Patient 1 received carteolol and captopril for hypertension. Three days after a slow-release diltiazem preparation (300 mg) had been introduced, he developed cardiogenic shock and sinus bradycardia (heart rate: 30/mn) with acidosis and severe hyperkaliemia. He was successfully treated by temporary pacing and dobutamine. Patient 2 had received sotalol and captopril for several years. Twelve hours after slow release diltiazem had been added, he was found in cardiogenic shock and extreme bradycardia with wide QRS, acidosis and hyperkaliemia. He died one hour later despite intensive emergency treatment. Concomitant use of beta-blockers and calcium channel blockers has been reported in patients suffering of severe coronary heart disease. However, several adverse reactions similar to our cases have been described. Slow-release diltiazem should be avoided in hypertensive patients taking beta-blockers.