Management of Opioid-Induced Pruritus

Introduction to Opioid-Induced Pruritus

The American Society of Anesthesiologists recommends starting with antihistamines, such as diphenhydramine 25-50 mg IV/PO every 6 hours or promethazine 12.5-25 mg PO every 6 hours, as first-line treatment for opioid-induced pruritus, with an evidence level of high 1, 2
Intrathecal/epidural opioids cause pruritus in 20-100% of patients, making this the highest-risk route of administration, according to the British Journal of Dermatology 3, 1, 2

The American College of Clinical Pharmacology suggests using nalbuphine 2.5-5 mg IV as a second-line treatment, which is superior to placebo, diphenhydramine, naloxone, and propofol for treating opioid-induced pruritus, with a moderate level of evidence 1
Naloxone continuous infusion starting at 0.25 mcg/kg/h, titrated carefully, is recommended as a third-line treatment by the American Society of Anesthesiologists, with a high level of evidence 1, 2
Methylnaltrexone, a peripheral antagonist with reduced CNS penetration, may be considered as an alternative treatment, according to the British Journal of Dermatology 3, 1

The PROSPECT guidelines note that intrathecal morphine 0.1 mg is associated with a higher incidence of pruritus compared to 0.05 mg, but provides superior pain relief, with a moderate level of evidence 4
Before attributing pruritus solely to opioids, it is essential to assess for other causes, including other medications and underlying conditions, as recommended by the American College of Clinical Pharmacology 1, 5

The American Society of Anesthesiologists advises against using full doses of opioid antagonists in opioid-dependent patients, as this can precipitate withdrawal, with a high level of evidence 5
The American College of Clinical Pharmacology recommends not relying on ondansetron as first-line treatment for opioid-induced pruritus, despite its efficacy for opioid-induced nausea, with a moderate level of evidence 5

Clinicians should evaluate patients with opioid‑induced pruritus for underlying dermatologic conditions that may mimic or exacerbate itching, especially in the postoperative setting. 6

The British Association of Dermatologists recommends naltrexone as the first‑choice therapy for opioid‑induced pruritus when discontinuation of the opioid is not feasible (Strength of recommendation B); methylnaltrexone is listed as an alternative option. 6, 7, 8