Cysteine


Concise Prescribing Info
Indications/Uses
Nutritional deficiciency.
Dosage/Direction for Use
Adult : PO 0.5-1.5 g/day.
Dosage Details
Oral
Nutritional deficiency
Adult: 0.5-1.5 g daily with at least 6-8 glasses of water to prevent cystine renal stones.

Parenteral
Nutritional deficiency
Child: As TPN for infants For use only after dilution in a crystalline amino acid solution. Each 0.5 g should be combined aseptically with 12.5 g of amino acids. Dilute the admixture with 250 ml of dextrose 50% or such lesser volume as indicated.
Special Precautions
Avoid in children, pregnancy, lactation, nephrolithiasis. Renal impairment.
Adverse Reactions
May increase zinc absorption. Ascorbic acid may inhibit the oxidation of L-cysteine to L-cystine.
Lab Interference
Produce a false-positive result in the nitroprusside test for ketone bodies used in diabetes & suspected hepatocellular injury.
Action
Description: Cysteine is synthesized from methionine via the trans-sulfuration pathway in the adult, but newborn infants lack the enzyme, cystathionase, necessary to effect this conversion. It also serves as a major precursor for synthesis of glutathione in certain conditions eg acetaminophen overdose which deplete hepatic glutathione & subject the tissues to oxidative stress resulting in loss of cellular integrity.
Pharmacokinetics:
Absorption: Following ingestion, some cysteine is oxidised to cystine & both are absorbed from the small intestine by active-transport processes. Cysteine absorption is largely sodium-dependent, while cysteine is absorbed by a sodium-independent transport system.
Distribution: Distributed to the liver. Unmetabolised cysteine enters the systemic circulation and distributes to various body tissues.
Metabolism: Metabolised hepatically to protein, glutathione, taurine & sulfate.
Disclaimer: This information is independently developed by MIMS based on Cysteine from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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