Nature

● Atropine is naturally occurring Atropa belladonna alkaloids.

● It is also called deadly nightside.

● It is perennial herb that grows in arid land.

● It grows to 2m in height with ovate leaves of 18cm long.

● The chemical formula of atropine is C₁₇H₂₃NO_3.

● It is usually needle-like or white colour crystalline powder.

● It is highly soluble in water.

● It has prominent anticholinergic effects and can cause full-fledged anticholinergic syndrome.

● It is also used as antidote to treat many types of poisonings.

Other Name – Daturin

Family – Solanaceae

Poisonous Parts

• Roots
• Leaves
• Fruits

Active Principle

The active principles are scopolamine, hyoscyamine.

Uses

● Treatment of bradycardia, vagal syncope.

● Preanaesthetic medication (for reducing salivation and bronchial secretions)

● Antidote for organophosphates, carbamates, and certain mushrooms.

● Treatment of iridocyclitis, and for facilitating refractory procedures in children (local application as eye drops or ointment).

Fatal Dose

About 10 to 100 mg of atropine (usually 60 to 75 mg). However, recovery has been recorded with 1000 mg of atropine.

Fatal Period

About 24 Hours through atropine poisoning is rarely fatal.

Administration

It is administered through injection by intravenous, subcutaneous, intramuscular or endotracheal.

Mode of Action

● The alkaloids competitively inhibit the muscarinic effects of acetylcholine.

● Site of action are at automatic effectors innervated by postganglionic cholinergic nerves or on sweat glands, smooth muscles which do not contain cholinergic innervations.

● Majority of the CNS actions are due to blockage of muscarinic receptors in the brain viz. vagal stimulation, decrease in heart rate. High doses cause cortical excitation, restlessness, disorientation, hallucinations and delirium followed by respiratory depression and coma.

Absorption, Metabolism and Excretion

► The alkaloids are quickly absorbed from all mucus membrane and skin.

► The alkaloids are excreted by the kidneys.

► Bioavailability – 95%

► Presystemic metabolism -860 ng/ml (after 40 mg 1% atropine in eye).

► Pharmacologic effects -2 to 3 ng/ml onwards

► Time to peak plasma level- 13 minutes (IM) 1 hour (oral) , 1.5 to 4 hours (aerosol), Volume of distribution -2 to 4 L/kg

► Plasma protein binding -50%

► Elimination half-life 2 to 4 hours

► Excreted unchanged -20 to 50%

Sign and Symptoms

● Dryness of mouth (dry as bone)

● Bitter taste

● Excessive thirst

● Difficulty in talking

● Dysphagia

● Dilated pupils

● Flushed face

● Diplopia

● Difficulty in speech

● Difficulty in vision (blurring of vision, blind as bat)

● Dry hot skin with flushing (red as beet)

● Hyperpyrexia (hot as hare)

● Drunken gait (ataxia)

● Increases cardiac and respiratory activity

● Elevate blood pressure

● Temperature elevation

● Inability to swallow Urine retention

● Hyperreflexia

● Convulsions

● Delirium

● Hallucinations

● Agitation

● Amnesia

● Inability to swallow

● Urine retention

● Incoherence

● Clouded sensorium

● Disorientation

● Depression

● Dehydration

● Anxiety

● Visual or auditory hallucinations.

● Deficit of recent memory.

● Remote memory undisturbed

● Dysuria

● Distention of bladder (retention of urine)

● Coma

● Death.

Management

► Treat the patient in quiet and dark environment.

► Gastric lavage with activated charcoal.

► Treat respiratory failure with endotracheal intubation and assisted ventilation. Catheterize bladder.

► Cathartic is given when patient is treated 24 hours after ingestion because intestinal motility is decreased.

► Monitor ECG, pulse and regulate patient’s temperature.

► Hyperpyrexia can be managed by hydration, cold sponging or cooling measures.

► Administer IV fluids, keeping a close watch on intake and output and renal function.

► Agitation can be controlled with judicious use of diazepam/lorazepam.

► Antidote is physostigmine should be administered. Intravenous physostigmine is given slowly over 5–10 minutes if hyperthermia, delirium, convulsions, hypertension and arrhythmias occurred.

► Drugs to be avoided during the treatment of datura poisoning such as antihistamines, phenothiazines, tricyclics, quinidine, disopyramide, procainamide, and morphine.

Isolation

► The minced tissues and other biological materials are treated with 5% of acetic acid.

► Ammonium sulphate is used for deproteinisation.

► The material is heated over boiling water bath for 6 hours.

► The filterate is extracted with organic solvent in alkaline medium.

Forensic Examination and Test for Detection

● Microscopic Test- Microscopic examination of seeds or fragments of seeds picked from stomach contents or vomitus shows characteristics features.

● Physiological Test- 1 drop of the purified extracted residue in 0.5% acetic acid is installed in cat’s eye which become dilated after a few hours.

● Mydriatic Test- If the pupils do not constrict within 15 to 30 minutes after instillation of 2–3 drops of 1% pilocarpine, then it indicates atropine or anticholinergic poisoning.

● Cat’s eye test– Instillation of a few drops of the patient’s urine into the eyes of a cat results in rapid mydriasis.

● Thin Layer Chromatography (TLC)– TLC give different Rf values for different constituents of dhatura such as atropine, hyoscine etc.

● Gas Chromatography- Mass Spectrometry – Minute traces of atropine in blood (as low as 10 ng/ ml) can be detected by GC-MS (gas chromatography-mass spectrometry).

● High performance Liquid chromatography.

Toxicological Materials

• Vomitus
• Purges and faeces
• Stomach contents and wash
• Blood and urine
• Intestine

Postmortem Findings

► There is nothing characteristics.

► Seeds may be found in viscera and gastrointestinal track.

► Gastrointestinal tract shoe inflammation and may be congested.

► Signs of asphyxia are often present.

► Pulmonary edema

Medicolegal Importance

► Accidental death may occur since atropine seeds may be mistaken for chilly seeds.

► The suicidal cases is rare but have been reported.

► Atropine is also used in Homicide cases.

► Atropines are used as stupefying agent to rob people.

► Robbers usually mix the atropine leaves with food or drinks and offer to travelers in train. Once the passengers are stupefied, they robbed them. Thus atropine gains popularity as railroad poison.

► The belladonna and smoked as hallucinogen.

► Belladona alkaloids resist putrefaction of body.

► Criminal responsibility- as atropine produces temporary insanity. Usually, the poison is administered without the victim’s knowledge. Hence the individual is not held responsible for his acts under the influence of atropine.

► Scopolamine is used as truth serum in narco analysis test.

► It also used as pesticide poisoning to kill human beings.

References

1. Dr. K.S. Narayan Reddy. The essential of forensic medicine and toxicology. 34^th edition.
2. VV Pillay. Modern medical toxicology. 4th edition.