Effectiveness and safety of dentist-led conscious sedation using fentanyl with midazolam in dentistry: a five-year retrospective service evaluation

Yeo, X., Shehabi, Z. Effectiveness and safety of dentist-led conscious sedation using fentanyl with midazolam in dentistry: a five-year retrospective service evaluation. BDJ (2023)

Background and aims

Intravenous conscious sedation is commonly used for anxiety control in dentistry involving various drugs. Fentanyl has been introduced in 2016 as an advanced sedation technique when used with Midazolam. This combination has now proven popular for patients undergoing surgical procedures and its benefits include establishing systemic analgesics before surgery and enhancing the effect of sedation for anxiolysis. This combination of opioids with benzodiazepines has never been studied and reported in dentistry. 

Therefore, the aim of this service evaluation is to review the use of fentanyl since its introduction. This includes auditing the indication for this multi-drug technique, doses required to achieve sedation endpoint, the effectiveness and determining the incidence of adverse events such as the need for flumazenil and naloxone reversal.


Retrospective data collection was carried out in the Special Care and Sedation Clinic at Bart’s Health NHS Trust from 2016 to 2021 where a fixed amount of fentanyl was given over three minutes followed by titration of midazolam until the sedation endpoint was achieved. 

Data collection included age, sex, medical history, ASA grade, indication for using fentanyl, doses of midazolam used with and without fentanyl, Ellis grading (Table 1), sedation score, treatment carried out, complications, and need for reversal. 

Ellis gradeDescriptions
INo interference with treatment; total cooperation and no restlessness
IISmall amount of uninvited movement; still total cooperation and no restlessness
IIIMore uninvited movement; small degree of restlessness and anxiety. Patient less cooperative but still able to perform all dental procedures
IVConsiderable degree of limb movement; perhaps also unhelpful head movements; cooperation poor; patient quite restless and anxious; able to perform only basic dentistry
VRestlessness, anxiety and limb movements severe; impossible to perform any dentistry
Table 1: Ellis Grade


• A lower average dose of midazolam was administered when fentanyl was used. 

• 2 out of 109 patients had an unsuccessful outcome with fentanyl and midazolam 

• 9 out of 109 cases experienced respiratory depression/desaturation but none of these patients required reversal with flumazenil or naloxone due to over-sedation with supplemental oxygen was sufficient. 

• Better operating conditions for dental treatment were reflected in a lower Ellis grade (Figure 1).

Figure 1: Comparison of the operating conditions (Ellis Grade) with and without fentanyl.


Fentanyl and midazolam have a synergistic effect as this drug combination resulted in an enhanced clinical sedative effect, greater anxiety relief and better intraoperative conditions compared to when used on its own. This technique is recommended by IACSD guidance for patients when midazolam alone does not produce adequate anxiolysis. 94.5% of patients who failed sedation with a benzodiazepine proceeded to have dental treatment completed successfully using fentanyl and midazolam sedation. Opioid first administration also results in a reduction in the amount of additional sedative needed, and it is reported to reduce clearance and prolong the duration of action of midazolam. This could increase clinical treatment time but may require longer post-operative monitoring by an escort.

However, this concomitant technique can lead to increased unpredictability and a reduced margin of safety which can lead to an increased risk of adverse events such as respiratory depression and vomiting. There is also a risk of administrating the wrong drug as this is a multi-drug technique. 


The fentanyl-midazolam sedation technique can be useful when single drug sedation has failed, or when additional pain relief is needed. As current access to general anaesthesia can be difficult, this is an alternative method for managing uncooperative patients. However, there are cardiorespiratory depression risks and morbidity. This service evaluation can demonstrate the safety and effectiveness of fentanyl in dental sedation but larger scale and long-term studies in different settings across dentistry are necessary to further support this practice.

Research Summary Written By: Hewitt Yau, Newcastle University, BDS5

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