Lidocaine iontophoresis for topical anesthesia before dermatologic procedures in children: a randomized controlled trial

Local anesthesia by injection in pediatric patients undergoing dermatologic procedures is not well received because of the pain of injection and the fear of needles. Lidocaine iontophoresis is a method of topical anesthesia where lidocaine is driven into the skin under the influence of electric current. We performed a prospective double-blind, placebo-controlled evaluation of iontophoresis of 2% lidocaine with 1:100,000 epinephrine. Sixty children requiring dermatologic procedures were enrolled (50 shave biopsy, 7 curettage, 2 injection, 1 punch biopsy). Twenty-nine of 31 patients in the lidocaine group versus 2 of 29 placebo patients required no supplemental anesthesia (p < 0.001). The pain reported by the patients on the Oucher pain scale subsequent to the procedure was significantly lower in the lidocaine group (p < 0.001). Investigators and parents also rated pain lower in the lidocaine group (p < 0.001). Blanching and/or erythema occurred in 58 of 60 patients, but resolved within 1 hour in all patients. There were no other adverse events. Lidocaine iontophoresis is a safe and effective method of topical anesthesia prior to dermatologic procedures in children.

Lidocaine iontophoresis for local anesthesia before shave biopsy

BACKGROUND

Lidocaine iontophoresis is a method of topical anesthesia in which lidocaine is driven into the skin under the influence of electric current.

OBJECTIVE

To compare lidocaine iontophoresis to placebo for topical anesthesia before shave biopsy in adult patients.

METHODS

This was a single-center, double-blind, placebo-controlled evaluation of iontophoresis of 2% lidocaine with 1:100,000 epinephrine in patients undergoing shave biopsy. Patients were evaluated for sensation to pinprick after iontophoresis. After completion of the procedure, those patients who did not receive supplemental lidocaine rated the pain associated with the procedure using a 10-cm visual analog scale. The investigator also evaluated the patient's pain after biopsy. Treatment sites were examined for evidence of adverse events such as erythema, urticaria, or burns.

RESULTS

Forty-one patients undergoing shave biopsy for evaluation of skin lesions were enrolled. Nineteen of 21 patients in the lidocaine group versus 2 of 20 placebo patients required no supplemental anesthesia (P<0.001). The pain reported by the patient on the visual analog scale subsequent to the procedure was significantly lower in the lidocaine group (P<0.001). In concordance with the results reported by the patients, investigators rated pain lower in the lidocaine group (P<0.001). Blanching and/or erythema occurring at the iontophoresis-treated site in 37 of 41 patients resolved within 1 hour. There were no other treatment-related events.

CONCLUSIONS

Lidocaine iontophoresis is a safe and effective method of administering topical anesthesia before shave biopsy in adult patients.

Tolerance of ocular iontophoresis in healthy volunteers

To evaluate ocular tolerance, healthy volunteers were iontophoresed transclerally using novel OcuPhor trade mark hydrogel drug delivery applicators filled with balanced salt solution. In this three-period crossover study in 24 male and female subjects, 16 subjects received 0 mA and two of the following DC currents: 0.1, 0.5., 1.0, 2.0, 3.0, or 4.0 mA for 20 min; 6 subjects received 3 mA for 20 min and 1.5 mA for 40 min (both equivalent to 60 mAmin total charge). Safety and tolerance were determined by subjective VAS and objective ophthalmic assessments. Subjects were evaluated before and up to 22 hr after dosing. The applicators were well-tolerated and no clinically significant changes in symptomology or in ophthalmic assessments were seen following exposure to 0-3.0 mA for 20 min or 1.5 mA for 40 min. At 4.0 mA 2 of 4 subjects reported a burning sensation under the applicator during dosing which resolved by 22 hr post-dose; superficial changes in fluorescein staining were observed at 1 hr, but not at 22 hr. The OcuPhor trade mark system has promise for noninvasive drug delivery to the eye.

In vivo transscleral iontophoresis of amikacin to rabbit eyes

The objectives of these studies were to determine the amount and distribution of the aminoglycoside antibiotic amikacin delivered to rabbit eyes following transscleral iontophoresis and to determine the inter-study reproducibility of delivery over three identical studies. New Zealand White rabbits (N = 6 per dose group) were treated with a 200-mg/mL amikacin solution at 0, 2, 3 or 4 mA of (+) DC current for 20 minutes. Amikacin concentrations in eye tissues were highest with the 4-mA treatment. Concentrations for all three studies at this current were approximately 5.4, 40, 41, 343, and 92 mcg/g in the vitreous humor, anterior segment, non-treated hemisphere of the sclera, treated hemisphere of the sclera, and retina/choroid, respectively. These values were approximately 27, 50, 40, 10, and 13 fold greater than in the 0-mA control group and are well above the in vitro minimum inhibitory concentrations (MICs) for this drug. Inter-study reproducibility (measured as %CV) depended on the tissue type and treatment group and ranged from 8% for the retina/choroid to 51% for the anterior segment in the 4-mA group. Pretreatment with topical proparacaine hydrochloride local anesthetic did not affect amikacin delivery and total drug delivered was not affected by delivery time for the same total charge administered. Therapeutically relevant amounts of amikacin were delivered into eye tissues in a reproducible and controllable manner.

A polymeric drug for treatment of inflammatory bowel disease

Sulfasalazine (SASP) consists of salicylic acid azo linked at the 5-position to a pyridine-containing sulfonamide. This drug, currently used in inflammatory bowel disease treatment, is reductively cleaved by anaerobic bacteria in the lower bowel to 5-aminosalicylic acid (5-ASA) and sulfapyridine (SP). Recent reports indicate that 5-ASA is the active therapeutic moiety and that SP is responsible for a variety of adverse clinical side effects. Water-soluble polymer 7, which contains salicylate residues azo linked at the 5-position to an inert polymer backbone, has been synthesized for the site-specific reductive release of 5-ASA in the lower bowel. Preparations of 7 deliver (chemical reduction) greater than 1.96 mmol of 5-ASA/g of polymer. In vitro studies with the polymer in anaerobic rat cecal bacteria demonstrated a reduction rate of approximately 1 mu equiv of azo bond h-1 (mL of cecal content)-1. A pharmacokinetic comparison of polymer and SASP showed similar deliveries of 5-ASA and metabolites to the lower bowel, blood, and urine of orally dosed rats. Polymer 7 proved more active than SASP or 5-ASA in the guinea pig ulcerative colitis model. Potential therapeutic advantages of 7 include nonabsorption/nonmetabolism in the small intestine, direct 5-ASA release at the disease site, and nonabsorption/nonmetabolism of the reduction-released carrier polymer.

Metabolic fate of food colorants

Evaluation of the chemical and biological data on synthetic and natural food colorants indicates that synthetic colorants in general have been studied more thoroughly than their natural counterparts. The increasing use of natural colorants in processed foods at levels higher than those found in natural sources has raised concern about deficiencies in knowledge, in some cases, of their exact chemical composition, stability, metabolic fate, and toxic potential. Additional studies, particularly of comparative metabolic fate in experimental animals and in man and of genotoxic potential, are required. Until studies with natural colorants comparable to those carried out with synthetic colorants have been completed and evaluated, greater safety of natural colorants cannot be assumed.

Intestinal absorption of polymeric derivatives of the food dyes sunset yellow and tartrazine in rats

1. Absorption and metabolism of 14C-labelled sunset yellow (FD & C Yellow No. 6), tartrazine (FD & C Yellow No. 5) and high molecular weight polymeric derivatives of the two azo dyes were compared in rats. 2. A trace to 1.5 percent of unchanged monomeric dyes was excreted in urine and bile during the first 24 h after dosing. No unchanged dye was absorbed after administration of the polymeric derivatives. 3. In animals dosed with sunset yellow and its polymer derivative, absorption of the azo-bound cleavage product 1-amino-2-naphthol-6-sulphonic acid was 8.5 and 6.9 percent, respectively, while absorption of the cleavage product sulphanilic acid was 37.4 and 0 percent, respectively. 4. In animals dosed with tartrazine and its polymer derivative, absorption of the cleavage product aminopyrazolone and its metabolites was 4.0 and 4.6 percent, respectively. 5. Azo bond cleavage did not appear to be decreased in the polymer derivatives. However, the sulphanilic acid moiety of both dyes remained attached to the polymer backbone, resulting in a 95 percent decrease in sulphanilic acid absorption with polymeric tartrazine. 6. Decreased absorption of unchanged dyes and certain metabolites with the stable, non-absorbed polymeric derivatives may be significant in developing non-sensitizing substitutes for these two commonly used food colourants.

Hypolipidemic effects of orally administered dextran and cellulose anion exchangers in cockerels and dogs

Various cellulose and dextran anion exchangers bind bile salts in vitro under conditions of pH and ionic strength resembling those in the lumen of the small intestine. Of these substances, diethylaminoethyl (DEAE) cellulose, guanidoethyl cellulose, and DEAE Sephadex reduced hypercholesterolemia when added to the diet of cholesterol-fed cockerels. In addition, DEAE Sephadex reduced serum sterols in normocholesterolemic cockerels and dogs, lowered serum phospholipids and triglycerides in cholesterol-fed hypercholesterolemic cockerels and in normocholesterolemic dogs, and increased fecal excretion of bile acids in hypercholesterolemic cockerels. The data indicate that these insoluble cationic polymers exert their hypocholesterolemic effects by interrupting the enterohepatic circulation of bile acids.