Nausea and vomiting caused by narcotics usually will disappear after a few days of taking the medicine. This type of nausea is like motion sickness. Do not take these medicines without checking with your doctor, nurse, or pharmacist. If pain itself is the cause of the nausea, using narcotics to relieve the pain usually makes this nausea go away. Ask your doctor or nurse if some other medical condition or other medications you are taking such as steroids, anticancer drugs, or aspirin might be causing your nausea.
Some people mistakenly think they are allergic to narcotics if the narcotic causes nausea.
Nausea and vomiting alone usually are not allergic responses. But nausea and vomiting accompanied by a rash or itching may be an allergic reaction. If this occurs, stop taking the drug and notify your doctor at once. I've Heard That Some People Who Stop Taking Narcotics Have Withdrawal Effects. You should not stop taking narcotic pain relievers suddenly.