AIIMS Bhuvneshwar NO…: The diluent used for reconstitution of BCG vaccine is?

AIIMS Bhuvneshwar NO- 2018

Pharmacology

Easy

Appeared in: AIIMS Bhuvneshwar NO- 2018

Explanation

The BCG vaccine is a live, freeze-dried (lyophilized) vaccine that requires reconstitution before administration.
Normal saline (0.9% sodium chloride) is the specific diluent recommended and supplied by the manufacturer for BCG vaccine.
Using normal saline maintains the correct isotonic environment, which is crucial for preserving the viability and potency of the live attenuated bacteria (Mycobacterium bovis).
Using an incorrect diluent can damage the bacterial cells, rendering the vaccine ineffective and potentially causing adverse local reactions.

Option A: Dextrose solutions are not used for reconstituting BCG vaccine. The sugar content and different osmolality can damage the live bacterial cells.
Option B: Distilled water is hypotonic and can cause local irritation at the injection site. It is specifically not recommended for BCG reconstitution.
Option D: Glycerine is a thick, viscous liquid used in various topical and oral pharmaceutical preparations as a humectant or solvent, but it is never used as a diluent for injectable vaccines.

Visual 1: Infographic: Step-by-step guide for reconstituting the BCG vaccine, showing how to draw up the normal saline, gently mix it with the powder, and draw the correct dose.
Visual 2: Diagram: Illustration of a correct intradermal injection technique for BCG, showing the 10-15 degree angle of the needle and the formation of a distinct wheal on the skin surface.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain BCG Vaccine Reconstitution and Administration as background academic context rather than a clinical decision trigger.
Using the correct diluent is a critical step in the vaccine administration process that directly impacts patient safety and public health. It ensures vaccine efficacy and prevents adverse reactions.
A nurse's adherence to the 'five rights' of medication administration (right patient, right drug, right dose, right route, right time) extends to using the right diluent for reconstitution.
What if? If a nurse accidentally uses sterile water instead of normal saline for BCG, they must discard the reconstituted vaccine, report the incident according to hospital policy, and prepare a new dose correctly. The patient should not be injected with the incorrectly mixed vaccine due to the risk of irritation and reduced efficacy.

How to Approach the Question

First, identify the core of the question, which is about the specific diluent for the BCG vaccine.
Recall or deduce that BCG is a live vaccine, which often have very specific handling and reconstitution requirements to maintain viability.
Evaluate the options. Normal saline is an isotonic solution, which is generally safest for live cells. Distilled water is hypotonic and can cause cells to lyse. Dextrose and glycerine are not standard vaccine diluents.
Access your knowledge of the National Immunization Schedule and associated protocols, which specify Normal Saline for BCG.
Eliminate the other options based on standard pharmaceutical principles and vaccine-specific guidelines.
Confirm that Normal Saline is the standard, manufacturer-provided diluent for BCG to ensure potency and prevent local reactions.

Concept Tested & Keywords

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KD Tripathi - Essentials of Medical Pharmacology (6th Edition) p. 53-59