Читать книгу Clinical Pharmacology and Therapeutics - Группа авторов - Страница 83

Age‐related changes such as reduced blood flow and loss of hepatic volume can cause a reduction in oxidising capacity and therefore altered metabolism of some drugs. It is thought, however, that these changes are clinically, minimally significant. Drugs that undergo microsomal oxidation, such as chlordiazepoxide are likely to be metabolised slower, but the evidence is for this is not established. Conjugation pathways appear unaffected by age.

First‐pass metabolism may be reduced in the elderly, possibly a consequence of the reduction in liver mass and blood flow. As a result, drugs that undergo extensive first‐pass metabolism (e.g. labetalol and propranolol) may show considerably increased bioavailability in the elderly, an effect amplified by the presence of chronic liver disease.