Emla Cream-Lidocaine/Prilocaine HCL

 

Patient Education Quick Reference Guide Diablo Valley Oncology/Hematology Medical Group Phone Number: 925-677-5041

DESCRIPTION Lidocaine and prilocaine cream, 2.5%/2.5% is an emulsion in which the oil phase is a eutectic mixture of lidocaine and prilocaine in a ratio of 1:1 by weight. This eutectic mixture has a melting point below room temperature and therefore both local anesthetics exist as a liquid oil rather than as crystals. It is packaged in 30 gram tubes and 5 gram tubes for hospital use. Lidocaine is chemically designated as acetamide, 2-(diethylamino)-N-(2,6-dimethylphenyl), has an octanol:water partition ratio of 43 at pH 7.4. Prilocaine is chemically designated as propanamide, N-(2-methylphenyl)-2-(propylamino), has an octanol:water partition ratio of 25 at pH 7.4. Each gram of lidocaine and prilocaine cream, 2.5%/2.5% contains lidocaine 25 mg, prilocaine 25 mg, polyoxyethylene fatty acid esters (as emulsifiers), carbomer 934 (as a thickening agent), sodium hydroxide to adjust to a pH approximating 9, and purified water. Lidocaine and prilocaine cream, 2.5%/2.5% contains no preservative, however it passes the USP antimicrobial effectiveness test due to the pH. The specific gravity of lidocaine and prilocaine cream, 2.5%/2.5% is approximately 1.

INDICATIONS AND USAGE

Lidocaine and prilocaine cream, 2.5%/2.5% (a eutectic mixture of lidocaine 2.5% and prilocaine 2.5%) is indicated as a topical anesthetic for use on:
  • normal intact skin for local analgesia.
  • genital mucous membranes for superficial minor surgery and as pretreatment for infiltration anesthesia.
Lidocaine and prilocaine cream, 2.5%/2.5% is not recommended in any clinical situation in which penetration or migration beyond the tympanic membrane into the middle ear is possible because of the ototoxic effects observed in animal studies (see WARNINGS).

CONTRAINDICATIONS

Lidocaine and prilocaine cream, 2.5%/2.5% is contraindicated in patients with a known history of sensitivity to local anesthetics of the amide type or to any other component of the product.  

WARNINGS

Application of lidocaine and prilocaine cream, 2.5%/2.5% to larger areas or for longer times than those recommended could result in sufficient absorption of lidocaine and prilocaine resulting in serious adverse effects. Patients treated with class III anti-arrhythmic drugs (eg, amiodarone, bretylium, sotalol, dofetilide) should be under close surveillance and ECG monitoring considered, because cardiac effects may be additive. Studies in laboratory animals (guinea pigs) have shown that lidocaine and prilocaine cream, 2.5%/2.5% has an ototoxic effect when instilled into the middle ear. In these same studies, animals exposed to lidocaine and prilocaine cream, 2.5%/2.5% in the external auditory canal only, showed no abnormality. Lidocaine and prilocaine cream, 2.5%/2.5% should not be used in any clinical situation in which its penetration or migration beyond the tympanic membrane into the middle ear is possible.

PRECAUTIONS

Carcinogenesis, Mutagenesis, Impairment of Fertility

Use in Pregnancy: Teratogenic Effects: Pregnancy Category B. Reproduction studies with lidocaine have been performed in rats and have revealed no evidence of harm to the fetus (30 mg/kg subcutaneously; 22 times SDA). Reproduction studies with prilocaine have been performed in rats and have revealed no evidence of impaired fertility or harm to the fetus (300 mg/kg intramuscularly; 188 times SDA). There are, however, no adequate and well- controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, lidocaine and prilocaine cream, 2.5%/2.5% should be used during pregnancy only if clearly needed. Reproduction studies have been performed in rats receiving subcutaneous administration of an aqueous mixture containing lidocaine HCl and prilocaine HCl at 1:1 (w/w). At 40 mg/kg each, a dose equivalent to 29 times SDA lidocaine and 25 times SDA prilocaine, no teratogenic, embryotoxic or fetotoxic effects were observed.

Geriatric Use

Of the total number of patients in clinical studies of lidocaine and prilocaine cream, 2.5%/2.5%, 180 were age 65 to 74 and 138 were 75 and over. No overall differences in safety or efficacy were observed between these patients and younger patients. Other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out. Plasma levels of lidocaine and prilocaine in geriatric and non-geriatric patients following application of a thick layer of lidocaine and prilocaine cream, 2.5%/2.5% are very low and well below potentially toxic levels. However, there are no sufficient data to evaluate quantitative differences in systemic plasma levels of lidocaine and prilocaine between geriatric and non-geriatric patients following application of lidocaine and prilocaine cream, 2.5%/2.5%. Consideration should be given for those elderly patients who have enhanced sensitivity to systemic absorption. (See PRECAUTIONS.) After intravenous dosing, the elimination half-life of lidocaine is significantly longer in elderly patients (2.5 hours) than in younger patients (1.5 hours).

ADVERSE REACTIONS

OVERDOSAGE

Peak blood levels following a 60 g application to 400 cm2 of intact skin for 3 hours are 0.05 to 0.16 mcg/mL for lidocaine and 0.02 to 0.10 mcg/mL for prilocaine. Toxic levels of lidocaine (>5 mcg/mL) and/or prilocaine (>6 mcg/mL) cause decreases in cardiac output, total peripheral resistance and mean arterial pressure. These changes may be attributable to direct depressant effects of these local anesthetic agents on the cardiovascular system. In the absence of massive topical overdose or oral ingestion, evaluation should include evaluation of other etiologies for the clinical effects or overdosage from other sources of lidocaine, prilocaine or other local anesthetics. Consult the package inserts for parenteral Xylocaine (lidocaine HCl) or Citanest (prilocaine HCl) for further information for the management of overdose.

DOSAGE AND ADMINISTRATION

Adult Patients-Intact Skin A thick layer of lidocaine and prilocaine cream, 2.5%/2.5% is applied to intact skin and covered with an occlusive dressing. Adult Female Patients-Genital Mucous Membranes For minor procedures on the female external genitalia, such as removal of condylomata acuminata, as well as for use as pretreatment for anesthetic infiltration, apply a thick layer (5-10 grams) of lidocaine and prilocaine cream, 2.5%/2.5% for 5 to 10 minutes. Occlusion is not necessary for absorption, but may be helpful to keep the cream in place. Patients should be lying down during the lidocaine and prilocaine cream, 2.5%/2.5% application, especially if no occlusion is used. The procedure or the local anesthetic infiltration should be performed immediately after the removal of lidocaine and prilocaine cream, 2.5%/2.5%.

INSTRUCTIONS FOR APPLICATION

Lidocaine and Prilocaine Cream, 2.5%/2.5%
  • In adults, apply 2.5 g of cream per 20 to 25 cm2 (approx. 2 in. by 2 in.) of skin in a thick layer at the site of the procedure. For pediatric patients, apply ONLY as prescribed by your physician. If your child is below the age of 3 months or small for their age, please inform your doctor before applying lidocaine and prilocaine cream, 2.5%/2.5%, which can be harmful, if applied over too much skin at one time in young children. If your child becomes very dizzy, excessively sleepy, or develops duskiness of the face or lips after applying lidocaine and prilocaine cream, 2.5%/2.5%, remove the cream and contact your physician at once.
  • Take the dressing (may be supplied in this package) or other occlusive dressing and remove the center cut-out piece.
  • Peel the paper liner from the dressing. (Instructions continued on reverse side.)
  • Cover the lidocaine and prilocaine cream, 2.5%/2.5% so that you get a thick layer underneath. Do not spread out the cream. Smooth down the dressing edges carefully and ensure it is secure to avoid leakage. (This is especially important when the patient is a child.)
  • The time of application can be marked directly on the occlusive dressing. Lidocaine and prilocaine cream, 2.5%/2.5% must be applied at least 1 hour before the start of a routine procedure and for 2 hours before the start of a painful procedure.
  • Remove the occlusive dressing, wipe off the lidocaine and prilocaine cream, 2.5%/2.5%, clean the entire area with an antiseptic solution and prepare the patient for the procedure. The duration of effective skin anesthesia will be at least 1 hour after removal of the occlusive dressing.

PRECAUTIONS

  • Do not apply near eyes or on open wounds.
  • Keep out of reach of children.