Lord Alfred Tennyson wrote, “In the spring, a young man’s fancy lightly turns to thoughts of love,” and an optometrist’s thoughts turn to…ocular allergy. The product selection has definitely improved since the old four-times-a-day antihistamine/decongestants. We are always looking for better products to care for our patients, and a major ophthalmic pharmaceutical company has a new entry in the ocular allergy toolbox.

A New Chemical Entity
Lastacaft (alcaftadine ophthalmic solution 0.25%, Allergan) is a once-daily histamine receptor antagonist indicated for the prevention of itching associated with allergic conjunctivitis. According to the manufacturer, the active ingredient of alcaftadine is a new chemical entity with an affinity for H1—a histamine receptor in the early phase of allergic conjunctivitis.2 Alcaftadine is a mixed mechanism antihistamine that acts as an H1, H2 and H4 antagonist. H4 receptor antagonists may have therapeutic use for treating pruritic diseases, where histamine H1 receptor antagonists are not effective for pruritis.2 Alcaftadine has also demonstrated decreased chemotaxis and inhibition of eosinophil activation.

Relative tolerability, or comfort, of the alcaftadine ophthalmic solution was assessed in two double-masked, randomized, placebo-controlled, contralateral studies in which formulations were compared to a placebo (Tears Naturale II, Alcon) in normal adult subjects. Over a range of formulations and concentrations (0.05% to 0.5%), alcaftadine was well tolerated and subjects reported little or no discomfort or taste perversion in any treatment group. Topical administration of alcaftadine 0.25% ophthalmic solution was well tolerated and had an acceptable safety profile.3

In another study, clinical efficacy was evaluated in conjunctival allergen challenge (CAC) studies.4 Alcaftadine was effective in the prevention of ocular itching based on both clinically relevant and statistically significant differences, compared with the vehicle (placebo). Alcaftadine significantly reduced conjunctival redness, and almost all other allergic signs and symptoms, at both 15 minutes and 16 hours after drug administration. No significant safety issues were reported. Between-group differences in ocular itching were higher at 16 hours after drug administration than at 15 minutes after drug administration.4

Lastacaft is FDA approved for dosing once daily in patients aged two years and older. No overall differences in safety or effectiveness were observed between elderly and younger subjects. The safety of Lastacaft was evaluated in a randomized clinical study of 909 subjects over a period of six weeks.1

The most frequent ocular adverse reactions—occurring in less than 3% of Lastacaft-treated eyes—were eye irritation, burning and/or stinging upon instillation, eye redness and eye pruritus. The most frequent non-ocular adverse reactions—occurring in less than 3% of subjects with Lastacaft-treated eyes—were nasopharyngitis, headache and influenza.1 Some of these events were similar to the underlying disease being studied.

Patients should be advised that this medication should not be used to treat contact lens-related irritation. Patients should also be advised to remove contact lenses prior to instillation of Lastacaft. The preservative in Lastacaft, benzalkonium chloride 0.005%, may be absorbed by soft contact lenses. Lenses may be reinserted after 10 minutes following administration of Lastacaft.

This medication is in the FDA Pregnancy Category B. Reproduction studies performed in rats and rabbits revealed no evidence of impaired female reproduction or harm to the fetus due to alcaftadine.

Lastacaft is supplied in an opaque, white, low-density polyethylene bottle with a white polypropylene cap. There is 3mL of the medication in a 5mL bottle.

With an onset of action within three minutes, combined with duration of action of at least 16 hours, the statistically and clinically significant effect of alcaftadine 0.25% on itching make it an important addition to therapy for ocular allergy.   

1. Allergan, Inc. Lastacaft Prescribing Information.
2. Dunford PJ, Williams KN, Desai PJ, et al. Histamine H4 receptor antagonists are superior to traditional antihistamines in the attenuation of experimental pruritus. J Allergy Clin Immunol. 2007 Jan;119(1):176-83.
3. Bohets H, McGowan C, Mannens G, et al. Clinical Pharmacology of Alcaftadine, a Novel Antihistamine for the Prevention of Allergic Conjunctivitis. J Ocul Pharmacol Ther. 2011 Feb. [Epub ahead of print]
4. Torkildsen G, Shedden A. The safety and efficacy of alcaftadine 0.25% ophthalmic solution for the prevention of itching associated with allergic conjunctivitis. Curr Med Res Opin. 2011 Mar;27(3):623-31.