Generic name: cysteamine ophthalmic
Brand names: Cystadrops, Cystaran
Drug class: Miscellaneous ophthalmic agents

Medically reviewed by  A Ras MD.

What is Cystaran?

Cystaran is a prescription medicine that is used to get rid of a protein called cystine from the eye.


CYSTARAN is a sterile ophthalmic solution containing 6.5 mg/mL of cysteamine hydrochloride, equivalent to 4.4 mg/mL of cysteamine (0.44%) as the active ingredient. Cysteamine is a cystine-depleting agent which lowers the cystine content of cells in patients with cystinosis.

Chemical Structure

  • Molecular Formula:   C2H7NS HCl
    Molecular Weight:     113.61

Each milliliter of CYSTARAN contains: Active: cysteamine 4.4 mg (equivalent to cysteamine hydrochloride 6.5 mg); Preservative: benzalkonium chloride 0.1 mg; Inactive Ingredients: sodium chloride, hydrochloric acid and/or sodium hydroxide (to adjust pH to 4.1-4.5), and purified water.

 Mechanism of Action

Cysteamine acts as a cystine-depleting agent by converting cystine to cysteine and cysteine-cysteamine mixed disulfides and reduces corneal cystine crystal accumulation.

Before taking Cystaran, tell your doctor:

  • If you are allergic to Cystaran; any part of this medicine; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.

This medicine may interact with other drugs or health problems.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take Cystaran with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take Cystaran?

  • Tell all of your health care providers that you take Cystaran. This includes your doctors, nurses, pharmacists, and dentists.
  • Bright lights may bother you. Wear sunglasses.
  • Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using Cystaran while you are pregnant.
  • Tell your doctor if you are breast-feeding. You will need to talk about any risks to your baby.

How is Cystaran best taken?

Use Cystaran as ordered by your doctor. Read all information given to you. Follow all instructions closely.

  • For the eye only.
  • Take out contact lenses before using Cystaran. Lenses may be put back in 15 minutes after Cystaran is given. Do not put contacts back in if your eyes are irritated or infected.
  • Do not touch the container tip to the eye, lid, or other skin.
  • Tilt your head back and drop drug into the eye.
  • After use, keep your eyes closed. Put pressure on the inside corner of the eye. Do this for 1 to 2 minutes. This keeps the drug in your eye.

What do I do if I miss a dose?

  • Use a missed dose as soon as you think about it.
  • If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
  • Do not use 2 doses at the same time or extra doses.

What are the side effects of Cystaran that I need to call my doctor about immediately?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Change in eyesight, eye pain, or very bad eye irritation.

What are some other side effects of Cystaran?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

  • Headache.
  • Eye irritation.
  • Eye redness.
  • Eye is bothered by bright light.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at

If overdose is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

How do I store and/or throw out Cystaran?

  • Store unopened bottles in the freezer.
  • Each week, take out a new bottle from the freezer to use for that week. Store at room temperature.
  • Let bottle thaw for 24 hours before using.
  • Do not put bottle back in the freezer after thawing.
  • Keep lid tightly closed.
  • Throw away any part of thawed bottle not used after 7 days.
  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.




  • NDC 54482-020-02
  • cystaran®
  • (cysteamine ophthalmic
    solution) 0.44%
  • For Topical Ophthalmic Use
  • Sterile
  • 15 mL
  • Rx only
  • Active Ingredient: Each mL
    contains 6.5 mg cysteamine
    hydrochloride, equivalent to 4.4 mg
    cysteamine. Inactive Ingredients:
    Benzalkonium chloride
    (preservative); Sodium chloride;
    hydrochloric acid and/or sodium
    hydroxide (to adjust pH) and
    purified water.
  • Dosage: See Prescribing Information.