RESUMO
Chronopharmacology aims at the use of biological rhythms in the clinical treatment to enhance both effectiveness and tolerance and minimizes the side effects of a drug by determining the best biological time for its administration. It involves bot h the investigation of drug effects as a function of biologic timing and the investigation of drug effects upon rhythm characteristics. Rhythmicity has been detected in several physiological variables such as pulse, temperature, blood pressure and hormonal secretions like diurnal variation insulin effects on blood glucose. The goal of chronopharmacology is to optimize the therapeutic effect and control or reduce the adverse effects without altering the functioning of the drug in the body. Auto-induction, auto- inhibition and food effects are considered to be the reasons of chronopharmacology. The effectiveness and toxicity of many drugs vary depending on dosing time associated with 24 hrs rhythm of biological, physiological and behavioral processes under the control of the circadian clock. Now a day, the chronopharmacological principle is used in the therapy of various diseases such as angina, hypertension, asthma, peptic ulcer, diabetes, migraine, etc. This article aims to introduce chronopharmacology, their terminologies, causes and need of it, biological clock and biological rhythms in various biological systems and the dependence of diseases on biological rhythms.