| Abstract (english) | It has been known for more than 50 years that drugs are not chemically stable
compounds providing the desired therapeutic effect and then being excreted from the
body. Studies of drug metabolism can predict the consequences of interactions of
drug to drug, food to drug, and herbal medicine to drug, and explain the unexpected
patients' responses to the drug regimen, especially in long-term therapy and treatment
with multiple drugs simultaneously. Drug metabolism includes absorption,
distribution, biotransformation, and elimination reactions under the name ADME
(Administration, Distribution, Metabolism, Excretion).
Drug structure changes during the biotransformation reactions, thereby changing
its physicochemical and biological properties. The role of biotransformation is
detoxification and faster elimination of the drug, but in some cases toxicity is increased
due to formation of toxic intermediates and metabolites. Besides inactive metabolites,
biotransformation reactions of analgesics, substances used in therapeutic doses to
relieve or eliminate pain, produce also active metabolites, and in some cases toxic
metabolites responsible for adverse drug effects. Mechanisms of some biotransformation
reactions of analgesics are not yet fully understood and the presence of certain
metabolites in the bile, feces or urine is based on assumptions, so the metabolisms of
some analgesics are still investigated. |
