Open AccessEfficacy and systemic side‐effects of topical 0.5% timolol aqueous solution and 0.1% timolol hydrogel
Author(s) -
Uusitalo Hannu,
Niño Juanita,
Tahvanainen Kari,
Turjanmaa Väinö,
Ropo Auli,
Tuominen Juhani,
Kähönen Mika
Publication year - 2005
Publication title -
acta ophthalmologica scandinavica
Language(s) - English
Resource type - Journals
eISSN - 1600-0420
pISSN - 1395-3907
DOI - 10.1111/j.1600-0420.2005.00562.x
Subject(s) - timolol , medicine , intraocular pressure , anesthesia , crossover study , pharmacokinetics , dose , bioavailability , ocular hypertension , heart rate , blood pressure , pharmacology , ophthalmology , alternative medicine , pathology , placebo
. Purpose: The objective of this randomized, double‐blind, controlled crossover trial was to compare 0.1% timolol hydrogel formulation eyedrops with 0.5% timolol aqueous solution in terms of systemic effects, hypotensive efficacy and pharmacodynamics.Methods: Twenty‐four healthy subjects underwent careful ocular, cardiovascular and pulmonary function evaluation before and after 2 weeks of topical treatment with 0.1% timolol hydrogel or 0.5% aqueous timolol maleate. Intraocular pressure (IOP), heart rate, blood pressure, forced expiratory volume and plasma levels of timolol were measured.Results: There was a statistically significant difference in the systemic absorption of timolol between these two ophthalmic timolol solutions. The peak concentration and mean area under the plasma drug concentration−time curve (AUC) were about 10‐fold higher after 0.5% timolol aqueous solution. The mean peak heart rate during exercise was reduced by 19 bpm (SD 6.4 bpm) after 0.5% timolol aqueous solution and by only 4.6 bpm (SD 3.8 bpm) after 0.1% timolol hydrogel (p < 0.0001). There was no difference between the two formulations in efficacy in reducing IOP. No differences between treatments were found in respect of pulmonary function.Conclusions: The lower timolol concentration in the hydrogel vehicle and its better bioavailability resulted in reduced systemic absorption and side‐effects without loss of efficacy.