A randomized controlled trial to evaluate S-Caine patch for reducing pain associated with vascular access in children

A randomized, double-blinded trial was performed to evaluate the efficacy and safety of the S-Caine Patch (ZARS, Inc., Salt Lake City, UT), a eutectic mixture of lidocaine and tetracaine, for pain relief during venipuncture in children.

With institutional review board approval, parental consent, and patient assent, 64 children who were scheduled for medically indicated vascular access at two centers were randomly assigned (2:1) to receive either an S-Caine Patch or a placebo patch for 20 min before venipuncture procedures. The primary outcome measure was the child's rating of pain during venipuncture using the Oucher pain scale. Additional measures of efficacy included the blinded investigator's and an independent observer's four-point categorical scores. Variables were compared between treatments using Mantel-Haenszel summary chi-square tests or Pearson chi-square tests.

The S-Caine Patch produced significantly greater pain relief compared with placebo (median Oucher scores of 0 vs. 60; P < 0.001). Fifty-nine percent of the children in the S-Caine Patch group reported no pain compared with 20% of the children in the placebo patch group. The investigator estimated that 76% of the children in the S-Caine Patch group experienced no pain during venipuncture versus 20% in the placebo patch group (P = 0.001). Independent observer ratings also favored the S-Caine Patchtrade mark (P < 0.001). Mild skin erythema (< 38%) and edema (< 2%) occurred with similar frequencies between the groups.

This study demonstrated that a 20-min application of the S-Caine Patch is effective in lessening pain associated with venipuncture procedures. Adverse events after S-Caine Patch application were mild and transient.