Because they can mask symptoms of hypoglycemia, beta blockers should be used with caution in patients with insulin- dependent diabetes mellitus. Abrupt beta-blocker withdrawal should be avoided because heightened beta-receptor density and sensitivity can result in a rebound phenomenon associ- ated with an increased risk for AMI and sudden death. If withdrawal is necessary, beta blockers should be tapered over a 1- to 3-week period, with consideration given to use of sublingual nitroglycerin or substitution with a nondihydro- pyridine calcium channel blocker during the withdrawal period. The principle adverse effects of beta blockers are fatigue, exercise intolerance, lethargy, insomnia, nightmares, and impotence. 4.4.2.3. Renin-Angiotensin-Aldosterone Blocker Therapy Class I 1. ACE inhibitors should be prescribed in all patients with SIHD who also have hypertension, diabetes mellitus, LVEF 40% or less, or CKD, unless contra- indicated.295 298,301 (Level of Evidence: A) 2. ARBs are recommended for patients with SIHD who have hypertension, diabetes mellitus, LV systolic dysfunction, or CKD and have indications for, but are intolerant of, ACE inhibitors.792 794 (Level of Evidence: A) Class IIa 1. Treatment with an ACE inhibitor is reasonable in patients with both SIHD and other vascular dis- ease.795,796 (Level of Evidence: B) 2. It is reasonable to use ARBs in other patients who are ACE inhibitor intolerant.797 (Level of Evidence: C) (Table 15) A substantial body of evidence supports the concept that ACE inhibitors have cardiovascular protective effects, reducing the risks of future ischemic events. ACE inhibitors result in a reduction in angiotensin II with an increase in bradykinin. 