Olopatadine: Formula, Indications, Mechanism of Action, Dosage, Side Effects, Warnings, Contraindications and Interactions

Treats allergy symptoms such as itching, swelling, and rashes by blocking the effects of a chemical messenger, histamine, in the body.

Olopatadine is an antihistamine medication.

Olopatadine is an antihistamine and mast cell stabilizer, marketed as an ophthalmic solution to prevent eye pruritus due to allergic conjunctivitis and as a nasal spray for seasonal allergic rhinitis.

Chemical formula

  • C21H23NO3.


It comes in two ways; eye drops and also in nasal spray.


Ophthalmic olopatadine is used to treat eye symptoms of allergic conjunctivitis and other allergic conditions, such as inflammation, itching, and burning.

In the nasal spray presentation, it is used for seasonal allergic rhinitis in the treatment of sneezing and runny nose due to these allergies.

Mechanism of action

The mechanism of action of olopatadine exhibits two distinct mechanisms of action. It inhibits histamine release from mast cells and is a relatively selective antagonist of H1 receptors.


As a result, olopatadine prevents type 1 immediate hypersensitivity reactions. Topical ocular administration relieves the ocular itching associated with allergic conjunctivitis.

Intranasal administration relieves symptoms associated with seasonal allergic rhinitis.

Olopatadine does not act on alpha-adrenergic, dopamine, type 1 or type 2 muscarinic or serotonergic receptors.


For the treatment of the signs and symptoms of allergic conjunctivitis, including eye itching:

  • The ophthalmic dosage is in adults, adolescents, and children three years and older, with one drop in each affected eye twice a day for 6 to 8 hours.

For the treatment of symptoms associated with seasonal allergic rhinitides such as runny nose, sneezing, and nasal itching:

  • The intranasal dosage is in adults, geriatric patients, adolescents, and children older than 12 years; it is two applications (665 mcg/spray) in each nostril twice a day.

In children 2 to 11 years old, one spray (665 mcg/spray) in each nostril twice a day.

Side effects

If you have symptoms of an allergic reaction such as difficulty breathing, or swelling of the face, lips, tongue, or throat, you should seek immediate medical attention.

Stop using olopatadine ophthalmic and call your doctor right away if you have severe redness, swelling, burning, stinging, drainage, or other irritation when using the eye drops.

Less serious side effects from using olopatadine may include:

  • Mild burning, stinging, irritation, itching, redness, or dryness of the eyes.
  • Blurry vision.
  • Feeling that something is in the eye.
  • Swollen eyelids
  • Stuffy or runny nose, cough, and sore throat.
  • Soft spot.
  • Back pain.
  • Headache.
  • Unpleasant taste in the mouth.

Warnings and Contraindications

  • You should not use this medicine if you are allergic to olopatadine.
  • The doctor must be informed if the patient has an eye infection.
  • The physician should be notified if the patient is pregnant or plans to become pregnant.
  • This medicine can be harmful to an unborn baby.
  • It is not known whether olopatadine ophthalmic passes into breast milk, so this medicine should not be used if the patient is breastfeeding.
  • Do not use this medicine in children under three years of age without a prescription.
  • Do not use olopatadine ophthalmic while wearing contact lenses.
  • Ophthalmic olopatadine may contain a preservative that soft contact lenses can absorb.
  • Avoid concomitant use of other ophthalmic medications with olopatadine without a prescription.
  • Drowsiness has been reported in patients using olopatadine nasal spray. Caution should be exercised when driving vehicles, operating machinery, or participating in activities that require mental attention.
  • The safe and effective use of olopatadine ophthalmic and intranasal olopatadine has not yet been established in newborns, infants, or young children between 3 and 6 years. Therefore, only administer olopatadine in this age group on the condition that your doctor prescribes it.


Studies have shown that olopatadine ophthalmic and intranasal olopatadine do not inhibit metabolic reactions in the body, indicating that interactions are unlikely to occur when olopatadine is administered in conjunction with other medications.