Mepivacaine hydrochloride (HCl) is an amide-type local anesthetic commonly used in dental procedures and other minor surgeries. Developed by A.F. Ekenstam in 1957, it was introduced into dentistry in 1960 as a 2% solution containing levonordefrin and in 1961 as a 3% solution without a vasoconstrictor. Mepivacaine is favored for its relatively mild vasodilating properties and its effectiveness in providing anesthesia in situations where vasoconstrictors are contraindicated.
Mepivacaine is an amide-type anesthetic with the chemical formula 1-methyl 2′,6′-pipecoloxylidide hydrochloride. Its metabolism occurs in the liver via microsomal mixed-function oxidases, with hydroxylation and N-demethylation playing key roles. Mepivacaine is excreted through the kidneys, with approximately 1% to 16% of the administered dose excreted unchanged. It has a rapid onset of action, typically within 3 to 5 minutes, and its anesthetic half-life is around 1.9 hours. However, it does not have topical anesthetic action in clinically acceptable concentrations.
Mepivacaine is available in two main formulations: a 3% solution without a vasoconstrictor and a 2% solution with levonordefrin. The 3% plain solution provides pulpal anesthesia for about 20 minutes via infiltration and 40 minutes via nerve block, with soft tissue anesthesia lasting 2 to 3 hours. The 2% solution with levonordefrin offers longer pulpal anesthesia, approximately 60 minutes, and soft tissue anesthesia lasting 3 to 5 hours. Mepivacaine's mild vasodilating properties contribute to its extended duration of anesthesia even when used without a vasoconstrictor, making it a preferred choice for pediatric and geriatric patients when vasoconstrictors are not recommended.
The maximum recommended dose (MRD) for mepivacaine is 6.6 mg/kg, or 3.0 mg/lb of body weight, not exceeding an absolute maximum of 400 mg. Adjustments to the dose should be made for elderly or debilitated patients. For healthy individuals (ASA 1), the dosage is outlined based on body weight, ranging from 66 mg for a 10 kg individual to 400 mg for those weighing 70 kg and above.
Mepivacaine has a relatively mild vasodilatory effect, which is less pronounced than other local anesthetics, such as lidocaine. This characteristic results in a longer duration of anesthesia when administered without a vasoconstrictor. In cases where vasoconstrictors are not indicated, such as in pediatric or geriatric patients, mepivacaine is often the anesthetic of choice due to its ability to provide effective anesthesia without significantly increasing blood flow at the injection site. For patients undergoing shorter dental procedures or those who cannot tolerate vasoconstrictors, mepivacaine offers a safe and effective alternative.
