Reverse Pharmacology

Reverse Pharmacology

1. Definition & conceptual overview

• Reverse pharmacology (RP) can be defined as the integrating science of developing candidate drugs from a clinical lead to experiential hits and leads by transdisciplinary exploratory studies, and ultimately to understanding their mechanisms of action at different pathological stages of the biological organism — followed by confirmation of candidate drugs from experimental to clinical use on the basis of safety, efficacy and acceptability on relevant science (Medhi Ch.39, pp.350–1).
• In its India/Ayurveda framing, RP is essentially a rediscovery of a drug's activity and its mechanism of action — the molecule is already in human use; the science works backwards to validate and explain it (Medhi Ch.39, p.350).
  • The framing rests on the premise that Ayurvedic drugs are generally regarded as safe and are commonly used in many acute and chronic illnesses, so the human-safety question that normally dominates early drug development is, for these agents, already substantially answered by long traditional use (Medhi Ch.39, p.350).
• The defining directional contrast: conventional ("forward") pharmacology runs laboratory → clinic (target → molecule → animal → human), whereas reverse pharmacology runs clinic/bedside observation → laboratory (observed human effect → mechanism → formal validation) (Medhi Ch.39, pp.350–1; contrast paradigm G&G 14e Ch.1, pp.3–4).
• RP therefore inverts the usual order of evidence-gathering: it starts from a documented clinical observation/experience and then seeks the experimental and mechanistic basis, rather than starting from a molecular target and seeking a clinical effect (Medhi Ch.39, p.350).
• Boundary clarification: Medhi Ch.39 sits within a chapter titled Recent Advances in Pharmacology and presents RP alongside, but distinct from, Translational Medicine and Microdosing/Phase 0 — three separate "recent advances," each with its own definition. They are related strategies for accelerating/validating drug development but are not synonyms (Medhi Ch.39, pp.350–2).

Note on the two senses of "reverse pharmacology": the literature uses the term in two related ways. (1) The India/Ayurveda sense — clinic-to-lab rediscovery and validation of traditional-medicine leads (the sense Medhi defines explicitly). (2) The molecular/orphan-receptor sense — deorphanising an orphan receptor by finding its endogenous/synthetic ligand and working back to physiology (reflected in Medhi's cited reading on chemerin, the RF-amide peptides metastin and QRFP, and orexin/orphan-GPCR integrative physiology). Both share the "work backwards from an observed entity to its mechanism" logic. The molecular sense draws on the orphan-receptor deorphanisation literature, while Medhi's explicit definition is the India/Ayurveda clinic-to-lab sense. (Medhi Ch.39, pp.350, 352, Suggested Reading 5–6.)