warnings and cautions
5 WARNINGS AND PRECAUTIONS • Potentiation of Respiratory Reactions Including Asthma ( 5.1 ) • Cardiac Failure ( 5.2 ) • Sulfonamide Hypersensitivity ( 5.3 ) • Obstructive Pulmonary Disease ( 5.4 ) • Increased Reactivity to Allergens ( 5.5 ) • Potentiation of Muscle Weakness ( 5.6 ) • Masking of Hypoglycemic Symptoms in Patients with Diabetes Mellitus ( 5.7 ) • Masking of Thyrotoxicosis ( 5.8 ) • Renal and Hepatic Impairment ( 5.9 ) • Impairment of Beta-Adrenergically Mediated Reflexes During Surgery ( 5.10 ) 5.1 Potentiation of Respiratory Reactions Including Asthma Dorzolamide hydrochloride and timolol maleate ophthalmic solution contains timolol maleate, a beta-adrenergic blocking agent; and although administered topically, is absorbed systemically. Therefore, the same types of adverse reactions that are attributable to systemic administration of beta-adrenergic blocking agents may occur with topical administration. For example, severe respiratory reactions, 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 [see Contraindications (4.1) ]. 5.2 Cardiac Failure Sympathetic stimulation may be essential for support of the circulation in individuals with diminished myocardial contractility, and its inhibition by beta-adrenergic receptor blockade may precipitate more severe failure. In patients without a history of cardiac failure continued depression of the myocardium with beta-blocking agents over a period of time can, in some cases, lead to cardiac failure. At the first sign or symptom of cardiac failure, dorzolamide hydrochloride and timolol maleate ophthalmic solution should be discontinued [see Contraindications (4.2) ]. 5.3 Sulfonamide Hypersensitivity Dorzolamide hydrochloride and timolol maleate ophthalmic solution contains dorzolamide, a sulfonamide; and although administered topically, it is absorbed systemically. Therefore, the same types of adverse reactions that are attributable to sulfonamides may occur with topical administration of dorzolamide hydrochloride and timolol maleate ophthalmic solution. Fatalities have occurred, although rarely, due to severe reactions to sulfonamides including Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic ...