In chemical mechanisms, drugs act by producing chemical reactions in the body. These include:
- Chemically acting antacids– NaHCO3
- Chelating agents– Dimercaprol, penicillamine, desferrioxamine
1. Chemically acting antacids
Chemically acting antacids react chemically with HCl of stomach, causing neutralization. Sodium bicarbonate chemically binds HCl forming NaCl and water.
2. Chelating agents
Chelating agents are the drugs used to treat poisoning with various metals. They incorporate or chelate metal ions into inner ring structure and in this way inactivate or neutralize the effects of metals.
Pralidoxime is a choline esterase reactivator. Poisoning of drugs like acetyl choline esterase inhibitors or organophosphate poisoning (insecticides, war gases) irreversible cause inactivation of acetyl choline esterase enzyme. This drug reacts chemically with phosphate of organophosphate compounds causing dephosphorylation. Thus acetyl choline esterase is released