Some patients have reported to have itching (in more than 10%), rash and development of
The possibilities for
allergy are due to presence of
Phenanthrene in opioids. You can even develop hypersensitivity reactions to other phenanthrene derivative opioid agonists (codeine, hydrocodone, hydromorphone, levorphanol, oxycodone, oxymorphone).
Another precipitating factor is morphine is known to release histamine which can further precipitate the allergy.