2. Active
Principle
Entire plant is toxic
Digitalis contain many cardio active or
steroid glycosides
Most powerful constituent is Digitoxin which
is cumulative in action
Physiologically active chemical constituents
include digitonin and digitoflavone
3. Mechanism
of Action
Digoxin induces an increase in intracellular sodium that
will drive an influx of calcium in the heart and cause an
increase in contractility. Cardiac output increases with a
subsequent decrease in ventricular filling pressures.
AV Node Inhibition: Digoxin has vagomimetic effects on
the AV node.
By stimulating the parasympathetic nervous system, it
slows electrical conduction in the atrioventricular node,
therefore, decreases the heart rate. Slower conduction
through the AV node carries a decreased ventricular
response
4. Fatal dose
and fatal
period
• Fatal dose: digitalin(15-30 mg)
digitoxin(4mg)
digoxin(10 mg) and leaf(2mg)
• Fatal period: 1-24 hrs
5. Clinical
features
• GI effects - nausea, severe vomiting ,
abdominal pain and diarrhoea
• CNS and visual – mental confusion,
drowsiness ,tremor and convulsions, visual
disturbances i.e. coloured vision and
diplopia
• Cardiac effects – cardiac arrythmia,
conduction defects etc. leading to death due
to cardiovascular collapse
6. Treatment
• Stomach wash with tannic acid solution
• Bowel evacuation
• Activated charcoal in repeated dose
• Digoxin specific antibody fragments one vial i.v. in 30 min(10-20 vial)
• In absence of fab fragments, ventricular irritability can be treated by
phenytoin 50mg/min i.v. upto 1 gm followed by 300-400 mg daily
• Trisodium EDTA lower the serum Ca
• Potassium salts to reduce extra systoles and tacchyarrythmias
• Bradycardia treated with atropine sulphate(0.6mg iv)
7. PM Appearances
• No specific signs
• May be irritation of gastric mucosa and digitalis leaves or seeds may
be found in the stomach(seeds are reddish brown, small and angular
in shape)
• Lungs are often congested
8. Medicolegal
Importance
• Most cases of poisoning are accidental,
arising out of therapeutic overdose
• Suicidal ingestion is rare, quite suitable as a
homicide poison but murder is uncommon
