Clinical pharmacokinetics of nitrates

• Published in: Cardiovascular drugs and therapy 1994-10, Vol.8 (5), p.693-699
• Main Author: BOGAERT, M. G
• Format: Article
• Language: English
• Subjects: Angina Pectoris - drug therapy; Antianginal agents. Coronary vasodilator agents; Biological and medical sciences; Cardiovascular system; Delayed-Action Preparations; Drug Administration Routes; Half-Life; Humans; Isosorbide Dinitrate - administration & dosage; Isosorbide Dinitrate - analogs & derivatives; Isosorbide Dinitrate - blood; Isosorbide Dinitrate - pharmacokinetics; Isosorbide Dinitrate - therapeutic use; Liver - metabolism; Medical sciences; Nitrates - administration & dosage; Nitrates - blood; Nitrates - pharmacokinetics; Nitrates - therapeutic use; Nitroglycerin - blood; Nitroglycerin - pharmacokinetics; Pharmacology. Drug treatments; Structure-Activity Relationship; Vasodilation - drug effects; Vasodilator Agents - blood; Vasodilator Agents - pharmacokinetics; Vasodilator Agents - therapeutic use
• ISSN: 0920-3206; 1573-7241
• DOI: 10.1007/bf00877116

The pharmacokinetics of organic nitrates are discussed with emphasis on the possible clinical relevance. For glyceryl trinitrate, the measurement of plasma concentrations is very difficult. Its pharmacokinetics are unusual, with a very rapid disappearance from plasma, and large intraindividual and interindividual variations. After oral administration, there seems to be a very extensive first-pass hepatic extraction and the plasma concentrations are often below the detection limit; after sublingual administration, glyceryl trinitrate appears in plasma. With transdermal glyceryl trinitrate controlled-release systems, plasma concentrations of glyceryl trinitrate can be maintained over 24 hours, although with fluctuations and important intraindividual and interindividual variability. After administration of glyceryl trinitrate via different routes, glyceryl dinitrates and mononitrates are present in plasma. The pharmacokinetics of isosorbide dinitrate are somewhat easier to understand. The substance disappears less rapidly from the plasma than does glyceryl trinitrate. After oral administration, there is also a hepatic first-pass extraction; the plasma concentrations can be prolonged by administering slow-release products. Sublingual administration leads to higher plasma concentrations than oral administration. Isosorbide dinitrate is metabolized in the organism to isosorbide 5-mononitrate and isosorbide 2-mononitrate, which both have vasodilator activity: after administration of isosorbide dinitrate, the mononitrates, and mainly the 5-mononitrate, reach very high concentrations in plasma. Isosorbide 5-mononitrate has been studied in its own right as an antianginal agent: it is completely absorbed after oral administration; it has a half-life of around 4 hours, and oral standard and controlled-release formulations have been extensively studied.