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Supportive Care

Brand names:

LMX 4 Plus; LMX 4; LMX 5; Xylocaine®

Often used for:

Pain; abnormal heart rhythms

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What is Lidocaine?

Lidocaine is a medicine used to control pain. It is often used as an anesthetic to numb an area of the body. Lidocaine may also be used to treat skin irritation or itching, mouth sores, or nerve problems. When given by IV, lidocaine may also be used to treat abnormal heart rhythms.

Patients receiving lidocaine infusions may be monitored for changes in heart rate and blood pressure and for central nervous system effects such as dizziness, seizures, or loss of consciousness.

This medicine is available in prescription and over-the-counter (OTC) forms.

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May be applied on the skin (topical)

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May be given as a solution in the mouth (oral)

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May be given as a liquid by injection

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May be given as a liquid through an endotracheal tube

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Possible Side Effects

Possible side effects with all forms:
  • Ringing in the ears
  • Drowsiness
  • Metallic taste
  • Dizziness or fainting
  • Shakiness
  • Change in eyesight
  • Nausea and vomiting
  • Nervousness or restlessness
  • Twitching or seizures 
  • Burning or tingling
  • Feeling cold or hot
  • Breathing problems
  • Decreased heart rate
  • Symptoms of a blood problem called methemoglobinemia include: blue or gray color of skin, lips, or nails, headache, increased heart rate, shortness of breath, dizziness, fatigue, weakness, seizures
  • Symptoms of an allergic reaction include: rash, hives, itching, chills, fever, headache, muscle ache, shortness of breath, coughing, tightness in the throat, swelling of the face or neck

Possible side effects with topical form:

  • Swelling, redness, or irritation
  • Tiny red, purple, or brown spots on the skin caused by bleeding (petechiae)
  • Itching
  • Changes in skin color

Possible side effects with IV or injection form:

  • Headache
  • Fatigue or weakness
  • Dry mouth
  • Change in mood (depression or anxiety)
  • Problems moving or controlling urine or stools (if given as in injection into the spine)

Not all patients who take lidocaine will experience these side effects. Common side effects are in bold, but there may be others. Please report all suspected side effects to your doctor or pharmacist.

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Tips for Families

Be sure to discuss these and other recommendations with your doctor or pharmacist.

  • Families should talk to a doctor or pharmacist before using a product containing lidocaine, even when using over-the-counter medicine.
  • Do not switch brands or forms of lidocaine without talking to a doctor or pharmacist.
  • Numbness or loss of feeling after lidocaine treatment can increase risk of burns, cuts, or other injury. Protect the area until feeling has returned to normal.
  • Lidocaine may cause temporary dizziness, decreased alertness, or problems controlling movements. This may lead to an increased risk of falls or injury. Be careful doing tasks involving motor activity until the effects of the medicine have worn off.
  • High temperatures may cause too much medicine to be released. Avoid heat sources such as heating pads, hot tubs, sunbathing, and hot baths.
  • When using oral products, patients should not eat or chew gum if the mouth or tongue is numb.
  • Patients who have a G6PD deficiency are at greater risk for blood problems (methemoglobinemia) with lidocaine.
  • Patients should tell their doctor if they are pregnant, attempting to get pregnant, or breastfeeding.

Lidocaine at home:

  • Each form of lidocaine has specific directions for use. Discuss any questions with your doctor or pharmacist. The information below is for general understanding only. Always follow the instructions given with your prescription or on the medicine label.
  • Lotion, spray, gel, or liquid applied to the skin: Wash hands before and after applying the medicine. Apply to clean, dry skin. Avoid getting in the eyes, nose, or mouth.
  • Skin patch: Apply to clean, dry skin. Patch can remain in place up to 12 hours. Do not apply new patch in the same place. Do not use more than 1 patch a day (24 hour period).
  • Oral liquid: Shake well, and use as directed. For oral rinse, swish in mouth and then spit or swallow as instructed. Wait at least 1 hour before eating or chewing gum.
  • Give a missed dose as soon as possible. If it is near the time for the next dose, skip the dose. Do not give 2 doses at the same time. 
  • Store at room temperature.
  • Do not use the medicine past the expiration date.
  • Follow instructions for safe storage and disposal.