prilokaiini

Prilocaine is an amide-type local anesthetic used to produce local infiltration and regional nerve block anesthesia. It is employed in various medical fields, including dentistry and dermatology, and is often formulated for topical use in combination with lidocaine in eutectic mixtures (EMLA) to provide dermal anesthesia.

Prilocaine acts by blocking voltage-gated sodium channels in nerve membranes, preventing the initiation and propagation of nerve impulses. It tends to have a relatively low vasodilatory effect, so vasoconstrictors such as epinephrine are frequently added to injectable preparations to reduce systemic absorption and extend duration of action.

Pharmacokinetics and metabolism vary with formulation and route of administration. Prilocaine is primarily metabolized in the liver to o-toluidine, a metabolite associated with methemoglobinemia. The risk of methemoglobinemia is particularly important with high systemic exposure, in neonates or very young infants, and in individuals with certain enzyme deficiencies such as G6PD deficiency. Methemoglobinemia can impair oxygen transport and presents with symptoms such as cyanosis, weakness, and shortness of breath; in severe cases it can be life-threatening. Consequently, topical formulations containing prilocaine are usually avoided in neonates, and dosing and monitoring are important in other patients.

Safety and adverse effects include local irritation at the administration site and, with systemic exposure, signs of local anesthetic systemic toxicity affecting the central nervous and cardiovascular systems. Prilocaine is contraindicated in individuals with hypersensitivity to prilocaine or other amide anesthetics and is used with caution in patients with liver disease or conditions that increase the risk of methemoglobinemia. As with other local anesthetics, dosing should follow established guidelines to minimize risk, with attention to patient age, health status, and whether a vasoconstrictor is used.