BACKGROUND AND PURPOSE:

• EMLA cream, widely used to prevent or reduce pain in infants undergoing venipuncture, is composed of lidocaine (25 mg/g) and prilocaine (25 mg/g) in a cream base
• Evidence that it may be helpful but conflicting evidence in younger infants
  • In addition, both lidocaine and prilocaine can result in an increase in methemoglobin in infants, which has reduced oxygen binding capacity
• Shahid et al. (Pediatrics, 2019) assessed the efficacy and safety of EMLA cream in infants <3 months requiring venipuncture

METHODS:

• Meta-analysis of randomized controlled trials (RCTs) comparing EMLA with nonpharmacological interventions
• Nonpharmacological comparators were
  • Placebo | No EMLA (no treatment at all) | Sucrose | Breastfeeding | Skin-to-skin care
• Pain in infants was assessed using validated pain scales and measures
• Methemoglobinemia: >5% methemoglobin
• Primary outcomes
  • Pain reduction | Change in physiologic variables | Methemoglobinemia
• Secondary outcomes
  • Total duration of crying | Heart rate and desaturation | Venipuncture attempts | Skin-blanching events (white or pale skin due to vasoconstriction)

RESULTS:

• Ten randomized controlled trials were included, totaling 907 infants
• Compared to sucrose, breastfeeding, and placebo, EMLA provided little or no effect on pain reduction
  • Standardized mean difference: 0.14 (95% CI, 0.17 to 0.45; 6 trials, n = 742; moderate-quality evidence)
• Compared to placebo
  • EMLA revealed a small-to-moderate effect on increasing methemoglobin levels
  • Mean difference: 0.35 (95% CI: 0.04 to 0.66; 2 trials, n = 134; low-quality evidence)
• EMLA group had an increased risk of blanching of the skin
  • Relative risk: 2.63 (95% CI: 1.58 to 4.38; 2 trials, n = 123; very low-quality evidence)

CONCLUSION:

• EMLA provides minimal benefits while elevating methemoglobin levels and increasing risk of skin blanching
• The authors found EMLA to be inferior to sucrose or breastfeeding for pain control
• The authors suggest that EMLA should be avoided and nonpharmacologic interventions to reduce pain should be used instead in infants <3 months of age

Learn More – Primary Sources:

Efficacy and Safety of EMLA Cream for Pain Control Due to Venipuncture in Infants: A Meta-analysis.

Methemoglobinemia and Medications A to Z

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