TOXICOLOGYDIAGNOSIS
■ Specific testing for strychnine is not available.
TREATMENT
■ Benzodiazepines or barbituates are administered to relieve excessive mus-
cular activity.
■ More severe cases may require intubation and neuromuscular blockade.
SEDATIVE HYPNOTICSSedative-hypnotic agents are medications used to treat anxiety, panic disorders,
and insomnia.
Medications in this class include barbiturates, benzodiazepines, antihista-
mines, antidepressants, and other agents with sedating side effects.
This section is limited to a discussion of barbiturates and benzodiazepines.
Barbiturates
Barbiturates are used as sedatives, to induce anesthesia, and to treat epilepsy,
including status epilepticus.
They are categorized by their duration of action.
■ Ultrashort-acting (eg, methohexital, thiopental)
■ Short-acting (eg, pentobarbital)
■ Intermediate-acting (eg, amobarbital)
■ Long-acting (eg, phenobarbital)
The magnitude and duration of effect depends on the agent and dose.
Chronic exposure often leads to tolerance.
MECHANISM/TOXICITY
■ Bind to GABA-A chloride channel →depression of neuronal firing
■ Depress medullary respiratory centers
■ Inhibit myocardial contractility and conduction
SYMPTOMS/EXAM
■ Mild to moderate intoxication: Lethargy, nystagmus, ataxia, slurred speech
(similar to alcohol intoxication)
■ Severe intoxication: Small/midsized pupils, hypothermia, coma, respira-
tory depression, hypotension, bradycardia
DIAGNOSIS
■ Usually based on history of exposure and clinical examination
■ Serum levels may be available for agents used to treat epilepsy (eg,
phenobarbital).
■ In overdose, clinically correlate levels, and monitor for peak and decline.
TREATMENT
■ Supportive therapy
■ Gastric lavage if life-threatening ingestion and<60 minutes from ingestion
Severe barbiturate
intoxication
depressed/decreased:
HR
BP
RR
Temperature
CNS