Randomized Controlled Trial Show
. 2012 May;32(4):495-503. doi: 10.1177/1090820X12442672. Epub 2012 Mar 26. Affiliations
Randomized Controlled Trial Comparison of five commonly-available, lidocaine-containing topical anesthetics and their effect on serum levels of lidocaine and its metabolite monoethylglycinexylidide (MEGX)Georgette Oni et al. Aesthet Surg J. 2012 May. AbstractBackground: Topical anesthetics are commonly applied for a variety of indications. Several lidocaine-containing topical anesthetics are available for purchase over the counter (OTC). Recently, the authors' group has shown that there is great interindividual discrepancy in the manner in which lidocaine is absorbed and metabolized for even a single OTC product. Objectives: The authors compare five commonly-available lidocaine preparations and their levels of absorption when applied to the face. Three of the preparations are available OTC; two require prescriptions and were compounded in a pharmacy. Methods: Twenty-five subjects enrolled in this Institutional Review Board-approved study were randomly assigned to one of five groups. The five topical anesthetics were LMX-4 (4% lidocaine; Biopelle/Ferndale Laboratories, Ferndale, Michigan), Topicaine (4% lidocaine; Ebsa Laboratories, Jupiter, Florida), 2.5% lidocaine/2.5% prilocaine (generic EMLA preparation; High Tech Pharmaceuticals, Amityville, New York), LET (4% lidocaine, 1:2000 epinephrine, and 0.5% tetracaine), and BLT (20% benzoncaine, 6% lidocaine, and 4% tetracaine). After a patch test for adverse reactions, the topical anesthetic was applied to each patient's face and neck and covered with an occlusive dressing for 60 minutes. Blood was drawn at 90, 120, 150, 240, and 480 minutes to measure serum levels of lidocaine and monoethylglycinexylidide (MEGX). Results: The average age of the 17 women and eight men included in the study was 26 years (range, 22-62 years), and the average weight was 70.9 kg (range, 46.4-96.4 kg). The OTC preparations had the highest serum lidocaine and MEGX levels. Topicaine had the greatest serum levels of individual lidocaine absorption (0.808 µg/mL), followed by generic EMLA (0.72 µg/mL), LMX-4 (0.44 µg/mL), BLT (0.17 µg/mL), and LET (0.13 µg/mL). On average, Topicaine had the highest serum lidocaine and MEGX levels: 0.438 µg/mL and 0.0678 µg/mL, respectively. There were significant interindividual differences between the serum levels of MEGX and lidocaine in all groups except LET (P<.0001). There were significant differences between the 4% lidocaine-containing preparations (P=.0439); the 2.5% preparation had a greater absorption than the 4% lidocaine-containing preparation and the 6% lidocaine preparation (P=.0016). There were three adverse reactions in patients who received OTC preparations, one of which resulted in postinflammatory hyperpigmentation. Conclusions: This study demonstrates that although topical anesthetics are considered safe, some individuals have unpredictably high absorption levels. This study also demonstrates that the concentration of lidocaine, the formulation of the drug, and the individual patient all have significant effects on serum levels of lidocaine. The authors recommend that even OTC topical anesthetics be used under the supervision of a healthcare professional to avoid adverse toxic effects and, in rare cases, death. Level of evidence: 2. Similar articles
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Do you need a prescription for lidocaine gel?Lidocaine belongs to the family of medicines called local anesthetics. This medicine prevents pain by blocking the signals at the nerve endings in the skin. This medicine does not cause unconsciousness as general anesthetics do when used for surgery. This medicine is available only with your doctor's prescription.
How do you use lidocaine gel?Adults—Apply to the affected area 3 or 4 times a day. The largest amount of ointment that should be used in a single application is 5 grams. If you use the 5% ointment, this is about 6 inches of ointment from the tube. Children—Dose is based on body weight and must be determined by your doctor.
Can lidocaine gel be used on open wounds?Unless otherwise directed by your doctor, do not apply this medicine to open wounds, burns, or broken or inflamed skin. Be careful not to get any of the ointment in your eyes, because it can cause severe eye irritation.
What are the side effects of lidocaine cream?Advertisement. Blistering, crusting, irritation, itching, or reddening of the skin.. cracked, dry, or scaly skin.. hives or welts, itching, skin rash.. irritation.. joint pain, stiffness, or swelling.. large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals.. |
Can you buy lidocaine gel over the counter
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