What are the alternatives for pain management in a patient with a codeine allergy?

Pain Management 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

Assessment of Pain Severity

Before selecting an alternative analgesic, assess pain severity using:

• Visual analog scales (VAS), verbal rating scales (VRS), or numerical rating scales (NRS) to determine appropriate treatment 1
• Pain-related behaviors and discomfort observation in patients with cognitive impairment 1

Alternatives for Mild Pain (WHO Level I)

• Acetaminophen/paracetamol (500-1000 mg every 4-6 hours, max 4000 mg/day) 1
• NSAIDs such as:
  • Ibuprofen (400-600 mg every 6-8 hours) 1
  • Diclofenac (50 mg every 6-8 hours) 1
  • Ketoprofen (25-75 mg every 6-8 hours) 1

Alternatives for Mild to Moderate Pain (WHO Level II)

• Tramadol (50-100 mg every 4-6 hours) - a synthetic opioid with different structure than codeine 1
• Dihydrocodeine (note: use with caution as cross-sensitivity with codeine may occur) 1
• Low doses of strong opioids in combination with non-opioid analgesics 1

Alternatives for Moderate to Severe Pain (WHO Level III)

• Hydromorphone (0.015 mg/kg IV) - recommended as comparable or potentially superior to morphine 1

  • Has quicker onset of action compared to morphine 1
  • More potent at smaller doses (1.5 mg hydromorphone vs. 10 mg morphine) 1

• Morphine (oral route preferred when possible) 1

  • For IV administration: 0.1 mg/kg, then 0.05 mg/kg at 30 min, maximum 10 mg 1
  • Titrate using immediate-release formulations 1

• Fentanyl (1 mcg/kg, then ~30 mcg every 5 min) 1

  • People with morphine allergies do not have allergies to fentanyl 1
  • Shorter onset of action and 100 times more potent than morphine 1
  • Transdermal or IV fentanyl is safest for patients with renal impairment 1

• Buprenorphine (transdermal or IV) - safe option for patients with renal impairment 1

Patient-Driven Protocols

• Consider a 1 mg + 1 mg patient-driven hydromorphone protocol for patients unable to clearly communicate their pain level 1

Special Considerations

Route of Administration

• Oral route should be advocated as first choice when possible 1
• For patients unable to take oral medications, consider transdermal (e.g., fentanyl) or continuous parenteral administration 1

Renal Impairment

• All opioids should be used with caution, at reduced doses and frequency in renal impairment 1
• Fentanyl and buprenorphine are the safest opioids for patients with chronic kidney disease stages 4 or 5 1

Managing Side Effects

• Prescribe laxatives routinely for prophylaxis and management of opioid-induced constipation 1
• Use metoclopramide or antidopaminergic drugs for opioid-related nausea/vomiting 1

Multimodal Approach

• Consider combining different classes of analgesics for enhanced pain relief 2
• For breakthrough pain, prescribe rescue doses of immediate-release formulations 1
• Adjuvant medications like pregabalin may be beneficial for neuropathic pain 3

Common Pitfalls to Avoid

• Avoid assuming that all opioids will cross-react with codeine allergy - fentanyl is safe in patients with morphine allergies 1
• Be cautious with tramadol in patients with epilepsy risk or those taking antidepressants 1
• Avoid abrupt discontinuation of opioid treatments - taper by 30-50% over about a week 1
• Remember that some weak opioids like codeine have a ceiling effect where increasing doses only increases side effects without improving analgesia 1