Things you might see when ketroperidol is NOT administered

Hi folks

In the latest July-September 2012 edition of Prehospital Emergency Care Journal, there are two case studies published on the same issue of managing combative agitated patients in the prehospital setting. Here are the article abstract links

Laryngospasm and Hypoxia After Intramuscular Administration of Ketamine to a Patient in Excited Delirium

Prehospital Chemical Restraint of a Noncommunicative Autistic Minor by Law Enforcement

Ketamine and Droperidol in these case studies, what a coincidence! Both used separately but I thought a good opportunity to highlight a practice that I am using lately in retrieval sedation/analgesia

Rationale explained:

Ketamine is a great analgesic and sedative. BUT it has issues. It makes you dysphoric and hallucinatory state. It causes release of catecholamines, raising heart rate and BP. It makes you vomit. It can cause laryngospasm ( illustrated by case study above)


Midazolam has been well studied and does reduce delirium/dysphoria/hallucinations when coadministered with ketamine. It does not prevent or treat nausea though and has a nasty habit of unpredictably making patients stop breathing.

Propofol and ketamine = ketofol. Nice combination, addressing nausea issues and counteracting delirium and hallucinations. Still issues with potential apnoea. Recent research indicating not superior to propofol alone.

Droperidol works well with ketamine. It is an antiemetic and sedative yet does not affect respiration/ventilation at doses of 0.1mg/kg

Noninvasive evaluation of breathing pattern and thoraco-abdominal motion following the infusion of ketamine or droperidol in humans.

It also helps ameliorate the haemodynamic effects of ketamine on BP and HR

Droperidol Inhibits the Effects of Intravenous Ketamine on Central Hemodynamics and Myocardial Oxygen Consumption in Patients with Generalized Atherosclerotic Disease

The DORM study supported the safety of droperidol over midazolam for acute ED sedation of agitated patients.




1. Agitated patient of uncertain cause

2.Extrication/movement of patient with limited monitoring or access for airway/ventilatory support.

3. Procedural sedation in limited resource setting ( Ketamine alone would suffice but improved sedation profile with droperidol)

DOSING ( What I do in retrieval practice)

Droperidol 1-2mg IV  followed 5 minutes later by  Ketamine 0.5-1mg/kg IV

Like any sedation, there is individual patient variability so you need to adjust things for each case. The safest technique I have found that establishes a reliable and steady level of sedation with minimal respiratory problems or haemodynamic perturbations is to initiate the sedation with the boluses above, then start a ketamine infusion of 1mg/kg/hr initial rate, supplementing with boluses of droperidol rather than increasing the infusion rate. You need to run the infusion rate for around 40 minutes to reach steady state plasma levels with ketamine so little point in increasing the rate too quickly.

This technique provides a safe and effective prehospital balanced sedation for a broad range of scenarios, from trauma to acute mental health related agitation.

Ketroperidol. You come up with a better name.


15 thoughts on “Ketroperidol

  1. hi Chris
    Both agents work fine via IMI. >90% absorbed via IMI route for both agents. Similar onsets of action as well as clinical duration. you could give both in one syringe. have never done that. usually give droperidol dose..if works well, no need to give ketamine. if inadequate sedation post droperidol, then ready for ketamine

  2. Hi Minh! Comment of the laryngospasm problem. Laryngospasm may be avoided if the patient is also administered an anticholinergic along with the ketamine.

    Ketamine requires an antisialogogue (anticholinergic) to prevent all sorts of drool from overwhelming the airway. Atropine, Glycopyrrolate are two that will do the job. If coronary artery disease is a problem, beta blocker gets given with the anticholingergic.

    Just a little advice from the Operating Theater.

    Droperidol is chemicaly similar to the phenothiazine antipsychotics, and now has a black box warning from the US FDA for prolonged QT syndrome. Droperidol has fallen out of favor in anesthesia use lately as an anti nausea drug due to this black box warning.

    One other caution–it is rare, but neuroleptic malignant syndrome can occur after droperidol administration (case report 2001 in Hong Kong Medical Journal, Hong Kong Med J. 2001 Mar;7(1):101-3.).

    Just so you guys know what the potential side effects of this medication are. It also acts like an alpha blocker, reducing blood pressure.

    1. Jim, thanks for input! To be honest, the literature does not seem to support the notion that anticholinergics as adjuncts to ketamine prevent laryngospasm

      Click to access Laryngospasm%20during%20ketamine%20sedation%20PEM%20Nov%202010.pdf

      I dont routinely give anticholinergic with ketamine if its going to be a short lived procedure.
      BUT I do give anticholinergic if I initiate an infusion of ketamine for prolonged sedation particularly in the unintubated patient as I have observed hypersecretions as you mention. typically I give 300mcg atropine for an average adult and that lasts for up to an hour to dry things up.

    2. The QTc warning is kind of crazy considering the low doses we give to effect a chemical restraint. Our medical director moved heaven and earth it seemed to get it back in the ED and back on the trucks. Granted we’re giving 1.25mg at a time up to 5mg.

      1. I agree– while drop has been linked to longer QT, and patients who have gotten drop have later turned up dead in ditches, not sure how strong the actual linkage is. Also, I think getting drop in ED is independent risk factor for being found dead in a ditch

  3. Great post! For the continued sedation with ketamine infusion, do you continue with droperidol boluses of 1-2 mg iv if needed, or different bolus dosing?

    1. Hi Thomas
      2 mg droperidol boluses seem to work fine but you can go up to 5mg. wait for ten minutes for peak effect just like ketamine.

  4. Hi Minh.
    I was just wondering whether you couldn’t possibly get away with droperidol alone in some of the situations you describe, at least if agitation is the main issue. Ketamine could be “sprinkled on top” for the procedures or extrications as usual.

    I have seen a few agitated patients given 10mg droperidol IM, as in the drop trail, and the great thing is that they would usually sleep for the rest of the shift. When they woke they were often settled and more reasonable.

    It could possibly remove the need for ketamine infusion (if the problem is agitation and not severe pain) for the duration of transport?

    Just a thought, I have only used droperidol in ED, and been a happy customer every time. I understand the black box warning is controversial (to say the least).

    1. thsnks, Tony. I agree with you. you need a backup though. Midazolam is traditional backup to droperidol but has issues as discussed. Ketamine has a specific antidepressant effect well documented in over one hundred patients in RCT series with depressive disorder and suicidal ideation. So yes my practice now is droperidol first then wait and see. if no joy in ten minutes and it is still fight club going on, they get ketamine. if that fails , they get tubed esp for aeromedical retrieval.

  5. Hydromorphone 1 mg + Fentanyl 100 mcg diluted to 10 ml total volume = Hydromentanil. I use it 1-3 ml at a time (rapid onset fentanyl, long duration Hydromorphone). 1 ml has hydromorphone 0.1 mg, fentanyl 10 mcg–pretty much an equipotent mixture.

    “Triple 50 Superjuice” = Ketamine 50 mg + Remifentanil 50 mcg added to 50 ml Propofol.

    Anesthesiologists call this polypharmacy by the name “Balanced Anesthesia”

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