Chapter Updates

Content Update for Chapter 28, "Ophthalmic Disorders"

FDA Approval of OTC Zaditor

The following information supplements and updates text in Chapter 28, "Ophthalmic Disorders," in the Handbook of Nonprescription Drugs, 15th Edition.

Zaditor

Nonprescription Zaditor (ketotifen 0.025%) ophthalmic solution was approved by the Food and Drug Administration (FDA) on October 19, 2006, in the same dosage as the prescription strength.1 On December 1, 2006, Alaway, which also contains ketotifen 0.025%, was approved for the same indication.2

Mechanism of Action  Ketotifen belongs to the drug class antihistamines. According to the manufacturer, Zaditor has three modes of action: (1) an antihistamine relieves itchy eyes, (2) mast cell stabilizers provide extended relief up to 12 hours, and (3) late-phase allergic reactions are stopped by the prevention of release of chemical mediators.3

    A 2002 clinical study4 showed that ketotifen fumarate 0.025% significantly inhibited itching (P < 0.05) compared with placebo at all time points after the 5- and 15-minute conjunctival allergen challenges conducted after administration of ketotifen eyedrops. A later study5 compared the efficacy, safety, and comfort of ketotifen fumarate 0.025% and nedocromil sodium 2.0% ophthalmic solutions for the prevention of ocular itching, on the basis of conjunctival allergen challenges at 5 minutes and 12 hours posttreatment. Ketotifen was significantly more effective and comfortable than nedocromil at both the 5-minute and 12-hour challenges.

Indications  Ketotifen is approved for temporary relief of itchy eyes due to pollen, ragweed, grass, animal hair, and dander.6

Dosage and Administration Guidelines  For adults and children older than 3 years, the approved dosage is 1 drop in the affected eye(s) twice daily, every 8 to 12 hours, no more often than twice daily. For use in children younger than 3 years, a primary care provider must be consulted.6

    The product should be administered according to the directions in Table 28-2 (page 582) of the Handbook. Patients should wait at least 10 minutes before reinserting contact lenses to prevent soft lenses from absorbing the preservative benzalkonium chloride.2

 Safety Considerations  Ketotifen may cause the side effects listed below.7 If any of these symptoms are severe or do not go away, the patient should be advised to consult a primary care provider.


    According to clinical studies, conjunctival infection, headaches, and rhinitis (incidence, 10%-25%) were the adverse effects associated mostly commonly with use of ketotifen. The majority of cases were mild, with some resembling the underlying condition being treated. Adverse effects that occurred at a rate of less than 5% included allergic reactions, burning/stinging, conjunctivitis, discharge, dry eyes, eye pain, eyelid disorder, itching, keratitis, lacrimation disorder, mydriasis, photophobia, and rash.2 Patients should be advised to discontinue treatment and contact their primary care provider if they experience eye pain, changes in vision, or redness in the eye, or if itching worsens or extends beyond a 72-hour period.6
    Contraindications include sensitivity to any ingredients in the product and use in contact lens–related irritation. Solutions that have changed color or become cloudy should not be used.6


References

  1. US Food and Drug Administration, Center for Drug Evaluation and Research. Rx-to-OTC switch list. Available at: http://www.fda.gov/CDER/Offices/OTC/rx-to-otc.htm. Accessed June 26, 2007.     

  2. Medscape Today. FDA approvals: FluMist and Alaway. Available at: http://www.medscape.com/viewarticle/550649. Accessed June 26, 2007.     

  3. Novartis Pharmaceuticals Corporation. About Zaditor® eye drops. Available at: http://www.zaditor.com/index.jsp. Accessed June 26, 2007.

  4. D’Arienzo PA, Leonardi A, Bensch G. Randomized, double-masked, placebo-controlled comparison of the efficacy of emedastine difumarate 0.05% ophthalmic solution and ketotifen fumarate 0.025% ophthalmic solution in the human conjunctival allergen challenge model. Clin Ther. 2002;24(3):409-16.
  5. Grenier JV, Minno G. A placebo-controlled comparison of ketotifen fumarate and nedocromil sodium ophthalmic solutions for the prevention of ocular itching with the conjunctival allergen challenge model. Clin Ther. 2003;25(7):1988-2005.     
  6. Zaditor [package insert]. East Hanover, NJ: Novartis Pharmaceuticals Corp; 2006.     
  7. MedlinePlus. Ketotifen, ophthalmic. Available at: http://www.nlm.nih.gov/medlineplus/druginfo/medmaster/a604033.html. Accessed June 26, 2007.