Prilocaine

Purpose A eutectic mixture of local anesthetics (EMLA) is commonly used to provide topical anesthesia for intravenous (iv) cannulation. One of its side effects is vasoconstriction, which may render cannulation more difficult. A gel formulation of amethocaine (Ametop™) is now commercially available. The aim of this study was to compare EMLA and Ametop™ with regard to the degree of topical anesthesia afforded, the incidence of vasoconstriction and the ease of iv cannulation. Methods Thirty two ASA 1 adult volunteers had a # 16 gauge iv cannula inserted on two separate occasions using EMLA and Ametop™ applied in a double blind fashion for topical anesthesia. Parameters that were recorded after each cannulation included visual analogue pain scores (VAPS), the presence of vasoconstriction and the ease of cannulation, graded as: 1 = easy, 2 = moderately difficult, 3 = difficult and 4 = failed. Results The mean VAPS ± SD after cannulation with Ametop™ M was 12 ± 9.9 and with EMLA was 25.3 ± 16.6 (P = 0.002). Vasoconstriction occurred after EMLA application on 17 occasions and twice after Ametop™ (P = 0.001). The grade of difficulty of cannulation was 1.44 ± 0.88 following EMLA and 1.06 ± 0.25 with Ametop™ (P = 0.023). Conclusions Intravenous cannulation was less painful following application of Ametop™ than EMLA. In addition, Ametop™ caused less vasoconstriction and facilitated easier cannulation. Its use as a topical anesthetic agent is recommended, especially when iv access may be problematic. Objectif Un mélange eutectique d’anesthésiques locaux (MEAL) est souvent utilisé pour l’anesthésie topique lors d’une canulation intraveineuse (iv). La vasoconstriction, qui est l’un des effets secondaires du MEAL, peut compliquer la mise en place d’une canule. Une présentation en gel d’améthocaïne (Ametop™) est maintenant offerte dans le commerce. Le but de la présente étude était de comparer le MEAL et l’Ametop™ en regard du degré d’anesthésie topique fourni, de l’incidence de la vasoconstriction et de la facilité de la canulation iv. Méthode: On a inséré, en deux occasions séparées chez 32 volontaires adultes d’état physique ASA 1, une canuleiv de calibre 16 en utilisant en double aveugle le MEAL et Ametop™ pour réaliser l’anesthésie topique. Après chaque canulation, on a enregistré les paramètres suivants: les scores de douleur à l’échelle visuelle analogue (EVA), la présence de vasoconstriction et la facilité de canulation notée 1 = facile, 2 = modérément difficile, 3 = difficile et 4 = impossible. Résultats Les scores moyens à l’EVA ± l’écart type ont été de 12 ± 9,9 à la suite de la canulation avec Ametop™ M et de 25,3 ± 16,6 après le MEAL (P = 0,002). La vasoconstriction est survenue en 17 occasions après l’application du MEAL et deux fois plus souvent après Ametop™ (P = 0,001). Le degré de difficulté de canulation a été de 1,44 ± 0,88 après le MEAL et de 1,06 ± 0,25 après Ametop™ (P = 0,023). Conclusion La canulation intraveineuse est moins douloureuse après l’application d’Ametop™ que celle du MEAL. De plus, l’Ametop™ a provoqué moins de vasoconstriction et a facilité l’introduction d’une canule. Son usage comme anesthésique topique est recommandé, surtout lorsqu’une action rapide est nécessaire ou que l’accèsiv peut être problématique.

PURPOSE This study reports the development and in vivo evaluation of a liposomal system for the local anesthetic, prilocaine. METHODS Liposomal prilocaine was prepared with egg phosphatidylcholine, cholesterol and a-tocopherol (4:3:0.07 molar ratio). The size of the liposomes was measured by laser light scattering and the effect of prilocaine on membrane fluidity made use of electron spin resonance (ESR). The anesthetic effect of liposomal prilocaine was compared to that of plain prilocaine solution (with or without vasoconstrictor) in a rat infraorbital nerve blockade model. RESULTS Laser light-scattering analysis showed one major vesicle population of liposomes with ca 400 nm (100%), without size changes after prilocaine incorporation. The ESR results showed a decrease in the orientation of the phospholipid molecules into the liposomes (ca 11%) in the presence of prilocaine, which characterized the prilocaine-liposome interaction. A prolongation of anesthetic effect was produced b...

To describe current newborn circumcision pain interventions and to identify which forms of analgesia were most effective. Each male newborn was assessed for pain during the circumcision procedure and at 15-minute intervals after the procedure using the FLACC pain scale. The type and combination of analgesia was also recorded on the pain assessment record. Pain scores were highest for newborns receiving no analgesia during circumcision. Newborns circumcised with the dorsal block and the ring block in combination with the concentrated oral sucrose had the lowest pain scores. The sucrose alone did not provide sufficient analgesia; however, it did reduce the FLACC score somewhat when used in conjunction with other analgesics/anesthesia. Information obtained from this project facilitated a change in policy wherein newborn circumcision is performed only with the use of analgesia and not concentrated oral sucrose alone.

The aim of our study is to evaluate the efficacy of applying lidocaine 25 mg-prilocaine-25 mg/G cream (EMLA 5%) on the uterine cervix for pain relief when performing hysterosalpingography (HSG). Eighty-two patients undergoing HSG as part of infertility evaluation were randomized into groups receiving EMLA (42) or placebo cream (40) in a double-blinded prospective study from which four women were later excluded. The cream was applied to the uterine cervix by means of a cervical cup 30 min before the HSG. Pain perception related to the HSG procedure was scored by visual analogue scale (VAS) at five predefined steps: after speculum application, after cervical instrumentation of the tenaculum and cannula, at the end of uterine filling, at completion of tubal spillage, and immediately following instrument removal. In addition, the patients were asked to retrospectively rate the pain during the entire procedure in a telephone interview the following day. Cervical instrumentation was found...

The purpose of this study was to determine whether changes occur in pulpal blood flow when capsaicin is applied to the adjacent gingival or alveolar mucosa in human beings. Laser Doppler flowmetry was used to measure changes in pulpal blood flow (PBF) after applying capsaicin to adjacent gingival mucosa in 20 human volunteers. The procedure was repeated on 10 subjects after administration of an ipsilateral inferior alveolar nerve block and on the other 10 subjects after application of topical anesthetic to their adjacent gingival and alveolar mucosa. PBF increased in 16 subjects and did not change in 4 subjects after capsaicin application. Ipsilateral inferior alveolar nerve block did not alter this effect. Pretreatment with topical lidocaine resulted in no change or decreased PBF in 8 subjects and increased PBF in 2 subjects. Changes occur in the PBF of the mandibular canine teeth of some humans when capsaicin is applied to the adjacent gingival or alveolar mucosa.

E. RussellVickers, MDSc, BDS,* Nirvana Marzbani, BDS,t Tania M. Gerzina, PhD, MDS, FRACDS,t Colin McLean, Dip Chem,§ A. Punnia-Moorthy, PhD, FDSRCS, FFDRCSI,II and Laurence Mather, PhD, FANZCA* *Department of Anaesthesia and Pain Management,University of ...

The local anaesthetics used in day-case spinal anaesthesia should provide short recovery times. We aimed to compare hyperbaric prilocaine and bupivacaine in terms of sensory block resolution and time to home readiness in day-case spinal anaesthesia. MeTHODS: Fifty patients undergoing perianal surgery were randomized into two groups. The bupivacaine-fentanyl group (Group B) received 7.5 mg, 0.5% hyperbaric bupivacaine + 20 μg fentanyl in total 1.9 mL. The prilocaine-fentanyl group (Group P) received 30 mg, 0.5% hyperbaric prilocaine + 20 μg fentanyl in the same volume. Time to L1 block and maximum block was shorter in Group P than in Group B (Group P 4.6 ± 1.3 min versus Group B 5.9 ± 01.9 min, P = 0.017, and Group P 13.2 ± 7.5 min versus Group B 15.3 ± 6.6 min, P = 0.04). The time to L1 regression and S3 regression of the sensorial block was significantly shorter in Group P than in Group B (45.7 ± 21.9 min versus 59.7 ± 20.9 min, P = 0.024, and 133.8 ± 41.4 min versus 200.4 ± 64.8 m...

The analgesic effects of intradermal lidocaine infiltration and topical EMLA cream applications (eutectic mixture of local anaesthetics) were studied in 8 patients with Ehlers Danlos syndrome type III, a heritable disorder of connective tissue, and in 8 controls. Cutaneous analgesia was evaluated by sensory and pain thresholds to short argon laser stimulation, and the depth of cutaneous analgesia was measured by sensory and pain thresholds to controlled needle insertion. Five minutes after lidocaine infiltration, the laser-induced pain was abolished in both groups, but 1 h later only the skin of the controls remained analgesic. EMLA cream was applied for 30, 60, and 120 min, but none of the patients obtained sufficient analgesia. Full analgesia was obtained for the controls after 60 and 120 min of application. The depth of cutaneous EMLA analgesia was significantly less for the patients compared to controls. The present quantitative findings support clinical observations that long-lasting cutaneous analgesia is difficult to obtain for this group of patients.

Literature cautions against applying lidocaine 15%/prilocaine 5% over an area larger than 300 cm(2). The area of the face, neck, and chest is 400 cm(2) or greater. To investigate the safety of lidocaine 15%/prilocaine 5% topical anesthetic ointment used as anesthesia for intense pulsed light (IPL) treatment. Lidocaine 15%/prilocaine 5% ointment was applied to the face only (n=10) for 30 +/- 15 minutes or to the face, neck, and chest (n=10) for a total of 60 +/- 15 minutes before IPL. Blood lidocaine and prilocaine levels were measured. Adverse events were recorded. For the entire cohort, blood was drawn 25.6 +/- 6.6 minutes after IPL was completed. In the face only group, the mean lidocaine level was 0.122 +/- 0.125 microg/mL, and the mean prilocaine level was 0.048 +/- 0.029 microg/mL. In the face, neck, and chest group, the mean lidocaine level was 0.272 +/- 0.208 microg/mL, and the mean prilocaine level was 0.087 +/- 0.060 microg/mL. No adverse events related to systemic toxicity were observed or reported to the nurse. At the 24-hour follow-up, no subject reported symptoms of systemic toxicity after leaving the clinic. Under the conditions of this study, topical lidocaine 15%/prilocaine 5% produces low levels of systemic absorption.