Diabetic nerve pain: the codeine in his coat pocket

Clinical Rounds, the GPAtlas podcast. Neurology. 17 minutes. Published 16 October 2026. Free to listen.

From our Ocean topic Neuropathic Pain, reviewed May 2026.

Transcript

Sarah: Hello, and welcome to GPAtlas Clinical Rounds. I'm Sarah, and this is the podcast where we take one thing you'll genuinely see this week and work out what to do with it.

Ben: And I'm Ben. Today it's painful diabetic neuropathy, because of this week's news about spotting nerve entrapment in people who already have it. The sharp angle is that the prescription is the easy part, and very often the wrong place to start.

Sarah: So. Mr Hussain is sixty-seven, he's had type two diabetes for years, and he's booked in about his feet. Burning, he says, like walking on hot sand. Worse at night. He can't stand the duvet touching his toes. He's been buying co-codamol from the chemist and it's doing nothing, so he wants something stronger. He's polite, a bit embarrassed to be bothering me. And the version of me at the end of a long morning types gabapentin and calls the next patient.

Ben: Three things today. How to hear nerve pain in the history and find it on examination. What to rule out before you settle on the label. And how to choose, start and stop the drugs safely, gabapentin above all.

Sarah: Let's start with the news, because it's why Mr Hussain has been on my mind all week. I read the headline and thought, hang on, should I have been thinking about surgery for him? So what's actually been reported?

Ben: A new algorithm to help GPs pick out people with diabetic peripheral neuropathy who might have a nerve entrapment on top of it. The point is to flag the ones who may be worth a surgical referral. A tool, essentially, to help you decide who to send. That's the headline, and honestly that's all we know from it.

Sarah: So it's not saying every burning foot needs a surgeon. Good, because I've got a lot of burning feet on my list. What doesn't it settle?

Ben: Quite a lot, from what's been reported. The headline doesn't tell us how well it performs in an ordinary surgery, or who actually ends up better after a referral. So I'd take it as a nudge to look carefully at each patient. Not a new pathway, and not a reason to skip the basics. Everything else we'd do for Mr Hussain stays exactly the same.

Ben: A new tool flags possible entrapment for surgical referral. It doesn't replace your history and examination.

Sarah: So, the history. He'd given me most of it before I'd asked a single question. Burning. Worse at night. The duvet on his toes. And I think on a bad day I'd have nodded straight past the duvet, because it sounds like a detail.

Ben: It isn't a detail. That's allodynia: pain from something that shouldn't hurt, like bedsheets or clothing. Put it alongside burning, shooting, stabbing or electric shock pain, or pins and needles, and you're hearing neuropathic pain. Not the dull ache of nociceptive pain. Ask whether it follows a nerve or a dermatome, ask about numbness, and ask what sets it off. Cold, touch, movement, stress.

Sarah: He said his feet feel like they belong to someone else, and the cold makes them sing. Then I go looking for other causes, which feels a bit silly when he's had diabetes for years and it seems to explain everything.

Ben: It's not silly. Old shingles, stroke, multiple sclerosis, spinal injury. Surgery like amputation, mastectomy or thoracotomy. Excess alcohol, chemotherapy. Every medicine, including opioids and over-the-counter codeine, which matters later. And then the impact. Sleep, mood, work, daily function, and whether the pain has ever made him think of harming himself.

Sarah: Burning pain, and light touch that hurts. Then ask about the codeine he buys, and about self-harm.

Ben: Then, before the label goes on, NICE's neuropathic pain guidance sets out two priorities. Find and treat the underlying cause. And exclude the dangerous and the reversible: cord compression, malignancy, diabetes and vitamin B twelve deficiency. Only then do you settle on neuropathic pain.

Sarah: Honestly, cord compression isn't where my head goes with a man whose feet burn. So what am I actually asking him?

Ben: Bilateral leg weakness, saddle anaesthesia, bladder or bowel dysfunction: emergency admission. A rapidly progressive deficit, so severe weakness or sensory loss: emergency assessment. Unexplained weight loss or a history of cancer: suspect malignant nerve compression and investigate urgently. And severe pain that isn't responding, or pain driving suicidal thoughts, needs urgent pain or mental health input.

Sarah: His trousers were loose, and I'd have put that down to better sugars. Turned out he'd been walking every day since his last review. But I only knew because I asked. And he'd said no to self-harm, but slowly, and looked at the floor. So I made a note to come back to it.

Ben: And one more, which diabetes makes very easy to miss. A new, painful, red or swollen diabetic foot. That's not simply neuropathy. Think ischaemia, infection or Charcot, and get it reviewed urgently, not prescribed for.

Ben: Ask about weakness, saddle, bladder, bowel and weight. A new red, swollen foot isn't just neuropathy.

Sarah: Then socks off. And I'll be honest, in a busy diabetic review I sometimes have a quick look at the feet and move on. For nerve pain, what does a proper examination actually involve?

Ben: You map it. Light touch, pinprick and vibration, to define the area of deficit and confirm it fits a neuroanatomical pattern. Then gently stroke the skin with cotton wool. Pain from that supports a neuropathic mechanism. Then power, looking for weakness, wasting or fasciculation. And reflexes, for asymmetry, or low reflexes against brisk ones.

Sarah: And that mapping is where this week's news sits for me. The headline is about people who might have an entrapment on top of their neuropathy. So if what I find doesn't fit the picture I expected, I want to stop and think, rather than filing it all under diabetes.

Ben: Fair, as long as it's a nudge and not a new rule. Then the skin. Hair loss, shiny skin, shingles scars, ulcers, deformity. And the pulses. The common pitfall is blaming every painful diabetic foot on neuropathy, when a numb foot that turns painful, red, warm or swollen may be ischaemia, infection or acute Charcot. Act on the new sign.

Sarah: Map sensation, stroke with cotton wool, check power and reflexes. Then the skin and pulses, with the socks off.

Sarah: His examination was what I expected. Both feet, the same on each side. The cotton wool made him flinch. Pulses present, skin intact, no ulcers. So, bloods. And I'd have checked his sugar and stopped there, if I'm truthful.

Ben: Glycated haemoglobin, the HbA1c, or a fasting glucose, because diabetes is the leading reversible driver. That's the first step of management too, not just a test. Then vitamin B twelve, folate and thyroid function tests, to exclude reversible metabolic causes. And urea and electrolytes.

Sarah: The kidney bloods are for the drugs, aren't they? And what about those questionnaires? I keep seeing DN four in clinic letters and wondering if I should be doing it.

Ben: Yes. Gabapentin and pregabalin both need dose reduction in renal impairment, so check before and during. The Leeds assessment, LANSS, or DN four supports a clinical diagnosis, but it stays a clinical diagnosis. Magnetic resonance imaging is for specialists, when they suspect compression, tumour or demyelination. And if his B twelve comes back low, replace it. Fix the cause first.

Ben: HbA1c, B twelve, folate, thyroid and kidneys. Treat the cause before you treat the pain.

Sarah: His HbA1c had crept up, so we talked about that. B twelve was fine. His kidney function was a bit down for his age. So then, the prescription, which is what he'd come in for. And he'd made it very clear the co-codamol wasn't touching it.

Ben: It won't. You want a drug that calms abnormal nerve signalling. There are four first-line choices, and you offer one, by patient choice. Amitriptyline, starting ten milligrams at night, titrating towards seventy-five. It's off-label, so document why and get consent. Careful with anticholinergic burden, heart disease and older people, and it's cardiotoxic and dangerous in overdose.

Sarah: Which is where his slow answer about self-harm comes back to me. A drug that's dangerous in overdose needs more thought there. What about duloxetine? That's the one I think of when mood is low too.

Ben: Right, it's useful with depression or anxiety. Thirty to sixty milligrams once daily, and it's licensed for diabetic peripheral neuropathic pain. Caution with bleeding risk and liver impairment. Then the gabapentinoids. Gabapentin, three hundred milligrams daily, or one hundred three times a day or lower in older people or renal impairment. Pregabalin, seventy-five milligrams twice daily, maximum six hundred a day.

Sarah: Four first-line drugs. Offer one, by patient choice, and start low.

Ben: With either gabapentinoid, warn about drowsiness, dizziness, weight gain and oedema, and with pregabalin, the risk of congenital malformation in pregnancy. But the bigger danger is the one your reflex prescription was about to walk straight into.

Sarah: I know. He's sixty-seven, his kidneys are down, he's taking co-codamol most days, and he told me he likes a few pints at the weekend. And my first instinct was gabapentin on top of all of that.

Ben: That's the gabapentinoid, opioid and alcohol triangle. Gabapentin and pregabalin can cause fatal respiratory depression. The risk multiplies with opioids or alcohol, and in chronic obstructive pulmonary disease, COPD, renal impairment and older people. He'd ticked four boxes before you'd typed a thing. They're also Schedule three controlled drugs. Twenty- eight days' validity, quantity in words and figures, and regular review for dependence and diversion.

Sarah: And the codeine wasn't on his repeat list. It was in his coat pocket. That's the bit I'd never have found from the screen. In the end we went through all four drugs, and he chose duloxetine, partly because of his mood. Once a day, licensed for exactly this, and well away from the triangle.

Ben: Before a gabapentinoid, ask about opioids, alcohol, lungs and kidneys. Including the codeine he buys himself.

Sarah: So he's started. When do I see him again, and what do I do if it just doesn't work?

Ben: NICE's advice is to review early, for response and side effects. If the drug's ineffective or not tolerated, switch to another first-line drug, and work through the rest in turn. Keep reviewing benefit, harms and whether he still needs it. And when you stop one, taper it rather than just dropping it.

Sarah: And then there's the Friday afternoon phone call. The pain's flared, the duloxetine hasn't kicked in yet, and he wants something stronger now.

Ben: Tramadol, but only as short-term rescue, say two to four weeks with review. Never maintenance. No long-term opioids at all, morphine included: they don't work for neuropathic pain and carry a high risk of harm and dependence. If the pain's localised and oral drugs don't suit, low-strength capsaicin cream, three to four times daily. Warn him it burns at first, and keep it off broken skin.

Sarah: Switch through the first-line drugs in turn. Tramadol only for a short flare, never long term.

Ben: When first-line drugs aren't controlling it, or the pain's severe, really limiting or getting worse, refer to a specialist pain service. Combinations, like amitriptyline with gabapentin, are usually their call. And don't start the capsaicin patch, lamotrigine, venlafaxine or the like unless a specialist advises. Trigeminal neuralgia is its own pathway, by the way, with carbamazepine first line.

Sarah: And whatever we prescribe, the thing I've learned to say on day one is that it won't make the pain disappear. If I don't say it, every review turns into a conversation about failure.

Ben: NICE frames the goal as partial relief and better function. Around half the pain gone, not a cure. The drugs take weeks and go up slowly. And you judge it on sleep, mood and daily function, not the pain score alone. That changes what the review is for.

Sarah: So I asked him what better would look like. He said sleeping through with the duvet on his feet. That's my outcome measure now. What sits alongside the tablets?

Ben: Cognitive behavioural therapy, or acceptance and commitment therapy, for coping and low mood. Graded exercise to stop deconditioning. Transcutaneous electrical nerve stimulation, TENS, as an adjunct. Sleep hygiene and pacing for flares. And for him, daily foot checks, well-fitting shoes and podiatry, because that numb foot needs protecting.

Sarah: Aim for half the pain and a full night's sleep. And protect the numb foot.

Ben: Right, exam corner. A fifty-eight-year-old man with type two diabetes has painful diabetic neuropathy. He couldn't tolerate duloxetine. He's now been on gabapentin for some weeks, titrated up, with no real benefit. He asks what's next. A, switch him to long-term tramadol. B, add amitriptyline to the gabapentin yourself. C, try the remaining first-line drugs in turn, and refer to a pain service if they fail. D, start lamotrigine.

Ben: C. If a first-line drug is ineffective or not tolerated, you switch to another from the list and try the rest in turn, then refer to a specialist pain service if they don't control it. So amitriptyline and pregabalin are still on the table. The tempting one is A, because he's in pain and wants something stronger. But tramadol is short-term rescue only, never maintenance. B is a specialist decision, and D shouldn't be started without specialist advice.

Sarah: So. Three things for Monday. One. Burning pain and a duvet that hurts is nerve pain, but ask the cord, cancer and foot questions before you call it that. Two. Take the socks off, map the sensation, feel the pulses, and check the bloods, kidneys included. And three. Offer one first-line drug by patient choice, and before any gabapentinoid, ask about opioids, alcohol and the codeine in their pocket.

Sarah: One thing to reflect on, if you're logging this. Think of the last patient you started on gabapentin or pregabalin. Did you ask about over-the-counter codeine and alcohol before you prescribed it? The full transcript and the sources are on the episode page. Ben and I are natural AI voices, and what we've said comes from our reviewed Ocean topic. Check your local guidance before you act on it. See you next week.

More from Clinical Rounds

Every episode of Clinical Rounds, free to listen with a full transcript.