n of more than the recommended number of patches, smaller patients, or impaired elimination may all contribute to increasing the blood concentration of lidocaine. with recommended dosing of lidocaine patch 5%, the average peak blood concentration is about 0.13 mcg/ml, but concentrations higher than 0.25 mcg/ml have been observed in some individuals.

h 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.

eported 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. systemic (dose-related) reactions systemic adverse reactions following appropriate use of lidocaine patch 5% are unlikely, due to the small dose absorbed (see clinical pharmacology , pharmacokinetics ). systemic adverse effects of lidocaine are similar in nature to those observed with other amide local anesthetic agents, including cns excitation and/or depression (light-headedness, nervousness, apprehension, euphoria, confusion, dizziness, drowsiness, tinnitus, blurred or double vision, vomiting, sensations of heat, cold or numbness, twitching, tremors, convulsions, unconsciousness, respiratory depression and arrest). 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. to report suspected adverse reactions, contact actavis at 1-800-272-5525 or fda at 1-800-fda-1088 or www.fda.gov/medwatch for voluntary reporting of adverse reactions.

ine patch normal volunteers (n = 15, 12-hour wearing time) lidocaine patch application site area (cm 2 ) dose absorbed (mg) c max (mcg/ml) t max (hr) 3 patches (2100 mg) back 420 64 ± 32 0.13 ± 0.06 11 hr when lidocaine patch is used according to the recommended dosing instructions, only 3 ± 2% of the dose applied is expected to be absorbed. at least 95% (665 mg) of lidocaine will remain in a used patch. mean peak blood concentration of lidocaine is about 0.13 mcg/ml (about 1/10 of the therapeutic concentration required to treat cardiac arrhythmias). 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. figure 1: mean lidocaine blood concentrations after three consecutive daily applications of three lidocaine patches simultaneously for 12 hours per day in healthy volunteers (n = 15). image description distribution: when lidocaine is administered intravenously to healthy volunteers, the volume of distribution is 0.7 to 2.7 l/kg (mean 1.5 ± 0.6 sd, n = 15). at concentrations produced by application of lidocaine patch, lidocaine is approximately 70% bound to plasma proteins, primarily alpha-1-acid glycoprotein. at much higher plasma concentrations (1 to 4 mcg/ml of free base), the plasma protein binding of lidocaine is concentration dependent. 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. the blood concentration of this metabolite is negligible following application of lidocaine patch 5%. following intravenous administration, megx and gx concentrations in serum range from 11 to 36% and from 5 to 11% of lidocaine concentrations, respectively. excretion: lidocaine and its metabolites are excreted by the kidneys. less than 10% of lidocaine is excreted unchanged. the half-life of lidocaine elimination from the plasma following iv administration is 81 to 149 minutes (mean 107 ± 22 sd, n = 15). the systemic clearance is 0.33 to 0.90 l/min (mean 0.64 ± 0.18 sd, n = 15).

blood concentration of lidocaine is about 0.13 mcg/ml (about 1/10 of the therapeutic concentration required to treat cardiac arrhythmias). 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. figure 1: mean lidocaine blood concentrations after three consecutive daily applications of three lidocaine patches simultaneously for 12 hours per day in healthy volunteers (n = 15). image description distribution: when lidocaine is administered intravenously to healthy volunteers, the volume of distribution is 0.7 to 2.7 l/kg (mean 1.5 ± 0.6 sd, n = 15). at concentrations produced by application of lidocaine patch, lidocaine is approximately 70% bound to plasma proteins, primarily alpha-1-acid glycoprotein. at much higher plasma concentrations (1 to 4 mcg/ml of free base), the plasma protein binding of lidocaine is concentration dependent. 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. the blood concentration of this metabolite is negligible following application of lidocaine patch 5%. following intravenous administration, megx and gx concentrations in serum range from 11 to 36% and from 5 to 11% of lidocaine concentrations, respectively. excretion: lidocaine and its metabolites are excreted by the kidneys. less than 10% of lidocaine is excreted unchanged. the half-life of lidocaine elimination from the plasma following iv administration is 81 to 149 minutes (mean 107 ± 22 sd, n = 15). the systemic clearance is 0.33 to 0.90 l/min (mean 0.64 ± 0.18 sd, n = 15).

y average pain relief, and patient’s preference of treatment. 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.