Randomized double-blind crossover trial of a transdermal maltose dissolvable microneedle patch for topical anesthesia before intravenous cannulation for thalassemia children.

The efficacy and safety of transdermal dissolvable microneedle array patch (MNAP) in enhancing topical anesthesia delivery was studied in transfusion-dependent thalassemia children who had intravenous cannulation (IVC) for blood transfusion. We also compared the use of skin conductance algesimeter index (SCAI) as a pain assessment tool against the visual analog score (VAS) in these children with ages between 6 and 17 years, who had the topical anesthetic cream (EMLA) applied on the hand dorsum before IVC. This was a double-blind, randomized crossover trial involving 19 children with each child randomized to four intervention arms sequentially: MNAP and 1 finger-tip-unit (FTU) EMLA applied for 30 min (A), MNAP and 0.5 FTU EMLA for 30 min (B); MNAP and 1 FTU EMLA for 15 min (C); and no MNAP (sham) patch and 1FTU EMLA for 30 min (D), before IVC. The primary and secondary endpoints were, respectively, VAS and SCAI scores measured immediately after IVC. The MNAP with 1 FTU EMLA for 30 min resulted in significantly lower VAS scores than sham patch [MeanMNAP (SE),1.839 (0.560) vs. [Meansham (SE): 3.063 (0.534); p = 0.048], but not SCAI [MeanMNAP (SE): 0.200 (0.024) versus Meansham (SE): 0.203 (0.026); p = 0.926]. The SCAI was not significantly correlated with VAS for all groups (r = -0.040 to 0.378; p (all) > 0.05). Only 1 participant reported pruritus as a mild adverse event. The MNAP is a safe adjunct method to enhance effectiveness of pain relief from EMLA skin anesthetic before IVC.