Ketotifen is an antihistamine and mast cell stabilizer that has been used in medicine for nearly 50 years. It is available in the FDA-approved form of an ophthalmic solution (topically administered to the eyes). In this form it is indicated to be used for reduction of eye itching associated with seasonal allergies. Besides this indication, doctors through the world prescribe ketotifen for managing other conditions like nasal allergies, irritable bowel syndrome, atopic dermatitis, food allergy, mast cell activation syndrome, and more. Recent research shows that ketotifen may effectively be used as a nasal spray for treating seasonal allergies affecting the nasal passages and sinuses.

Oral Form of Ketotifen

While not available in the United States in an FDA approved form, ketotifen can be made by a compounding pharmacy in capsules for oral use. This form of the drug is often prescribed for treating allergies and mast cell activation syndrome. A typical side effect is mild sedation in 10-20% of patients, although this side effect decreases after a week or two of use.

One use of oral ketotifen has been in treating patients with chronic obstructive pulmonary disease (COPD). Ketotifen inhibits the release of histamine by bronchial mast cells, which decreases inflammation. A study found that ketotifen combined with singulair may be an effective treatment for patients with COPD and airway hyperresponsiveness (AHR). Researchers concluded that this combination, “can significantly improve the curative effect, improve the lung function of patients, reduce the inflammatory response, and improve the Th17/Treg balance, and effectively control the disease.”

Oral ketotifen has been studied as a possible treatment for melasma. Upper dermal mast cells are more prevalent in skin that has been overexposed to the sun. These mast cells are also more prominent in skin that is affected by melasma than in surrounding skin. One theory is that by stabilizing these mast cells, it may be possible to reduce the visible changes in the skin that occur with melasma. Small studies have shown this possible application of ketotifen warrants further research.

Intranasal Ketotifen

In a study of 96 patients with allergic rhinitis (nasal allergy symptoms) it was found that ketamine and budesonide combined in a nasal spray was effective. After treatment, symptoms of allergic rhinitis were reduced including itching, sneezing, and runny nose.

Studies have compared the use of intranasal drops with oral ketotifen and found that the nasal drops are more effective at reducing allergic rhinitis than the oral form. In a study of 140 patients, one group was given nasal ketotifen with an oral placebo and the other group was given a nasal placebo with oral ketotifen. Both groups experienced an improvement in their symptoms including nasal congestion, nasal itching, coughing, and sneezing.

The safety of intranasal ketotifen was examined in vitro and researchers concluded: “Ketotifen is neither ciliotoxic nor ciliostimulatory, and no long-term cellular toxicity was observed.” Cilotoxicity refers to toxic effects on the mucous membrane cilia of the respiratory system. Cilia are small hair-like structures that have a few different functions including removing mucus and dirt from the respiratory system.  The research basically concluded that there are no negative effects on the essential functioning of the nose after intranasal use.

Intranasal ketotifen is actually available commercially in other countries as an OTC nasal spray. In Japan, for example, ketotifen 0.05% nasal solution is sold as Zaditen. Capsules, syrup, nasal drops, and eye drops are also available in Japan. In the United States, the nasal spray form must be made by a compounding pharmacy.

Articles

Combination treatment of allergic rhinitis using ketotifen fumarate and budesonide administered as nasal sprays – International Journal of Clinical Pharmacology and Therapeutics

In vitro safety of ketotifen as a topical nasal rinse – Allergy & Rhinology

Ketotifen in the management of chronic urticaria: resurrection of an old drug – Annals of Allergy, Asthma & Immunology

Oral ketotifen associated with famotidine for the treatment of facial melasma: a randomized, double-blind, placebo-controlled trial – Journal of the European Academy of Dermatology & Venereology

Comparing the effects of ketotifen fumarate eye drops and ketotifen oral pills on symptom severity and quality of life in patients with allergic rhinitis: a double-blind randomized clinical trial – International Forum of Allergy & Rhinology

Observation of the Effect of Singulair Combined With Ketotifen in the Treatment of Acute Exacerbation of Chronic Obstructive Pulmonary Disease With Airway Hyperresponsiveness and Its Influence on Th17/Treg – Frontiers in Surgery