L.M.X.4 (Lidocaine 4%)

L.M.X.4 is a topical anesthetic cream that is similar to EMLA.

At the nerve endings, L.M.X.4 causes numbing of the skin and surrounding tissue.

  • DO NOT CLEANSE THE SKIN prior to L.M.X.4 application (although you should not apply over moisturizers or other topical medications).
  • L.M.X.4 works best when it mixes with the skin surface oils.
  • While wearing gloves, begin by rubbing a small amount of L.M.X.4 cream into each of the sites for about 30 seconds.
  • Apply another layer of L.M.X.4 cream, this time with a thicker coating of the cream. Cover cream with an occlusive dressing (Tegaderm or round bandages).  
  • Although L.M.X.4 does not require the use of an occlusive dressing, one is recommended for use in children to ensure adequate contact of the cream with the skin and to prevent the accidental ingestion of the cream.
  • Do NOT flatten the cream (L.M.X.4 works best when it is applied thickly).
  • After the product is removed, the skin should be cleaned and prepared as usual for the procedure.

L.M.X.4 starts to work in about 30 minutes.

Total application time should usually not exceed 60 minutes. (Rubbing it in longer has not been shown to increase its effect).

It lasts approximately 60 minutes.

  • Keep this medication out of the reach of children.
  • If too much medicine is taken by accident, call the Drug and Poison Information Center (DPIC), 513-636-5111 or 1-800-222-1222, or call your child's doctor immediately.
  • Do not repeat application / dose to the same part of the body within two hours.
  • Make sure to wear gloves during application and wash hands after applying.
  • Redness, irritation at the site of the cream
  • Swelling, abnormal sensation at the site of the cream
  • Rash
Over-the-counterPrescription only
Lidocaine 4%Lidocaine 2.5% / Prilocaine 2.5%
Application Time
30 min – Venipuncture/LP60 min – Venipuncture / LP

120 min – Skin graft harvesting
5-15 min – genital mucosa

Application Time
60 min (no added benefit with longer application) May be left on up to 120 min60 min (<3mo or <5kg)
240 min (4 hrs) for all others
of Effect
60 min after removal60-120 min after removal
ADRsRedness, irritation, itching, rashLocal blanching, redness, erythema, methemoglobinemia
Approved Ages
>2 years old>37 weeks EGA
Approved Uses
Minor cuts, minor burns, minor scrapes, minor skin irritations, sunburn, and insect bitesIV catheter placement, venipuncture, split skin graft harvesting, genital mucosa (adjunct to local infiltration)
Approved uses
studied in children
IV catheter placement, Venipuncture, circumcision, LPCircumcision, anal fissures, IM immunizations, LP, cryotherapy for warts
Warnings /
Do no use on raw areas or blistersUse with caution in patients at risk for developing methemoglobinemia or with severe hepatic disease
Size5, 15, 30gm tubes. 5gm tube has 3 Tegaderm patches.30gm tube

Last Updated 11/2013