Benzodiazepines were first marketed in the 1960s. It has only been recently that an awareness has developed that benzodiazepines share many of the undesirable side effects of the barbiturates. A number of toxic CNS effects are seen with chronic high dose benzodiazepine therapy. These include headache, irritability, confusion, memory impairment, depression, insomnia and tremor. The risk of developing over-sedation, dizziness and confusion increases substantially with higher doses of benzodiazepines.
Prolonged use can lead to physical dependence even at recommended dosages.
Unlike barbiturates, large doses of benzodiazepines are rarely fatal unless combined with other drugs or alcohol. Although primary abuse of benzodiazepines is well documented, abuse of these drugs usually occurs as part of a pattern of multiple drug abuse. There are marked similarities among the withdrawal symptoms seen with all drugs classified as depressants. In it mildest form, the withdrawal syndrome may produce insomnia and anxiety, usually the same symptoms that initiated the drug use. With a greater level of dependence, tremors and weakness are also present, and in its most severe form, the withdrawal syndrome can cause seizures and delirium.