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Chlorhexidine-SLS Interaction — NDEB AFK MCQ

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ModeratePharmacologyChlorhexidine-SLS InteractionNDEB AFK

Chlorhexidine mouthwash should NOT be used immediately after toothbrushing because of which interaction?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: B — Sodium lauryl sulfate (SLS) in toothpaste inactivates chlorhexidine by forming an insoluble precipitate

Sodium lauryl sulfate (SLS), the anionic detergent (surfactant/foaming agent) present in most toothpastes, forms an insoluble, poorly absorbed complex with the cationic chlorhexidine molecule, significantly reducing chlorhexidine's antimicrobial efficacy and substantivity. To avoid this interaction, patients should wait at least 30 minutes after toothbrushing before using chlorhexidine rinse, or use a toothpaste without SLS.

Reference: Newman – Newman and Carranza's Clinical Periodontology, 13th ed., 2019