Pharmacology for Anaesthesia and Intensive Care

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7 Medicinal chemistry

Isoquinoline:Aheterocyclic ring system, part of bis-benzylisoquinolinium

structure of certain non-depolarizing blockers and found in papaverine.

Keto:Aketo group is the equivalent of an aldehyde group (=O) but in a ring

structure. Under certain circumstances it exists in equilibrium with its enol form.

Laudanosine:One of the products of atracurium and cis-atracurium breakdown

byHofmann degradation. It is neurotoxic in certain non-primate species. The

other product is an acrylate (CH 2 CH–R).

Mandelic acid:Derivatives of mandelic acid are formed as a result of adrenaline

and noradrenaline metabolism by MAO and COMT, e.g. 3-methoxy-

4-hydroxymandelic acid.

Methoxy:–OCH 3 group, this has better lipid solubility than –OH. Codeine is

3-methoxymorphine. There are several methoxy- group substitutions in the

benzylisoquinolinium non-depolarizing muscle relaxants which make them

water-soluble.

Methyl:–CH 3 group (seeAlkyl). Methylation and de-methylation are important

routes of metabolism for many drugs, both in the liver and in other tissues. Nor-

adrenaline is methylated to adrenaline in adrenal medullary cells whereas

diazepam is de-methylated to nordiazepam and ketamine de-methylated to

norketamine in the liver. Note that the prefix nor- and the prefix desmethyl- can

both imply the removal of a methyl group from a parent structure.

Oxicam:Piroxicam and meloxicam are two examples of the NSAIDs with this

underlying structure.