Hypotension and sinus arrest with exercise-induced hyperkalemia and combined verapamil/propranolol therapy.

A case of life-threatening hypotension due to sinus arrest is described in a patient in whom exercise-induced hyperkalemia developed during a stable regimen that included verapamil, propranolol, and ibuprofen. Renal and extrarenal handling of the endogenous potassium load induced by heat and exertion in this patient may have been compromised by the presence of ibuprofen and propranolol. When superimposed upon the negative chronotropic effects of verapamil and propranolol, the hyperkalemia precipitated sinus arrest. Clinicians should be aware of this potential metabolic-drug interaction in patients taking verapamil and/or propranolol who perform strenuous exercise in hot weather or who may be exposed to other hyperkalemic precipitants.