L-Cysteine Side Effects
Generic name: cysteine
Medically reviewed by Drugs.com. Last updated on Mar 29, 2025.
Note: This document provides detailed information about L-Cysteine Side Effects associated with cysteine. Some dosage forms listed on this page may not apply specifically to the brand name L-Cysteine.
Applies to cysteine: intravenous solution.
Your doctor will check your or your child's progress closely while you are receiving this medicine. This will allow your doctor to see if the medicine is working properly. Blood and urine tests will be needed to check for unwanted effects.
Tell your doctor right away if you or your child have chest pain, cough, fainting, fast heartbeat, trouble breathing, or dizziness or lightheadedness after receiving this medicine. These could be symptoms of pulmonary embolism caused by the precipitates found in the TPN solution, infusion set, and catheter.
Tell your doctor if you or your child develop pain, tenderness, changes in skin color, or swelling of foot or leg after receiving this medicine. These could be symptoms of a vein damage or thrombophlebitis.
Check with your doctor right away if you have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, vomiting, or yellow eyes or skin. These could be symptoms of a serious liver problem.
Serious side effects of L-Cysteine
Along with its needed effects, cysteine (the active ingredient contained in L-Cysteine) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor or nurse immediately if any of the following side effects occur while taking cysteine:
Incidence not known
- anxiety
- chest pain
- confusion cough
- dizziness or lightheadedness
- drowsiness
- fainting
- fast heartbeat
- feeling of warmth
- fever
- muscle tremors
- nausea
- pain, tenderness, or swelling of the foot or leg
- rapid, deep breathing
- redness of the face, neck, arms, and occasionally, upper chest
- restlessness
- stomach cramps
- sudden shortness of breath or troubled breathing
- unusual tiredness or weakness
- warmth, redness, pain, or changes in skin color at the infusion site
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Further information
L-Cysteine side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.