From the Guidelines
Post-operative pruritus is most commonly caused by opioid medications, which can trigger itching by activating mast cells to release histamine and by directly affecting opioid receptors in the central nervous system. This is supported by the British Association of Dermatologists' guidelines for the investigation and management of generalized pruritus in adults without an underlying dermatosis, 2018 1. Other significant causes of post-operative pruritus include:
- Allergic reactions to medications like antibiotics or anesthetics
- Histamine release from surgical trauma
- The use of certain anesthetic agents such as neuraxial morphine
- Dry skin resulting from antiseptic preparations, environmental factors in hospitals, and the inflammatory response to surgery itself
- Underlying conditions like liver or kidney dysfunction that become more pronounced after surgery
According to the NCCN Clinical Practice Guidelines in Oncology 1, pruritus occurs in 10% to 50% of patients receiving opioids, and it is more likely to occur early in the course of treatment. The guidelines suggest that if pruritus develops, other causes of pruritus such as use of any other medication must first be assessed, and consider changing to another opioid if it is persistent despite attempted symptom management.
The British Association of Dermatologists' guidelines 1 recommend naltrexone as the first-choice treatment for opioid-induced generalized pruritus without visible skin signs, and suggest alternative antipruritic agents such as methylnaltrexone, ondansetron, droperidol, mirtazapine, or gabapentin. For postoperative generalized pruritus without visible skin signs, the guidelines suggest considering diclofenac 100 mg given rectally.
Management of post-operative pruritus typically involves antihistamines like diphenhydramine (25-50mg every 4-6 hours), opioid antagonists such as naloxone or naltrexone in low doses, or switching to non-opioid pain management when possible 1. Topical treatments with moisturizers or 1% hydrocortisone cream can provide relief for localized itching. Understanding these mechanisms helps healthcare providers select appropriate preventive measures and treatments for this common and distressing post-operative symptom.
From the FDA Drug Label
Manifestations of histamine release and/or peripheral vasodilation may include pruritus, flushing, red eyes, sweating, and/or orthostatic hypotension.
- Postoperative pruritis may be caused by histamine release and/or peripheral vasodilation associated with the use of nalbuphine 2.
- Other possible causes of pruritis mentioned in the drug label include opioid-induced effects and allergic reactions 2.
From the Research
Causes of Postoperative Pruritis
- Postoperative pruritus can be caused by various factors, including opioid use, particularly after neuraxial administration 3, 4, 5, 6
- The mechanism of opioid-induced pruritus is not yet fully understood, but it is believed to involve micro opioid receptors, serotonin and dopamine D(2) receptors, prostaglandins, and spinal inhibitory pathways 3, 5
- Other potential causes of postoperative pruritus include preexisting systemic diseases and drug-induced reactions 4
Opioid-Induced Pruritus
- Opioid-induced pruritus is a common side effect of opioid treatment, particularly with neuraxial administration 3, 5, 6
- The incidence of opioid-induced pruritus differs with different opioids and routes of administration 5
- Central mechanisms, including the spinal dorsal horn, are believed to play a significant role in opioid-induced pruritus 5
Treatment Options
- Various pharmacological agents have been used to treat opioid-induced pruritus, including micro opioid receptor antagonists, mixed opioid receptor agonist-antagonists, serotonin 5-HT(3) receptor antagonists, propofol, NSAIDs, and D(2) receptor antagonists 3, 7
- Nalbuphine has been shown to be effective in treating opioid-induced pruritus without attenuating analgesia or increasing adverse outcomes 7