**Question:** Disodium EDTA is used as an antidote for: DNB 10

A. Lead poisoning
B. Calcium overload
C. Iron overload
D. Arsenic poisoning

**Core Concept:**

Disodium EDTA (Ethylenediaminetetraacetic acid) is a chelating agent with the ability to bind to heavy-metal ions, including lead, calcium, iron, and arsenic. The purpose of using EDTA as an antidote is to chelate and neutralize these toxic heavy-metal ions, thereby reducing their harmful effects in the body.

**Why the Correct Answer is Right:**

Disodium EDTA is primarily used as an antidote for lead poisoning (option A) due to its ability to bind and remove lead ions from the body, preventing further neurological and renal damage.

**Why Each Wrong Option is Incorrect:**

- Option B (Calcium overload) is incorrect because EDTA primarily targets other heavy-metal ions and does not specifically address calcium overload.
- Option C (Iron overload) is incorrect as Disodium EDTA is not effective in neutralizing iron ions and treating iron overload conditions.
- Option D (Arsenic poisoning) is also incorrect as Disodium EDTA does not effectively counteract arsenic toxicity. Other treatments are typically employed for arsenic poisoning, such as chelation therapy using other chelating agents.

**Clinical Pearl:**

In clinical practice, Disodium EDTA is primarily used to treat heavy-metal poisoning, particularly for lead poisoning. Its use is limited to heavy-metal chelation therapy, excluding calcium, iron, and arsenic poisonings. Always consult a physician for appropriate treatment guidance, as the choice of antidotes depends on the specific poison involved.