Antidotes

Antidotes

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  Antidotes By Ms.Preeti SMVDCoN
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  • According toWHO “Antidote was defined as a therapeutic substance used to counteract the toxic action(s) of a specified xenobiotic.” • Antidotes reduce the overall burden of health service in managing of poisoning cases
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  INTRODUCTION • An antidoteis a substance thatcan counteract a form of poisoning.The term ultimately derives from the Greek term (pharmakon) antidoton, "(medicine) given as aremedy". • Antidotes for anticoagulants are sometimes referred to asreversal agents.
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  INTRODUCTION • The antidotesfor some particular toxins are manufactured by injecting the toxin into an animal in small doses and extracting the resulting antibodies from the host animals' blood. This results in an antivenom that can be used to counteract venom produced by certain species of snakes, spiders, and other venomous animals. Some animal venoms, especially those produced by arthropods (e.g., certain spiders, scorpions, bees, etc.) are only potentially lethal when they provoke allergic reactions and induce anaphylactic shock; as such, there is no "antidote" for these venoms because it is not a form of poisoning and anaphylactic shock can be treated (e.g., by the use ofepinephrine).
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  ANTIDOTES Supportiv e therapy Correc t antidot e 1 Patient surviva l
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  CLASSIFICATION OF ANTIDOTE •According to mode of Action: Physic al Chemica l Physiological/ pharmacological
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  Physical Antidote: • Agentuse to interfere with poison through physical properties, not change their nature. • a) Adsorbing: The main example is activated charcoal. • b) Coating: A mixture of egg & milk make a coat over the mucosa. • c) Dissolving: 10% alcohol or glycerin for carbolic acid
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  Chemical Antidote: Interact specificallywith a toxicant, or neutralize the toxicant. e.g. metal chelators combine with metals to form complexes that can then be eliminated by the kidneys Mainly act by twomechanisms: Complex Formation: Antidote make complex with the toxicant making it unavailable to cross the membrane or to interact with receptors. DMSA(dimercaprol and dimercaptosuccinic acid are sulfohydral compounds that bind metal such as arsenic acid,lead.
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  Pharmacological antidote counteract theeffects of a poison by producing the opposite pharmacological effects, e.g., ACHE inhibitors,atropine. •Pharmacologic antidotes may neutralize or antagonize the effects of a toxicant. •This type of antidote may act by following 5 mechanism.
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  Some specific Antidotesfor drugs and chemicals S.No. Agent causing toxicity Antidotes Dose 1. Paracetamol N-acetyl cysteine Oral =140mg/kg followed by 70mg/kg even 4hrs,or IV 150mg/kg infusion over 15min. Repeated as required. 2. Morphine andother opoids naloxone 1-2mg IV repeatedevery 10-15 minutes 3. heparin Protamine sulphate 1mg iv for every100units of heparin 4. cyanide sodium nitrate+ Sodium thiosulfate 10 ml of 3% solutionIV 50 ml of 25% solution iv
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  Some specific Antidotesfor drugs and chemicals S.No. Agent causing toxicity Antidotes Dose 5. Copper D-penicillamine 100mg/kg/day orally in 4 divided dose for 3-7 days 6. Iron Desferrioxamine 15mg/kg/hour IV 7. Arsenic Dimercaprol 1st day 400-800 mg deep IM in divided dose 2nd and 3rd day 200-400mg.4th day onwards 100-200mg. 8. Led calcium disodium edetate 1 gram in 250mlsaline infusion twice aday
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  Some specific Anidotesfor drugs and chemicals S.No. Agent causing toxicity Antidotes Dose 9. Insulin Glucose 50ml of 50% solution 10. Mathanol, ethylene glycol Ethanol 10% ethanol is givenorally 11. Carbon monoxide Oxygen 100% by high flownon- rebreathing mask 12. Nitrites Methyline blue 0.1% solution slow IV in the dose of 1-2 mg/kg body weight
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  Some specific Antidotesfor drugs and chemicals S.No. Agent causing toxicity Antidotes Dose 13 Warfarin Vitamin K 1 oxide 10mg IM followed by 5mg 4 hrly asrequired 14 Benzodiazepines Flumazenil 0.2 mg IV repeatedas required (max. 3mg) 15. Caffeine Esmolol 25-50µ/kg/min-IV 16. Atropine physostigmine 1-2mg IV slowly may be repeated if symptoms re- appear.