Topical anaesthesia for circumcision WARNING

EMLA topical anaesthetic for neonatal circumcision

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1996 PHYSICIANS' DESK REFERENCE, 545-547.

"EMLA Cream is not recommended for use on mucous membranes because limited studies show much greater absortion of lidocaine and prilocaine than through intact skin. Safe dosing recommendations for use on mucous membranes cannot be made because it has not been studied accurately."

"EMLA Cream should not be used in infants under the age of one month, nor in infants under the age of twelve months, who are receiving treatment with methemoglobin-inducing agents (see Methemoglobinemia subsection of WARNINGS).

1996 PDR:545-547.

The Canadian Nurse, August 1994, pp. 5-6

[Material in brackets added. CIRP]

Editor's note: Recently we received a copy of the following letter from Grace Boudreau, RN, Director of Quality Assurance, G. R. Baker Memorial Hospital, Quesnel, B.C. [British Columbia, Canada]. The letter was sent to all general practitioners, hospitals and pharmacies in Northern British Columbia on March 28, 1994. We have permission from the letter's author, Dr. Marie Hay, to print the letter in its entirety (bold type represents emphasis expressed in original letter.)

Dear Doctor,

The Department of Paediatrics at Prince George Regional Hospital recently discussed the unfortunate case of a 21-day-old male child who was circumcised using Prilocaine as a local anesthetic agent. A few hours after the circumcision the baby developed significant Methaemo-globinaemia [reaction with the blood] due to the Prilocaine anesthetic.

The department of Paediatrics is issuing a strong warning to all physicians who perform circumcisions. We strongly advise that Prilocaine local anesthetic not be used under any circumstances for neonatal circumcision. It is also interesting to note that EMLA cream contains 2.5% Prilocaine. It also therefore should not be used on the mucous membranes of newborns when they are circumcised.

It is the Department of Paediatrics' recommendation that no infant under the age of 3 months gets Prilocaine or EMLA cream in any form because of the serious risk of Methaemo-globinaemia.

I understand from speaking with an Intensivist at B.C. Children's Hospital that two other cases of Methaemo-globinaemia due to Prilocaine have also been noted in B.C. in the past recent months. As you know Methaemoglobinaemia can cause brain damage and death in small infants.

Abstract:

EMLA (eutectic mixture of lidocaine and prilocaine) cream is currently not recommended for use in infants < 1 month of age because of the potential risk of methemoglobinemia as a result of the o-toluidine metabolite of prilocaine. We studied bioavailablitiy and changes in methemoglobin levels following topical penile exposure to 1 g of EMLA cream for 1 hour in piglets. Lidocaine, prilocaine, and o-toluidine concentrations were measured simultaneously using a high-performance liquid chromatography method. The systemic bioavailability of EMLA was low: 4.0 +/- (SD) 4.7% for lidocaine (range 0-13.6; n=8) and 7.2 +/- 5.7% for prilocaine (range 0-14.5; n=8). The ratio between exposure to o-toluidine with EMLA versus intravenous administration (i.e. AUC EMLA/ AUC IV; see text) was also low: 4.2 +/- 9.3% (range 0-28.6; n=9). The mean maximum methemaglobin value after intravenous administration was 1.23 +/- 0.64% (range 0.5-3.0; n=12) and after penile application 0.99 +/- 0.36% (range 0.5-2.0; n=12). The methemoglobin value was elevated significantly above baseline after intravenous administration (p=0.03), but not after penile application of EMLA. These findings suggest that penile administration of 1 g or EMLA may be safe for neonatal circumcision, but further study is required.

Puthoff TD, Visconti JA, Tschampel MM.
Use of EMLA Prior to Circumcision.
Annals of Pharmacology (1996), Vol 30, pp 1327-1330

Conclusion:

There are insufficient data to support the use of EMLA cream for circumcision in newborn infants at this time. There are no studies that adequately address safety or efficacy. Before efficacy studies can be evaluated, pharmacodynamic stidies need to be completed. These studies are in progress and are closed (personal communication, Vivian Broach etc). Subsequent studies should be performed within the first 72 hours of birth and assess the following parameters: 1) serum concentrations of metHb, lidocaine, and prilocaine and its metabolites from time zero to at least 24 hours after application of the cream; 2) application time and dose applied should be varied to assess differences in absorption, as well as onset and duration of analgesia; 3) application technique could be varied to assess the depth of analgesia, that is, application to the inner and outer surface of the prepuce versus the outer surface only. Until these studies are completed, routine use of EMLA cream for local anesthesia during circumcision cannot be recommended.

FROM ASTRA/HOSPITAL DIVISION (Makers of Emla):

Contraindications:  "EMLA is contraindicated in patients...who are less
than 6 months of age or younger, until further clinical data are
available."

Precautions:  "EMLA cream is not sterile.  Therefore it should not be
applied to open wounds or used as an analgesic dressing following
cannulation or venipuncture.  EMLA cream is presently not recommended
for use on genital skin or mucosa."

Dosage and Administration:  "Use in infants under the age of 6 months:
Not recommended"

"DO NOT APPLY EYES OR ON OPEN WOUNDS.  Not for use in children under 6
months of age."

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