Nature
Chloral hydrate is one of the inebriant poisons. These types of poisons depress the central nervous system. It is a colourless, crystalline substance having a characteristics pungent smell and a bitter taste. It is also known as Mickey Finn or Knock out drops. It is readily soluble in water and alcohol.
In certain districts, it is known as Sukha sharab (dry liquor). It is added to alcoholic drinks by clandestine vendors to increase the potency of the drinks. It is also known as a hypnotic in medicine.
Uses
Chloral hydrate is used as a sedative or hypnotic.
Fatal Dose
The fatal dose of chloral hydrate is about 5 to 10g.
Fatal Period
The fatal period of chloral hydrate is 8 to 12 hours.
Absorption, metabolism and excretion
● Chloral hydrate is well absorbed through stomach and intestine.
● It is readily metabolised to trichloroethanol in liver by enzyme alcohol dehydrogenase. This is the active form which is later conjugated with glucuronic acid.
● It is excreted in urine as urochloralic acid.
Sign and symptoms
- Nausea
- Vomiting
- Gastric irritation
- Miosis
- Hypotension
- Renal and hepatic damage
- Cardiac arrhythmias
- Ventricular fibrillation
- Ventricular tachycardia
- Torsades de pointes
- Cardiac arrest
- Respiratory depression
- Coma
- Non-cardiogenic pulmonary oedema
- Aspiration pneumonitis have been also reported after massive overdose.
- Renal tubular toxicity may occur between 2 and 5 days followed by ingestion.
- Pupils are usually miotic initially, but later may be dilated.
- Breath may have a pear-like odour.
- Death usually occurs from paralysis of the respiratory Centre.
Chronic Poisoning
- It occurs due to prolonged therapeutic use.
- Gastrointestinal irritation with erythematous and urticarial eruptions on skin.
- Tremors and dyspnoea.
- Convulsions
- Mental degeneration and liver damage may occur.
- Habitual use can lead to tolerance and physical dependence with delirium when the drug is withdrawn.
Treatment
● Gastric lavage should be administered immediately.
● Cardiac arrhythmias should be managed.
● The patient should be managed on conservative lines.
● Emesis is not recommended.
● In the case of liquid ingestions, a small flexible tube may be indicated to prevent oesophageal damage.
● Anti-arrhythmic drugs, a beta-adrenergic antagonist or adrenergic neurone blocking drug such as bretylium may have to be administered.
● Propranolol has been the most commonly used beta-adrenergic blocker for chloral hydrate-induced arrhythmias. Doses are given as 1 mg/dose intravenously, administered no faster than 1 mg/min repeated every 5 minutes until the desired response is seen, or a maximum of 5 mg has been given.
● Esmolol, a short-acting beta-blocker, may be effective to propranolol because of rapid onset and short duration of action, enabling rapid attenuation of adverse effects if the patient’s status deteriorates. Doseis preferred as Infuse 500 mcg/kg for one minute. Follow loading dose with infusion of 50 mcg/kg per minute for 4 minutes. If inadequate response to initial loading dose and 4 minute maintenance dose, repeat loading dose (infuse 500 mcg/kg for one minute), followed by a maintenance infusion of 100 mcg/kg /min for 4 minutes.
● Arrhythmias refractory to propranolol or esmolol may respond to lignocaine.
● Torsades de pointes usually respond to magnesium sulfate or isoproterenol or amiodarone.
● For hypotension, infuse 10 to 20 ml/kg of isotonic fluid and place in Trendelenburg position.
● Flumazenil of 200 micrograms followed by three additional 100-microgram doses, at one minute intervals may be effective as dramatic improvement in chloral hydrate poisoning according to some investigators.
●Haemodialysis and haemoperfusion have been managed as beneficial, and may be effective in a patient unresponsive to normal supportive care, or in whom acid-base or fluid and electrolyte problems may become uncontrollable.
Post Mortem Findings
- Gastric mucosa becomes softened.
- Gastric mucous become reddened and eroded
- Smells of chloral hydrate.
- Brain and lungs are congested.
- Hepato-renal damage is seen.
Test of Detection or Forensic Examination
● If victims is administered with Chloral hydrate tablets and capsules then it may be visualize by X-ray.
● Diagnostic test involves the instillation of a small amount of the suspected liquid in 10 ml of water, to which 2 ml of purified aniline and 4 ml of 20% sodium hydroxide are added and heated gently. Then, the evolution of a foul odour (skunk odour) is an indication of chloral hydrate poisoning which also occurs with chloroform and carbon tetrachloride. The test can also be done on 10 ml of distillate.
● Chloral hydrate and trichloroethane in plasma can be analyzed by gas chromatography.
Medico Legal Aspects
● Accidental poisoning is common which results by taking large doses as hypnotic medicine.
● Suicidal cases are rare but have been reported.
● It has been also used to stupefy the victim by giving it in food or drink to render a person suddenly helpless for the purpose of robbery or rape. Its action is so rapid under such conditions that it has been given the name of ‘knockout drops’ and a combination of alcohol and chloral is commonly known as ‘Mickey Finn’.
● It is often added to liquor to increase its potency or intoxication.
● Homicide is also rarely but has been reported.
References
- Dr. K.S. Narayan Reddy. The essential of forensic medicine and toxicology.34th edition.
- VV Pillay. Modern medical toxicology.4th edition.
- R.K.Sharma. Concise textbook of forensic medicine and toxicology. 3rd edition.
