Call 2-1-1 for local resources · Life-threatening emergencies: 9-1-1
Back to education guides

Substance education guide

Barbiturates (Phenobarbital, Butalbital, Secobarbital)

GABA-A positive allosteric modulators · Central nervous system depressants

· How it works

Classification and primary mechanism

Barbiturates prolong GABA-A chloride-channel opening and, at high concentrations, can directly open the channel while also blocking excitatory AMPA and kainate signaling. This deep neural suppression creates a narrow therapeutic index without the safety ceiling of benzodiazepines.

· Immediate effects

Recognize the effects

Signs of Use

  • Slurred speech, drowsiness, poor coordination, and slowed thinking
  • Ataxia, nystagmus, impaired judgment, and confusion
  • Hypotension, hypothermia, weak reflexes, and shallow breathing
  • Stupor, coma, aspiration, or absent breathing
  • Paradoxical agitation or disinhibition in some people

Short Term

  • Low exposure: relaxation, sedation, impaired coordination, and slowed reaction time
  • Moderate exposure: confusion, ataxia, nystagmus, and poor airway protection
  • Severe exposure: coma, hypotension, hypothermia, respiratory arrest, and death
  • Alcohol, opioids, and benzodiazepines can make respiratory depression rapidly fatal
  • Overdose requires airway and breathing support, not simply observation

Long Term

  • Tolerance, severe physical dependence, and dangerous withdrawal
  • Withdrawal seizures, delirium, hallucinations, and autonomic instability
  • Cognitive impairment, falls, and aspiration risk
  • Liver enzyme interactions that alter other medication levels

· Long-term consequences

Respiratory depression and withdrawal

Call 911 for unresponsiveness or abnormal breathing. Support the airway, provide rescue breathing if trained, and do not abruptly stop regular barbiturate use without medical supervision because withdrawal can cause fatal seizures.

Back to education guides