Which plant is listed under cardiotoxicity due to andromedotoxicosis (grayanotoxins)?

• A. azalea (rhododendron)
• B. dogbane (apocynum)
• C. laurel + lambkill + calfkill (kalmia)
• D. coffee senna (cassia)

Answer: (C)

Grayanotoxins cause cardiotoxic effects by binding to voltage-gated sodium channels in excitable membranes, keeping them open and leading to persistent depolarization. In the heart this disrupts conduction, producing bradycardia, hypotension, and sometimes AV block. Mountain laurel, known as laurel, lambkill, or calfkill (Kalmia latifolia), is the classic plant associated with andromedotoxicosis from grayanotoxins, hence it’s listed under this cardiotoxic group. Other plants in the list involve different toxins or toxic effects (for example, dogbane contains cardiac glycosides with a different mechanism, while coffee senna causes laxative effects).