Last updated on RxList: 5/2/2019
Elcys Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Last reviewed on RxList 5/2/2019

Elcys (cysteine hydrochloride injection) is a sulfur-containing amino acid indicated to meet the nutritional requirements of newborn infants requiring total parenteral nutrition (TPN); and of adult and pediatric patients with severe liver disease who may have impaired enzymatic processes and require TPN. It can also be added to amino acid solutions to provide a more complete profile of amino acids for protein synthesis. Common side effects of Elcys include:

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

The recommended dosage and volume of Elcys is based upon the recommended daily protein (amino acids) requirement. For pediatric patients from birth to less than 12 years of age, the recommended dosage of Elcys is 22 mg/gram of amino acids. For adults and pediatric patients 12 years of age and older, the recommended dosage of Elcys is 7 mg/gram of amino acids. Elcys may interact with other drugs. Tell your doctor all medications and supplements you use. Tell your doctor if you are pregnant or plan to become pregnant before using Elcys; it is not expected to harm a fetus. Elcys passes into breast milk but is not expected to harm a nursing infant. Consult your doctor before breastfeeding.

Our Elcys (cysteine hydrochloride injection), for Intravenous Use Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


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Elcys Professional Information


The following serious adverse reactions are discussed in greater detail in other sections of the prescribing information:

  • Pulmonary embolism due to pulmonary vascular precipitates [see WARNINGS AND PRECAUTIONS]
  • Vein damage and thrombosis [see WARNINGS AND PRECAUTIONS]
  • Acid-base imbalance [see WARNINGS AND PRECAUTIONS]
  • Hepatobiliary disorders [see WARNINGS AND PRECAUTIONS]
  • Hyperammonemia [see WARNINGS AND PRECAUTIONS]
  • Aluminum toxicity [see WARNINGS AND PRECAUTIONS]

Adverse reactions with the use of cysteine hydrochloride injection were identified in clinical studies or postmarketing reports. Because some of these reactions were reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Local infusion site reactions, including a warm sensation, erythema, phlebitis and thrombosis at the infusion site

Generalized flushing, fever and nausea

Read the entire FDA prescribing information for Elcys (Cysteine Hydrochloride Injection)


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© Elcys Patient Information is supplied by Cerner Multum, Inc. and Elcys Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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