For infants younger than 3 months undergoing venipuncture, eutectic mixture of lidocaine (EMLA) cream has only minimal pain relieving effects relative to placebo and no benefit over sucrose and / or breastfeeding, according to a meta-analysis of published studies.
The analysis also supports "concerns" regarding elevation of methemoglobin levels and skin blanching with EMLA use, the authors say. "On the basis of our assessment, we think clinicians may want to avoid the routine use of EMLA before venipuncture in both term and preterm infants and consider nonpharmacological interventions such as sucrose or breastfeeding," concludes Dr. Shaneela Shahid and colleagues from McMaster University in Hamilton, Canada.
The authors reviewed 10 randomized controlled trials comparing EMLA with non-drug interventions for control of pain during venipuncture in a total of 907 infants aged 3 months and younger.
There is evidence that EMLA cream is an effective topical anesthetic for venipuncture in infants older than 3 months of age and in children. However, its use for venipuncture pain reduction in infants younger than 3 months of age (the focus of the current study) has led to "conflicting conclusions," they point out in their article.
In their analysis, EMLA was "similar to no treatment or placebo in most outcomes and lower outcomes in safety outcomes." In six trials with "moderate quality" evidence, EMLA cream had "little or no effect" in reducing pain (mean difference: 0.14; 95% confidence interval, -0.17 to 0.45) when EMLA was compared with sucrose, breastfeeding, or placebo.
When EMLA was compared with placebo or no treatment, it had a "small effect on pain scores during the venipuncture." Hence, EMLA is better than placebo or no treatment, "the investigators note.
Pain scores were lower with sucrose and breastfeeding compared with EMLA. Therefore, "in most of the cases, sucrose or breast milk will likely reduce the pain due to venipuncture as compared with EMLA," they say.
In two trials with "low-quality" evidence that compared EMLA to placebo, EMLA had a "small-to-moderate effect" on increasing methemoglobin levels (mean difference: 0.35; 95% CI: 0.04 to 0.66). There was an increased risk of blanching of the skin in the EMLA group (relative risk: 2.63; 95% CI: 1.58 to 4.38) in two trials with "very low-quality" evidence.
The current results might not apply to older infants, Dr. Shahid and colleagues note. They conclude, "Future high-quality, blinded, randomized, and well-powered trials are needed in both term and preterm infants to address several important questions relating to different dosing of EMLA in term infants and other pharmacological and nonpharmacological strategies for pain management and their long-term effects, particularly in preterm infants. "