Barbiturates, such as phenobarbital, are a class of drugs known as central nervous system depressants. Before the discovery of benzodiazepines, they were used to treat anxiety and sleep disorders. Because of their high addiction potential and risk of overdose, they have been largely replaced by benzodiazepines; although they are still prescribed for surgeries or to treat seizure disorders. Barbiturates are metabolized by CYP2E1, so concurrent ethanol use competes for this enzyme, slowing barbiturate clearance (272), and raising plasma drug concentrations. However, clinical studies have also documented cross-tolerance between ethanol and barbituric such thatethanol clearance is faster after barbiturate administration (272). In addition, there are pharmacodynamically mediated additive sedative effects that heighten the risk of respiratory depression and overdose when these two drugs are combined (273).
