Hemlock Poisoning Medication

Updated: Jan 29, 2021
  • Author: Daniel E Brooks, MD; Chief Editor: Michael A Miller, MD  more...
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Medication Summary

Do not use ipecac during gastric decontamination because of risk of inducing seizures. Other agents, if indicated, can be used.


GI Decontaminants

Class Summary

Used to limit amount of adsorbed toxin.

Activated charcoal (Liqui-Char)

Emergency treatment in poisoning caused by drugs and chemicals. Network of pores present in activated charcoal adsorbs 100-1000 mg of drug per gram of charcoal. Does not dissolve in water.

For maximum effect, administer within 30 min after ingesting poison.



Class Summary

Useful in treatment of symptomatic nausea. Consider risks or benefits of increased sedation and possibility of lowering seizure threshold.

Ondansetron (Zofran)

Selective 5-HT3-receptor antagonist that blocks serotonin both peripherally and centrally.

Metoclopramide (Reglan)

Works as antiemetic by blocking dopamine receptors in the chemoreceptor trigger zone of CNS.



Class Summary

Can be used to control/prevent seizures and may decrease agitation. Rapid onset of action is advantageous, as is their improved safety profile vs barbiturates.

Diazepam (Valium)

Depresses all levels of CNS (eg, limbic and reticular formation), possibly by increasing activity of GABA.

Lorazepam (Ativan)

Sedative hypnotic with short onset of effects and relatively long half-life.

Increasing action of GABA, which is a major inhibitory neurotransmitter in the brain, may depress all levels of CNS, including limbic and reticular formation.

Monitoring patient's blood pressure after administering dose is important. Adjust prn.

Lorazepam contains benzyl alcohol, which may be toxic to infants in high doses.

Midazolam (Versed)

Used as alternative in termination of refractory status epilepticus. Because water soluble, takes approximately three times longer than diazepam to peak EEG effects. Thus, the clinician must wait 2-3 min to fully evaluate sedative effects before initiating procedure or repeating dose. Has twice the affinity for benzodiazepine receptors than diazepam. May be administered IM if unable to obtain vascular access.



Class Summary

Can be used to control/prevent seizures and may decrease agitation. Rapid onset of action is advantageous.

Pentobarbital (Nembutal)

Short-acting barbiturate with sedative, hypnotic, and anticonvulsant properties and can produce all levels of CNS mood alteration.

Phenobarbital (Barbita, Luminal, Solfoton)

Can be administered orally; in status epilepticus, it is important to achieve therapeutic levels as quickly as possible. IV dose may require approximately 15 min to attain peak levels in the brain. If injected continuously until convulsions stop, brain concentrations may continue to rise and can exceed that required to control seizures. Important to use minimal amount required and wait for anticonvulsant effect to develop before giving a second dose.

If IM route chosen, administer into areas with little risk of encountering a nerve trunk or major artery such as one of large muscles like gluteus maximus, vastus lateralis, or other. Permanent neurological deficit may result from injecting into or near peripheral nerves.

Restrict IV use to conditions in which other routes are not possible, either because patient is unconscious or because prompt action is required.


General anesthetics

Class Summary

Can be used to control seizures.

Propofol (Diprivan)

Phenolic compound unrelated to other types of anticonvulsants. Has general anesthetic properties when administered IV.