What pain medication can be given to a patient with a codeine allergy?

Pain Medication Alternatives for Patients with Codeine Allergy

For patients with a codeine allergy, non-steroidal anti-inflammatory drugs (NSAIDs) are recommended as first-line alternatives for mild to moderate pain, while hydromorphone, morphine, or fentanyl are recommended for moderate to severe pain. 1

Pain Severity Assessment and Treatment Algorithm

• Pain severity should be assessed using visual analog scales (VAS), numerical rating scales (NRS), or verbal rating scales (VRS) to determine appropriate treatment 1
• For patients with cognitive impairment, observe pain-related behaviors and discomfort 1

Alternatives for Mild Pain (WHO Level I)

• Acetaminophen/paracetamol (500-1000 mg every 4-6 hours, maximum 4000 mg/day) is effective for mild pain with minimal side effects 2, 1
• NSAIDs such as ibuprofen (400-600 mg every 6-8 hours) are effective for inflammatory pain, particularly bone pain 2, 1
• Other NSAID options include:
  • Diclofenac (50 mg every 6-8 hours) 1
  • Naproxen (250-500 mg twice daily) 2, 3
  • Ketoprofen (25-75 mg every 6-8 hours) 2, 1
• Caution: NSAIDs can cause gastrointestinal toxicity, renal impairment, and should be used with caution in patients with bleeding risk or taking nephrotoxic medications 2, 3

Alternatives for Mild to Moderate Pain (WHO Level II)

• Tramadol (50-100 mg every 4-6 hours, maximum 400 mg/day) can be used but with caution due to potential cross-sensitivity with codeine 2, 1
• Tramadol should not be combined with monoamine oxidase inhibitors and should be used cautiously in patients with epilepsy risk or those taking antidepressants 2, 1
• Low doses of strong opioids combined with non-opioid analgesics can be effective for mild to moderate pain 2, 1
• Hydrocodone/ibuprofen combination has shown better efficacy than codeine/acetaminophen for chronic pain management 4

Alternatives for Moderate to Severe Pain (WHO Level III)

• Hydromorphone (0.015 mg/kg IV) is recommended as comparable or potentially superior to morphine with quicker onset of action 2, 1
• Hydromorphone causes little or no histamine release, making it safer for patients with allergic reactions to other opioids 2
• Morphine (oral route preferred when possible) at 0.1 mg/kg IV can be used, with careful monitoring 2, 1
• Fentanyl (1 mcg/kg, then ~30 mcg every 5 min) has shorter onset of action and is safe for patients with morphine allergies 1
• Oxycodone/acetaminophen is marginally superior to codeine/acetaminophen for acute pain management 2

Administration Routes and Special Considerations

• The oral route should be the first choice when possible 1
• For patients unable to take oral medications, consider transdermal (e.g., fentanyl) or continuous parenteral administration 2, 1
• All opioids should be used with caution in patients with renal impairment, with fentanyl and buprenorphine being the safest options for chronic kidney disease stages 4 or 5 1
• Prescribe laxatives routinely for prophylaxis of opioid-induced constipation 1

Important Pitfalls to Avoid

• Don't assume all opioids will cross-react with codeine allergy - fentanyl is generally safe in patients with morphine allergies 1
• Avoid abrupt discontinuation of opioid treatments - taper by 30-50% over about a week 2, 1
• Be aware that codeine dependence is a growing concern in countries where it's available over-the-counter 5
• Remember that diflunisal has been shown to cause fewer and more tolerable side effects than acetaminophen with codeine in treating acute soft tissue injuries 6
• Consider that some patients may have genetic variations (CYP2D6 polymorphisms) that affect codeine metabolism, which may contribute to allergic reactions or ineffective pain control 2, 1