Vatsanabh (Aconitum ferox) - Dosage & Toxicology

Nomenclature

• Botanical name: Aconitum ferox (Indian Aconite)
• Common names: Mitha Bish, Mitha Zahar, Bikh, Monk's Hood, Blue Rocket, Bear's Foot
• Active alkaloid in A. ferox: Pseudoaconitine (Veratroyl-aconine) - most toxic of all aconite alkaloids

Therapeutic / Ayurvedic Dose

• Purified Vatsanabha (Shodhita): 15 mg (as per Ayurvedic Formulary of India)
• Some sources cite: 60-125 mg (likely for prepared/compound formulations)
• Used as: antipyretic, analgesic, anti-rheumatic, appetizer, digestive

"Foetal dose" in the context of Ayurvedic pharmacology refers to the minimum effective dose for a potent drug - for Vatsanabha this is 15 mg of purified root powder (post-Shodhana purification).

Fatal Dose

• P.C. Dikshit Textbook of Forensic Medicine, p. 542
• Essentials of Forensic Medicine & Toxicology, 36th ed. (2026)

Mechanism of Action

1. Stimulates then paralyzes sensory nerve endings (tingling → numbness)
2. Depresses medullary centers (sparing higher CNS)
3. Negative inotropic and chronotropic effects → heart block / ventricular tachycardia/fibrillation
4. Depresses smooth and skeletal muscle
5. Hypothermia via thermoregulatory center depression

Clinical Features

• Immediate onset after ingestion
• Bitter taste, burning oral sensation, nausea, vomiting, salivation
• Hippus (alternating pupillary dilation/constriction), diplopia
• Slow, irregular pulse; subnormal temperature
• Consciousness remains clear till death
• Death by ventricular fibrillation / respiratory paralysis

Management

• Gastric lavage with tannic acid or milk
• Activated charcoal
• Atropine sulfate 1 mg IV for bradycardia
• Magnesium sulfate for arrhythmia
• Oxygen + assisted ventilation
• Maintain normothermia

Autopsy Findings

• Asphyxial signs
• Congestion of all organs and GI mucosa
• Frothy mucoid bronchial secretions
• Aconitine/pseudoaconitine are unstable - degrade rapidly postmortem (forensically significant)

Medico-Legal Significance

• Accidental poisoning common (therapeutic use in Ayurveda, mistaken for horseradish root)
• Used in homicidal poisoning - taste masked with betel leaf
• Used as arrow poison in hilly tribal areas
• Added to liquor to increase intoxicating effect

Vatsanabh (Aconitum ferox) When Injected

Key Point

Routes of Absorption - Comparison

• Vatsanabha can be absorbed through intact skin (percutaneous absorption), which is forensically significant - handlers must take precautions.
• Injected aconitine bypasses all first-pass and GI barriers, delivering the full dose directly to systemic circulation.

What Happens When Injected

• Binding voltage-gated sodium channels - keeps them in a persistently open state
• This causes sustained depolarization of cardiac, neural, and muscle cells

1. Immediate local effect: Intense burning, tingling, and paresthesia at injection site
2. Rapid systemic absorption: Within seconds (IV) or 1-2 minutes (SC/IM)
3. Neurological: Paresthesia spreading throughout body, muscle weakness, ataxia
4. Cardiovascular (most dangerous):
   • Severe bradycardia or paradoxical tachyarrhythmia
   • Ventricular fibrillation / fatal arrhythmia
   • Hypotension, circulatory collapse
5. Respiratory: Paralysis of respiratory muscles
6. Death: Can occur within minutes (vs. 1-5 hours with oral ingestion)

LD50 Data (Animal Studies - Aconitine)

Fatal Dose (Injected) vs. Oral

• Oral fatal dose: 1-2 g root / 2-5 mg aconitine
• Minimum lethal oral dose (human): ~1-2 mg aconitine
• Injected (estimated): much lower - fractions of a milligram IV can be fatal due to 100% bioavailability and direct cardiac access

Medico-Legal Significance

• Injection of aconitine has been used in homicidal poisoning - it is nearly undetectable postmortem as pseudoaconitine degrades rapidly
• The rapid fatal period after injection (minutes) makes it extremely dangerous as a homicidal agent
• Forensic detection requires LC-MS/MS or GC-MS analysis of blood/urine/gastric contents within a short postmortem window

Key Warning

Vatsanabha is contraindicated for injection. Even handling the raw root without gloves poses a risk of percutaneous poisoning. Its use is strictly limited to purified (Shodhita) oral preparations in tiny doses under Ayurvedic supervision.

• P.C. Dikshit Textbook of Forensic Medicine, p. 542
• Essentials of Forensic Medicine & Toxicology, 36th ed. (2026)
• PMC research on aconitine forensic toxicology