Local anaesthetics amide-type

Local anaesthetics are readily absorbed through mucous membranes and damaged skin. These are weak bases and at tissue pH diffuse through the connective tissue and cellular membranes to reach the nerve fibres where ionization can occur. Amide type local anaesthetics (lignocaine, bupivacaine) are metabolised in the liver and in some cases the kidneys. These are considerably protein bound. For certain procedures the duration of action is prolonged by adding... 

Another amide-type local anaesthetic (cf. lidocaine) is cinchocaine (dibu-caine, Nupercaine ) 7.15) one of the most used spinal anaesthetics. It is 2-butoxy-iV-[2-(diethylamino)ethyl]quinoline-4-carboxamide. 

It is a local anaesthetic of the amide type which is employed for surface, infiltration and nerve block anaesthesia. Its duration of action is in between the shorter-acting lidocaine and longer-acting mepivacaine. It possesses less vaso-dilator activity than lidocaine and hence may be used without adrenaline. Therefore, solutions of prilocaine hydrochloride are specifically beneficial for such patients who cannot tolerate vasopressor agents patients having cardiovascular disorders, diabetes, hypertension and thyrotoxicosis. 

It is a long-acting local anaesthetic of the amide type, similar to mepivacaine and lidocaine but about four times more potent. The effects of bupivacaine last longer to lidocaine hydrochloride. It is mainly employed for regional nerve block, specifically epidural block, when a prolonged effect is required. 

Clinical examples of this interaction seem to be few and of poor quality (note that the patients were given repeated lumbar punctures, up to four times daily in some instances). E should also be noted that the supporting evidence (human, animal and in vitro studies) dates back to the mid-1940s with nothing more recent apparently on record. Local anaesthetics of the ester type that are hydrolysed to PABA (e.g. tetracaine, procaine, benzo-caine) present the greatest risk of a reaction, whereas those of the amide type (bupivacaine, cinchocaine, lidocaine, mepivacaine and prilocaine) would not be expected to interact adversely. The evidence seems to be too... 

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