In the WHO analgesic ladder for cancer pain, which statement about Step 3 (strong opioids) is MOST accurate?

• A Step 3 mandates parenteral opioid administration; oral route is ineffective for severe cancer pain
• B Strong opioids should only be used after step 2 has been maximally dosed and failed for at least 2 weeks
• C All patients at step 3 require adjuvant tricyclic antidepressants for neuropathic pain component
• D Morphine is the reference drug; there is no ceiling dose for opioid analgesics in cancer pain when titrated to effect ✓

Explanation

The WHO analgesic ladder (1986, revised 2018 as a two-step model) uses strong opioids (morphine, oxycodone, hydromorphone, fentanyl) for moderate-to-severe cancer pain at step 3. A key principle is that strong opioids have no ceiling dose — the dose is titrated upward until adequate analgesia is achieved or intolerable side-effects occur (dose-limiting toxicity). This is distinct from paracetamol and NSAIDs which have ceiling doses. Oral morphine is first-line at step 3; parenteral is reserved when oral is not feasible. Adjuvants (antidepressants, anticonvulsants) are added when neuropathic features are present but are not universal requirements.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.