Prilocaine
Anton C. de Groot in Monographs in Contact Allergy, 2021
Prilocaine is an intermediate-acting local anesthetic of the amide type chemically related to lidocaine. It is used for local anesthesia by infiltration and is the most often used local anesthetic in dentistry. In pharmaceutical products, both prilocaine and prilocaine hydrochloride (CAS number 1786-81-8, EC number 217-244-0, molecular formula CHCINO ) may be employed (1). It is present, together with lidocaine, in a frequently used anesthetic cream for surface anesthesia called EMLA ® (4,5,7,8,11,12,13,22).
Techniques: Regional
Brian J Pollard, Gareth Kitchen in Handbook of Clinical Anaesthesia, 2017
The choice of local anaesthetic drugs depends on:Speed of onsetPotencyDuration of actionSensory-motor differentiationPotential toxicityAs shown in Table 29.6. Lidocaine and bupivacaine are widely used for regional blocks although due to its decreased cardio-toxicity levo-bupivaine is gaining popularity. Ropivacaine has a better sensory-motor differentiation than bupivacaine mainly affecting the sensory fibres. This makes it ideal for postoperative analgesia. Prilocaine is the agent of choice for intravenous regional anaesthesia.
Local Anesthetics
Sahab Uddin, Rashid Mamunur in Advances in Neuropharmacology, 2020
Prilocaine and in a lesser extend other LAs, mainly benzocaine and lidocaine have been associated to methemoglobinemia. This condition refers to a reduced ability of hemoglobin to transport oxygen in the blood. When mild, this condition can be asymptomatic but, when the degree of severity increases the symptoms can progress from cyanosis, discoloration of the skin, dyspnea, fatigue, dizziness to even syncope. Importantly, prilocaine-induced methemoglobinemia is mediated by orthotoluidine. Orthotoluidine, hepatic metabolite of prilocaine, oxidizes hemoglobin converting it into methemoglobin. The oxidative potency of orthotoluidine results in a methemoglobinemia that does not respond appropriately to supplemental oxygen at high flow. Although the doses of prilocaine required to reduce the oxygen saturation levels are typically higher than the standard doses used in clinical regional anesthesia, some countries have prohibited the use of prilocaine in regional anesthesia procedures. Furthermore, to prevent potential complications, preparations containing prilocaine (e.g., EMLA cream) should not be used in particularly susceptible patients (e.g., suffering from either congenital or idiopathic methemoglobinaemia) neither in children younger than 1 year old that are under drug treatments such as sulphonamides or phenytoin characterized by their well-known ability to induce methemoglobinemia (Berkman, 2012). Although methemoglobinemia is usually reversible and short-lasting, the reversal can be accelerated by a slow IV infusion of a methylene blue solution (Sekimoto et al., 2017). Methylene blue is as a substrate for the enzyme erythrocyte methemoglobin reductase. Methylene blue, by being reduced to leukomethylene blue allows methemoglobin to revert into oxyhemoglobin, therefore restoring the normal ability of hemoglobin for carrying oxygen.
Anesthetic efficacy of liposomal prilocaine in maxillary infiltration anesthesia
Published in Journal of Liposome Research, 2011
Patricia Maria Wiziack Zago, Daniela Belisario Baroni, Francisco Carlos Groppo, Eneida de Paula, José Ranali, Maria Cristina Volpato
Animal studies have shown that liposome encapsulation increases prilocaine anesthetic efficacy. This randomized, blind, crossover, three-period study evaluated the anesthetic efficacy of liposome-encapsulated 3% prilocaine, compared to 3% plain prilocaine and 3% prilocaine with 0.03IU/mL felypressin, after a 1.8-mL infiltration in the buccal sulcus of the maxillary right canine, in 32 volunteers. Anesthesia success, onset, and duration of pulpal and gingival anesthesia in the lateral incisor, and canine and first premolar were evaluated. Injection pain was assessed by a visual analog scale (VAS). Results were submitted to Kruskal-Wallis (onset and duration of pulpal anesthesia), Tukey (VAS), Friedman (duration of gingival anesthesia), and log-rank and McNemar tests (anesthesia success) (α = 5%). Liposomal prilocaine did not differ from plain prilocaine (P > 0.05), but presented lower anesthesia success and duration for canine, premolar, and gingival anesthesia (P 0.05); plain prilocaine presented lower success rates and slower onset of anesthesia for this tooth, in comparison to prilocaine with felypressin (P 0.05). In conclusion, liposomal prilocaine presents similar anesthetic efficacy in relation to plain prilocaine and lower efficacy, in comparison to prilocaine with felypressin in maxillary infiltration. Prilocaine does not seem to benefit from liposomal encapsulation.
Inhibitoty Effects of Local Anesthetics on Migration, Extracellular Release of Lysosomal Enzyme, and Superoxide Anion Production in Human Polymorphonuclear Leukocytes
Published in Immunopharmacology and Immunotoxicology, 1991
This study examined the effects of four typical local anesthetics, lidocaine, prilocaine, procaine and tetracaine, on the functioning of human polymorphonuclear leukocytes (PMN). PMN were stimulated by fMet-Leu-Phe (FMLP) or phorbol myristate acetate (PMA) to elicit chemotaxis, extracellular release of beta-glucuronidase (BGL) and superoxide anion (SOA) production. the four agents inhibited chemotaxis efficiently and in a concentration-dependent manner but had only weak effects on the release of BGL. the effect of tetracaine was strongest, followed by lidocaine, then prilocaine, whereas the effect of procaine was blunt. the 50% inhibitory concentrations (IC50 in molarity) of the four local aesthetics for chemetaxis were as follows: tetracaine=4.1×10−4, lidocaine=3.2×10−3, prilocaine=3.6×10, procaine=4.9×10−3, those for SOA production induced by FMLP were : tetraaine=3.1×10−4, lidocine=5.9×10−3, prilocaine=1.9×10−2, procaine=1.2×10−2, those for SOA production indced by PMA were : tetracaine=1.1×10−3, lidocine=1.2×10−2, prilocaine=1.5×10–2, procaine=2.5×10−2, and those for rlease of BGL were : tetracaine=1.6×10−, lidocaine=5.3×10−3, prilocaine=2.8×10−2, procaine=1.2×10−1. the IC50 seemed to relate to the anesthetic's chemical structures and their inhibitory properties on PMN functions, as lidocaine and prilocaine, which are aminoamide type anesthetics, preferentially inhibited chemotaxis, whereas tetracaine and procaine, aminoester type anesthetics, inhibited SOA production induced by FMLP. the results suggest that the inhibitory effects of local anesthetics on human PMN functions are also correlated with local anesthetic potency and vary according to differences in their chemical structures.
Sustained delivery of prilocaine and lidocaine using depot microemulsion system:
Published in Drug Development and Industrial Pharmacy, 2020
Xiaomin Zhang, Minyan Dang, Wenzhi Zhang, Yan Lei, Wentao Zhou
Topical drug delivery for local anesthetics has been an interesting area of research for formulators considering the resistance and barrier properties of skin and high clearance rate of drugs like prilocaine and lidocaine (duration of action < 2.5 h). In this study, efforts have been made to sustain the release of prilocaine and lidocaine by using depot microemulsion system. Drug loaded microemulsions were formulated using Capmul MCM, Pluronic F127, polyethylene glycol 200 (PEG 200) and water from pseudo-ternary diagrams. The Smix at 1:4 ratio showed larger microemulsion area in comparison to 1:2 ratio. The ex-vivo studies indicate sustained release of prilocaine and lidocaine from the microemulsion up to 8 h, in comparison to 4 h with ointments. Skin irritation study on rabbits confirmed the safety of drug loaded microemulsions for local drug delivery. The improved ex vivo data is reflected in the in vivo studies, were radiant heat tail-flick test and sciatic nerve model showed prolong duration of action for both prilocaine and lidocaine microemulsions in comparison to ointment. The in vitro and in vivo efficacy of prilocaine and lidocaine was non-significant. The improved efficacy was due to high penetration of microemulsion and depot effect due to local precipitation (destabilization of microemulsion) of drug in the skin layer. The sustained local anesthetic effect is highly desirable for the treatment of skin irritation due to skin burns and pre- and post-operative pain.
Related Knowledge Centers
- Dentistry
- Parenteral
- Paresthesia
- Local Anesthetic