Cysteine Brand Name– ELCYS
What is Cysteine
Cysteine is a sulfur-containing amino acid indicated to meet the nutritional needs of neonates requiring parenteral nutrition (PN) and of adults and pediatric patients with severe liver disease who may have impaired enzymatic processes and require PN.
Cysteine can also be added to amino acid solutions to provide a more complete profile of amino acids for protein synthesis.
Cysteine is considered to be a conditionally essential amino acid in neonates due to the biochemical immaturity of the enzyme necessary to convert methionine to cysteine in these patients.
Cysteine injection should only be used for admixing in PN; it should not be given by direct IV administration.
Cysteine injection is FDA-approved for patients as young as neonates, including premature neonates.
Indications
- nutritional supplementation
- Cysteine is added as a fixed ratio to amino acid solutions; the dosage will vary with the daily amino acid dosage.
- The dosage of cysteine should be individualized based on the patient’s clinical condition (ability to adequately metabolize amino acids), body weight and nutritional/fluid requirements, as well as additional calories given orally/enterally to the patient.64232
For nutritional supplementation as an additive to amino acid solutions in infants requiring parenteral nutrition and for other patients with severe liver disease who may have impaired enzymatic processes and require parenteral nutrition
Side Effects
- aluminum toxicity
- azotemia
- cholecystitis
- cholelithiasis
- cholestasis
- cirrhosis
- coma
- erythema
- fever
- flushing
- hepatic failure
- hyperammonemia
- injection site reaction
- metabolic acidosis
- metabolic alkalosis
- nausea
- parenteral nutrition-associated liver disease
- phlebitis
- steatosis
- thrombosis
Monitoring Parameters
- activated partial thromboplastin time (APTT)
- blood glucose
- CBC
- INR
- LFTs
- serum creatinine/BUN
- serum electrolytes
- serum osmolality
Contraindications
- acid/base imbalance
- breast-feeding
- cholelithiasis
- cholestasis
- galactosemia
- hepatic disease
- hereditary fructose intolerance
- metabolic acidosis
- metabolic alkalosis
- phenylketonuria
- pregnancy
- premature neonates
- pulmonary edema
- renal disease
- renal impairment
- thrombophlebitis
- thrombosis
Interactions
There are no drug interactions associated with Cysteine products.
