About This Page
This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- Step 1: non-opioid (paracetamol 1 g QDS, ± NSAID e.g. ibuprofen 400 mg TDS)
- Step 2: weak opioid (codeine 30–60 mg QDS, or tramadol) + non-opioid adjunct
- Step 3: strong opioid (morphine, oxycodone, fentanyl) ± non-opioid adjunct
- Adjuvants at any step: amitriptyline or gabapentin/pregabalin for neuropathic pain, corticosteroids for inflammation/compression
- Always prescribe a laxative with regular opioids (tolerance does NOT develop to constipation)
Overview
The WHO analgesic ladder was originally developed for cancer pain but is widely applied to all types of pain. It provides a stepwise approach: start at the step appropriate to the severity of pain (do not necessarily start at step 1 for severe pain), and step up if pain is not adequately controlled. Key principles include: "by mouth" (oral route preferred), "by the clock" (regular dosing, not PRN, for chronic pain), "by the ladder" (stepwise escalation), and "for the individual" (tailored to the patient). Adjuvant analgesics (drugs with primary indications other than pain but which have analgesic properties in certain conditions) should be considered at every step.
Epidemiology
Chronic pain affects approximately 28 million adults in the UK (43% of the population). It is the most common reason for GP consultation. Opioid prescribing in England has increased significantly, with approximately 5.6 million patients receiving opioid prescriptions in 2017–2018. Neuropathic pain affects 7–8% of the general population and requires specific adjuvant analgesics rather than standard analgesics alone.
Clinical Features
Symptoms
This topic covers a prescribing framework rather than a specific clinical condition
Signs
Investigations
First-line
Pain assessmentUse validated tools: numerical rating scale (0–10), visual analogue scale, or ABBEY pain scale for cognitive impairment
Second-line
Identify pain typeNociceptive (somatic/visceral) vs neuropathic — different treatment approaches
1
Step 1: Non-opioid ± adjuvant
- Paracetamol 1 g QDS (max 4 g/day) — first-line for mild pain
- NSAID: ibuprofen 400 mg TDS or naproxen 250–500 mg BD (always co-prescribe PPI if at risk of GI bleeding)
- Avoid NSAIDs in: renal impairment, heart failure, peptic ulcer disease, aspirin-sensitive asthma, elderly, anticoagulant use
2
Step 2: Weak opioid + non-opioid
- Codeine 30–60 mg every 4–6 hours (max 240 mg/day)
- Tramadol 50–100 mg every 4–6 hours (max 400 mg/day) — also has serotonergic and noradrenergic effects
- Continue paracetamol alongside (additive effect)
- NICE NG193 (chronic primary pain, 2021): do NOT start opioids, antidepressants (for pain), gabapentinoids, or paracetamol for chronic primary pain — this was controversial guidance
3
Step 3: Strong opioid + non-opioid
- Oral morphine (immediate-release) 5–10 mg every 4 hours for opioid-naive patients
- Once total daily requirement established: convert to modified-release morphine (MST) BD + IR morphine PRN for breakthrough
- Breakthrough dose = 1/6 of total daily morphine dose
- Alternatives: oxycodone (if morphine intolerant or renal impairment), fentanyl patch (if unable to take oral)
- ALWAYS prescribe: laxative (senna + lactulose or macrogol) — tolerance does NOT develop to opioid constipation
- PRN antiemetic (metoclopramide or cyclizine) for first 5–7 days
4
Adjuvant analgesics
- Neuropathic pain: amitriptyline 10–75 mg ON, duloxetine 60 mg OD, gabapentin (titrate slowly), or pregabalin 75–300 mg BD
- Bone pain: NSAIDs, bisphosphonates, radiotherapy (for bone metastases)
- Muscle spasm: baclofen, diazepam
- Corticosteroids: dexamethasone for raised intracranial pressure, nerve compression, hepatic capsule pain
Complications
- Opioid side effects: Constipation (always prescribe laxative), nausea (usually transient), drowsiness, respiratory depression, pruritus
- Opioid dependence and tolerance: Increasing concern with long-term prescribing for non-cancer pain
- NSAID side effects: GI bleeding (co-prescribe PPI), renal impairment, cardiovascular risk
- Codeine ultra-rapid metabolisers: CYP2D6 polymorphism — convert codeine to morphine very rapidly → toxicity
UKMLA Exam Tips
- 1Step 1: paracetamol ± NSAID. Step 2: weak opioid (codeine/tramadol). Step 3: strong opioid (morphine/oxycodone/fentanyl)
- 2Breakthrough morphine dose = 1/6 of total daily dose
- 3ALWAYS prescribe a laxative with regular opioids — constipation does NOT develop tolerance
- 4Neuropathic pain responds poorly to standard analgesics — use amitriptyline, duloxetine, or gabapentin/pregabalin
- 5NSAIDs: always co-prescribe a PPI if risk factors for GI bleeding (age >65, anticoagulants, history of PUD)
- 6Codeine is a PRODRUG — converted to morphine by CYP2D6. Poor metabolisers get no effect; ultra-rapid metabolisers get toxicity
- 7Opioid conversion: oral morphine 10 mg ≈ oral oxycodone 5 mg ≈ SC morphine 5 mg ≈ SC diamorphine 3.3 mg
practicetest your knowledge on who analgesic ladderApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — clinical pharmacology and beyond.
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