Pseudocholinesterase, drug reaction

Flydrolysis is an important metabolic reaction for drugs whose structures contain ester and amide groups. All types of ester and amide can be metabolized by this route. Ester hydrolysis is often catalysed by specific esterases in the liver, kidney and other tissues as well as non-specific esterases such as acetylcholinesterases and pseudocholinesterases in the plasma. Amide hydrolysis is also catalysed by non-specific esterases in the plasma as well as amidases in the liver. More specific enzyme systems are able to hydrolyse sulphate and glucur-onate conjugates as well as hydrate epoxides, glycosides and other moieties. 

Other hereditary enzyme deficiencies that may result in adverse reactions to certain drugs are comparatively rare, often familial, and of worldwide distribution. Examples of these conditions are pseudocholinesterase deficiencies in certain people who, when given succinylcholine or suxamethonium, develop a profound, general neuromuscular blockade with apnea (38). 

Differences in metabolism among patients can lead to differences in susceptibility to ADRs e.g. patients with abnormal pseudocholinesterase levels have prolonged apnea after receiving succi-nylcholine patients with low activity of A-acetyl transferase are more likely to develop lupus-like reactions to procainamide, hydralazine, and isonia-zid and variants of the cytochrome P-450 family of enzymes can lead to altered metabolism of a variety of drugs, including antidepressants, antiarrhythmic agents, codeine, metoprolol terfenadine, cyclosporine, calcium channel blockers, and others (Peck et al 1993). 

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