Chronopharmacology & Chronotherapeutics

Introduction & definitions

• Chronopharmacology — the branch of pharmacology that correlates drug effects with the body's circadian rhythm — i.e. how the time of day at which a drug is given influences its effect, its kinetics and its toxicity.
• Rationale — many physiological functions and disease processes themselves oscillate across the 24-hour day, so an identical dose can produce a different effect depending on when it is administered.
• Chronotherapeutics — 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.
• Significance — for several common conditions (MI, asthma, hypertension, peptic ulcer) correct timing can improve efficacy or reduce adverse effects without changing the drug or the dose — a high-yield, examination-favourite concept in clinical pharmacology.