Lisinopril serious side effects. Tell your doctor right away if you have any serious side effects, including fainting, symptoms of a high potassium blood level (such as muscle weakness, slow/irregular heartbeat). Although lisinopril may be used to prevent kidney problems or treat people who have kidney problems, it may also rarely cause serious kidney problems or make them worse. Tell your doctor right away if you have any signs of kidney problems such as a change in the amount of urine.