Dosing for lidoderm patch

Absorption The amount of lidocaine systemically absorbed from LIDODERM is directly related to both the duration of application and the surface area over which it is applied. Blood samples were withdrawn for determination of lidocaine concentration during the application and for 12 hours after removal of patches. The results are summarized in Table 1. Mean peak blood concentration of lidocaine is about 0. Repeated application of three patches simultaneously for 12 hours recommended maximum daily dose , once per day for three days, indicated that the lidocaine concentration does not increase with daily use.

The mean plasma pharmacokinetic profile for the 15 healthy volunteers is shown in Figure 1. Distribution When lidocaine is administered intravenously to healthy volunteers, the volume of distribution is 0. Lidocaine crosses the placental and blood brain barriers, presumably by passive diffusion. Metabolism It is not known if lidocaine is metabolized in the skin. Lidocaine is metabolized rapidly by the liver to a number of metabolites, including monoethylglycinexylidide MEGX and glycinexylidide GX , both of which have pharmacologic activity similar to, but less potent than that of lidocaine.

A minor metabolite, 2,6-xylidine, has unknown pharmacologic activity but is carcinogenic in rats. Excretion Lidocaine and its metabolites are excreted by the kidneys. The systemic clearance is 0. Single-dose treatment with LIDODERM was compared to treatment with vehicle patch without lidocaine , and to no treatment observation only in a double-blind, crossover clinical trial with 35 post-herpetic neuralgia patients.

Pain intensity and pain relief scores were evaluated periodically for 12 hours. The constant type of pain was evaluated but not the pain induced by sensory stimuli dysesthesia. About half of the patients also took oral medication commonly used in the treatment of post-herpetic neuralgia. The extent of use of concomitant medication was similar in the two treatment groups. It should be applied only to intact skin. LIDODERM 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.

Cases of methemoglobinemia have been reported in association with local anesthetic use. Although all patients are at risk for methemoglobinemia, patients with glucosephosphate dehydrogenase deficiency, congenital or idiopathic methemoglobinemia, cardiac or pulmonary compromise, infants under 6 months of age, and concurrent exposure to oxidizing agents or their metabolites are more susceptible to developing clinical manifestations of the condition.

If local anesthetics must be used in these patients, close monitoring for symptoms and signs of methemoglobinemia is recommended. Methemoglobin levels may continue to rise; therefore, immediate treatment is required to avert more serious central nervous system and cardiovascular adverse effects, including seizures, coma, arrhythmias, and death.

Depending on the severity of the signs and symptoms, patients may respond to supportive care, i. A more severe clinical presentation may require treatment with methylene blue, exchange transfusion, or hyperbaric oxygen. The potential exists for a small child or a pet to suffer serious adverse effects from chewing or ingesting a new or used LIDODERM patch, although the risk with this formulation has not been evaluated.

The blood concentration of lidocaine is determined by the rate of systemic absorption and elimination. Longer duration of application, application of more than the recommended number of patches, smaller patients, or impaired elimination may all contribute to increasing the blood concentration of lidocaine.

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.

Non-intact Skin Application to broken or inflamed skin, although not tested, may result in higher blood concentrations of lidocaine from increased absorption. External Heat Sources Placement of external heat sources, such as heating pads or electric blankets, over LIDODERM patches is not recommended as this has not been evaluated and may increase plasma lidocaine levels. If eye contact occurs, immediately wash out the eye with water or saline and protect the eye until sensation returns.

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.

Antiarrhythmic Drugs LIDODERM should be used with caution in patients receiving Class I antiarrhythmic drugs such as tocainide and mexiletine since the toxic effects are additive and potentially synergistic. Patients who are administered local anesthetics are at increased risk of developing methemoglobinemia when concurrently exposed to the following drugs, which could include other local anesthetics:.

Examples of Drugs Associated with Methemoglobinemia :. Carcinogenesis A minor metabolite, 2,6-xylidine, has been found to be carcinogenic in rats. Teratogenic Effects Pregnancy Category B. There are, however, no adequate and well-controlled studies in pregnant women.

Lidocaine is not contraindicated in labor and delivery. Lidocaine is excreted in human milk, and the milk:plasma ratio of lidocaine is 0. These reactions are generally mild and transient, resolving spontaneously within a few minutes to hours. A minor metabolite, 2, 6-xylidine, has unknown pharmacologic activity but is carcinogenic in rats. Excretion Lidocaine and its metabolites are excreted by the kidneys.

The systemic clearance is 0. Pain intensity and pain relief scores were evaluated periodically for 12 hours. The constant type of pain was evaluated but not the pain induced by sensory stimuli dysesthesia.

About half of the patients also took oral medication commonly used in the treatment of post-herpetic neuralgia. The extent of use of concomitant medication was similar in the two treatment groups. It should be applied only to intact skin. Cases of methemoglobinemia have been reported in association with local anesthetic use. Although all patients are at risk for methemoglobinemia, patients with glucosephosphate dehydrogenase deficiency, congenital or idiopathic methemoglobinemia, cardiac or pulmonary compromise, infants under 6 months of age, and concurrent exposure to oxidizing agents or their metabolites are more susceptible to developing clinical manifestations of the condition.

If local anesthetics must be used in these patients, close monitoring for symptoms and signs of methemoglobinemia is recommended. Methemoglobin levels may continue to rise; therefore, immediate treatment is required to avert more serious central nervous system and cardiovascular adverse effects, including seizures, coma, arrhythmias, and death.

Depending on the severity of the signs and symptoms, patients may respond to supportive care, i. A more severe clinical presentation may require treatment with methylene blue, exchange transfusion, or hyperbaric oxygen. The blood concentration of lidocaine is determined by the rate of systemic absorption and elimination. Longer duration of application, application of more than the recommended number of patches, smaller patients, or impaired elimination may all contribute to increasing the blood concentration of lidocaine.

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. Non-intact Skin Application to broken or inflamed skin, although not tested, may result in higher blood concentrations of lidocaine from increased absorption.

If eye contact occurs, immediately wash out the eye with water or saline and protect the eye until sensation returns. 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. Patients who are administered local anesthetics are at increased risk of developing methemoglobinemia when concurrently exposed to the following drugs, which could include other local anesthetics:.

Examples of Drugs Associated with Methemoglobinemia:. Carcinogenesis A minor metabolite, 2, 6-xylidine, has been found to be carcinogenic in rats.

Teratogenic Effects Pregnancy Category B. There are, however, no adequate and well-controlled studies in pregnant women.

Lidocaine is not contraindicated in labor and delivery. Lidocaine is excreted in human milk, and the milk: plasma ratio of lidocaine is 0. These reactions are generally mild and transient, resolving spontaneously within a few minutes to hours.

Allergic and anaphylactoid reactions associated with lidocaine, although rare, can occur. They are characterized by angioedema, bronchospasm, dermatitis, dyspnea, hypersensitivity, laryngospasm, pruritus, shock, and urticaria. If they occur, they should be managed by conventional means. The detection of sensitivity by skin testing is of doubtful value. Due to the nature and limitation of spontaneous reports in postmarketing surveillance, causality has not been established for additional reported adverse events including:.

Asthenia, confusion, disorientation, dizziness, headache, hyperesthesia, hypoesthesia, lightheadedness, metallic taste, nausea, nervousness, pain exacerbated, paresthesia, somnolence, taste alteration, vomiting, visual disturbances such as blurred vision, flushing, tinnitus, and tremor.

Excitatory CNS reactions may be brief or not occur at all, in which case the first manifestation may be drowsiness merging into unconsciousness. Cardiovascular manifestations may include bradycardia, hypotension and cardiovascular collapse leading to arrest. Lidocaine overdose from cutaneous absorption is rare, but could occur.