Antipyretic refers to any drug or intervention that reduces fever. The word combines anti- (against) and pyretic (feverish). Antipyretics act on the body's temperature regulation to bring down an elevated core temperature and are widely used in clinical practice to relieve discomfort and prevent complications of very high fever. For a basic definition see antipyretic overview.

How antipyretics work

Fever is generated when the brain's temperature set point in the hypothalamus is raised in response to infection or inflammation. Endogenous mediators called prostaglandins — produced at sites of inflammation — play a central role in raising that set point. Common antipyretic drugs reduce the synthesis or action of prostaglandins and so allow the hypothalamus to reset toward normal temperature; for more on the anatomy involved see hypothalamus. The net effect is increased heat loss and reduced heat production until body temperature falls toward the normal range; prostaglandin biology is discussed at prostaglandin.

Common agents and categories

Most medicines labeled as antipyretics have other primary uses:

  • NSAIDs (nonsteroidal anti-inflammatory drugs) such as ibuprofen and aspirin relieve pain and inflammation and also lower fever. In many countries these are the most commonly used antipyretics (usage data).
  • Acetaminophen (paracetamol) is primarily an analgesic and antipyretic with only weak anti-inflammatory effects; see paracetamol for clinical notes.

Uses, precautions and alternatives

Antipyretics are given to reduce discomfort, prevent very high fevers, and lower metabolic strain in vulnerable patients. They are also used as part of perioperative and palliative care. Safety considerations influence choice: aspirin is generally avoided in children with viral infections because of its association with Reye-like syndromes; acetaminophen overdoses can cause serious liver injury; NSAIDs can cause gastric irritation, bleeding and affect kidney function. Nonpharmacological options such as tepid sponging, light clothing and adequate fluids are often beneficial and may be used alone or together with drugs.

For discussion of fever as an immune response and clinical implications see fever and immunity.

Debate and evidence

There is ongoing discussion about whether routinely suppressing fever is always beneficial. Fever is part of the host response to infection and some studies and reviews have suggested that indiscriminate fever suppression might modestly influence outcomes in certain illnesses. Evidence is mixed and context-dependent: benefits in comfort and reduced metabolic demand must be balanced against theoretical or observed effects on infection course. Careful reviews and population analyses have been reported; for one analysis see related study. Clinical guidance often emphasizes treating the patient's symptoms and risk factors rather than lowering temperature alone.

Key points and practical guidance

  • Antipyretics reduce fever by interfering with prostaglandin-mediated resetting of the hypothalamic set point.
  • Common drugs: ibuprofen, aspirin (NSAIDs) and acetaminophen/paracetamol; each has different safety profiles.
  • Use antipyretics to relieve discomfort and prevent complications of very high fever; follow dosing guidance and consider age- and comorbidity-related risks.
  • Non-drug measures (cooling, hydration, rest) are useful adjuncts.
  • Decisions about treating fever should consider the underlying cause, patient comfort and clinical risk rather than temperature alone.

For further reading on specific agents, mechanisms and clinical recommendations, follow links in the sections above or consult clinical treatment guidelines and pharmacology references.