Tox: Sedative hypnotics

Question 1

Examples of ‘sedative hypnotics’

Answer 1

Barbiturates, benzos, antihistamines, antidepressants.

Agents to treat anxiety, panic disorders, insomnia

Question 2

MOA of barbiturates

Answer 2

Binds to GABA -> depression of neuronal firing, depression of medullary respiratory centers.
Inhibition of myocardial contractility/conduction.

Question 3

Symptoms of barbiturate toxicity

Answer 3

Lethargy, nystagmus, ataxia, slurred speech (similar to EtOH).
Severe intox: miosis, hypothermia, coma, resp depression, hypoTN, brady.

Essentially everything depressed/decreased: HR, BP, RR, temp, CNS

Question 4

Diagnosis of barbiturate toxicity

Answer 4

Typically on hx.

Can get serum levels for some agents (e.g. phenobarb).

Question 5

Tx of barbiturate OD

Answer 5

1) Supportive
2) MSAC in phenobarb OD (if airway protected)
3) WBI if large ingestion of long acting agents and conditions appropriate.
4) HD for some

Question 6

Antidote for benzos

Answer 6

Flumazenil

Question 7

Contraindications to flumazenil

Answer 7

1) chronic benzo use
2) Co- ingestion of seizure inducing medication/drug (e.g. TCA)
3) Suspected increased ICP

not routinely used in benzo OD

Question 8

Duration of flumazenil effect

Answer 8

1 hr (recurrent sedation possible)