Many opioids (like morphine) are potent histamine releasers, which can cause puritis and anaphylactoid reactions (such as seen in this patient with the facial flushing, drop in blood pressure and corresponding increase in heart rate). Puritis is actually a common side effect of morphine.
solidshakeOpioids (morphine), radio contrasts, some antibiotics (vancomycin), and several other medications can trigger IgE independent mast cell degranulation. (Uworld Qid# 11852)+1
submitted by โcassdawg(1781)
Many opioids (like morphine) are potent histamine releasers, which can cause puritis and anaphylactoid reactions (such as seen in this patient with the facial flushing, drop in blood pressure and corresponding increase in heart rate). Puritis is actually a common side effect of morphine.
Source: First Aid and
https://www.ncbi.nlm.nih.gov/pubmed/22417016