Propofol-diazepam or propofol-midazolam co-induction in healthy dogs: effects on propofol dosages, cardiovascular and respiratory events



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PICO question

In healthy dogs, does the use of diazepam or midazolam administered in co-induction with propofol result in a reduction in the dose of propofol required to induce anaesthesia and a decrease in adverse cardiovascular and respiratory events?


Clinical bottom line

Category of research question


The number and type of study designs reviewed

Eight papers were critically reviewed. A total of six manuscripts were prospective, randomised, blinded, clinical studies. One trial was prospective, randomised, blinded, clinical with a Latin square, incomplete design. One study was retrospective, randomised, blinded, crossover, experimental

Strength of evidence


Outcomes reported

Variables assessed in this Knowledge Summary included: propofol dose required to induce anaesthesia (considering successful orotracheal intubation as an end point), changes in cardiovascular variables (heart rate, systolic, mean and diastolic blood pressure) and changes in respiratory variables (development of apnoea, changes in respiratory rates)


In healthy dogs, using propofol-diazepam or propofol-midazolam co-induction resulted in a reduction in propofol dose required to induce anaesthesia in some trials only. Midazolam appeared more effective than diazepam in this context. The dosages, timing and sequence of drug administration seemed relevant. No evidence suggested that using propofol-diazepam or propofol-midazolam co-induction resulted in a reduction of adverse cardiovascular or respiratory events. In addition, although this was out of the scope of the PICO question addressed here, adverse events (e.g. excitement, poorer quality of induction) were reported in several studies when diazepam or midazolam were used in co-induction


How to apply this evidence in practice

The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources.

Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.


Open Access Peer Reviewed


Braun, C., Hofmeister, E. H., Lockwood, A. A. & Parfitt, S.L. (2007). Effects of diazepam or lidocaine premedication on propofol induction and cardiovascular parameters in dogs. Journal of the American Animal Hospital Association. 43(1), 8–12. DOI:

Covey-Crump, G. L. & Murison, P. J. (2008). Fentanyl or midazolam for co-induction of anaesthesia with propofol in dogs. Veterinary Anaesthesia and Analgesia. 35(6), 463–472. DOI:

Hopkins, A., Giuffrida, M. & Larenza, M. P. (2014). Midazolam, as a co-induction agent, has propofol sparing effects but also decreases systolic blood pressure in healthy dogs. Veterinary Anaesthesia and Analgesia. 41(1), 64–72. DOI:

Ko, J. C. H., Payton, M. E., White, A. G., Galloway, D. S. & Inoue T. (2006). Effects of intravenous diazepam or microdose medetomidine on propofol-induced sedation in dogs. Journal of the American Animal Hospital Association. 42(1), 18–27. DOI:

Liao, P., Sinclair, M., Valverde, A., Mosley, C., Chalmers, H., Mackenzie, S. & Hanna, B. (2017). Induction dose and recovery quality of propofol and alfaxalone with or without midazolam coinduction followed by total intravenous anesthesia in dogs. Veterinary Anaesthesia and Analgesia. 44(5), 1016–1026. DOI:

Minghella, E., Auckburally, A., Pawson, P., Scott, M. E. & Flaherty, D. (2016). Clinical effects of midazolam or lidocaine co-induction with a propofol target-controlled infusion (TCI) in dogs. Veterinary Anaesthesia and Analgesia. 43(5), 472–481. DOI:

Robinson, R. & Borer-Weir, K. (2013). A dose titration study into the effects of diazepam or midazolam on the propofol dose requirements for induction of general anaesthesia in client owned dogs, premedicated with methadone and acepromazine. Veterinary Anaesthesia and Analgesia. 40(5), 455–463. DOI:

Sánchez, A., Belda, E., Escobar, M., Agut, A., Soler, M. & Laredo, F. G. (2013). Effects of altering the sequence of midazolam and propofol during co-induction of anaesthesia. Veterinary Anaesthesia and Analgesia. 40(4), 359–366. DOI:

Vol. 7 No. 2 (2022): The second issue of 2022

Section: Knowledge Summaries

Categories :  Small Animal  /  Dogs  /  Cats  /  Rabbits  /  Production Animal  /  Cattle  /  Sheep  /  Pig  /  Equine  /  Exotics  /