Istalol is a once-daily beta-blocking agent for the treatment of elevated intraocular pressure for your patients with ocular hypertension or open-angle glaucoma.1  

The starting dose is one drop of 0.5% Istalol in the affected eye(s) once a day in the morning.1 If a patient's IOP is not at a satisfactory level on one drop of 0.5%/day, Istalol may be used as concomitant therapy with other agent(s), like a prostaglandin, which has demonstrated better efficacy when dosed in the evening.3 Timolol is a beta blocker and studies have suggested that its predominant action may be related to reduced aqueous humour production,1 which is mostly produced in the morning hours.The concomitant use of two topical beta-adrenergic blocking agents is not recommended. By adding Istalol to a patient who needs more IOP control and who is already on a PG, you can add a once-daily drug for the right patient at the right time.4

Clinical Study

In a well controlled, double-masked, parallel study of 332 patients with untreated intraocular pressures of 22 mm Hg or greater, Istalol administered once daily (AM) was equivalent to timolol maleate oph­thalmic solution 0.5% administered twice daily.1 In both groups, mean intraocular pressure decreased from 25 mm Hg at baseline to 18 mm Hg at peak and 19 mm Hg at trough.1 3% of Istalol patients discontinued use due to adverse events over a 12 month period.

The safety and efficacy of timolol solution once-daily formulations added to latanoprost as adjunctive therapy was studied in a multicenter, randomized study (N=30). As adjunctive therapy, timolol maleate once daily demonstrated a 14% reduction from baseline in trough IOP and a 19% reduction from baseline in peak IOP when added to latanoprost 0.005% QD at Week 6 (N=30).4





ISTALOL (timolol maleate ophthalmic solution) is a non-selective beta-adrenergic receptor blocking agent indicated in the treatment of elevated intraocular pressure in patients with ocular hypertension or open-angle glaucoma. 



Important Safety Information 

ISTALOL (timolol maleate ophthalmic solution) is contraindicated in patients with: bronchial asthma; a history of bronchial asthma; severe chronic obstructive pulmonary disease; sinus bradycardia; second or third degree atrioventricular block; overt cardiac failure; cardiogenic shock; hypersensitivity to any component of the product.  





The same adverse reactions found with systemic administration of beta-adrenergic blocking agents may occur with topical administration.  Severe respiratory reactions and cardiac reaction, including death due to bronchospasm in patients with asthma, and rarely death in association with cardiac failure, have been reported following systemic or ophthalmic administration of timolol maleate.  

Patients with a history of atopy or severe anaphylactic reactions to a variety of allergens may be unresponsive to the usual doses of epinephrine used to treat anaphylactic reactions. 

Timolol has been reported rarely to increase muscle weakness in some patients with myasthenia gravis or myasthenic symptoms. 





Beta-adrenergic blocking agents may mask signs and symptoms of acute hypoglycemia or certain clinical signs of hyperthyroidism. Patients subject to spontaneous hypoglycemia, or diabetic patients receiving either insulin or oral hypoglycemic agents, or patients suspected of developing thyrotoxicosis, should be managed carefully, with caution. 

The most frequently reported adverse reactions have been burning and stinging upon instillation in 38% of patients treated with ISTALOL. Additional reactions reported with ISTALOL at a frequency of 4 to 10% include: blurred vision, cataract, conjunctival injection, headache, hypertension, infection, itching and decreased visual acuity. 





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Istalol [package insert]. 
2 Brubaker R. Flow of aqueous humor in humans. IOVS. 1991;32:(13)3145-3166.
3 Alm A. Stjernschantz J. Effects on intraocular pressure and side effects of 0.005% latanoprost applied once daily, evening or morning. Ophthalmology. 1995;102:1743-1752.
4 Stewart W, Day DG, Sharpe ED. Efficacy and Safety of Timolol Solution Once Daily vs Timolol Gel Added to Latanoprost. Am J Ophthalmol. 1999;128(6)692-696.



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