Cysteine


Generic Medicine Info
Indications and Dosage
Intravenous
Nutritional deficiency
Adult: As part of parenteral nutrition regimen for patients with severe liver disease who may have impaired enzymatic processes and require TPN. Doses are based on the recommended daily protein (amino acid) requirement. As cysteine hydrochloride: 7 mg/g of amino acids (equivalent to 5 mg cysteine/g of amino acids) daily. Correct severe fluid, electrolyte, and acid-base disorders before administration.
Child: As additive to crystalline amino acid solution to meet the intravenous nutritional requirements of those receiving TPN: As cysteine hydrochloride: Infants and children ≤11 years 30-40 mg/g of amino acids daily; a lower dose of 20 mg/g of amino acids daily may also be given; ≥12 years Same as adult dose. Dosage recommendations may vary among individual products. Refer to specific product guidelines. Correct severe fluid, electrolyte, and acid-base disorders before administration.
Contraindications
Inborn errors of amino acid metabolism, pulmonary oedema or acidosis due to low cardiac output; hepatic coma or metabolic disorders involving impaired nitrogen utilisation.
Special Precautions
Patients with cardiac insufficiency, diabetes (including prediabetic patients), pulmonary disease. Renal and hepatic impairment. Children (especially, infants). Pregnancy and lactation.
Adverse Reactions
Significant: Hepatobiliary disorders (e.g. cholecystitis, cholelithiasis, cholestasis, cirrhosis, hepatic steatosis, fibrosis), increased BUN; hyperammonaemia, metabolic alkalosis, prerenal azotaemia, serum amino acid imbalances, stupor, coma; metabolic acidosis (in preterm infants).
Gastrointestinal disorders: Nausea.
General disorders and administration site conditions: Fever, infusion site reactions (e.g. erythema, phlebitis, thrombosis, warm sensation).
Vascular disorders: Flushing.
Monitoring Parameters
Monitor fluid and electrolyte status, blood glucose, kidney and liver functions, CBC and coagulation parameters; blood ammonia levels (if hepatic impairment is present), triglycerides (if adding lipid emulsion), acid-base balance, serum proteins, blood culture, urine osmolarity and glucose, nitrogen intake.
Lab Interference
May interfere with estimations of nitrogen-containing substances. May cause a false-positive result with the nitroprusside test for ketone bodies.
Action
Description: Cysteine is a non-essential amino acid. Endogenously, it is synthesised from methionine by cystathionase via the tran-sulfuration pathway and serves as a precursor substrate for glutathione and taurine. As an exogenous source it provides cysteine to the systemic circulation of patients who cannot synthesise adequate quantities due to deficient or insufficient cystathionase activity.
Synonym: l-cysteine.
Chemical Structure

Chemical Structure Image
Cysteine

Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 5862, L-Cysteine. https://pubchem.ncbi.nlm.nih.gov/compound/L-Cysteine. Accessed Feb. 26, 2021.

Storage
Store between 15-30°C. Protect from light and excessive heat.
MIMS Class
Supplements & Adjuvant Therapy
References
Anon. Cysteine. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 01/10/2020.

Buckingham R (ed). Cysteine. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 01/10/2020.

Cysteine. Gold Standard Drug Database in ClinicalKey [online]. Elsevier Inc. https://www.clinicalkey.com. Accessed 10/02/2021.

Elcys Injection, Solution (Exela Pharma Sciences, LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 01/10/2020.

Elcys Injection, Solution (Exela Pharma Sciences, LLC). U.S. FDA. https://www.fda.gov. Accessed 01/10/2020.

L-cysteine Hydrochloride Injection, Solution (Sandoz Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 01/10/2020.

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 © 2021 MIMS. All rights reserved. Powered by MIMS.com
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