Safety of lidocaine-prilocaine cream application four times a day in premature neonates: a pilot study

Although safety is established for lidocaine-prilocaine cream application t o the heel once a day in neonates, it is often necessary to repeat heel lan ces several times a day in the clinical situation. A pilot safety study app lying 0.5 g lidocaine-prilocaine cream to the heel covering an area of 5 cm (2) with an occlusive dressing during 30 min four times a day was carried o ut. Twelve neonates (5 male, 7 female) with a gestational age of 30.1-36.3 weeks (mean 31.6 weeks) and a birth weight of 1100-2910 g (mean 1665 g) wer e enclosed. To establish safety, methaemoglobin levels and plasma concentra tions of lidocaine, prilocaine and o-toluidine were measured until 24 h aft er the final application. Methaemoglobin levels were no different from base line measurements, ranging from 0.2-1.1% and 0.1-0.7% respectively. Plasma concentrations of lidocaine and prilocaine were very low, maxima at 0.230 a nd 0.223 mg/l respectively. Plasma o-toluidine concentrations remained belo w the detection limit (0.025 mg/l). Conclusion Application of 0.5 g lidocaine-prilocaine cream to the heel unde r occlusion four times a day during 30 min is safe in preterm neonates. Est ablishing safety by measuring the methaemoglobin level by daily application is recommended.