Norpethidine (normeperidine, pethidine intermediate B) is a 4-phenylpiperidine derivative that is both a precursor to, and the toxic metabolite of, pethidine (meperidine). It is scheduled by UNSingle Convention on Narcotic Drugs. It is a Schedule II Narcotic controlled substance in the United States and has an ACSCN of 9233. The 2014 annual manufacturing quota was 11 grams (0.39 oz).[2]
Norpethidine is a controlled drug because of its potential uses in manufacturing both pethidine itself and a range of N-substituted derivatives, but it has little opioid activity in its own right. Instead, norpethidine acts as a stimulant and causes convulsions.[3][4]
Bioaccumulation of norpethidine is a major complication when pethidine is used in medicine as an analgesic, as when pethidine is used in high doses[5] or administered by intravenous infusion,[6] norpethidine can accumulate in the body at a faster rate than it is being excreted, particularly in elderly patients[7] or those with compromised liver or kidney function,[8] resulting in a range of toxic effects, mainly convulsions, but also myoclonus[9] and hyponatremia.[10] These complications can be serious and have sometimes resulted in death.[11]
Metabolism of pethidine to norpethidine is carried out mainly by the CYP enzymes, CYP2B6, CYP2C19 and CYP3A4, in the liver, and since the activity of these enzymes can vary between individuals and can be influenced by concurrent use of other drugs, the rate and extent of norpethidine production can be difficult to predict.[12][13]
^Holmberg L, Odar-Cederlof I, Boreus LO, Heyner L, Ehrnebo M. Comparative disposition of pethidine and norpethidine in old and young patients. European Journal of Clinical Pharmacology. 1982;22(2):175-9.
^Pond SM, Tong T, Benowitz NL, Jacob P, Rigod J (August 1981). "Presystemic metabolism of meperidine to normeperidine in normal and cirrhotic subjects". Clinical Pharmacology and Therapeutics. 30 (2): 183–8. doi:10.1038/clpt.1981.146. PMID7249503. S2CID10117158.
^Ramírez J, Innocenti F, Schuetz EG, Flockhart DA, Relling MV, Santucci R, Ratain MJ (September 2004). "CYP2B6, CYP3A4, and CYP2C19 are responsible for the in vitro N-demethylation of meperidine in human liver microsomes". Drug Metabolism and Disposition: The Biological Fate of Chemicals. 32 (9): 930–6. PMID15319333.
^McHugh GJ (June 1999). "Norpethidine accumulation and generalized seizure during pethidine patient-controlled analgesia". Anaesthesia and Intensive Care. 27 (3): 289–91. PMID10389564.
^US granted 2858316, Henri M, "New piperidine derivatives", published 28 October 1958, assigned to UCB SA
^Frearson PM, Stern ES (1958). "622. Some new analogues of pethidine. Part III. 1-Aryloxy-alkylnorpethidines, and close analogues". Journal of the Chemical Society (Resumed): 3065–7. doi:10.1039/JR9580003065.
^Frearson PM, Hardy DG, Stern ES (1960). "426. Some new analogues of pethidine. Part IV. Substituents at the 1-position incorporating cyclic ether groups". Journal of the Chemical Society (Resumed): 2103–7. doi:10.1039/JR9600002103.