Can angiotensin-converting enzyme (ACE) inhibitors cause your blood pressure to get too low?

Hypotension rarely occurs in patients with uncomplicated hypertension treated with angiotensin-converting enzyme (ACE) inhibitors alone, but patients may report lightheadedness especially in the first few days of treatment.^1-13 Hypotension can occur at the first dose or any time during ongoing therapy.^11-13 Manufacturers recommend that if actual syncope occurs, the patient should discontinue the drug until they have spoken to their doctor.^1-10 Patients with heart failure taking an ACE inhibitor are more likely to have symptomatic hypotension, and care should be taken when starting therapy in patients with heart failure.^1-11,13

Rates of hypotension vary in studies and depend on dosage, risk factors such as heart failure, and whether it was asymptomatic or symptomatic (e.g. a patient would even notice it).¹² In a clinical trial of 2,314 patients taking enalapril, 0.9% had hypotension. In another study of 4,849 patients with hypertension taking captopril, 2.5% had hypotension. In a clinical trials of 2,677 patients taking enalapril, overall 1.4% had hypotension.¹⁴ However, 363 patients in this study were being treated for congestive heart failure with concomitant diuretics and digitalis.

Manufacturers note that hypotension and dizziness can happen while taking an ACE inhibitor, particularly for patients who are volume- and/or salt-depleted. Examples include those who:^1-13

• take water pills (diuretics)
• are on a low-salt diet
• take other medicines that affect your blood pressure
• get sick with vomiting or diarrhea
• do not drink enough fluids

If hypotension does occur, the patient should lie down and may need an intravenous infusion of normal saline.^1-11 Transient hypotensive episodes are not a contraindication to further treatment. Once blood pressure is stabilized, most patients can continue treatment without difficulty.

^References

1. Accupril [package insert]. New York, NY: Parke Davis, Pfizer; 2017.
2. Capoten [package insert]. Spring Valley, NY: Par Pharmaceutical Companies, Inc.; 2012.
3. Vasotec [package insert]. Bridgewater, NJ: Valeant Pharmaceuticals North America LLC; 2015.
4. Lotensin [package insert]. Parsippany, NJ: Validus Pharmaceuticals LLC; 2014.
5. Altace [package insert]. New York, NY: Pfizer Laboratories; 2017.
6. Aceon [package insert]. North Chicago, IL: Abbot Laboratories; 2011.
7. Moexipril hydrochloride [package insert]. Teva Pharmaceuticals USA Inc; 2016.
8. Fosinopril sodium [package insert]. Miami, FL: Ciplo USA Inc; 2015.
9. Trandolapril [package insert]. Laurelton, NY: Epic Pharma, LLC; 2017.
10. Prinivil [package insert]. Whitehouse Station, NJ: Merck Sharp & Dohme Corp.; 2016.
11. Sica DA. Angiotensin-converting enzyme inhibitors side effects--physiologic and non-physiologic considerations. J Clin Hypertens (Greenwich) 2004; 6 (7): 410-416.
12. Warner NJ, Rush JE. Safety profiles of the angiotensin-converting enzyme inhibitors. Drugs 1988; 35 Suppl 5: 89-97.
13. Izzo JL, Jr., Weir MR. Angiotensin-converting enzyme inhibitors. J Clin Hypertens (Greenwich) 2011; 13 (9): 667-675.
14. Irvin JD, Viau JM. Safety profiles of the angiotensin converting enzyme inhibitors captopril and enalapril. Am J Med 1986; 81 (4c): 46-50.