Screening of Antipyretic Drugs

Screening of Antipyretic Drugs

1. Definition, scope & rationale

• Antipyretic screening is the in-vivo experimental evaluation of a candidate compound's ability to lower an artificially raised (febrile) core body temperature back toward normal, without lowering normothermic temperature — distinguishing a true antipyretic (set-point–lowering) action from a non-specific hypothermic action (Vogel 4e V2 Part VIII, Anti-Pyretic Activity "General Considerations", pp.2025).
• The assay always has two obligatory steps: (i) induction of experimental pyrexia by injecting a pyrogen, and (ii) measurement of the antipyretic time-course — the fall in rectal/core temperature after the test drug versus a febrile untreated control (Vogel 4e, pp.2025–2027).
• Rationale / historical context — antipyretic therapy was central in the pre-antibiotic era; it remains necessary for symptomatic control of fever in acute viral illness and protozoal infection (e.g. malaria). For an anti-inflammatory candidate, demonstrable antipyretic activity is regarded as a positive side-effect — i.e. a confirmatory property expected of a classical NSAID-type molecule (Vogel 4e, "General Considerations", pp.2025).
• Antipyretic activity is one arm of the classical NSAID "analgesic–antipyretic–anti-inflammatory" triad; the three screening axes share a common prostaglandin/COX endpoint, which is why the antipyretic assay is routinely run alongside analgesic (hot-plate, tail-flick, Randall-Selitto) and anti-inflammatory (carrageenan-oedema) screens in the same compound work-up (SK Gupta Drug Screening Methods Ch.32, p.476–477; Ch.33, p.495).
• Positional note (topic boundary): the scope here is antipyretic screening only — the induction of fever and its pharmacological reversal. Analgesic screening (nociceptive-threshold models) and anti-inflammatory screening (oedema/exudate models) are separate topics and are referenced only where the mechanism or the shared reagent (brewer's yeast, PGE₂) links them.