Authors: Rob Hirst, Liz Farah, Andy Neill, Dave McCreary / Codes: GP10, PC1, SLO10, SLO2, SLO3, TP3 / Published: 16/05/2024

Clinical Question

Is clonidine a useful adjunct for analgesia in patients with a history of opiod misuse?

Title of Paper

Effect of oral clonidine on pain reduction in patients with opioid use disorder in the emergency department: A randomized clinical trial

Journal and Year

British Journal of Clinical Pharmacology. 2023

Lead Author

Zahra Rostamipoor


  • Opiate-dependant patients can be a real challenge to manage when they present to the ED with acute pain.
  • They often require significantly higher opiate doses than your average punter, and many clinicians are reluctant to give high enough doses to have an effect.
  • I often find myself reaching for low dose ketamine in these cases, which I find to be pretty effective, but not without its limitations, particularly its pretty short duration of action.
  • Clonidine is an alpha-blocker used as an antihypertensive, though has several other uses. I’ve most commonly used it for opiate withdrawl, and its apparently also FDA approved for treatment of ADHA, tourette’s, and severe cancer pain.
  • Our pain team would use it for inpatients, but to be honest it had never really been on my go to list for analgesia in the ED until I recently worked a locum shift in a regional ED with a locum ‘reg’ who was actually an ICU and anaesthetic consultant who mentioned in passing his routine use of clonidine as an analgesic and my ears pricked up in that “I’ve never done this - could it be a thing?” sort of way. We used it during that shift for an opiate-dependent patient and you know what, it really worked. Since then, I’ve used it several times for the same said patients, but also for patients whom opiates just aren’t hitting the mark, and it seems pretty good.
  • How does it work? I’ve done a little reading - there’s a good review article here - and they reckon its to do with alpha blockade in the dorsal horn, decreasing pain transmission.
  • It reaches peak action (PO) in 60-90 minutes, lasting 3-7 hours.
  • There are quite a few studies of its use in the perioperative period, particularly as part of an epidural cocktail. But there aren’t many ED trials (including this one, I’ve found 2). Spoiler alert - neither of them are great quality.

Study Design

  • Placebo-controlled, double blind, RCT

Patients Studied

  • Adult ED patients
  • History of opioid dependance >2 years
  • Fracture (closed, upper limb, lower limb, pelvis)
  • Pain ≥6/10


  • 200mcg clonidine PO


  • Placebo


  • Primary outcome(s!): pain score (when?) and morphine requirement
    • They did measured pain on NRS at 0, 30 and 60 minutes and at time of disposition from ED along with additional morphine doses required.
  • Secondary outcomes: HR and BP

Summary of Results

  • n=70
  • There was a significant difference between the groups at 60 mins and disposition:
    • 60m: 6.43 (placebo) vs 4.80 (clonidine) [CI 0.5-2.0]
    • Disposition (3-6h): 7.77 vs 5.46 [CI 0.0-1.2]
  • There was a significant reduction in the stingy total doses of morphine given:
    • 2.66 vs 4.43mg [0.5-3.1]
  • There was a small drop in SBP in the clonidine group at 30 and 60 minutes, that resolved by disposition.


Authors’ Conclusion

Oral clonidine showed promising potential for pain management in the ED. Clonidine, in reducing pain and morphine consumption, may not only improve patient outcomes but provide a cost-effective and easily administered option for ED staff.

Clinical Bottom Line

Ok, its not a great study so there’s only so much we can take from it. They haven’t given us much detail on their methods - what was the routine analgesic regime for these patients? Did they receive any other adjunct medications? How were they defining opiate dependents? What about the chronic pain patients on long term opiates?

Their dosing of morphine for these apparent opioid dependents seems on the low-side to me.

Despite that I still think its a drug worth keeping in the back of your mind for opioid-dependant patients in significant pain as an alternative to reaching for the ketamine. It very much needs more study, particularly in the ED population, however.

Other #FOAMed Resources / References:

The only other study I could find looking at clonidine use for pain in the ED assessing its addition to either morphine or ketorolac can be found here. Its not written much better than this trial, but also showed better pain control and lower morphine use, and might keep urology happy since you’ll be giving an alpha blocker and we know how much they love those for renal colic.

Clinical question - should we be prescribing bubbly beverages to those with food stuck in their gullet?

Title - Efficacy of cola ingestion for oesophageal food bolus impaction: open label, multicentre, randomised controlled trial.

Authors - Tiebie et al in the christmas BMJ 2023

Background - we have probably all had the sensation of eating a little fast and not chewing enough and the feeling of something going down a little slower than expected. For some people the food gets stuck in the oesophagus and progresses not further. As one might imagine this brings with it distress and discomfort and often a trip to the ED. There are not a huge number of options available to us and one of the commonly mentioned ones is a fizzy beverage. This papers is a randomised trial of just that intervention.

Methods - this was a multicentre randomised trial in the Netherlands. - patients with an impacted food bolus were randomised to routine guideline care of observation and endoscopy to Coca Cola. And they make no effort to be inclusive in their beverage or cola choice here. - this was taken 25mls at a time up to 200 ms. - it was understandably open label - none of your other drugs were used, no glucagon or scopolamine etc... - in the control group the endoscopy would be within 6 hrs if "complete" or 24 hrs if "incomplete". I am unsure what constitutes complete vs incomplete. - the time scales on the outcomes are a little unclear also.

Results - 50 or so patients - patients were middle ages, mostly men eating meat with many having a previous episode - 60 % improvement in both groups while in the ED. Those that improved did so fairly early, usually within an hr of attendance. - coke didn't help. the numbers look slightly better but the whole trial is tiny so hard to know what to do - it did cause some discomfort

Thoughts - I imagine most people will have googled this and tried it before they come to ED. - doesn't seem like a terrible thing to do and likely to be a hell of a lot safer than the glucagon induced emesis that seemed popular for a while. - one suspects a dr pepper may be more effective.