According to Van Amburgh, the medication's package insert shows hyponatremia as a potential adverse event associated with the drug, but there is no known incidence rate. Studies have reportedly indicated that patients taking 10–40 mg of lisinopril for varying periods of time (between six months and four years) showed some signs of hyponatremia and lower serum sodium levels.
In two of the cases, patients were reportedly given lisinopril a second time, and their serum sodium levels dropped once again. This led the researchers to conclude that the hyponatremia condition was likely a direct result of the medication, and not other factors, according to Van Amburgh.
Additionally, Van Amburgh went on to say that there were 17 cases of hyponatremia related to the use of ACE inhibitors published as of 2002, with five involving the drug captopril and nine involving enalapril.
Still, the author of the column writes that while it appears as though ACE therapy—including lisinopril—could lead to the development of hyponatremia even at the lowest doses, physicians need to consider other possible medical conditions that could be leading factors. Examples of these increased risk factors include patients with congestive heart failure and those on concomitant diuretic therapy, according to Van Amburgh.
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"Hyponatremia is recognized as a potential adverse effect of ACE inhibitor therapy, with grave consequences if left uncorrected. Both patients and providers should be aware of and monitor for the signs and symptoms of hyponatremia," she said.
According to the National Center for Biotechnology Information, lisinopril is typically prescribed to treat high blood pressure, and can also be used in combination with other medications to treat heart failure.
Other side effects of the medication can potentially include dizziness, excessive tiredness, decrease in sexual ability, difficulty breathing or swelling of the face, according to the NCBI. Overdose symptoms can often include fainting and lightheartedness as well.