Chronopharmacology & Chronotherapeutics

Chronopharmacology & Chronotherapeutics

1. Definition & overview

• Chronopharmacology is the branch of pharmacology that deals with the correlation of drug effects with the body's circadian rhythm — i.e. how the time of day at which a drug is given influences its effect (Padmaja 7e Ch.5, p.73).
• The discipline is built on the observation that many physiological functions and disease processes themselves vary across the 24-hour day (circadian rhythm), so the same dose of a drug can produce different effects depending on when it is administered (Padmaja 7e Ch.5, p.73).
• Chronotherapeutics is the clinical application of chronopharmacology — timing drug administration to the body's biological rhythms so that peak drug effect coincides with peak disease activity (or with the body's own rhythm of hormone secretion), thereby maximising benefit and/or minimising toxicity (Padmaja 7e Ch.5, pp.73–74).

Scope terms (chronobiology vocabulary)

• Chronesthesy (rhythmic variation in the susceptibility/sensitivity of a target biosystem to a drug), chronergy (the overall rhythm-dependent effect = chronokinetics + chronesthesy), and chronotoxicity (rhythm-dependent variation in drug toxicity) are part of the standard taxonomy of this topic.
• Chronopharmacokinetics is the circadian variation in absorption, distribution, metabolism and excretion.