Which of the following antidote is used for lead?

Appeared in: CIP Ranchi 2023

Explanation

Calcium disodium EDTA is a primary chelating agent specifically indicated for the treatment of lead poisoning.
It functions by binding to lead ions in the bloodstream, a process known as chelation.
This creates a stable, water-soluble complex (lead-EDTA) that can be easily excreted by the kidneys.
This mechanism effectively removes lead from soft tissues and reduces its toxic effects on the body.

Option B: Activated charcoal is a universal adsorbent used for many ingested toxins, but it is ineffective for heavy metals like lead because it does not bind well to them.
Option C: Lignocaine (Lidocaine) is a local anesthetic and an antiarrhythmic drug. It has no chelating properties and is not used for any type of poisoning.
Option D: Sodium bicarbonate is an alkalinizing agent and is not used for lead poisoning.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacology: Antidotes for Poisoning as background academic context rather than a clinical decision trigger.
Knowing the correct antidote for specific poisonings is a critical skill for nurses, especially in emergency settings, as timely administration can be life-saving.
When administering CaNa2EDTA, the nurse must monitor renal function closely (BUN, creatinine, urine output) as the lead-chelate complex is excreted via the kidneys and can be nephrotoxic. Ensuring adequate hydration is crucial.
What if? If a child presents with lead encephalopathy (a severe, acute manifestation), treatment is more aggressive and typically involves a combination of two chelating agents: BAL (dimercaprol) administered first, followed by CaNa2EDTA.

How to Approach the Question

This is a factual recall question that tests your knowledge of toxicology.
Identify the core of the question: it asks for the specific antidote for 'lead' poisoning.
Mentally review the categories of poisons. Lead is a heavy metal.
Evaluate each option based on its known pharmacological action.
Recall that Calcium disodium EDTA is a classic chelating agent used for heavy metal poisoning, particularly lead.
Eliminate the other options by identifying their primary use: Activated charcoal for GI decontamination (but not metals), Lignocaine as an antiarrhythmic, and Sodium bicarbonate for specific overdoses like TCAs or aspirin.

Concept Tested & Keywords

QlaUdLBYzcNRz9cdYbDr5c

E6 Pharmacology Katzung 16e pp. 1603-1605, 1602-1604

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 2252-2254

Practise the full CIP Ranchi 2023

Attempt every question from this paper in a timed mock, then review the full solution for each one.