Case Studies (July 2015)

CASE 1

JR is a 58-year-old man with a medical history of elevated low-density lipoprotein levels and well-controlled chronic stable angina (experiencing <1 angina attack per month) secondary to coronary artery disease (CAD). He presents to his primary care physician for a follow-up appointment after his blood pressure (BP) was found to be 165/94 mm Hg at his annual physical exam. At today’s visit, JR’s BP is found to be 166/93 mm Hg, resulting in a diagnosis of hypertension. JR is currently on atorvastatin 40 mg daily and metoprolol tartrate 100 mg twice daily, and he reports no adverse effects from either medication. He has no other medical history of note, and his resting heart rate is 65 to 70 beats per minute. JR’s physician would like to start him on a new medication to help control his BP and calls the pharmacy for advice.

What would be an appropriate BP goal for JR, and how would you help him achieve it?

CASE 2

CR is a 70-year-old woman who was recently admitted to the hospital after stating her heart “felt like it was racing.” On admission, CR was found to have a heart rate of 120 beats per minute and an electrocardiogram revealed atrial fibrillation. Her basic metabolic panel was normal, with a serum creatinine level of 0.6 mg/dL, and she weighed 165 lb (75 kg). In addition to starting CR on metoprolol tartrate 25 mg twice daily for rate control, the attending physician believes CR would be a good candidate for one of the novel target oral anticoagulants. CR has a medical history of hypertension, which is being adequately treated with lisinopril 20 mg daily. She has no other comorbidities.

Which of the novel target oral anticoagulants would be appropriate for CR?

ANSWERS

Case 1: According to the recently released American Heart Association/ American Society of Cardiology/American Society of Hypertension guidelines, a patient with chronic stable angina and hypertension should have a BP goal of <140/90 mm Hg to prevent cardiovascular events. In addition to diet and lifestyle modifications, beta-blockers are the medication of choice to control the BP of a patient with chronic stable angina. If beta-blocker therapy is inadequate to concomitantly treat a patient’s CAD and hypertension or is poorly tolerated, the guidelines suggest adding an angiotensin-converting enzyme (ACE) inhibitor or angiotensin-receptor blocker to the patient’s medication regimen. This can be then be followed by a thiazide or thiazide-like diuretic, if necessary. JR has tolerated beta-blocker therapy well, and his heart rate is wellcontrolled at 65 to 70 beats per minute at his current (and maximal) dose of metoprolol. At this time, his physician could consider adding an ACE inhibitor, such as lisinopril 5 mg once daily, to his medication regimen.

Case 2: Because CR is a woman between 65 and 74 years of age with new-onset atrial fibrillation and hypertension, her CHA2DS2-VASc score is 3 (deemed at high risk for thromboembolism, with a risk of 3.2%; 95% CI, 2.2%-4.6% annual risk). According to the 2014 American Heart Association/American Society of Cardiology/American Society of Hypertension Guideline for the Management of Patients with Atrial Fibrillation, a CHA2DS2-VASc score of ≥2 warrants anticoagulation. Available novel target oral anticoagulants approved for stroke prevention in atrial fibrillation in the United States include rivaroxaban, apixaban, dabigatran, and edoxaban. Although each of these oral anticoagulants is efficacious, edoxaban has a boxed warning stating it should not be used in patients with a creatinine clearance (CrCl) >95 mL/min. Results from the ENGAGE AF trial showed edoxaban patients were at a higher risk of ischemic stroke, compared with patients on warfarin, when their CrCl was >95 mL/min (HR 1.87; 95% CI, 1.10-3.17). Using the Cockcroft-Gault equation, which is the recommended way to calculate renal function for drug selection and dose adjustment for the novel target oral anticoagulants, CR’s CrCl is estimated to be 103 mL/min. Therefore, although CR is not a proper candidate for edoxaban, any of the other novel target oral anticoagulants would be reasonable to start.

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Dr. Brunault is a PGY-1 pharmacy practice resident at Tufts Medical Center in Boston. Dr. Coleman is a professor of pharmacy practice, as well as codirector and methods chief, at Hartford Hospital Evidence-Based Practice Center at the University of Connecticut School of Pharmacy.

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