1:100,000 epinephrine as an example. Lower MRD values for lidocaine are 2 mg/lb maxi- mum, with an absolute maximum of 300 mg per appointment.3 When calculating the MRD using these lower values, a healthy 150-pound individual may receive eight cartridges (14.4 ml; 288 mg) of 2% lidocaine, 1:100,000 epinephrine.3,4 The established FDA recom- mendations are 3.2 mg/lb, with an absolute maximum of 500 mg per appointment.2 When using these values for the same hypo- thetical patient, the result is significantly differ- ent: a maximum of 13 cartridges of the local anesthetic drug (23.4 ml; 468 mg) may be administered.2 number of cartridges that may be safely administered to the patient in this example is not 13; rather, the MRD is limited by the epi- nephrine content to 11 cartridges (19.8 ml; 396 mg).4 TABLE 1. Maximum Recommended Doses of Local Anesthetic Drugs for Healthy Individuals per Appointment, Based on the Pharmaceutical and Vasoconstrictor Used1–4,7 Drug Articaine 4% + 1:100,000 epinephrine Articaine 4% + 1:200,000 epinephrine Bupivacaine 0.5% + 1:200,000 epinephrine Lidocaine 2% +1:100,000 epinephrine Lidocaine 2% + 1:50,000 epinephrine However, the actual maximum Mepivacaine 2% + 1:20,000 levonordefrin Mepivacaine 3% Without vasoconstrictor Prilocaine 4% + 1:200,000 epinephrine Prilocaine 4% Without vasoconstrictor When using the lower values, the drug that limits the maximum number of car- tridges is the local anesthetic drug (in the first example of eight cartridges: 8 < 11). When using the FDA values, the limiting drug is epi- nephrine (using the second example of 11 car- tridges; 11 < 13). The use of articaine requires important considerations and modifications. The mg/lb MRD for articaine is the same in both sets of recommendations. Through at least 2013, product information leaflets for 4% articaine, 1:100,000 epinephrine list an absolute MRD of 500 mg, or approximately seven cartridges (12.5 ml; 500 mg).7 The current FDA recom- mendation lists a 3.2 mg/lb maximum, with no absolute maximum established; however, based on the epinephrine content, there is a maximum limit of 11 cartridges of 4% arti- caine,1:100,000 epinephrine.7 OVERDOSE POTENTIAL Many dentists and dental hygienists have grown accustomed to calculations based on the previously published absolute maximum dose of 500 mg of articaine per appointment. Recommended Dosages mg/kg mg/lb 7.0 7.0 N/A 7.0 7.0 6.6 6.6 8.8 8.8 3.2 3.2 N/A 3.2 3.2 3.0 3.0 4.0 4.0 Maximum Recommended Dosages (by mg) a Determined by weight b Determined by weight b 90 mg 500 mg 500 mg 400 mg 400 mg 600 mg 600 mg Maximum Maximum Cartridges b b 10 11 5.5 11 7 8 8 Limiting Factor for Maximum Recommended Dosages Local anesthetic b Local anesthetic b Local anesthetic Vasoconstrictor Vasoconstrictor Local anesthetic equal to vasoconstrictor Local anesthetic Local anesthetic Local anesthetic a Per appointment values represent dosages for healthy individuals weighing approximately 150 pounds. Values may need adjustment for children, older adults and medically compromised patients. b No absolute maximum provided, however, prudent practice dictates the use of the smallest possible effective dose. TABLE 2. The American Academy of Pediatric Dentistry’s Guidelines on the Use of Injectable Local Anesthetics In Children6 Duration in Minutes Maxillary Infiltration 2% plain 2% + 1:50,000 epinephrine 2% + 1:100,000 epinephrine Mepivacaine 3% plain 2% + 1:100,000 epinephrine 2% + 1:20,000 levonordefrin Articaine 4% + 1:100,000 epinephrine Prilocaine 4% plain 4% + 1:200,000 epinephrine Bupivacaine 0.5% + 1:200,000 epinephrine 40 340 240 440 Reprinted with permission from the American Academy of Pediatric Dentistry a Total dosage should be based on the child’s weight and should never exceed maximum total dosage. ARTHUR C. DIMARCO, DMD, is director and an affiliate assistant professor in the Regional Initiatives in Dental Education program at the University of Washington School of Dentistry in Spokane. He is also a professor of dental hygiene at Eastern Washington University in Cheney. DiMarco is a coauthor of the textbook Local Anesthesia for Dental Professionals. He can be reached at [email protected]. KATHY BASSETT, RDH, MEd, is a professor of dental hygiene at Pierce College in Lakewood, Washington, and an adjunct professor at University of Washington, School of Dentistry in Seattle. She is a coauthor of Local Anesthesia for Dental Professionals, and has written numerous articles and textbook chapters on local anesthesia. The authors have no commercial conflicts of interest to disclose. DecisionsInDentistry.com December 2017 • Decisions IN DENTISTRY 27 20 40 105 140 55 60 190 220 1.3 0.6 90 60 190 90 230 6.0 2.7 400 5 60 60 25 60 50 170 170 90 170 130 Mandibular Block 5–10 85 85 40 85 75 Maximum Dosage 4.4 2.0 Total Dosagea Maximum Anesthetic Pulp Soft Tissue Pulp Soft Tissue mg/kg mg/lb mg Lidocaine 190 190 4.4 2.0 300 165 190 185 7.0 3.2 500 300
