Procedural sedation and analgesia require a balance between adequate depth of sedation, hemodynamic stability, and preserved respiratory drive. Propofol and ketamine, used alone or together, are common sedative agents, and research has clarified the effects, risks, and best uses of each drug.
Propofol provides rapid-onset sedation and amnesia with a short recovery profile, but it lacks intrinsic analgesic properties and is associated with dose-dependent respiratory depression and hypotension (Shah et al., 2011; Miner et al., 2010). Ketamine, an NMDA-receptor antagonist, produces dissociative analgesia and amnesia while generally preserving respiratory drive and airway reflexes, but its use has historically been limited by concerns about recovery agitation, hypersalivation, and psychomimetic reactions (Miner et al., 2010).
Combining the two agents—often termed “ketofol”—was theorized to allow dose reduction of each drug, thereby minimizing side effects while maintaining sedation quality. Early work by Mortero et al. (2001) in patients needing sedation found that coadministration of small-dose ketamine with propofol significantly improved end-expiratory carbon dioxide values compared with propofol alone, was associated with better postoperative mood, faster cognitive recovery on Mini-Mental State Examination testing, and reduced postoperative pain and analgesic consumption.
Subsequent randomized trials extended these findings to additional settings. In a blinded trial of 136 pediatric patients undergoing orthopedic fracture reduction, Shah et al. (2011) found that ketamine/propofol produced modestly shorter total sedation and recovery times than ketamine alone, along with less vomiting and higher satisfaction scores, though airway and respiratory adverse events were similar between groups. In adults, however, results comparing ketamine and propofol directly have been less consistent. Miner et al. (2010) found a higher rate of subclinical respiratory depression in ER patients receiving ketamine alone than propofol alone, contrary to expectation, while recovery agitation was substantially more common with ketamine and time to return of baseline mental status was longer.
A 2016 systematic review and meta-analysis pooled 18 randomized trials comparing ketofol with propofol alone. Ketofol was associated with a significantly reduced risk of respiratory complications requiring intervention (relative risk 0.47), as well as reduced hypotension (relative risk 0.41) and bradycardia (relative risk 0.47) relative to propofol alone. No significant differences were found between the two regimens for psychomimetic complications, muscle rigidity, or nausea and vomiting.
Overall, data suggest that combining propofol and ketamine for procedural sedation may offer a favorable safety profile relative to monotherapy, particularly regarding cardiorespiratory stability, without a clear increase in psychomimetic or emetic complications. The clinical significance of these differences, however, remains debated; several authors note that observed reductions in respiratory or hemodynamic events, while statistically significant, may not always translate into differences in meaningful patient-centered outcomes, and study heterogeneity in dosing ratios, procedure type, and patient population limits direct comparison across trials.
Clinicians selecting between propofol alone, ketamine alone, or a ketamine-propofol combination should weigh procedure-specific analgesic needs, patient comorbidities, and institutional familiarity with each regimen, while recognizing that further high-quality trials are needed to define optimal dosing ratios and to clarify which patient populations benefit most from combination therapy.
References
- Jalili, M., Bahreini, M., Doosti-Irani, A., Masoomi, R., Arbab, M., & Mirfazaelian, H. (2016). Ketamine-propofol combination (ketofol) vs propofol for procedural sedation and analgesia: Systematic review and meta-analysis. American Journal of Emergency Medicine. https://doi.org/10.1016/j.ajem.2015.12.074
- Miner, J. R., Gray, R. O., Bahr, J., Patel, R., & McGill, J. W. (2010). Randomized clinical trial of propofol versus ketamine for procedural sedation in the emergency department. Academic Emergency Medicine, 17(6), 604–611. https://doi.org/10.1111/j.1553-2712.2010.00776.x
- Mortero, R. F., Clark, L. D., Tolan, M. M., Metz, R. J., Tsueda, K., & Sheppard, R. A. (2001). The effects of small-dose ketamine on propofol sedation: Respiration, postoperative mood, perception, cognition, and pain. Anesthesia & Analgesia, 92(6), 1465–1469. Available at: https://pubmed.ncbi.nlm.nih.gov/?term=Mortero+small-dose+ketamine+propofol+sedation+2001
- Shah, A., Mosdossy, G., McLeod, S., Lehnhardt, K., Peddle, M., & Rieder, M. (2011). A blinded, randomized controlled trial to evaluate ketamine/propofol versus ketamine alone for procedural sedation in children. Annals of Emergency Medicine, 57(5), 425–433. https://doi.org/10.1016/j.annemergmed.2010.08.032
