Topic: Anticancer drugs
Question: Describe shortly on the MOA, side-effects of chelating agents
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Chelating agents are drugs used to treat heavy metal poisoning.
some examples of common chelating agents and their uses:
– EDTA (ethylenediaminetetraacetic acid) – Used for lead, mercury, arsenic, cadmium poisoning. Binds lead in the blood and removes it through urine.
– DMSA (dimercaptosuccinic acid) – Approved for lead poisoning in children. Oral agent that binds lead in tissues and enhances its excretion.
– DMPS (dimercaptopropane sulfonate) – Used in mercury poisoning. Binds mercury and increases its urinary excretion.
– Deferoxamine – Binds excess iron in iron overload conditions like hemochromatosis, thalassemia. Reduces iron levels.
– Penicillamine – Used in copper toxicity like Wilson’s disease. Binds copper and increases its urinary elimination.
– Prussian blue – Used as an antidote in thallium and radioactive cesium poisoning. Binds and decreases absorption from GI tract.
– Cholestyramine – Binds bile acids but can also reduce absorption of some toxins like strychnine.
They work by binding to metals in the body and enhancing their excretion. Here is a short summary of their mechanism of action and side effects:
Mechanism of action:
– Chelating agents like EDTA, DMSA, DMPS have high affinity for heavy metals like lead, mercury, arsenic, iron, etc.
– They bind to these metals and form complexes that are more water-soluble and easier to excrete in urine or feces.
– This reduces the body burden of accumulated heavy metals.
– Different chelators have preference for binding different metals.
Side effects:
– Depletion of essential metals like zinc, copper along with toxic metals. Can cause deficiency.
– Nausea, vomiting, diarrhea – GI upset is common.
– Renal toxicity in some cases as metals are cleared by kidneys.
– Hypotension, headache, fatigue, body ache – systemic side effects.
– Skin rash, itching, redness – allergic reactions occur occasionally.
– Neurological side effects like sensory problems, muscle weakness if metals deposited in nervous system.
So in summary, chelators work by binding and enhancing excretion of heavy metals but can also cause depletion of essential metals and other adverse effects. Careful monitoring is required during chelation therapy.
