... Perphenazine, crestor, benzonatate, tamsulosin, lisinopril, loratadine, tramadol, metformin. Does anyone know if these drugs could be making him fall asleep. I did the drug interaction list and it said that Lisinopril can make you drowsy. I am afraid that he is going to fall asleep while he is walking or driving and be killed. Does anyone know what we can do to help him?