Alternative Inhaled Anti-Pseudomonal — SCE Infectious Diseases MCQ
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Correct answer: D — Inhaled Colistin (Colistimethate sodium) or inhaled Aztreonam lysine — both are licensed alternatives when Tobramycin resistance develops
When inhaled Tobramycin resistance develops in chronic Pseudomonas bronchiectasis/CF, alternatives include: inhaled Colistin (Colistimethate sodium — nebulised or dry powder inhaler) and inhaled Aztreonam lysine (Cayston — nebulised). Both achieve high local airway concentrations far exceeding systemic MICs. Alternating between inhaled agents (e.g. monthly cycling between Tobramycin and Colistin) may reduce resistance development. IV Meropenem cannot be nebulised (wrong formulation). Sputum culture with susceptibility testing should guide inhaled agent selection.
Reference: BTS 2019 – Bronchiectasis; CF Trust 2024; NICE NG117