Prokaiini

Prokaiini, commonly known as procaine, is a local anesthetic of the ester-type used to induce temporary loss of sensation in a targeted area. It is typically supplied as a sterile injectable solution for infiltration or nerve block procedures and is sometimes combined with a vasoconstrictor such as epinephrine to extend its duration and reduce systemic absorption.

Mechanism and pharmacology: Prokaiini works by reversibly blocking voltage-gated sodium channels in neuronal membranes, preventing initiation and propagation of action potentials and thereby interrupting pain signaling. As an ester, it is rapidly hydrolyzed in the plasma by cholinesterases to inactive metabolites and para-aminobenzoic acid byproducts. Due to its ester linkage, prokaiini generally has a shorter duration of action compared with amide-type anesthetics. When used with vasoconstrictors, the onset and duration can be enhanced, providing a larger window for procedures while limiting systemic exposure.

Medical uses and administration: Prokaiini is used for minor surgical procedures, dental anesthesia, and superficial regional blocks where short-acting anesthesia is appropriate. Dosing is procedure- and patient-dependent, and care is taken to monitor for signs of local anesthetic systemic toxicity, particularly with repetitive injections or larger volumes.

Safety and adverse effects: Common adverse effects include local tissue irritation, stinging at the injection site, and, less commonly, hypersensitivity reactions. As with other local anesthetics, overdose or inadvertent intravascular administration can lead to serious toxicity, necessitating appropriate monitoring and resuscitation readiness. Allergic reactions are more frequently associated with ester-type anesthetics due to PABA-related sensitivities.

History: Prokaiini was introduced in the early 20th century and marketed under names such as Novocain. It has largely been superseded by longer-acting amide anesthetics in many settings, but remains referenced in various medical and historical contexts.