What can be given to a patient with severe pain (10/10) who is allergic to hydrocodone (Vicodin)?

Severe Pain Management in Hydrocodone-Allergic Patients

For a patient with 10/10 pain who is allergic to hydrocodone, immediately initiate parenteral morphine 2-5 mg IV or subcutaneous (for opioid-naïve patients) or oral immediate-release morphine 5-15 mg if the patient can tolerate oral administration. 1

Immediate Management Algorithm

First-Line Parenteral Options (for urgent severe pain):

• Morphine IV/SC: 2-5 mg for opioid-naïve patients, titrate rapidly to effect 1
• Hydromorphone IV/SC: Alternative if morphine is not tolerated, using 1/7.5 the oral morphine equivalent dose 1
• Fentanyl IV: For patients requiring rapid titration, though transdermal formulations should be avoided initially 1

The parenteral route is specifically recommended for patients presenting with severe pain needing urgent relief, with the equivalent parenteral dose being one-third of the oral dose 1.

First-Line Oral Options (if patient can swallow):

• Immediate-release morphine: 5-15 mg orally (10 mg if >70 years old), the standard preferred starting drug for opioid-naïve patients 1, 2
• Oxycodone immediate-release: 20 mg total daily in divided doses as an alternative 3
• Hydromorphone oral: 8 mg starting dose, 7.5 times more potent than oral morphine 1

Critical Titration Protocol

Provide around-the-clock dosing with breakthrough doses equivalent to 10% of total daily dose for transient pain exacerbations. 1 If more than 4 breakthrough doses per day are necessary, increase the baseline opioid treatment. 1

• Short half-life opioid agonists (morphine, hydromorphone, oxycodone, fentanyl) are preferred because they can be more easily titrated than long half-life analgesics like methadone 1, 3
• Oral administration is the preferred route when feasible 1, 3
• Individual titration using immediate-release formulations every 4 hours plus rescue doses (up to hourly) for breakthrough pain is recommended 1

Adjunctive Non-Opioid Therapy

Combine opioids with acetaminophen/paracetamol (up to 4-6 grams daily) or NSAIDs unless contraindicated to enhance analgesia and potentially reduce opioid requirements. 1

• Paracetamol and/or NSAIDs are effective for all intensities of pain, at least in the short term 1
• Monitor NSAIDs closely for gastrointestinal bleeding, platelet dysfunction, and renal failure 1
• COX-2 selective inhibitors may increase thrombotic cardiovascular risk 1

Alternative Strong Opioids to Avoid Cross-Reactivity

Since hydrocodone is structurally related to codeine (both are phenanthrene derivatives), consider these alternatives with different chemical structures:

• Morphine (phenanthrene, but different metabolism than hydrocodone) 1
• Fentanyl (phenylpiperidine class - structurally distinct) 1
• Methadone (diphenylpropylamine class - structurally distinct, but requires experienced prescriber) 1

Avoid codeine, as it shares structural similarities with hydrocodone and may have cross-reactivity. 1

Common Pitfalls to Avoid

• Underdosing during initial treatment: Calculate full equianalgesic doses and titrate rapidly to effect rather than using inadequate starting doses 1, 3
• Delaying parenteral administration: For 10/10 pain, oral routes may be too slow; use IV/SC routes for urgent relief 1
• Forgetting prophylactic laxatives: Stimulant laxatives must be routinely prescribed for both prophylaxis and management of opioid-induced constipation 1
• Not providing breakthrough medication: Always prescribe immediate-release opioids for pain exacerbations, typically 10% of total daily dose 1
• Using transdermal fentanyl for acute titration: Transdermal fentanyl is not indicated for rapid opioid titration and should only be used after pain is controlled by other opioids in opioid-tolerant patients 1

Mandatory Monitoring

• Assess pain intensity at every contact using visual analog scales, numerical rating scales, or verbal rating scales 1
• Monitor for respiratory depression, especially during initial titration 1
• Institute prophylactic bowel regimen immediately with stimulant laxatives 1, 3
• Prescribe antiemetics (metoclopramide or antidopaminergic drugs) for opioid-related nausea/vomiting 1