We have numerous medications available for treatment of pain and we sometimes have to juggle with them to ensure that the patient remains pain free and gets the correct medication. Some patients are allergic to pain medications and this allergy may present as itchiness. If patient feels itchy after getting pain medications, we have medications available to decrease that itchy feeling. The itchiness may mean that the patient is allergic to that medication.
The determination then is made to continue the pain medication with the medication that decreases the itch or to change the pain medication all together. Allergy may manifest itself as little itchiness at one end of the spectrum to a severe anaphylactic reaction at the other. I use medications which the patient has used in the past and which have worked on the patient to ensure that the possibility of side reactions from medication are minimized.