INDICATIONS AND USAGE
COMBIGAN® (brimonidine tartrate/timolol maleate ophthalmic solution) 0.2%/0.5% is an
alpha-adrenergic receptor agonist with a beta-adrenergic receptor inhibitor indicated for the reduction of elevated intraocular pressure (IOP) in patients with glaucoma or ocular hypertension who require adjunctive or replacement therapy due to inadequately controlled IOP; the IOP-lowering of COMBIGAN® dosed twice a day was slightly less than that seen with the concomitant administration of 0.5% timolol maleate ophthalmic solution dosed twice a day and 0.2% brimonidine tartrate ophthalmic solution dosed three times per day.
IMPORTANT SAFETY INFORMATION
COMBIGAN® is contraindicated in patients with reactive airway disease including bronchial asthma; a history of bronchial asthma; severe chronic obstructive pulmonary disease; in patients with sinus bradycardia; second or third degree atrioventricular block; overt cardiac failure; cardiogenic shock; in neonates and infants (aged 2 years and younger); in patients with a hypersensitivity reaction to any component of COMBIGAN® in the past.
WARNINGS AND PRECAUTIONS
COMBIGAN® contains timolol maleate. COMBIGAN® is administered topically, but can be absorbed systemically. The adverse reactions with systemic administration of beta-adrenergic blocking agents may occur with topical use (eg, severe respiratory reactions and cardiac reactions, including death due to bronchospasm in patients with asthma, and rarely death in association with cardiac failure, have been reported with systemic or ophthalmic administration of timolol maleate). Ophthalmic beta-blockers may impair compensatory tachycardia and increase risk of hypotension.
Sympathetic stimulation may be essential to support the circulation in patients with diminished myocardial contractility, and its inhibition by beta-adrenergic receptor blockade may precipitate more severe failure. In patients with no history of cardiac failure, continued depression of the myocardium with beta-blocking agents over time can lead to cardiac failure. Discontinue COMBIGAN® at the first sign or symptom of cardiac failure.
Patients with chronic obstructive pulmonary disease (eg, chronic bronchitis, emphysema) of mild or moderate severity, bronchospastic disease, or a history of bronchospastic disease should not receive beta-blocking agents, including COMBIGAN®.
COMBIGAN® may potentiate syndromes associated with vascular insufficiency. Use caution in patients with depression, cerebral or coronary insufficiency, Raynaud's phenomenon, orthostatic hypotension, or thromboangiitis obliterans.
Patients taking beta-blockers with a history of atopy or severe anaphylactic reactions to a variety of allergens may be more reactive to repeated accidental, diagnostic, or therapeutic challenge with such allergens. Such patients may be unresponsive to the usual doses of epinephrine used to treat anaphylactic reactions.
Beta-adrenergic blockade can potentiate muscle weakness with myasthenic symptoms (eg, diplopia, ptosis, and generalized weakness). Although rare, timolol can increase muscle weakness in some patients with myasthenia gravis or myasthenic symptoms.
Beta-adrenergic receptor blocking agents may mask the signs and symptoms of acute hypoglycemia and clinical signs (eg, tachycardia) of hyperthyroidism. Use caution in patients subject to spontaneous hypoglycemia or in diabetic patients (especially those with labile diabetes) who are receiving insulin or oral hypoglycemic agents. Carefully manage patients who may develop thyrotoxicosis to avoid abrupt withdrawal of beta-adrenergic blocking agents that might precipitate a thyroid storm.
Ocular hypersensitivity has occurred with brimonidine tartrate ophthalmic solutions 0.2% (eg, increase in IOP).
Some authorities recommend gradual withdrawal of beta-adrenergic receptor blocking agents due to impairment of beta-adrenergically mediated reflexes during surgery. If necessary during surgery, the effects of beta-adrenergic blocking agents may be reversed by sufficient doses of adrenergic agonists.
The most frequent reactions with COMBIGAN® in about 5% to 15% of patients included: allergic conjunctivitis, conjunctival folliculosis, conjunctival hyperemia, eye pruritus, ocular burning, and stinging.
COMBIGAN® may reduce blood pressure. Use caution in patients on antihypertensives and/or cardiac glycosides.
Observe patients receiving a beta-adrenergic blocking agent either orally or intravenously and COMBIGAN® for additive effects of beta-blockade, both systemic and on intraocular pressure. Concomitant use of two topical beta-adrenergic blocking agents is not recommended.
Use caution in the co-administration of beta-adrenergic blocking agents (eg, COMBIGAN®) and oral or intravenous calcium antagonists due to possible atrioventricular conduction disturbances, left ventricular failure, and hypotension. Avoid co-administration in patients with impaired cardiac function.
Observe patients closely when a beta-blocker is administered to patients receiving catecholamine-depleting drugs (eg, reserpine) due to possible additive effects and the production of hypotension and/or marked bradycardia, which may result in vertigo, syncope, or postural hypotension.
Specific drug interaction studies have not been conducted with COMBlGAN®, but consider the possibility of an additive or potentiating effect with CNS depressants (alcohol, barbiturates, opiates, sedatives, or anesthetics).
Concomitant use of beta-adrenergic blocking agents with digitalis and calcium antagonists may have additive effects in prolonging atrioventricular conduction time.
Potentiated systemic beta-blockade (eg, decreased heart rate, depression) has been reported with combined use of CYP2D6 inhibitors (eg, quinidine, SSRls) and timolol.
Tricyclic antidepressants (TCAs) can blunt the hypotensive effect of systemic clonidine. It is not known whether the concurrent use of TCAs with COMBIGAN® in humans can interfere with the IOP-lowering effect. Caution is advised in patients taking TCAs, which can affect the metabolism and uptake of circulating amines.
Monoamine oxidase (MAO) inhibitors may theoretically interfere with the metabolism of brimonidine and potentially increase systemic side effects such as hypotension. Use caution in patients taking MAO inhibitors, which can affect the metabolism and uptake of circulating amines.
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