Barbiturates are sedative hypnotic agents, non selective in effects. At lower doses of barbiturates causes restlessness and emotional tension occurs. At increasingly higher doses, sedation is followed by increasing levels of anesthesia and eventually death.

 

Signs and symptoms

Neurological or CNS manifestation

• Lethargy/drowsiness
• Hypothermia- reduced temperature
• Decreased pupillary reflex
• Nystagmus
• Strabismus
• Vertigo
• Slurred speech
• Ataxia
• Decreased deep tendon reflexes
• Coma

Psychiatric manifestation

• Memory disturbances
• Poor judgment
• Limited attention span
• Delirium
• Irritability

Respiratory

• Respiratory depression
• Apnea or hypoxia
• Acute respiratory distress syndrome

Cardiovascular

• Tachycardia or bradycardia
• Hypotension
• Diaphoresis
• Shock

Gastrointestinal - reduced bowel sounds

Skin - Barbiturate blisters - bullous lesions typically found on the hands, buttocks, and knees

Barbiturates cause fetal craniofacial deformities and contribute to mental retardation.

Tests and diagnosis

• Complete blood count
• Serum electrolytes
• Blood glucose
• Renal function test- blood urea and serum creatine
• Arterial blood gas analysis
• Blood ethanol concentration – to rule out the presence of co- ingestant
• Pregnancy test in women of child bearing age

Barbiturate plasma concentration

• In short-acting barbiturates, a level of >35 mg/L carries an unfavorable prognosis.
• For long-acting barbiturates, a level of >90 mg/L carries an unfavorable prognosis.
• These levels do not apply to chronic barbiturate abusers.

Management of barbiturate poisoning

Cardio respiratory support

• Clean the air ways by thorough suctioning and insertion of oral airways
• If the patient is comatose, prompt intubation is strongly advocated because of worsening of respiratory failure.
• Correction of dehydration by CVP guided fluid therapy depending on the serum electrolytes.
• Treat hypotension by intravenous infusion of plasma expanders and vasopressors. In refractory cases, steroids are given.

Measures to prevent absorption

• Gastric lavage
• Activated charcoal is administrated orally or by nastrogastric tube.

Measures for removal barbiturates

• Frequent doses of activated charcoal
• Forced diuresis with alkalization of urine
• Hemodialysis and hemoperfusion

 

Supportive care

• Prophylactic antibiotics
• Good oral hygiene
• Temperature maintenance
• Posture change at regular intervals