What is the recommended blood pressure medication for patients with muscular dystrophy?

Blood Pressure Medication for Muscular Dystrophy Patients

ACE inhibitors or ARBs are the first-line blood pressure medications for patients with muscular dystrophy, and should be initiated by age 10 even before ventricular dysfunction is detected to delay the onset of left ventricular dysfunction and improve mortality. 1

First-Line Therapy: ACE Inhibitors/ARBs

ACE inhibitors or ARBs have become the cornerstone of cardiovascular management in muscular dystrophy patients, particularly those with Duchenne muscular dystrophy (DMD). The Working Group of the National Heart, Lung, and Blood Institute in collaboration with Parent Project Muscular Dystrophy recommends:

• Initiate ACE inhibitors/ARBs by 10 years of age, even before detectable cardiac dysfunction 1
• ARBs can be substituted for ACE inhibitors in patients who are intolerant to ACE inhibitors 1
• Early institution of ACE inhibition has been shown in randomized clinical trials to delay the onset of left ventricular dysfunction and improve mortality 1

Second-Line Therapy: Beta-Blockers

Beta-blockers are typically added after ACE inhibitor/ARB initiation:

• Add beta-blockers based on ventricular dysfunction or elevated heart rate 1
• Prospective open studies have shown improvement in left ventricular ejection fraction with beta-blocker therapy in DMD cardiomyopathy 1
• Combined therapy with ACE inhibitors and beta-blockers has demonstrated significant improvement in left ventricular fractional shortening compared to ACE inhibitors alone 2, 3
• Long-term use of beta-blockers is associated with reduced decline in left ventricular ejection fraction 4

Third-Line Therapy: Mineralocorticoid Receptor Antagonists

• Mineralocorticoid receptor antagonists like eplerenone have shown benefit in DMD cardiomyopathy 1, 5
• A randomized, prospective study demonstrated that eplerenone attenuated the decline in left ventricular function measured by circumferential strain 1, 6
• Consider adding eplerenone when early cardiomyopathy is detected 6

Blood Pressure Targets

When treating hypertension in muscular dystrophy patients:

• Target systolic blood pressure to 130 mmHg and <130 mmHg if tolerated, but not <120 mmHg 1
• Target diastolic blood pressure to <80 mmHg, but not <70 mmHg 1
• Be aware that DMD patients typically have lower systolic blood pressure, especially in advanced disease, which complicates medication titration 1, 5

Important Considerations and Caveats

1. Early Intervention: Don't wait for cardiac dysfunction to appear before starting therapy. The relatively low risk of ACE inhibitors/ARBs supports earlier therapy 1

2. Medication Monitoring: Careful monitoring is essential as muscular dystrophy patients often have:

   • Lower baseline blood pressure
   • Difficulty reporting symptoms due to skeletal muscle limitations
   • Atypical presentation of heart failure symptoms 5

3. Calcium Channel Blockers: Evidence does not support the use of calcium channel blockers for cardioprotection in DMD. A Cochrane review found no significant beneficial effect on muscle function 7

4. Combination Therapy: When initiating antihypertensive therapy, consider starting with a combination of a RAAS blocker with either a calcium channel blocker or a thiazide/thiazide-like diuretic for general hypertension management 1

5. Arrhythmia Risk: Greater burden of myocardial fibrosis (detected by cardiac MRI) is associated with increased arrhythmia risk in DMD. This should factor into medication selection and monitoring 1

The evidence strongly supports early intervention with ACE inhibitors/ARBs in muscular dystrophy patients, with addition of beta-blockers and mineralocorticoid receptor antagonists as the disease progresses, to improve mortality and delay cardiac dysfunction.