Chloral Hydrate
Chloral Hydrate: A Sedative Poison
Introduction
Chloral hydrate is a sedative and hypnotic drug first synthesized in 1832. It has been widely used in medicine as a sleep aid and pre-anesthetic sedative. However, due to its potential for abuse, toxicity, and availability, chloral hydrate has also been associated with poisonings, both accidental and intentional. In higher doses, it can become a lethal poison, leading to its classification as a dangerous substance when misused.
Source and Occurrence
Chloral hydrate is a synthetic compound derived from chloral. It is a clear, colorless liquid or crystalline solid with a distinctive, pungent odor. Initially used as a medical sedative, it can still be found in some preparations, though its use has significantly declined due to safer alternatives.
Mechanism of Action
Chloral hydrate works by depressing the central nervous system (CNS). When ingested, it is metabolized by the liver into trichloroethanol, the active form that exerts its sedative effects. This metabolite interacts with GABA (gamma-aminobutyric acid) receptors, enhancing inhibitory neurotransmission and leading to drowsiness, relaxation, and sleep.
In cases of poisoning, chloral hydrate can overwhelm the CNS, leading to severe depression of respiratory and cardiovascular function. In high doses, this can result in coma, respiratory failure, and death.
Symptoms of Poisoning in Humans
Chloral hydrate poisoning can occur when the drug is taken in excessive amounts. Symptoms of toxicity include:
- Severe drowsiness
- Slurred speech
- Confusion
- Loss of coordination
- Shallow breathing
- Irregular or slowed heart rate
- Nausea and vomiting
- Hypotension (low blood pressure)
- Coma
In lethal cases, death is typically caused by respiratory depression and cardiac arrhythmias.
Lethal Dose and Time to Kill
The lethal dose (LD50) of chloral hydrate varies depending on the individual and method of administration. The approximate lethal dose for an adult is 4–10 grams, though much lower doses can be fatal in certain situations, particularly when combined with alcohol or other CNS depressants.
Symptoms of toxicity can begin within 30 minutes of ingestion, with death occurring in a matter of hours without medical intervention.
Treatment
There is no specific antidote for chloral hydrate poisoning. Treatment is supportive and focuses on maintaining the patient’s breathing and circulation. Common treatment options include:
- Activated charcoal to reduce absorption if ingestion is recent.
- Intravenous fluids to stabilize blood pressure.
- Oxygen or mechanical ventilation to support breathing.
- Cardiac monitoring to detect and manage arrhythmias.
- Benzodiazepines to control seizures if they occur.
In cases of severe overdose, gastric lavage (stomach pumping) may also be considered.
Detection in Autopsy
Chloral hydrate can be detected during an autopsy by analyzing biological samples such as blood, urine, or stomach contents. Gas chromatography and mass spectrometry are common methods used to detect chloral hydrate and its metabolite, trichloroethanol. In cases of fatal poisoning, elevated levels of these substances will be found in the deceased’s system.
Use in Medical Settings
Despite its potential toxicity, chloral hydrate has been used in medical settings as a sedative, particularly in pediatric patients. It has historically been used to induce sleep or calm patients before surgical procedures. However, due to its risks, it has largely been replaced by safer alternatives, such as benzodiazepines.
Risks of Abuse and Poisoning
Chloral hydrate is also infamous for its role in “knockout drops” or “Mickey Finns”—drinks laced with sedatives to incapacitate victims for robbery or assault. Ingesting large amounts of chloral hydrate, especially when mixed with alcohol, dramatically increases the risk of respiratory failure and death.
Conclusion
Chloral hydrate is a powerful sedative with a history of both therapeutic use and abuse. While it can be beneficial in controlled medical settings, its potential for poisoning makes it a substance to handle with extreme caution.
