What is the mechanism of action of Pretomanid under the BPaLM regimen?

Appeared in: INI-CET EXAM -2026

Explanation

Pretomanid is a nitroimidazole prodrug that requires activation within the mycobacterium.
Its primary bactericidal effect on replicating bacteria is through the inhibition of mycolic acid synthesis, a critical component of the mycobacterial cell wall.
This disruption of the cell wall's integrity leads to cell lysis and death.
Additionally, it releases reactive nitrogen species (like nitric oxide) under anaerobic conditions, which acts as a respiratory poison.

Option A: This is the mechanism of action for Bedaquiline, not Pretomanid.
Option B: This is the mechanism of action for Rifampicin, a first-line anti-TB drug.
Option D: This is the mechanism of action for Ethambutol, a first-line anti-TB drug.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacology: Mechanism of Action of Anti-Tubercular Drugs as background academic context rather than a clinical decision trigger.
The use of combination therapy like BPaLM is a cornerstone of treating multidrug-resistant TB (MDR-TB) to increase efficacy and prevent the emergence of further resistance.
As a nurse administering the BPaLM regimen, it is vital to monitor for specific adverse effects of each component: QT prolongation (Bedaquiline, Moxifloxacin), myelosuppression and neuropathy (Linezolid), and hepatotoxicity (Pretomanid).
What if? If a patient on the BPaLM regimen develops severe peripheral neuropathy, the nurse should suspect Linezolid toxicity. The treatment plan may need to be adjusted by the physician, potentially by reducing the Linezolid dose, as this is a known, dose-dependent side effect.

How to Approach the Question

First, identify the drug in the question: Pretomanid. Recognize it as a newer drug for treating drug-resistant tuberculosis.
Next, identify the core question: it asks for the mechanism of action.
Recall or deduce the pharmacological class of Pretomanid (a nitroimidazole) and its specific mechanism. It has a dual action: inhibiting mycolic acid synthesis and releasing nitric oxide.
Evaluate the given options. Option C directly matches one of the primary mechanisms of Pretomanid.
Mentally check the other options to confirm they are incorrect. Associate 'inhibition of ATP synthase' with Bedaquiline, 'inhibition of RNA polymerase' with Rifampicin, and 'inhibition of arabinoglycan synthesis' with Ethambutol. This process of elimination confirms the correct choice.

Concept Tested & Keywords

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E6 Pharmacology Nursing Lilley 11e Part 3 p. 27-29

E6 Medicine Harrison 22e Part 1 p. 1207-1209

Practise the full INI-CET EXAM -2026

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