Cysteine

Cysteine is a sulfur-containing amino acid indicated for adults and children with severe liver disease who may have impaired enzymatic processes and require total parenteral nutrition (TPN).

• Cysteine is available under the following different brand names: Elcys, Nouress

Common side effects of Cysteine include:

• generalized flushing,
• fever, 
• nausea, and
• warm sensation, redness, inflammation of veins, and blood clots at the infusion site

Serious side effects of Cysteine include:

• hives,
• difficulty breathing, and
• swelling of the face, lips, tongue, or throat

Rare side effects of Cysteine include:

• none

Seek medical care or call 911 at once if you have the following serious side effects:

• Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
• Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
• Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheadedness, or passing out. 

This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

Adult and pediatric dosage

Injectable solution

• 50 mg/mL (single-dose 10-mL vial)

Total Parenteral Nutrition

Adult dosage

• Stable patients
  • Recommended protein requirement: 0.8-1 g AA/kg/day
  • Recommended dose: 7 mg/g AA
  • Recommended volume: 0.14 mL/g AA
• Critically ill patients
  • Recommended protein requirement: 1.5-2 g AA/kg/day
  • Recommended dose: 7 mg/g AA
  • Recommended volume: 0.14 mL/g AA

Pediatric dosage

• Preterm and term infants (aged below 1 month)
  • Recommended protein requirement: 3-4 g AA/kg/day
  • Recommended dose: 22 mg/g AA
  • Recommended volume: 0.44 mL/g AA
• 1 month to less than a year
  • Recommended protein requirement: 2-3 g AA/kg/day
  • Recommended dose: 22 mg/g AA
  • Recommended volume: 0.44 mL/g AA
• 1 to less than 12 years
  • Recommended protein requirement: 1-2 g AA/kg/day
  • Recommended dose: 22 mg/g AA
  • Recommended volume: 0.44 mL/g AA
• 12 to 17 years
  • Recommended protein requirement: 0.8-1.5 g AA/kg/day
  • Recommended dose: 7 mg/g AA
  • Recommended volume: 0.14 mL/g AA

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

• Cysteine has severe interactions with no other drugs.
• Cysteine has serious interactions with no other drugs.
• Cysteine has moderate interactions with no other drugs.
• Cysteine has minor interactions with no other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your healthcare professional or doctor for additional medical advice, or if you have health questions or concerns.

Contraindications

• Hypersensitivity to one or more AAs
• Inborn errors of AA metabolism due to the risk of severe metabolic or neurologic complications
• Pulmonary edema or acidosis due to low cardiac output

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Cysteine?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Cysteine?”

Cautions

• Pulmonary vascular precipitates causing pulmonary vascular emboli and pulmonary distress reported; in some fatal cases, pulmonary embolism occurred due to calcium precipitates; if signs of pulmonary distress occur, stop parenteral nutrition infusion, initiate a medical evaluation, and periodically inspect the solution and infusion set
• For admixture use only and must be diluted; it is not direct IV infusion; solutions with an osmolarity (more than 900 mOsm/L) infuse through a central catheter; infusion of hypertonic nutrient injections into a peripheral vein may result in vein irritation, vein damage, and/or thrombosis
• IV infusion of AAs may induce a rise in BUN, especially in patients with impaired hepatic or renal function; perform appropriate laboratory tests periodically and discontinue infusion if BUN levels exceed normal postprandial limits and continue to rise
• Administration may result in metabolic acidosis in preterm infants; administration of AA solutions to a patient with hepatic impairment may result in serum AA imbalances, metabolic alkalosis, prerenal azotemia, hyperammonemia, stupor, and coma; frequent clinical evaluation and laboratory determinations are necessary for proper monitoring of acid-base balance during parenteral nutrition
• Hepatobiliary disorders are known to develop in some patients without preexisting liver disease who receive parenteral nutrition (eg, cholecystitis, cholelithiasis, cholestasis, hepatic steatosis, fibrosis, cirrhosis, possibly leading to hepatic failure); etiology of these disorders is thought to be multifactorial and may differ between patients; monitor liver function parameters and ammonia levels