From the Guidelines
Zaditor (ketotifen fumarate) eye drops can be used continuously for up to 8 weeks, as recommended by the most recent and highest quality study 1. When using Zaditor, it's essential to follow the recommended dosage and usage guidelines to minimize potential side effects and ensure optimal relief from allergic eye symptoms.
- For acute allergic eye symptoms, use one drop in the affected eye(s) twice daily, about 8-12 hours apart.
- After opening the bottle, you should discard any remaining solution after 3 months. While Zaditor provides effective relief from eye allergy symptoms like itching, redness, and tearing, it's not intended for long-term continuous use beyond the recommended period.
- If your symptoms persist beyond 8 weeks of regular use, you should consult with a healthcare provider as this may indicate a condition requiring different treatment. Zaditor works by blocking histamine receptors and stabilizing mast cells in the eye, preventing the release of inflammatory chemicals that cause allergy symptoms.
- The medication typically begins working within minutes and can provide relief for up to 12 hours per dose, as supported by the study 1. It's crucial to note that prolonged use of ocular decongestants may lead to rebound hyperemia or conjunctivitis medicamentosa, although use limited to 10 days does not appear to induce this, as mentioned in the study 1.
- However, the study 1 provides more recent and higher-quality evidence, which prioritizes the safety and efficacy of Zaditor for up to 8 weeks of continuous use.
From the FDA Drug Label
Directions Adults and children 3 years of age and older: Put 1 drop in the affected eye(s) twice daily, every 8-12 hours, no more than twice per day. The FDA drug label does not answer the question.
From the Research
Duration of Zaditor Use
- The duration of Zaditor use can vary depending on the individual and the severity of their allergic conjunctivitis symptoms.
- According to a study published in 2004 2, patients with seasonal allergic conjunctivitis were treated with ketotifen fumarate 0.05% eye drops for a period of 2 to 6 months, with subjective symptoms disappearing after 10 days of treatment in 60% to 80% of patients.
- Another study published in 2003 3 found that ketotifen 0.025% eye drops were effective in preventing ocular itching, injection, and other signs and symptoms of allergic conjunctivitis at 15 minutes, 6 hours, and 8 hours after a single dose, and at 8 hours after the final dose of a 4-week twice daily regimen.
- A study published in 2019 4 compared the efficacy and tolerability of ketotifen 0.025% and 0.05% eye drops in the treatment of seasonal allergic conjunctivitis, and found that both concentrations were highly effective, but ketotifen 0.025% was better tolerated and had a better responder rate.
Treatment Duration and Efficacy
- The treatment duration for Zaditor can range from a few days to several weeks or months, depending on the individual's response to treatment and the severity of their symptoms.
- A study published in 2003 5 found that ketotifen fumarate 0.05% eye drops significantly reduced the total symptoms and signs score for each patient, as well as each symptom and sign, at all time points compared with day 0, after 30 days of treatment.
- Another study published in 2003 6 found that ketotifen 0.025% ophthalmic solution was safe and statistically effective in reducing ocular itching and hyperemia associated with allergic conjunctivitis, with a rapid onset of action and extended duration of action.