Hello! thank you for your query. I understand your concern and I would like to reassure you that there is no harmful effect or interaction of taking Losartan, Metoprolol and Amlodipine altogether. Metoprolol controls your heart rate and rhythm while your amlodipine and Losartan controls the blood pressure. However, if you would add up Furosemide to Metoprolol and Losartan, this may have possible interaction that would result to lowering your potassium(a mineral essential for maintaining proper fluid balance, nerve impulse function, muscle function, cardiac/heart muscle function) levels that s why you need to closely monitor your potassium levels. I could only discuss the possible interactions with the given medications you have stated but the overall management and treatment relies on your attending physician, please trust your Physician since He/she knows your history well and the overall condition of your body. I hope this helps, a feedback is greatly appreciated. Thank you!