Hepatic Disease
Patients with severe hepatic disease are at greater risk of developing toxic blood concentrations of lidocaine, because of their inability to metabolize lidocaine normally.
Allergic Reactions
Patients allergic to para-aminobenzoic acid derivatives (procaine, tetracaine, benzocaine, etc.) have not shown cross sensitivity to lidocaine. However, Lidocaine Patch 5% should be used with caution in patients with a history of drug sensitivities, especially if the etiologic agent is uncertain.
Non-intact Skin
Application to broken or inflamed skin, although not tested, may result in higher blood concentrations of lidocaine from increased absorption. Lidocaine Patch 5% is only recommended for use on intact skin.
External Heat Sources
MRI skin burns have been reported at the patch site in several patients wearing an aluminized transdermal system during a magnetic resonance imaging scan (MRI). Because the Lidocaine Patch 5% contains aluminum, it is recommended to remove the system before undergoing an MRI.
Placement of external heat sources, such as heating pads or electric blankets, over Lidocaine Patches 5% is not recommended as this has not been evaluated and may increase plasma lidocaine levels.
Eye Exposure
The contact of Lidocaine Patch 5% with eyes, although not studied, should be avoided based on the findings of severe eye irritation with the use of similar products in animals. If eye contact occurs, immediately wash out the eye with water or saline and protect the eye until sensation returns.
Information for Patients
Methemoglobinemia
Inform patients that use of local anesthetics may cause methemoglobinemia, a serious condition that must be treated promptly. Advise patients or caregivers to stop use and seek immediate medical attention if they or someone in their care experience the following signs or symptoms: pale, gray, or blue colored skin (cyanosis); headache; rapid heart rate; shortness of breath; lightheadedness; or fatigue.