increased prostaglandin E2 synthesis. Antipyretics act mainly by inhibiting cyclooxygenase enzymes and reducing prostaglandin production in the central nervous system, thereby lowering the hypothalamic set-point and promoting heat loss and cooling.

Common agents include acetaminophen (paracetamol) and nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, naproxen, and aspirin. In some regions, other agents like metamizol (dipyrone) are used. They are not antibiotics and do not treat the underlying infection; they address the symptom of fever and may be used alongside therapies targeting the cause.

Safety and cautions: Acetaminophen can cause severe liver injury in overdose or with chronic excessive use; NSAIDs can cause gastrointestinal irritation, ulcers, kidney impairment, and may have cardiovascular risks. Aspirin carries a bleeding risk and is generally avoided in children with viral illnesses due to the risk of Reye syndrome. NSAIDs are often avoided in pregnancy, renal impairment, peptic ulcer disease, or certain cardiovascular conditions. Careful consideration of age, comorbidities, and potential drug interactions is advised.

Nonpharmacologic measures, such as adequate hydration, rest, and, in appropriate situations, physical cooling, may complement pharmacologic antipyretic therapy.