Limitations: This safety classification applies only to preparations containing a combination of the two drugs mepivacaine and adrenaline (epinephrine). The same ATC-code (N01BB53) can in some countries be used for different combinations of mepivacaine and other drugs which in theory may be porphyrinogenic. Please refer to the classification and monograph of each individual substance. If the combination contains a substance which is not classified (NC) or has been classified as porphyrinogenic (PSP, PRP or P), the safety classification of such a combination as PNP is no longer valid. Mepivacaine differs structurally from the bupivacaine only in the in the substitution of a methyl group for the N-butyl group. Sharing the structural metabolic prerequisites of the non-porphyrogenic drug bupivacaine gives theoretical grounds to classify mepivacaine as probably not porphyrinogenic. Uneventful use has been reported in 13 patients. Mepivacaine is classified PNP. Adrenalin (epinephrine): Endogenous catecholamine. Metabolism is Not CYP-dependent . No data pointing to CYP-interaction. Epinephrine is classified NP

Mepivacaine hydrochloride is a local anaesthetic of the amide type. Mepivacaine differs structurally from the non-porphyrogenic drug bupivacaine only in the in the substitution of a methyl group for the N-butyl group. Adrenaline is a catecholamine added for longer duration of local anaesthesia.

Local anaesthetic. Administration in combination with adrenaline (epinephrine) (not porphyrogenic) prolongs the effect of mepivacaine, and reduces hepatic exposure and the risk of systemic reactions.

Mepivacaine is rapidly metabolised in the liver and less than 10% of a dose is reported to be excreted unchanged in the urine. Over 50% of a dose is excreted as metabolites into the bile but these probably undergo enterohepatic circulation as only small amounts appear in the faeces. Several metabolites are also excreted via the kidneys and include glucuronide conjugates of hydroxy compounds and an N-demethylated compound, 2´,6´-pipecoloxylidide. The drug has not been found to be an inducer or irreversible inhibitor of drug metabolizing cytochrome P450 species (Rendic, 2002) and is therefore most probably devoid of capacity for ALAS1-induction. Sharing the structural metabolic prerequisites of bupivacaine, the probability is that this substance will not take part in ALAS1-induction needed for porhyrogenic action. Adrenalin (epinephrine) is an endogenous compound. It is very rapidly inactivated by processes which include uptake into adrenergic neurones, diffusion, and enzymatic degradation in the liver and body tissues. Metabolism involves monoamine oxidase (MAO) and catechol-O-methyl transferase (COMT).

Thunell, S., study to be published: 11 patients exposed without porphyric adverse reaction reported.

Uneventful use reported in a case report of one 55 year old AIP woman devoid of clinical symptoms but with elevated PBG levels. Twenty ml of 1% mepivacaine was injected as postoperative pain control following a hip replacement surgery (Hiraki, T., Oishi, K. et al, 2001). Uneventful use in one 32 year old HCP woman who received routine dental local anesthesia consisting of 2% mepivacaine with 1:20,000 levonordefrin. (Moore, A.W.,& Coke,J.M., 2000).