Lisinopril is a commonly prescribed angiotensin converting enzyme (ACE) inhibitor. Although it is routinely given to patients with high blood pressure, it is also given to kidney patients without hypertension as a preventive measure. Understanding the connection between lisinopril and kidney function explains much about the benefits of this treatment.
Blood Pressure Regulation
Regulation of blood pressure is important for everyone, but especially for kidney patients. Kidneys are almost entirely composed of vascular tissue. The tiny filters known as glomeruli form the largest portion of this tissue. Since glomeruli are nothing more than tiny capillaries, they can be easily destroyed by elevated blood pressure. Even in the absence of any other kidney disease, hypertension alone can destroy kidneys so it can be especially dangerous for patients whose kidneys are already compromised. Since lisinopril lowers blood pressure, it can play an important role in prolonging kidney function.
The benefits of lisinopril go beyond just maintaining blood pressure. Lisinopril is an angiotensin converting enzyme (ACE) inhibitor. Research has shown that ACE inhibitors have a kidney-protective effect that goes beyond the ability to control blood pressure. A 2001 study published in the journal Nephrology Dialysis Transplantation examined the effect of lisinopril on kidney patients. Excess protein in the urine, or proteinuria, was reduced by 24 percent among patients who took lisinopril, and only 10 percent in the group that controlled blood pressure with drugs other than ACE inhibitors. These results have been repeatedly duplicated. The American Association of Family Practitioners says that lisinopril, when compared to other anti-hypertensive drugs, provides the best protection against the progression of kidney disease.
It is not clear how ACE inhibitors in general---and lisinopril in particular---protect the kidneys. In her review article for the American Association of Family Practitioners, Catherine S. Snively M.D. echoes the widely-held opinion that the kidney-protective benefits of ACE inhibitors are related to their ability to decrease urine protein.
Reduction of urine protein is important because kidney patients often have elevated urine protein. Normally, kidneys prevent proteins from spilling into the urine. Unfortunately, this is not always true for kidney patients. Since proteins are such large molecules and glomeruli are such fine filters, the glomeruli can be damaged when proteins pass through them. Since ACE inhibitors lower urine protein, they are thought to prolong kidney function.
Effects on Creatinine and Potassium
The most notable side effect experience by patients using lisinopril is a mild increase in serum creatinine. Since serum creatinine is a marker for kidney disease, patients mistakenly believe their kidney function is worsening. This side effect goes away when the drug is stopped.
Patients also may experience changes in their potassium levels. The American Association of Family Practitioners reports that mild increases have been observed. Given that elevated potassium levels can cause serious cardiac problems, it is important to monitor potassium after starting lisinopril, especially for patients whose kidney disease is so severe that potassium regulation is already a problem.
Other Side Effects
Lisinopril is generally well-tolerated. Cough, diarrhea, dizziness, headache and tiredness do occur in a small number of people. While serious side effects are very rare, Drugs.com cautions that a doctor should be consulted immediately if a patient experiences chest pain, darkly colored urine, diminished urination, trouble swallowing, changes in heartbeat, stomach pain and yellowing of eyes or skin.
Signs of allergic reaction should be reported immediately and include trouble breathing, rash and swelling of the face, lips, tongue and throat. Emergency medical care should be sought for symptoms of allergic reaction.