Impact of topical analgesia on injection pain perception in facial botulinum toxin injections: A systematic review and meta-analysis

This systematic review compared the effect of various topical analgesics on botulinum toxin injection pain perception.

Data search was conducted in PubMed, Web of Science and the Cochrane Library up to 30 November 2024. Inclusion criteria were (1) research articles in English, Dutch, French or German; (2) study population with adults ≥ 18 years; (3) facial botulinum toxin injections for cosmetic and/or functional indications; (4) comparison of different types of topical analgesia or topical analgesia with no analgesia applied and (5) inclusion of injection pain measurement. Exclusion criteria included (1) articles comparing solvent variations; (2) systematic reviews and meta-analyses and (3) injection areas other than the face.

Eleven RCTs (randomised controlled trials) and 3 controlled, non-randomised studies with a total of 472 patients were included. An evidence profile table showed that the quality of the studies according to the grading of recommendations, assessment, development and evaluation guidelines was in the low and moderate categories. A forest plot was used to display the results of pooled VAS (Visual Analogue Scale) scores for comparison after topical analgesia versus no analgesia. A statistically significant reduction in pain scores was observed with an anaesthetic gel or spray, vibration stimulus and cooling compared to no analgesia or placebo. Results can be pooled to an overall effect size of −1.20 in favour of the intervention (CI: −1.69, −0.70).

This systematic review was limited owing to bias, indirectness, imprecision, clinical and methodological heterogeneity, small study groups and few studies comparing different types of topical analgesia. Further research is needed to determine the optimal type of analgesia prior to botulinum toxin injections.