Taking Hydromorphone After Bi-lateral Knee Surgery, Sweating Profusely, Lightheaded, Nausea. What To Do ?

My husband had bi-lateral knee surgery on Thursday (torn meniscus in both knees). He started taking hydromorphone at 10:30pm on Thursday night for pain. He ended up taking 8 mg between 10:30pm and 12:50am. He then took 4mg at 6am this morning; 6mg at 10:15am; another 6mg at 2:15 (right before we ate lunch) and then another 6mg at 6:30 (right before we ate dinner). He did not eat a lot at either lunch or dinner. At around 7:00pm tonight, he took a walk outside for about 5 minutes (to have a couple of puffs of his cigarette). When he came in he was sweating profusely, light headed, dizzy and nauseous. He took 25mg of promethazine for the nausea and about 30 minutes later he said the nausea was gone but he had a really bad headache. He then took 3 ibuprofen. We realized that he had not been eating when he was taking the pain meds. Could not eating cause these symptoms? He is due for more pain meds but now says that when he tries to eat, it makes him nauseous, (I gave him war ginger ale to sip and saltine crackers but he said that didn't help - they made him nauseous also. What do I do?