Lidocaine

Medically Reviewed by Dr. Harshi Dhingra, M.D.

Last Reviewed: Apr 17, 2023

Warnings

Lidocaine Risks, Warnings, and Complications

Lidocaine can cause serious complications in some people. Talk to your doctor or pharmacist about other treatment options if you are at increased risk of complications from lidocaine use.

METHEMOGLOBINEMIA : Lidocaine patches can cause a serious blood problem called methemoglobinemia in which the red blood cells are unable to carry enough oxygen. The risk of this complication is higher in people with a genetic condition called G6PD deficiency. If you are using lidocaine patches, be careful around oxidizing chemicals like hydrogen peroxide and chlorine which are present in many household cleaning supplies and hair dyes. Signs and symptoms of methemoglobinemia may include tiredness, headache, and blue-gray discoloration of the skin. More serious complications can include dizziness, shortness of breath, heart rhythm problems, seizures, and loss of consciousness. Take the lidocaine patch off and get emergency medical help if this happens.
EXCESSIVE DOSING: Using a heating pad or electric blanket while wearing a lidocaine patch can lead to excessive dosing due to too much lidocaine being absorbed by your body. This can also occur if you use more than one patch at a time, leave the patches on for longer than recommended, or apply the patches to broken skin. People with liver problems are at greater risk of this happening. Too much lidocaine can cause life-threatening complications. Take the patch off and get emergency medical help if you develop lightheadedness, dizziness, muscle twitching, or uncontrolled shaking or movements.
ACCIDENTAL POISONING: If children or pets ingest or chew new or used lidocaine patches, it can lead to serious adverse effects. Fold the patches in half before throwing them away. Dispose of patches safely out of reach of others. Call 911 or the National Poison Control Center at 1-800-222-1222 if you suspect a child or pet has accidentally eaten or chewed a lidocaine transdermal patch.

Precautions Before Starting Lidocaine

Tell your doctor if you are allergic to lidocaine, other local anesthetics, or any other medications. Your pharmacy can give you a list of active and inactive ingredients in the patches.

Give your doctor and pharmacist a complete list of your medications, including prescription drugs, over-the-counter medicines, vitamins, supplements, and herbal products. This can help avoid possible drug interactions.

Give your doctor a complete medical history. Lidocaine patches may not be right for people with certain medical conditions such as heart disease, lung disease, liver disease, G6PD deficiency, or methemoglobinemia.

Tell your doctor if you are pregnant, could be pregnant, plan to get pregnant, or are breastfeeding.

Precautions During Use of Lidocaine

Keep all your medical appointments while using lidocaine patches. Your doctor may need to adjust your dose and monitor you for side effects.

Tell your doctor if you become pregnant while on lidocaine.

Tell all your healthcare providers you are using lidocaine patches before any surgery, including dental procedures.

Lidocaine Drug Interactions

Certain other drugs can affect lidocaine pharmacokinetics. Possible interactions between lidocaine and other medicines can increase the risk of severe adverse effects. The following medications can have drug interactions with lidocaine:

Acetaminophen (Tylenol)
Antimalarials such as chloroquine, quinidine, quinine (Qualaquin), and primaquine
Anti-infectives such as dapsone (Aczone)
Medications used for cardiac arrhythmias (irregular heartbeat) such as disopyramide (Norpace), moricizine (Ethmozine), flecainide (Tambocor), mexiletine (Mexitil), propafenone (Rythmol), quinidine (Quinidex), tocainide (Tonocard), and procainamide (Procanbid, Pronestyl)
Topical medications used to treat pain in the skin or mucous membranes
Prokinetic agents such as metoclopramide (Reglan)
Antibiotics such as nitrofurantoin (Furadantin)
Vasodilators such as nitroglycerin (Nitro-Dur) and nitroprusside (Nitropress)
Anti-seizure medications such as phenobarbital and phenytoin (Dilantin)
Anti-inflammatory drugs such as sulfasalazine (Azulfidine)

The above list may not describe all the medicines that can have potentially dangerous interactions with lidocaine. Give your doctor or pharmacist a complete list of your medications, including prescription drugs, OTC medications, dietary supplements, and herbal remedies. Also, tell your healthcare professional if you smoke, drink alcohol, or use recreational drugs because some of these substances can cause serious health complications when used with prescription and over-the-counter medications.

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