Olopatadine stabilizes ocular mast cells to prevent histamine release by allergens.
Environmental allergens can cause allergic conjunctivitis, also known as ocular allergies or pink eye. When allergens cause histamine release from ocular mast cells, it activates H1 histamine receptors to produce symptoms such as redness, itching, tearing, and swelling of the eye.1,2 Ocular itching is the most troublesome symptom, which motivates patients to seek medical care for allergic conjunctivitis.3
Olopatadine (Pataday) is an H1 histamine receptor antagonist approved by the FDA in 1996 for ocular itching due to allergic conjunctivitis. The manufacturer supplies olopatadine ophthalmic solution in 3 different strengths, all of which are now available OTC.
In 2 parallel-group, randomized, double-masked, placebo-controlled clinical trials using 547 patients, all 3 strengths of olopatadine provided ocular itching relief and reduced conjunctivital redness compared to placebo.4,5 The extra strength formulation (formerly Pazeo) has a longer duration of action of 24 hours and is superior to the lower strength formulation in reducing ocular itchiness and conjunctivital redness.5
Mechanism of Action6,7
Olopatadine stabilizes ocular mast cells to prevent histamine release by allergens. Olopatadine also blocks histamine H1 receptors that mediate ocular itching and conjunctivital redness.
Dosage and Administration6,7
The manufacturer supplies olopatadine sterile ophthalmic solution in 3 strengths with different durations of action: 0.1% (formerly Patanol, 8 hours), 0.2% (formerly Pataday, 16 hours), and 0.7% (formerly Pazeo, 24 hours). The manufacturer labels olopatadine formulations as Pataday Original Prescription Strength (0.1% and 0.2%) or Pataday Extra Strength (0.7%). Health care professionals and patients should store olopatadine between 2°-25°C (36-77°F).
Patients using olopatadine 0.1% solution should administer one drop in each affected eye twice daily but only once daily if using 0.2% or 0.7% solution and close the bottle tightly after use. If a patient misses a dose, they should administer olopatadine as soon as possible.
Adverse Events (AEs)7
During clinical trials, patients experienced blurred vision, dryness/abnormal sensations in eyes, corneal/conjunctivital staining, and dysgeusia. Post-marketing data also identified hypersensitivity, increased lacrimation, and nausea as additional AEs.
Health care professionals should advise patients not to use olopatadine if they are hypersensitive to olopatadine, any formulation ingredient, or any component of the container. Health care professionals or patients should not administer olopatadine orally or by injection.
Dose adjustment for geriatric patients, pediatric patients over 2 years of age, or for those suffering from hepatic or renal diseases is not needed. To prevent contamination, health care professionals should advise patients not to touch the tip of the dropper bottle with the eyelids or surrounding areas.
If patients use contact lenses, health care professionals should instruct patients to use them only if their eyes are not red. Patients should wait for at least 5 minutes after instilling olopatadine to insert their contact lenses because soft contact lenses can absorb the preservative used in olopatadine ophthalmic solutions. If eyes are red, patients should not wear contact lenses.
If blurred vision or other visual issues occur, patients must wait for clear vision before driving or using machinery. Patients should not double the dose for a missed dose.
Pregnancy and Lactation7
Researchers have not studied olopatadine in pregnant women, but oral administration of extremely high doses in rats reduced fertility index and implantation rate. Oral administration to pregnant rats caused cleft palate, reduced maternal and fetal body weight gain, and decreased fetal and neonatal survival.
Olopatadine crosses into milk in nursing rats and decreases body weight gain in offspring on oral administration. Health care professionals should therefore advise patients to use olopatadine during pregnancy and breastfeeding only if the benefits outweigh the risks.
About the Author
Alok Sharma, PhD, is a professor of Pharmaceutical Sciences at Massachusetts College of Pharmacy and Health Sciences in Manchester, NH.
1. Conjunctivitis: Gateway to Health Communication (CDC). Accessed May 8, 2022. https://www.cdc.gov/conjunctivitis/
2. Alcon Announces FDA APPROVAL of the OTC Switch of Pataday Once Daily Relief Extra Strength. Accessed May 8, 2022. https://www.alcon.com/media-release/alcon-announces-fda-approval-otc-switch-pataday-once-daily-relief-extra-strength
3. Rethinking once-daily dosing on allergy medications. Accessed May 8, 2022. https://www.optometrytimes.com/view/rethinking-once-daily-dosing-allergy-medications
4. McLaurin E, Narvekar A, Gomes P, Adewale A, Torkildsen G. Phase 3 Randomized Double-Masked Study of Efficacy and Safety of Once-Daily 0.77% Olopatadine Hydrochloride Ophthalmic Solution in Subjects with Allergic Conjunctivitis Using the Conjunctival Allergen Challenge Model. Cornea. 2015; 34(10): 1245-1251.
5. Torkildsen G, Narvekar A, Bergmann M. Efficacy and Safety of Olopatadine Hydrochloride 0.77% in Patients with Allergic Conjunctivitis Using a Conjunctival Allergen-Challenge Model. Clin Ophthalmol. 2015; 9: 1703-1713.
6. Patadayâ Relief Lasts All Day – Available Without Prescription. Accessed May 8, 2022. https://pataday.myalcon.com/eye-care/pataday/family-of-products/
7. PAZEO Product Monograph. March 2017. Accessed May 8, 2022. https://www.ask.novartispharma.ca/download.htm?res=pazeo_scrip_e.pdf&resTitleId=1434