Blood Level of Tacrolimus in Patients with Severe Allergic Conjunctivitis Treated by 0.1% Tacrolimus Ophthalmic Suspension

Background: To estimate the efficacy and safety of 0.1% tacrolimus ophthalmic suspension based on the blood level of tacrolimus in patients with severe allergic conjunctivitis. Methods: Fifty-two patients in whom topical anti-allergic agents had been ineffective were treated with 0.1% tacrolimus ophthalmic suspension twice daily for 12 weeks. Adverse drug reactions were monitored, as well as ocular symptoms and signs. The blood concentration of tacrolimus was measured before the initiation of treatment and 4 and 12 weeks later. Results: About 75% of the patients without concomitant using of tacrolimus ointment had blood levels of tacrolimus below the detection limit of the assay (0.5 ng/mL). On the other hand, 71% (week 4) and 57% (week 12) of patients with concomitant using of tacrolimus ointment had blood levels above the detection limit of the assay. However, the maximum blood concentration was less than 2 ng/mL. Adverse drug reactions occurred in 16 patients. These were disorders of the eye such as warmness, irritation, and a burning sensation. However, all of the patients could continue treatment with tacrolimus for 12 weeks. There were no serious adverse events such as increased intraocular pressure or ocular infection during the study. All symptoms and signs improved over time. Conclusions: The good safety profile of 0.1% tacrolimus ophthalmic suspension based on the low blood concentration of tacrolimus, coupled with demonstrated efficacy, make it an important tool for treating severe allergic conjunctivitis.