Abstract

Barbiturate overdose is poisoning due to excessive doses of barbiturates. Symptoms typically include difficulty thinking, poor coordination, decreased level of consciousness, and a decreased effort to breathe (respiratory depression). Complications of overdose can include noncardiogenic pulmonary edema. If death occurs this is typically due to a lack of breathing.

Barbiturate overdose may occur by accident or purposefully in an attempt to cause death. The toxic effects are additive to those of alcohol and benzodiazepines. The lethal dose varies with a person's tolerance and how the drug is taken. The effects of barbiturates occur via the GABA neurotransmitter. Exposure may be verified by testing the urine or blood.

Treatment involves supporting a person's breathing and blood pressure. While there is no antidote, activated charcoal may be useful. Multiple doses of charcoal may be required. Hemodialysis may occasionally be considered. Urine alkalinisation has not been found to be useful. While once a common cause of overdose, barbiturates are now a rare cause.

Mechanism

Barbiturates increase the time that the chloride pore of the GABA receptor is opened for, thereby increasing the efficacy of GABA. This is as opposed to benzodiazepines which increase the frequency that the chloride pore is opened, thereby increasing GABA's potency.

Treatment

The treatment of barbiturate abuse or overdose is generally supportive. The amount of support required depends on the person's symptoms. If the patient is drowsy but awake and can swallow and breathe without difficulty, the treatment can be as simple as monitoring the person closely. If the person is not breathing, it may involve mechanical ventilation until the drug has worn off.

Supportive treatment often includes the following:

- Activated charcoal may be given via nasogastric tube.

- Intravenous administration of saline, naloxone, thiamine, and/or glucose.

- Intubation and bemegride, or a hand-breather where these are not available until the patient can breathe under their own power.

- Observation in the Emergency Department for a number of hours or admission to the hospital for several days of observation if symptoms are severe.

- Advise the patient about drug misuse or refer for psychiatric consult.

Notable cases

In famous cases, Marilyn Monroe, Dalida, Judy Garland, George Sanders, Pier Angeli, Jimi Hendrix, Alan Wilson, Scotty Beckett and Edie Sedgwick died from a barbiturate overdose.