Poison , Antidotes (Inorganic) and Cyanide poisoning

Poison

  • Poison are thechemicalsubstances which can injure, damage cells, tissues, organs, or even result in death.
  • Poisoning are taken place accidentally or intentionally to commit suicide.
  • Mostly common poisoning occurs by heavy metals or metallic contamination of food and water.
  • Poisoning may occur by the insecticides or pesticides.
  • Poisoning may occur by the over dose of drugs or medicine.

Antidote

Antidotes are the agent which counteract the Poison.

Basing upon their mechanism of action the antidotes are classified as

1. Physiological antidote

 The antidotes which are counteract the effect of poison by physiologically or may have opposite effect that of poison.

Ex -Sodium Nitrite

2. Chemical Antidote

The antidote which the chemical nature of the poison

Ex-Sodium Thiosulphate

3. Mechanical Antidote

The antidote which are prevent the absorption of poison or, expel by emesis or excrete by urine.

 

Ex- Activated Char coal, Cupric sulfate, Sodium monohydrogen phosphate (Na2HPO4),

Universal Antidote

It is a mixture of 2parts of activated charcoal, 1 part of Magnesium or Zinc Oxide and 1 part of Tannicacid.

2 parts activated Charcoal + 1 parts Magnesium Oxide or Zinc Oxide + 1 part of Tannic acid

 

Generally, it is found in first aid kits and are used to treat emergency poisioning .

Heavy metal poisoning

  • Mostly salts of Arsenic,mercury,lead, Iron and cadmium are responsible for heavy metal poisoning.It may be occur due to excess intake,overdose or because of their incomplete metabolism and excretion in the body.
  • Initially for heavy metal poisoning,activated charcoal is administered for adsorbing the heavy metals,than an emesisis  is administered for further explusion of  GIT contents. Certain cases,  some inorganic compounds precipitates the heavy metals and stop their absorption to  systemic circulation.

Cyanide poisoning and its treatment

Cyanide poisoning

·     Cyanide poisoning occurs accidentally or by intentionally commit to suicide attempt.

·   During cyanide poisoning,the cyanide ions easily combine with  ferric ions of cytochrome oxidase enzyme,which is solely responsible for electron transfer chain reaction.Thus ,it leads stoppage of cellular respiration or oxidation –reduction reactions and metabolic reaction.

 

·    If the treatment is not done immediately cyanide poisoning severity may leads to fatal and death of the person.

Treatment

·         First Intravenous infusion (IV) of Sodium nitrite injection is given,further a slow IV infusion of Sodium thiosulfate is administered.

·         The Sodium Nitrite (NaNO2) convert haemoglobin to Methaemoglobin (oxidation of Fe2+ ions of haemoglobin to Fe3+ ion of methaemoglobin)

·         Methaemoglobin binds with cyanide ions and forms Methaemoglobin-cyanide complex

 

·         Sodium thiosulphate(Na2S2O3) converts the cyanide ions to water soluble thiocyanide ions which is easily excreted through kidney in the form of urine.  (The thiosulfate ions react with cyanide ions and catalysed by rhodanese to form thiocyanate)

·         Thiocyanate oxidase can reverse the reaction may slowly toxic symptoms may have return followed by initial antidotal therapy.

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Some important inorganic antidotes are

1. Activated Charcoal

It is prepared from destructive distillation of different organic substances or from burning of organic matter.

It is generally a good adsorbent (which adsorbs the adsorbate) for heavy metal also it adsorbs the other drugs like alkaloid,hypnotic,sedative and gases like carbon dioxide, carbon  monoxide, andnitrous oxide.It is also use in diarrhoea to adsorb toxins.

2. Light Kaolin (Al2O3.2SiO2.2H2O)

Kaolin is the hydrated Aluminium Silicate.

It is mainly used as Adsorbent in the treatment of alkaloid poisoning and food poisoining.

It is also used in the treatment of diarrhoea,dysentery and for symptomatic treatment of cholitis and cholera.

3. Sodium Nitrite   (NaNO2)

It is mainly used as antidote in cyanide poisoningfor this purpose 3 %w/v solution is given intravenously.

It has also hypotensive effectalso  it was used as vasodilator.

It has smooth muscle relaxant activity.

It prevents rusting of surgical instruments

It is also used as food preservative.

4. SodiumThiosulphate (Na2S2O3)

It is used as an antidote for Cyanide Poisoning. For this purpose 10% w/v solution is used intravenously although a 2.98%w/v solution is isotonic with blood serum.

It is a reducing agent, so it is used as standard titrant in Iodimetric analysis.

 

REFERENCES

1. Inorganic Medicinal and Pharmaceutical Chemistry

John.H.Block,Edward B.Roche,TaitoO.Soine,CharlesO.Wilson,Varghese Publishing House-1986.

2. Pharmaceutical Chemistry-Inorganic

Gurdeep R.Chatwal,Himalaya Publishing House-2012.