Hi. I have gone through your question and understand your concerns. Lisinopril is ACE i group of medicine and hyperkalemia is known side effect of ACEi. It depends that when did you left taking lisinopril ,if its yesterday than its very early to say that its due to some other cause , but having hyperkalemia is very dangerous thing to have so i suggest you to consult your physician to get potassium levels under normal range. There are many causes of hyperkalemia so i suggest you to consult your physician so he/she should look for any treatable cause. Depending on the clinical findings and the results of the laboratory work, the following may be indicated: Glucose level - In patients with known or suspected diabetes mellitus Digoxin level - If the patient is on a digitalis medication Arterial or venous blood gas - If acidosis is suspected Urinalysis - If signs of renal insufficiency without an already known cause are present (to look for evidence of glomerulonephritis) Serum cortisol and aldosterone levels - To check for mineralocorticoid deficiency when other causes are eliminated Serum uric acid and phosphorus tests - For tumor lysis syndrome Serum creatinine phosphokinase (CPK) and calcium measurements - For rhabdomyolysis Urine myoglobin test - For crush injury or rhabdomyolysis; suspect if urinalysis reveals blood in the urine but no red blood cells are seen on urine microscopy. Hope this answers your question. If you have additional questions or follow up questions then please do not hesitate to ask. I will be happy to answer your questions. Wishing you good health.