Azelastine (Optilast eye drops)

How does it work?

Optilast eye drops contain the active ingredient azelastine hydrochloride, which is a type of medicine called an antihistamine. It works by preventing the actions of histamine.

Histamine is a substance produced by the body as part of its defence mechanisms. It is stored in cells called mast cells, in almost all tissues of the body. When the body reacts to a foreign substance (known as an allergen, eg flower pollen, pet fur, dust mites), the mast cells stimulated by the allergen release their stores of histamine.

The released histamine then binds to its receptors (H-1 receptors), causing a chain reaction that results in allergic symptoms. It causes an increase in blood flow to the area of the allergy, and the release of other chemicals that add to the allergic response.

All this results in the symptoms of an allergic reaction. In eye allergies, such as hay fever (seasonal allergic conjunctivitis), eg caused by flower pollen or grasses, histamine causes inflammation of the eyes, making them red, itchy and watery.

Azelastine eye drops work by blocking the histamine receptors in the eyes. This stops it causing inflammation and thus provides relief from the symptoms of the eye allergy.

What is it used for?

  • Preventing and relieving eye inflammation due to hay fever (seasonal allergic conjunctivitis) in adults and children aged four years and older.
  • Relieving eye inflammation due to allergies such as pet allergies that occur thoughout the year (perennial allergic conjunctivitis) in adults and children aged 12 years and older.

How do I use it?

  • Wash your hands before using the eye drops.
  • One drop should be put into each eye twice a day when needed to relieve symptoms. If necessary, this can be increased to one drop in each eye up to four times a day. Follow this link for instructions on how to use your eye drops.
  • For hay fever, you can also use these eye drops (as above) to help prevent your symptoms if you know you are going to be exposed to the type of pollen that causes your allergy.
  • For other eye allergies, you can use these eye drops to relieve your symptoms for up to six weeks at a time. Follow the instructions given by your doctor.


  • Optilast eye drops are for use in the eyes only and must not be taken by mouth.
  • You should not wear soft contact lenses while you are using these eye drops. This is because they contain a preservative that can be absorbed by soft contact lenses and cause eye irritation.
  • These eye drops may cause your vision to blur temporarily after you have applied them into your eye. Do not drive or operate machinery until this has worn off.
  • When using the eye drops you should take care to not touch the dropper tip to any surface, or to your eye, in order to avoid contaminating the eye drops.
  • Your eye drops should be discarded four weeks after the bottle is first opened. This is because they could be contaminated with dirt or germs that could cause eye infections. Write the date of opening on the bottle so you know when to throw them away. Dispose of carefully, preferably by returning to your pharmacy.

Not to be used in

  • People who are allergic to any ingredient.

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.

If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

  • The safety of this medicine for use during pregnancy has not been established. Only minimal amounts of the medicine pass into the bloodstream after putting in the eye drops, but the manufacturer states that they should be used with caution during pregnancy, and only if the benefits to the mother outweigh any potential risks to the developing baby. Seek medical advice from your doctor.
  • Only very small amounts of this medicine may pass into breast milk after putting in the eye drops. They should be used with caution by women who are breastfeeding and only if the benefits to the mother outweigh any potential risks to the nursing infant. Seek medical advice from your doctor.

If you are pregnant or breastfeeding and do use these eye drops (only on your doctor's advice), you can minimise the amount of medicine that is absorbed into your bloodstream by pressing on your tear duct while putting in the drops, and for a few minutes after. The tear duct is at the corner of the eye closest to your nose.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

  • Mild, temporary eye irritation after putting in the drops.
  • Bitter taste.

The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.

For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

If you are using more than one type of eye drop you should administer them at least five minutes apart, to prevent the second drop washing away the first. Use eye gels or ointments last.

This medicine has not been reported to affect any other medicines.

Other medicines containing the same active ingredient

  • Rhinolast nasal spray.