Mepivakaiini

Mepivakaiini, known in English as mepivacaine, is an amide-type local anesthetic used to produce local and regional anesthesia. It is supplied as injectable solutions, either plain or with vasoconstrictors such as epinephrine to prolong effect. It is used for dental procedures, minor surgical procedures, and regional nerve blocks.

Mechanism and properties: Like other amide local anesthetics, mepivacaine blocks voltage-gated sodium channels in nerve membranes, preventing action potential generation and propagation. It has a moderate onset and intermediate duration, with the onset typically faster in smaller fibers. Adding vasoconstrictors reduces systemic absorption and prolongs anesthesia.

Pharmacokinetics and administration: Mepivacaine is primarily metabolized in the liver by amidases and excreted in the urine. The elimination half-life in adults is about 1.5–2 hours. Infiltration anesthesia typically begins within 2–5 minutes; nerve blocks may take longer. With vasoconstrictors, the duration is extended and the required dose may be reduced to limit systemic exposure.

Safety and adverse effects: At high plasma levels, central nervous system stimulation followed by depression and cardiovascular toxicity can occur. Common adverse effects relate to the autonomic nervous system and CNS; hypersensitivity is rare. Formulations containing epinephrine can raise heart rate and blood pressure and should be used with caution in patients with cardiovascular disease or severe peripheral vascular disease. Methemoglobinemia is not a prominent concern with mepivakaiin.

History and availability: Mepivakaiini was developed in the mid-20th century as an alternative to earlier local anesthetics and is widely used worldwide. It is available in various concentrations and formulations, with or without vasoconstrictors, depending on local practice and procedure.