Action of Poisons
After entering and being absorbed into the body, poisons exert their action through one or more of the following ways:
1. Local Actions
Some poisons exert their effect directly at the site of contact.
Examples:
- Potent mineral acids cause corrosion (kharaash/خراش).
- Whereas irritants cause congestion (امتلا) and inflammation (التهاب) at the site of contact (the place where they are applied).
Result: These changes can be prominently observed in post-mortem findings.
2. Remote Actions
Some poisons, after being absorbed into the body, affect a particular system of the body.
This effect of poisons can be Specific (مخصوص) or Non-specific.
Examples of Specific Effects:
- Opium on the brain.
- Nux Vomica on the spinal cord.
- Squill on the cardiac muscle.
Example of Non-specific Effects:
Poison like toxic shock (corrosive poison) produce effects that non-specifically affect the brain.
3. Both Local and Remote Actions
Some poisons, such as Oxalic Acid and Carbolic Acid, produce both local and remote effects.
4. General Actions
Some poisons, after being absorbed into the body, affect multiple systems simultaneously.
- Examples: Arsenic, Mercury, Lead, and Barbiturates etc., render multiple systems of the body non-functional simultaneously.
🧠 Factors Affecting the Effects of Poisons :
The following factors can either delay or accelerate the effects of poisons (toxins):
- Dose of Poison
- Forms of Poison (Chemical/Physical State)
- Route of Administration (Method of Use)
- Physical Condition (of the Subject)
1. Dose of Poison
The general principle states that a small dose of poison acts as a “medicine.” while a larger dose produces “fatal effects.” However, this principle is negated in the following specific conditions:
Condition Explanation Example/ Mechanism Temperament Some individuals are predisposed by nature to develop severe symptoms from specific drugs or foods, even in small amounts. A normal dose of morphine, Cocaine, or Aspirin may cause severe distress in these individuals. Hypersensitivity Certain individuals are extremely sensitive to a drug, and its use may endanger their life due to an intense allergic reaction. Penicillin is a prime example of a drug causing severe hypersensitivity reactions. Habit If a person has habitually used a drug or poison in small quantities, an increased dose may not produce lethal effects, as the body develops tolerance. Higher doses of Tobacco, Alcohol, or Opium may prove ineffective in habitual users. Similarly, sleeping pill users gradually need to increase the dosage. Combined Effect Small doses of individual poisons may not produce effects, but when two poisons are used simultaneously, their combined action can produce cumulative effects. Mode of Action (Nature of Action) If a poison is emetic (causes vomiting) in a small dose, a large dose can cause violent vomiting, thereby nullifying the poisonous effects by expelling the toxin from the body. A small dose of Arsenic irritates the gastrointestinal tract, whereas a large dose can cause death by inducing Shock. Cumulative Poisons Certain poisons are not easily excreted from the body and accumulate. Small, repeated doses gradually build up in the system, causing Chronic Poisoning. Arsenic, Mercury, Lead, Barbiturates, Digitalis, and Carbon Monoxide.
2. 
Forms of Poison
Forms of PoisonLorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo.
The form of poisons significantly affects their action. The forms of poisons themselves consist of three main components: (1) Physical State, (2) Chemical Combination, and (3) Mechanical Combination. A brief description of all three is given below:
1. Physical State
The physical state (solid, liquid, or gas) of the poison determines the speed of its effect:
- Gas and Vapour: A poison in the form of gas or vapor acts faster compared to a liquid poison.
- Fine Powder: Fine powder poisons are rapid-acting compared to coarse or gritty poisons.
2. Chemical Combination
The chemical components included in the poison mixture either neutralize the poison or make it more potent:
Neutralization (Deactivation):
- Acid, when combined with Alkali, becomes inactive.
- Nux Vomica (Kutchla), when combined with Tannic Acid, becomes inactive.
Increased Potency:
- Components like Lead Carbonate and Copper Arsenite are generally insoluble in water.
- However, they dissolve in the stomach’s acid (Gastric Acid) and immediately produce toxicity (Poisoning)
3. Mechanical Combination
When certain poisons are mixed with inactive elements, their nature changes significantly:
Deactivation:
- Alkaloids, when ground with Animal Charcoal, become inactive.
Reduced Potency (Dilution):
- When an acid is diluted with water, it merely remains an irritant (i.e., its severe chemical effect is reduced).
3. Mode of Administration
Mode of Administration- Poisons act more rapidly when inhaled in the form of a gas or vapor.
- Similarly, an intravenous (IV) injection is quicker in action than an intramuscular (IM) injection.
- A poison taken after a meal does not act as quickly as it does on an empty stomach.
- Likewise, a poison acts much faster on wounded or broken skin than on healthy skin.
- Certain poisons show their effect only when administered through a specific route.
For example:
- Snake venom is ineffective if swallowed, but if administered by injection, it shows a fatal effect.
- Similarly, if cocaine is used by injection, it reduces local sensation, but if ingested, it causes delirium and convulsions.
4. ✨ Condition of the Body
The Condition of the Body is a crucial determinant in how severely a poison affects an individual. Age, state of health, and the presence of sleep or intoxication significantly alter the body’s reaction to toxins.
1. Age
- Vulnerability: Children and the Elderly are highly susceptible. They can be severely affected even by the usual dose of poisons or medicines.
- Resistance: Young Adults generally show better resistance, and toxins often have less severe effects on them.
2. State of Health
Increased Sensitivity: Individuals who are physically weak or suffering from specific diseases show heightened sensitivity to poisons.
- Example 1 (Cardio-Respiratory): In a physically weak patient, even a 30% concentration of Carbon Monoxide can be fatal.
- Example 2 (Renal Disease): In kidney diseases, a small quantity of Mercury becomes toxic.
Decreased Sensitivity/Tolerance: Conversely, in certain diseases, the body develops a high tolerance, making larger doses of specific poisons ineffective.
Examples:
- Delirium Tremens: Sedatives and Opium do not produce toxicity.
- Paralysis: Nux Vomica does not cause toxic effects.
3. Sleep or Intoxication
- Slowed Metabolism: During sleep or intoxication, the body’s Metabolism slows down drastically.
- Delayed Effects: If a poison is administered in such a state, its effects and symptoms are delayed because the body processes it much slower.
📝 Fate of Poisons in the Body
When a poison is administered in a small quantity and in liquid form, most of it is expelled from the body through vomiting or diarrhea. However, after absorption into the body, its Fate can be different:
1. Different Routes of Excretion
Direct Excretion:
- The poison is excreted via urine or sweat without undergoing any metabolic change.
Biotransformation & Excretion:
- Poisons are usually completely metabolized in the body, or
- They are converted into another active component, which is called Biotransformation.
Incomplete Metabolism:
- If the poison is incompletely metabolized, it accumulates in the liver or bile in its original form or in an intermediate form.
- Later, it is expelled through urine or feces.
2. Long-term Storage in the Body
Even after excretion, certain Inorganic Poisons remain stored in the body for a long period. Examples:
- Poisons like Arsenic, Lead, and Copper can persist for long periods in specific body tissues such as nails, hair, and bones.