[Local anesthetics--maximum recommended doses]

"Maximum doses" determined up to now do not take account of such important pharmacokinetic and toxicological data as: 1) the dependence of blood levels measured on the technique of regional anaesthesia, 2) and the raised toxicity of a local anaesthetic solution containing adrenaline following inadvertent intravascular (intravenous) injection. A maximum dose recommendation differs according to the technique of local anaesthesia for A: subcutaneous injection, B: injection in regions of high absorption, C: single injection (perineural, e.g. plexus), D: protracted injection (catheter, combined techniques), E: injection into vasoactive regions (near to the spinal cord, spinal, epidural, sympathetic). This sequential categorization also underscores the need to select appropriate techniques as well as concomitant monitoring according to the technique of administration and to the expected and possible plasma level curve. The "maximum recommended doses" (in mg) of mepivacaine for use with the above five different techniques of regional anaesthesia are (doses together with the vasoconstrictor adrenaline are in brackets): A: 400 (500), B: 200, C: 400 (500), D: 500, E: 1-25 ml; those for lidocaine: A: 400 (500), B: 200, C: 400 (500), D: 500, E: 1-25 ml, for prilocaine: A: 600, B: 300, C: 600, D: 700, E: 1-25 ml, for bupivacaine: A: 150, B: 75, C: 150, D: 200, E: 1-25 ml, for etidocaine: A: 300, B: 150, C: 300, D: 300, E: up to 25 ml (no spinal anaesthesia). These "recommended maximum doses" are low for zones of raised absorption and higher for techniques of protracted injection. For prilocaine, bupivacaine and etidocaine, the "maximum recommended doses" are the same regardless of whether or not the solutions contain adrenaline. The preparation containing adrenaline is limited by the total adrenaline content (0.25 mg). The dose spectrum must be specified for all injections carried out close to the spinal cord because of the specific risk: even very tiny volumes can have an intensive effect and they involve high risks. The values specified for techniques C and D also restrict the overall dose for the techniques specified under E when high doses are necessary. The amount of the repetition dose of bupivacaine can be reliably given as 30 mg/h. Recommended maximum doses given here relate to normal conditions (70 kg body weight). They must be varied individually depending on the body weight and condition of the patient. Recommended maximum doses are of orientative significance, they do not constitute a maximum dose. There is no quantitative limit for ropivaccine because the recommended techniques do not allow higher volumes of this long acting local anaesthetic.