DEAR DR. ROACH: I have suffered from high blood pressure since I was a young man in my early 20s. I recently turned 70 years old. My blood pressure has been controlled by various medications. Most recently, I have been taking 20 mg of lisinopril once each day. I also take amlodipine.

Recently, my primary care physician spotted some abnormal numbers related to my kidney function. He suspects that this is related to lisinopril. As a result, he decreased my daily dosage to just 10 mg. Before he made this change, my blood pressure was running at pretty good numbers of approximately 125/60 or 125/70 mm Hg.

Since the change, my blood pressure has been running higher — about 160/70 mm Hg on average. Once I reduced the lisinopril dosage, my creatinine level decreased from 1.46 to 1.25. I also worked hard to make sure that I was well-hydrated at this time.

I am concerned about the higher blood pressure levels and the potential negative effects on my heart condition. My cardiologist is concerned as well. He wants my blood pressure to be no more than 130/60 or 130/70 mm Hg. If lisinopril is the culprit for the apparent kidney dysfunction, I’m thinking there must be an alternative blood pressure medication that can get me to the level I should be at without negatively affecting my kidney function.

Can you make any suggestions that both my primary care physician and cardiologist might want to consider? — T.L.

ANSWER: Lisinopril works by relaxing the blood vessels so that the pressure is reduced and the heart does not have to work so hard. It’s an excellent choice for many people with high blood pressure since the side effects are generally uncommon. More importantly, lisinopril and other drugs like it in the ACE inhibitor class are very good at protecting the heart and kidney.

The kidney protection is complicated because ACE inhibitors always increase the creatinine level, making it look like they hurt the kidney. Deep inside the kidney, blood flow to the nephron (the fundamental unit of filtration) is regulated by two types of blood vessels. One brings fluid to the nephron (the afferent arteriole), and one carries it away (the efferent arteriole).

Lisinopril constricts the afferent arteriole and dilates the efferent arteriole, with the result that less fluid enters the nephron. This decreases the glomerular filtration rate and increases the creatinine level. This can be scary because a rising creatinine level sometimes signifies ongoing kidney damage, but it’s just the way the drug works. An increase of up to 25% of the creatinine level is expected.

If your normal creatinine is 1 mg/dL, then lisinopril could increase it to 1.25 mg/dL, but this is not considered kidney damage. The lab value would be expected to go right back to 1 mg/dL if lisinopril was stopped. In fact, the decrease in fluid to the nephron protects the kidney, so lisinopril is used to slow the progression of kidney disease for many people, especially those who have diabetes.

However, in people with blockages to both the renal arteries, lisinopril can dangerously drop blood flow to the nephrons. So, when we see a higher-than-expected rise in creatinine levels, we will stop lisinopril entirely and often look to see if there are any blockages.

I don’t have the precise numbers of when you began lisinopril, but decreasing it seemed to decrease your creatinine level by 15%. This is within the range of what is expected. I would consider going back on lisinopril and seeing what happens to your creatinine.

If your doctor is uncomfortable with a higher dose of lisinopril, another option as a third agent would be a diuretic, such a hydrochlorothiazide.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu. (c) 2025 North America Syndicate Inc. All Rights Reserved