Interindividual variability - pharmacodynamics

Variation in the response to equivalent drug concentrations arises because of various factors, such as differences in receptor number and structure, receptor-coupling mechanisms and physiological changes in target organs resulting from differences in genetics, age and health. For example, the beneficial natriuresis produced by the loop diuretic furosemide is often significantly reduced at a given dose in patients with renal impairment while confusion caused by opioid analgesics is more likely in the elderly.