A 62-year-old man comes to the office for follow-up of hypertension. He was diagnosed with hypertension 10 years ago and has been treated with a number of different medications. However, the patient has had to discontinue several medications due to side effects such as dizziness, palpitations, and headaches. Currently he takes ramipril and chlorthalidone and is tolerating them well. Blood pressure is 160/92 mm Hg and was 158/89 mm Hg at his most recent prior visit. ECG shows sinus bradycardia (55/min) with PR interval prolongation (280 msec). Which of the following medications would be most effective for lowering this patient's blood pressure without worsening his ECG abnormalities?

Question

A 62-year-old man comes to the office for follow-up of hypertension.  He was diagnosed with hypertension 10 years ago and has been treated with a number of different medications.  However, the patient has had to discontinue several medications due to side effects such as dizziness, palpitations, and headaches.  Currently he takes ramipril and chlorthalidone and is tolerating them well.  Blood pressure is 160/92 mm Hg and was 158/89 mm Hg at his most recent prior visit.  ECG shows sinus bradycardia (55/min) with PR interval prolongation (280 msec).  Which of the following medications would be most effective for lowering this patient's blood pressure without worsening his ECG abnormalities?

Quizplus · Accepted Answer

11ec160b_3b81_662d_9249_ad5e4d5ea49e_MD0001_00 Calcium channel blockers are frequently used in the treatment of several cardiovascular disorders, including hypertension, angina pectoris, and certain cardiac arrhythmias. They inhibit the L-type calcium channel on vascular smooth muscle and cardiac cells and are divided into 2 major categories based on their predominant actions: This patient's ECG shows sinus bradycardia (rate <60/min) with first-degree atrioventricular (AV) block (PR interval >200 msec). Of the choices above, nifedipine is the most appropriate agent to manage hypertension as it has minimal effect on cardiac conduction. Dihydropyridines can cause reflex tachycardia in response to peripheral vasodilation and are therefore useful in hypertensive patients with resting bradycardia. (Choices A and E) Verapamil is a nondihydropyridine calcium channel blocker with a significant depressive effect on cardiac conduction. Diltiazem has combined effects and acts at both the myocardium and peripheral arterial beds. These medications can worsen bradycardia and AV block and should not be used in patients with underlying conduction abnormalities. (Choices B and D) Metoprolol is a cardioselective beta blocker with negative chronotropic and dromotropic (decreased AV conduction) effects. Sotalol is a class III antiarrhythmic drug with significant beta-blocking properties. These drugs can worsen bradycardia and AV conduction defects and would not be recommended for this patient. Educational objective: Calcium channel blockers inhibit the L-type calcium channel on vascular smooth muscle and cardiac cells. Dihydropyridines (eg, nifedipine, amlodipine) primarily affect peripheral arteries and cause vasodilation. Nondihydropyridines (eg, verapamil, diltiazem) affect the myocardium and can cause bradycardia and slowed atrioventricular conduction. __________ References: Calcium channel blockers in cardiovascular pharmacotherapy. (http://www.ncbi.nlm.nih.gov/pubmed/24872348)

A 62-Year-Old Man Comes to the Office for Follow-Up of Hypertension