Barbiturates are a high-risk drug. Their therapeutic index is slim, meaning there is a narrow margin between the minimally effective therapeutic dose and the toxic or lethal dose. In addition to acute risk factors, barbiturate dependence is characterized by a particularly severe abstinence syndrome upon discontinuation - untreated withdrawal in heavy users is known to cause serious complications and death.Pharmacology:
Though barbiturates target the same receptor type as benzodiazepines and similarly act as positive allosteric modulators for GABA-a, they elicit a cellular response which slightly differs from that of benzodiazepines; Barbiturates increase the amount of time which ion channels of the GABA-a receptor remain opened, increasing the efficacy of GABA; while benzodiazepines cause ion channels to open more frequently, enhancing the potency of GABA. The specific action of barbiturates at this ion channel leads to a greater toxicity compared to benzodiazepines (particularly in cases of overdose).
Barbiturates were at one time heavily used to treat anxiety and insomnia. They have been largely replaced since the advent of benzodiazepines, which are preferred for their favorable safety profile and lower capacity for producing dependence. They are however still available, but their use is limited mostly to surgical anaesthesia, seizure disorders, severe alcohol & opioid withdrawal, hastening death (i.e. assisted suicide), and execution by lethal injection.
Common Barbiturates, Past or Present Include: