[Benzodiazepines. Factors altering pharmacokinetic parameters and drug interactions]

Drug level at receptor site dictates the intensity of the pharmacological response. The level which is achieved depends upon several factors such as gastrointestinal absorption, protein binding, distribution, biotransformations and excretion. Modification of anyone of these processes can influence drug level at the site of action and thus the therapeutic effect of the drug. Physiological and pathological states or drug interactions can influence pharmacokinetics of benzodiazepines and thus modification of dosage regimen may be necessary. The influence of aging, liver disease, drug interactions such as alcohol, antidepressants... is of importance. Consequences of these modifications are discussed.