What should be given to a patient who continues to complain of headache after receiving intravenous (IV) paracetamol (acetaminophen)?

Management of Headache After IV Paracetamol

For a patient who continues to complain of headache after receiving IV paracetamol, the next step should be to add a nonsteroidal anti-inflammatory drug (NSAID) such as ketorolac, or if NSAIDs are contraindicated, consider adding a triptan. 1, 2

Stepped Care Approach for Persistent Headache

First-line options after failed IV paracetamol:

• Add an NSAID such as ketorolac 30-60mg IV/IM, which has a relatively rapid onset of action and approximately six hours of duration 2
• If the patient has nausea or vomiting, add metoclopramide 10mg IV which provides both antiemetic effects and synergistic analgesia for headache pain 2
• Prochlorperazine 10mg IV is another effective option that relieves headache pain and has been shown to be comparable to metoclopramide in efficacy 2

Second-line options:

• If the patient doesn't respond to the combination of IV paracetamol and an NSAID, consider adding a triptan 1, 3
• All triptans have well-documented effectiveness, but they are most effective when taken early in an attack 1
• For patients with severe nausea or vomiting, consider non-oral triptans such as sumatriptan by subcutaneous injection 1, 4

Third-line options:

• Dihydroergotamine (DHE) can be considered if triptans and NSAIDs fail or are contraindicated 1, 2
• For patients who don't respond to all other treatments, lasmiditan may be considered, though its use is associated with temporary driving impairment 1

Important Considerations

Medication combinations with strong evidence:

• The combination of an NSAID plus metoclopramide has shown excellent efficacy for acute headache treatment 2, 4
• Combination therapy with a triptan and an NSAID or acetaminophen is recommended for moderate to severe headaches 1, 4

Medications to avoid:

• Opioids or butalbital-containing medications should not be used for headache treatment due to the risk of dependency, rebound headaches, and eventual loss of efficacy 1, 2, 4
• These medications can lead to medication-overuse headache, especially with frequent use 1, 3

Special populations:

• For patients with cardiovascular disease, triptans are contraindicated due to their vasoconstrictive properties 3
• In pregnant patients, acetaminophen remains the safest first-line option, but additional treatment should be discussed with an obstetrician 3

Common Pitfalls and Caveats

• Failure to use adequate dosing before concluding treatment failure - consider increasing the dose of initial medications without exceeding maximum daily recommendations 3
• Not recognizing medication-overuse headache, which can occur with frequent use of acute medications (≥15 days/month with NSAIDs; ≥10 days/month with triptans) 1, 3
• Delayed treatment - medications are most effective when taken early in an attack 1, 4
• Not addressing accompanying symptoms like nausea and vomiting, which may require specific treatment with antiemetics 2

By following this stepped care approach and being mindful of potential pitfalls, you can effectively manage patients with persistent headache after IV paracetamol administration.