Poison is a substance that puts people’s lives at risk because of its poisonous reaction/poisoning on the body’s vital functions. Very high dosages of drugs, industrial chemicals/gases, and household chemicals such as insecticides (DDT, BHC, etc.) are some examples of dangerous substances.
Antidotes are substances that counteract the effects of poisons and toxins. Antidotes work by stopping the toxin from being absorbed, binding and neutralising the poison, antagonising the poison’s end-organ impact, or inhibiting the toxin’s conversion to more dangerous metabolites.
Read Also: Drugs and Their Antidotes
Antidotes are agents that neutralise the effects of poison. They are classified as:
Physical or Mechanical antidote inhibits the action of a poison mechanically, without eliminating or neutralising the poison’s harmful effects. Adsorbents such as activated charcoal, demulcents such as egg albumin, starch, or milk, diluents such as water or milk, and bulky foods such as cooked rice or vegetables are examples.
Chemical antidotes are compounds that dissolve and inactivate toxins through a chemical process. Weak acids and alkalis, common salt, egg albumin, and KMNO4 are a few examples.
Physiological antidotes have their own effect, causing indications and symptoms that are opposite to those caused by the toxin. For instance, Naloxone for morphine, Neostigmine for datura or the hyoscin group, and Barbiturate for strychnine.
The term “universal antidote” refers to a cocktail of physical and chemical antidotes. When the precise nature of the poison is unknown, a universal antidote that is effective against a wide spectrum of poisons is applied.
▪ Activated charcoal acts as an adsorbent,
▪ Magnesium oxide neutralises acids and toxins, and,
▪ Tannic acid precipitates alkaloids.
Read Also: Specific Antidotes
Antidotes found at home are known as household antidotes. Some of them are given below:
1. Alkaloid and metallic poisons are precipitated by strong liquid tea (which contains tannic acid).
2. Starch for iodine.
3. Milk and raw eggs for mercury, arsenic, and heavy metals.
4. Flour suspension and mashed potatoes can be substituted for activated charcoal.
5. For acid poisoning, use milk of magnesia or a soap solution.
6. For alkali poisoning, use orange juice, lemon juice, or vinegar.
Anti-snake venom serum is a serological antidote for snake bite poisoning.
Snake venom has just one distinct antidote: antivenom.
Antivenom is an immunoglobulin extracted from the serum or plasma of a horse or sheep immunised against the venoms of one or more snake species. Antivenom should be administered intravenously. For any suspected anaphylactic responses, adrenaline should always be prepared before antivenom is delivered.
Chelating agents are compounds that act on metal toxins that have been ingested. When compared to indigenous enzymes, they have a higher affinity for metals. Because the complex of agent and metal is more water soluble than the metal itself, the complex is excreted more efficiently by the kidneys. Eg: British anti-lewisite (B.A.L., dimercaprol), E.D.T.A. (ethylene diamine acetic acid), Penicillamine (Cuprimine), Desferroxamine etc.
a.) British Anti-Lewisite (B.A.L., 2-3 dimercaptopropanol) has two unsaturated SH radicals that react with metal in circulation, sparing tissue enzymes. Useful in situations of arsenic, mercury, copper, bismuth, gold, and other heavy metals.
b.) E.D.T.A. (Ethylene diamine tetra-acetic acid) reacts with sodium to generate sodium salt, then with calcium to form disodium calcium edentate, which reacts with free metal and physiologically inactivates it. It is the most effective chelate for lead. Adults should take 1 gm twice daily at a 12-hour interval, using a slow I.V. injection mixed with 5% glucose saline.
c.) D-Penicillamine is used to treat copper, mercury, and lead toxicity, as well as Wilson’s disease, cystinuria, scleroderma, and rheumatoid arthritis.
d) Calcium Disodium Edetate – This medicine is used to treat lead poisoning. It helps with iron, zinc, copper, manganese, and radioactive metal poisoning, but not mercury poisoning.
e) Deferiprone is an iron chelator that can be taken orally. It can help with acute iron poisoning, cirrhosis iron overload, and thalassemia patients’ transfusion siderosis.
f) Desferrioxamine – This chelator is used to treat acute iron poisoning as well as chronic iron overload in individuals with thalassemia who require multiple transfusions. Desferrioxamine is a specific antidote for iron. Orally, take 8-12 gm. 2 gm iron absorbed I.V. in a 50 percent laevulose solution.
Disulfiram is a medication that is used to treat chronic alcoholism. When even modest amounts of alcohol are drunk, it has adverse affects.
a) Leucovorin- It is utilised as a calcium leucovorin (calcium folinate). It’s a tetrahydrofolic acid derivative that works as an antidote to folic acid antagonists like methotrexate and pyrimethamine, which stop the enzyme dihydrofolate reductase from working.
b) Pralidoxime- It is used as an antidote for organophosphorus poisoning caused by substances such as malathion, TEPP, and parathion.
c) Nicotine- Nicotine is used to treat nicotine addiction and as a smoking cessation aid.
Read Also: Forensic Toxicology (Poisoning)
d) Bupropion— It’s used to help people quit smoking.
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