What is the major disadvantage of barbiturate use?

Potential for drug dependence

Patients can become dependent on barbiturates, especially with prolonged use. Because of the rapid distribution of some barbiturates, no correlation exists between duration of action and half-life. Barbiturates are absorbed well and do not cause hepatotoxicity, although existing hepatic damage does require cautions use of the drug because barbiturates are metabolized in the liver.