How does this medication work? What will it do for me?

Ketotifen belongs to a group of medications called antihistamines. Ketotifen eye drops are used to treat the signs and symptoms of a condition called allergic conjunctivitis (an allergic reaction affecting the eyes). Signs and symptoms include itchy eyes, red eyes, and swelling of the eyes or eyelids.

Ketotifen works by blocking histamine, a substance released by the body during an allergic reaction. It also works by preventing the release of natural chemicals from cells in the body (mast cells) involved in an allergic reaction. Ketotifen eye drops work within a few minutes after use.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. As well, some forms of this medication may not be used for all of the conditions discussed here. If you have not discussed this with your doctor or are not sure why you are using this medication, speak to your doctor. Do not stop using this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to use this medication if their doctor has not prescribed it.

What form(s) does this medication come in?

Multi-Dose Containers (With Preservative)
Each mL of ophthalmic solution contains 0.345 mg ketotifen fumarate equivalent to 0.25 mg ketotifen. Nonmedicinal ingredients: benzalkonium chloride 0.01%, glycerol, hydrochloric acid/sodium hydroxide, and purified water.

How should I use this medication?

The usual recommended dose for adults and children over 3 years old is one drop in the affected eye(s) every 8 to 12 hours.

The single dose containers (preservative free), do not contain any preservatives and must be discarded after use. Once the single dose containers are open, they are no longer sterile so do not open the container until you are ready to use the eye drops. Blocks of 5 single-dose containers are packaged together in a blister. Any unused single-dose containers of an open blister should be discarded after 4 weeks. They can be discarded after 3 months if they have been stored in the outer carton.

If you are using the multi-dose containers (with preservative), do not use the eye drop while wearing soft contact lenses since they contain the preservative benzalkonium chloride. If you wear soft contact lenses, remove them before instilling the drops, and wait at least 10 minutes before putting your lenses back in.

Before using the eye drops, wash your hands thoroughly. Follow your doctor or pharmacist's instructions on how to use the eye drops. Do not allow the eye dropper to touch any surface. This could contaminate the dropper and lead to an eye infection. Keep the bottle tightly closed when you are not using it.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are using the medication without consulting your doctor.

It is important to use this medication exactly as prescribed by your doctor. If you miss a dose, instill it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not instill a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not use this medication if you are:

  • allergic to ketotifen or any ingredients of the medication.

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who uses this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people using this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • burning or stinging in the eyes
  • dry eyes
  • headache
  • red eyes

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • changes in eyelid
  • discharge from eye

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Contact lenses: If you wear soft contact lenses, remove them before instilling the drops, and wait at least 10 minutes before putting your lenses back in. If your eyes become red, take out your lenses and consult your eye doctor.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if ketotifen passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children under 3 years of age.

What other drugs could interact with this medication?

There may be an interaction between ketotifen eye drops and any of the following:

  • other eye medications

If you are using other eye medications, your doctor or pharmacist may advise you to wait at least 5 minutes between the medications.

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.