Pharmacology · single question
A patient with burning mouth syndrome (BMS) is taking a medication that works by depleting substance P. Which medication is this?
Show answer and explanation
Correct answer: B. Capsaicin
Topical capsaicin works by initially stimulating and then depleting substance P (a key neuropeptide in pain transmission) from sensory nerve endings, which is why it has been studied for burning mouth syndrome and other neuropathic pain conditions. Viscous lidocaine works by blocking sodium channels (a typical local anesthetic mechanism), and chlorhexidine is an antiseptic — neither acts on substance P.
- A. Chlorhexidine is an antiseptic with no substance P-depleting mechanism.
- B. Viscous lidocaine blocks sodium channels; it does not deplete substance P.
- C. Clonazepam (benzodiazepine) is also used for BMS but works via GABA modulation, not substance P depletion.