Had Open Heart Surgery, On Medicines For Preventing Re-infection, Arms Started Shaking Vigorously. Side Effects Of Medicines?

My husband had open heart surgery on October first to have his Aortic valve replace with a mechanical valve. Last night he kept dozing off and his arms and hands would start shaking really bad and he would try and hold his chest when I woke him he doesn t remember and says he is fine and woudn t let me take him to the ER. I don t know if it is a side effect of the medicine or normal or what?? He is on iv vancamicine and cefpime to prevent reinfection of his heart. he is also on metroprolol, omepraxole, lipator, aspirin , caumadin, and prilisec