Clonidine: An Adjuvant to Adrenaline in Local Anesthesia for Third Molar Surgery

Comparing the efficacy of adrenaline, clonidine, and dexmedetomidine in enhancing local anesthesia for impacted third molar extraction: a randomized controlled trial

Background

In human dentition, the most commonly impacted teeth are the mandibular third molars (M3M). The removal or extraction of these teeth often causes anxiety in patients due to the perceived pain involved in the process. Therefore, pain must be effectively managed using anesthesia. The use of newer local anesthetic drugs can help minimize side effects and drug interactions. Traditionally, adrenaline is used as a vasoconstrictor along with lignocaine. When combined with lignocaine, the alpha agonists dexmedetomidine and clonidine can extend the duration of anesthesia, thereby reducing the need for additional pain-relieving medications.

Methods

This study used a randomized, triple-blind, parallel-arm design. Sixty patients were screened, and 45 systemically healthy patients requiring unilateral surgical removal of impacted mandibular third molars with similar difficulty (moderate-to-difficult according to the Modified Pederson's Index) were included in the study. Patients were allocated into three groups as follows: Group A: 2% Lignocaine Hydrochloride with 1:100,000 Adrenaline, Group C: 2% Lignocaine Hydrochloride with 15 µg/mL Clonidine, and Group D: 2% Lignocaine Hydrochloride with 1 µg/mL Dexmedetomidine. The evaluated parameters were the time of onset of anesthesia, depth of anesthesia, hemodynamic parameters, and duration of postoperative analgesia.

Results

Group D had a faster onset of action and prolonged duration of postoperative analgesia compared with Groups A and C. No statistically significant differences were observed between the three groups in terms of the depth of anesthesia and hemodynamic parameters.

Conclusion

Group D exhibited a significantly more rapid onset of anesthesia than Groups A and C, and the postoperative analgesic effect in Group D was significantly prolonged (7.22 hours) compared with that in Groups A (4.54 hours) and C (2.1 hours). Patients receiving the Group D solution experienced an extended period of comfort without the need for analgesics for up to 7.22 hours post-procedure.

Clonidine versus Adrenaline as an Adjunct to Lignocaine on Haemodynamic Parameters during Nerve Block for Third Molar Surgical Removal - A Systematic Review and Meta-Analysis

Background

Adrenaline or clonidine is used as adjuncts in conjunction with lignocaine to improve the depth of local anaesthesia in dental procedures.

Objectives

This systematic review and meta-analysis intends to compare the haemodynamic parameters when clonidine or adrenaline is used in conjunction with lignocaine for third-molar surgical removal.

Data Sources

Cochrane, PubMed and Ovid SP databases were searched using "MeSH" terms (((nerve block) OR (IANB)) AND ((clonidine) OR (adrenaline))) AND (lignocaine).

Study Eligibility Criteria

Clinical studies where Clonidine + lignocaine and Adrenaline + lignocaine were compared directly during nerve block administration exclusively for third molar surgical removal were selected.

Participants Study Appraisal

This current systematic review is registered in Prospero database CRD42021279446. Two independent reviewers were involved in collection, segregation and analysis of electronic data. The data were compiled in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Search was conducted till June 2021.

Synthesis Methods

Qualitative analysis of the selected articles was performed for systematic review. Meta-analysis is performed using RevMan 5 Software. Heterogeneity through the I2 statistics. Change in the haemodynamic parameters was the primary outcome evaluated, and secondary outcomes evaluated were onset and duration of anaesthesia in both the groups.

Results

In all databases, 1141 records were screened, out of which a total of 21 articles were included for the evaluation for full-text analysis. Out of these, 16 articles were excluded and 5 articles were included for the final systematic review. Meta-analysis was performed only for 4 studies.

Conclusion

Amongst the evaluated haemodynamic parameters, there was a significant reduction in the heart rate (baseline to intraoperative period) in clonidine and lignocaine groups than in adrenaline and lignocaine groups during nerve block administration for third molar surgical removal. There was no significant difference between other primary and secondary outcomes evaluated.

Limitations

Blinding was not performed in all the studies, randomisation was performed in only three studies. The volume of local anaesthesia deposited varied in the studies (2 mL in three studies and 2.5 mL in two studies). Most of the studies (n = 4) were evaluated on normal adults and only one study evaluated mild hypertensive patients.

Comparative Evaluation of Effectiveness of 2% Lignocaine Hydrochloride with Clonidine Hydrochloride versus 2% Lignocaine Hydrochloride with Adrenaline Bitartrate as Local Anesthetic for Adult Patients Undergoing Surgical Extraction of Impacted Mandibular Third Molars: A Randomized Controlled Clinical Study

Background and Objectives:

Clonidine is a common additive to local anesthetics for various regional and local nerve blocks. However, its effectiveness in dentistry has not yet been fully explored. Thus, this study was performed to evaluate the quality of anesthesia, vasoconstrictive effects, hemodynamic response, and pain control using a solution of 2% lignocaine hydrochloride with clonidine hydrochloride in comparison with the standard solution of 2% lignocaine hydrochloride and adrenaline bitartrate for pterygomandibular nerve blocks.

Materials and Methods:

A parallel arm, triple-blind randomized controlled study was conducted on 152 patients belonging to ASA-I (American Society of Anesthesiologists) category in the age group of 18-45 years, requiring surgical extraction of impacted mandibular third molars. The patients were divided equally into two groups randomly by computer-generated sequence; Group 1: 2% lignocaine hydrochloride with 1 ml of clonidine hydrochloride (150 μg/ml) and Group 2: 2% lignocaine hydrochloride with adrenaline bitartrate 1: 80,000 (12.5 μg/ml). The variables evaluated were systolic, diastolic, and mean arterial blood pressures, heart rate (HR), blood loss, onset, depth (pain), and duration of anesthesia.

Results:

There was a statistically nonsignificant difference seen between the two groups (P > 0.05) for the onset of anesthesia, pain assessed, and blood loss, whereas a statistically highly significant difference was seen for cardiovascular variables (systolic, diastolic and mean arterial blood pressures, and HR) at various intervals with higher values for Group 2 (P < 0.001) and for the duration of action of local anesthesia (LA), with higher values for Group 1 (P < 0.001).

Conclusions:

Clonidine as an additive to lignocaine has proved to have the onset of action, vasoconstrictive properties, and pain control, equivalent to adrenaline. However, with better stability of hemodynamic variables and prolonged duration of action of LA with clonidine, it can be considered as a better, safer, and more effective additive to lignocaine than adrenaline