From the Guidelines
Opioid-related itch can be effectively treated with naltrexone, which is the first-choice recommendation for opioid-induced generalized pruritus without visible skin signs, as it blocks the mu-opioid receptors responsible for both pain relief and itch 1. The treatment of opioid-related itch should prioritize the patient's quality of life, morbidity, and mortality.
Treatment Options
- First-line treatment includes antihistamines such as diphenhydramine (25-50mg every 4-6 hours) or hydroxyzine (25-50mg every 6 hours), which work by blocking histamine receptors that mediate itch sensation 1.
- For more severe or persistent cases, opioid antagonists like naloxone (0.25-2mcg/kg/hr IV infusion) or naltrexone (12.5-50mg orally) can be effective as they block the mu-opioid receptors responsible for both pain relief and itch 1.
- Ondansetron (4-8mg IV or orally every 8 hours), a 5-HT3 receptor antagonist, has shown efficacy in reducing opioid-induced itch without affecting pain control 1.
Non-Pharmacological Approaches
- Applying cool compresses and keeping the skin moisturized can help reduce itching.
- Switching to a different opioid medication or using a different route of administration may also help reduce itching. The underlying mechanism of opioid-induced itch involves activation of mu-opioid receptors in the central nervous system and mast cell degranulation, which releases histamine and other pruritogenic substances.
Individualized Treatment
Treatment should be individualized based on itch severity, patient comorbidities, and the need for continued opioid therapy 1. Key considerations include:
- Assessing for other causes of pruritus, such as use of other medications 1.
- Careful titration of mixed opioid agonist-antagonists or mu-opioid receptor antagonists to reduce opioid-induced adverse effects 1.
From the Research
Treatment Options for Opioid-Related Itch
- Opioid receptor antagonists and mixed agonist and antagonists, especially μ-opioid antagonists and κ-opioid agonists, have been shown to be effective in relieving opioid-induced pruritus 2, 3.
- A multimodal analgesic treatment regimen combined with a mixed antagonist and κ agonists, especially μ-opioid antagonists, and κ-opioid agonists, seems to be the current best treatment modality for the management of opioid-induced pruritus and pain 2.
- Nalbuphine has been found to be superior in treating opioid-induced pruritus when compared with placebo, control, diphenhydramine, naloxone, or propofol in patients receiving neuraxial opioids for acute pain related to surgery or childbirth 4.
- Intranasal butorphanol, an opioid agonist-antagonist, has been shown to provide significant relief from pruritus in patients with opioid-induced pruritus unresponsive to antihistamines 5.
- Other pharmacological agents that have been used to treat opioid-induced pruritus include serotonin 5-HT(3) receptor antagonists, propofol, NSAIDs, and D(2) receptor antagonists 6.
Mechanisms of Opioid-Induced Pruritus
- The mechanisms of opioid-induced pruritus are not yet fully understood, but there is increasing evidence of the important role played by micro opioid receptors 6.
- Serotonin and dopamine D(2) receptors, prostaglandins, and spinal inhibitory pathways may also be involved in the genesis of pruritus 6.
- The incidence of opioid-induced pruritus differs with different opioids and routes of administration, and the various mechanisms can be broadly divided into peripheral and central mechanisms 2.