Which of the following statements about Rifampicin is incorrect?

INI-CET EXAM -2025

Pharmacology

Medium

Appeared in: INI-CET EXAM -2025

Explanation

Rifampicin should be administered on an empty stomach, either 1 hour before or 2 hours after a meal, to ensure optimal absorption.
Food, particularly a high-fat meal, has been shown to significantly reduce the rate and extent of Rifampicin absorption.
Taking Rifampicin with food can lead to lower peak serum concentrations, which may compromise its bactericidal activity and increase the risk of treatment failure or the development of drug resistance.

Option A: This is a correct statement. The primary mechanism of resistance to Rifampicin in Mycobacterium tuberculosis is the development of point mutations in the rpoB gene, which alters the drug's binding site on RNA polymerase.
Option B: This is a correct statement. Rifampicin and its active metabolite are excreted into the bile and subsequently reabsorbed from the intestines. This process, known as enterohepatic recirculation, contributes to its pharmacokinetic profile.
Option D: This is a correct statement. Rifampicin is a known substrate for the P-glycoprotein (P-gp) efflux pump located at the blood-brain barrier. This pump actively transports the drug out of the central nervous system, thereby limiting its concentration and effectiveness within the brain and cerebrospinal fluid.

Visual 1: Diagram illustrating the pharmacokinetic pathway of Rifampicin, showing oral absorption, impairment by food, distribution, metabolism by the liver (CYP450 induction), and enterohepatic recirculation.
Visual 2: Infographic explaining the mechanism of Rifampicin resistance through mutation of the rpoB gene.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacology of Rifampicin as background academic context rather than a clinical decision trigger.
Patient education is a critical nursing responsibility. Nurses must clearly instruct patients to take Rifampicin on an empty stomach to maximize drug absorption and ensure the effectiveness of tuberculosis treatment.
Failure to adhere to proper administration guidelines can lead to sub-therapeutic drug levels, increasing the risk of treatment failure and the emergence of drug-resistant TB strains.
What if? If a patient experiences severe gastrointestinal upset when taking Rifampicin on an empty stomach, the nurse should advise them to take it with a small, light, non-fatty snack and to notify the prescribing physician. This is a compromise to improve tolerance, but the potential for reduced absorption must be acknowledged.

How to Approach the Question

First, recognize that the question asks for the 'incorrect' statement. This means you are looking for the false statement among the four options; three of them will be true.
Systematically evaluate each option based on your knowledge of Rifampicin's pharmacology.
For Option A, recall the mechanism of action and resistance for major antibiotics. The rpoB gene mutation is a classic resistance mechanism for Rifampicin.
For Option B, consider the drug's pharmacokinetic pathway. Enterohepatic recirculation is a notable feature of Rifampicin.
For Option C, think about drug-food interactions. Many antibiotics have specific administration requirements relative to meals. It is a common clinical point that Rifampicin absorption is hindered by food.
For Option D, consider drug distribution, especially into protected sites like the CNS. The role of efflux pumps like P-glycoprotein is a key concept in pharmacology.

Concept Tested & Keywords

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