Systemic Absorption and Safety of Topical Timolol for Chronic Wounds

Background: Chronic wounds pose a major challenge on the health care system, with rising costs and associated morbidities. Better understanding of chronic wound biology and the advancement of technology have led to the use of an array of wound care therapies, including the off-label application of topical timolol for healing chronic wounds. 

Timolol is a non-selective, beta1/beta2 adrenergic receptor antagonist well established for the treatment of glaucoma.  Clinical experience has broadened its use for a number of dermatologic indications such as infantile hemangiomas and recently chronic wounds. Although systemic absorption and safety studies have been performed for the ocular administration, to date no studies have documented absorption of timolol post application to chronic wounds.  

Purpose: Thus, a single center, open label, prospective, observational, cross-sectional comparative study was conducted to determine the blood plasma levels of timolol in patients after topical administration to a chronic wound, compared to those after ocular topical administration of the same drug formulation for glaucoma treatment. This study received approval from the Institutional Review Board of the VA Northern California Health Care System. 

Methods: There were a total of 40 patients enrolled in the study that met inclusion criteria, 20 in each group diagnosed with either a chronic wound or glaucoma.

Results: The findings showed that there was no statistical significance in the average plasma level of timolol between the 2 groups, those with wounds and glaucoma. There were no cardiac or respiratory adverse events reported.

Conclusion: Therefore, topical timolol for the use in chronic wounds may be safely applied in patients who have no contraindications, as an adjunctive therapy for chronic wounds with little potential for cardiac effects of systemic beta adrenergic receptor blockade.