Brimonidine Tartrate and Timolol Maleate

Brimonidine Tartrate/Timolol Maleate Ophthalmic Solution, 0.2%/0.5% is 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 brimonidine tartrate/timolol maleate ophthalmic solution 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. Brimonidine Tartrate/Timolol Maleate Ophthalmic Solution is a combination of brimonidine tartrate, an alpha-adrenergic receptor agonist, and timolol maleate, 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 brimonidine tartrate/timolol maleate ophthalmic solution dosed twice a day was slightly less than that seen with the concomitant administration of timolol maleate ophthalmic solution, 0.5% dosed twice a day and brimonidine tartrate ophthalmic solution, 0.2% dosed three times per day.

Ophthalmic solution containing 0.2% brimonidine tartrate and 0.5% timolol (6.834 mg/mL timolol maleate). Ophthalmic Solution: 0.2% brimonidine tartrate and 0.5% timolol.

Bronchial asthma, a history of bronchial asthma, severe chronic obstructive pulmonary disease. ( 4.1 , 5.1 , 5.3 ) Sinus bradycardia, atrioventricular block, overt cardiac failure, cardiogenic shock. ( 4.2 , 5.2 ) Neonates and infants (pediatric patients younger than 2 years old). ( 4.3 ) Hypersensitivity to any component of this product. ( 4.4 )

4.1 Reactive Airway Disease Including Asthma, COPD Brimonidine tartrate/timolol maleate ophthalmic solution is contraindicated in patients with reactive airway disease including bronchial asthma; a history of bronchial asthma; severe chronic obstructive pulmonary disease [see Warnings and Precautions ( 5.1 , 5.3 )] .

4.2 Sinus Bradycardia, AV Block, Cardiac Failure, Cardiogenic Shock Brimonidine tartrate/timolol maleate ophthalmic solution is contraindicated in patients with sinus bradycardia; second or third degree atrioventricular block; overt cardiac failure [see Warnings and Precautions ( 5.2 )] ; cardiogenic shock.

4.3 Neonates and Infants (Pediatric Patients Younger Than 2 Years Old) Brimonidine tartrate/timolol maleate ophthalmic solution is contraindicated in neonates and infants (pediatric patients younger than 2 years old) [see Use in Specific Populations ( 8.4 )] .

4.4 Hypersensitivity Reactions Local hypersensitivity reactions have occurred following the use of different components of brimonidine tartrate/timolol maleate ophthalmic solution. Brimonidine tartrate/timolol maleate ophthalmic solution is contraindicated in patients who have exhibited a hypersensitivity reaction to any component of this medication in the past.

Potential for Severe Respiratory or Cardiac Reactions ( 5.1 ) Cardiac Failure ( 5.2 ) Obstructive Pulmonary Disease ( 5.3 ) Potentiation of Vascular Insufficiency ( 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 ) Ocular Hypersensitivity ( 5.9 )

5.1 Potential for Severe Respiratory or Cardiac Reactions Brimonidine tartrate/timolol maleate ophthalmic solution contains timolol maleate; and although administered topically can be absorbed systemically. Therefore, the same types of adverse reactions found with systemic administration of beta-adrenergic blocking agents may occur with topical administration. For example, 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 following systemic or ophthalmic administration of timolol maleate [see Contraindications ( 4.1 )] . Additionally, ophthalmic beta-blockers may impair compensatory tachycardia and increase risk of hypotension.

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, brimonidine tartrate/timolol maleate ophthalmic solution should be discontinued [see Contraindications ( 4.2 )] .

5.3 Obstructive Pulmonary Disease Patients with chronic obstructive pulmonary disease (e.g., chronic bronchitis, emphysema) of mild or moderate severity, bronchospastic disease, or a history of bronchospastic disease (other than bronchial asthma or a history of bronchial asthma, in which brimonidine tartrate/timolol maleate ophthalmic solution is contraindicated [see Contraindications ( 4.1 )] ) should, in general, not receive beta-blocking agents, including brimonidine tartrate/timolol maleate ophthalmic solution.

5.4 Potentiation of Vascular Insufficiency Brimonidine tartrate/timolol maleate ophthalmic solution may potentiate syndromes associated with vascular insufficiency. Brimonidine tartrate/timolol maleate ophthalmic solution should be used with caution in patients with depression, cerebral or coronary insufficiency, Raynaud’s phenomenon, orthostatic hypotension, or thromboangiitis obliterans.

5.5 Increased Reactivity to Allergens While taking beta-blockers, patients with a history of atopy or a history of 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.

5.6 Potentiation of Muscle Weakness Beta-adrenergic blockade has been reported to potentiate muscle weakness consistent with certain myasthenic symptoms (e.g., diplopia, ptosis, and generalized weakness). Timolol has been reported rarely to increase muscle weakness in some patients with myasthenia gravis or myasthenic symptoms.

5.7 Masking of Hypoglycemic Symptoms in Patients with Diabetes Mellitus Beta-adrenergic blocking agents should be administered with caution in patients subject to spontaneous hypoglycemia or to diabetic patients (especially those with labile diabetes) who are receiving insulin or oral hypoglycemic agents. Beta-adrenergic receptor blocking agents may mask the signs and symptoms of acute hypoglycemia.

5.8 Masking of Thyrotoxicosis Beta-adrenergic blocking agents may mask certain clinical signs (e.g., tachycardia) of hyperthyroidism. Patients suspected of developing thyrotoxicosis should be managed carefully to avoid abrupt withdrawal of beta-adrenergic blocking agents that might precipitate a thyroid storm.

5.9 Ocular Hypersensitivity Ocular hypersensitivity reactions have been reported with brimonidine tartrate ophthalmic solutions 0.2%, with some reported to be associated with an increase in intraocular pressure [see Contraindications ( 4.4 )].

5.10 Contamination of Topical Ophthalmic Products After Use There have been reports of bacterial keratitis associated with the use of multiple-dose containers of topical ophthalmic products. These containers had been inadvertently contaminated by patients who, in most cases, had a concurrent corneal disease or a disruption of the ocular epithelial surface. Do not touch the tip of the dispensing container to the eye or surrounding structures. Serious damage to the eye and subsequent loss of vision may result from using contaminated solutions [see Patient Counseling Information ( 17 )].

5.11 Impairment of Beta-adrenergically Mediated Reflexes During Surgery The necessity or desirability of withdrawal of beta-adrenergic blocking agents prior to major surgery is controversial. Beta-adrenergic receptor blockade impairs the ability of the heart to respond to beta-adrenergically mediated reflex stimuli. This may augment the risk of general anesthesia in surgical procedures. Some patients receiving beta-adrenergic receptor blocking agents have experienced protracted severe hypotension during anesthesia. Difficulty in restarting and maintaining the heartbeat has also been reported. For these reasons, in patients undergoing elective surgery, some authorities recommend gradual withdrawal of beta-adrenergic receptor blocking agents. If necessary during surgery, the effects of beta-adrenergic blocking agents may be reversed by sufficient doses of adrenergic agonists.

5.12 Contact Lens Use Brimonidine Tartrate/Timolol Maleate Ophthalmic Solution contains benzalkonium chloride which may be absorbed by soft contact lenses. Contact lenses should be removed prior to administration of the solution. Lenses may be reinserted 15 minutes following administration of Brimonidine Tartrate/Timolol Maleate Ophthalmic Solution.

The following serious adverse reactions are described elsewhere in the labeling: Hypersensitivity Reactions [see Contraindications ( 4.4 )] Potential for Severe Respiratory or Cardiac Reactions [see Warnings and Precautions ( 5.1 )] Cardiac Failure [see Warnings and Precautions ( 5.2 )] Potentiation of Vascular Insufficiency [see Warnings and Precautions ( 5.4 )] Increased Reactivity to Allergens [see Warnings and Precautions ( 5.5 )] Potentiation of Muscle Weakness [see Warnings and Precautions ( 5.6 )] Masking of Hypoglycemic Symptoms in Patients with Diabetes Mellitus [see Warnings and Precautions ( 5.7 )] Masking of Thyrotoxicosis [see Warnings and Precautions ( 5.8 )] Ocular Hypersensitivity [see Warnings and Precautions ( 5.9 )] Contamination of Topical Ophthalmic Products after Use [see Warnings and Precautions ( 5.10 )] Impairment of Beta-adrenergically Mediated Reflexes During Surgery [see Warnings and Precautions ( 5.11 )] Most common adverse reactions occurring in approximately 5% to 15% of patients included allergic conjunctivitis, conjunctival folliculosis, conjunctival hyperemia, eye pruritus, ocular burning, and stinging. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Gland Pharma Limited at 866-770-7144 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .

6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Brimonidine Tartrate/Timolol Maleate Ophthalmic Solution In clinical trials of 12 months duration with brimonidine tartrate/timolol maleate ophthalmic solution, the most frequent reactions associated with its use occurring in approximately 5% to 15% of the patients included: allergic conjunctivitis, conjunctival folliculosis, conjunctival hyperemia, eye pruritus, ocular burning, and stinging. The following adverse reactions were reported in 1% to 5% of patients: asthenia, blepharitis, corneal erosion, depression, epiphora, eye discharge, eye dryness, eye irritation, eye pain, eyelid edema, eyelid erythema, eyelid pruritus, foreign body sensation, headache, hypertension, oral dryness, somnolence, superficial punctate keratitis, and visual disturbance. Other adverse reactions that have been reported with the individual components are listed below. Brimonidine Tartrate (0.1% – 0.2%) Abnormal taste, allergic reaction, blepharoconjunctivitis, blurred vision, bronchitis, cataract, conjunctival blanching, conjunctival edema, conjunctival hemorrhage, conjunctivitis, cough, dizziness, dyspepsia, dyspnea, fatigue, flu syndrome, follicular conjunctivitis, gastrointestinal disorder, hypercholesterolemia, hypotension, infection (primarily colds and respiratory infections), hordeolum, insomnia, keratitis, lid crusting, lid disorder, muscular pain, nasal dryness, ocular allergic reaction, pharyngitis, photophobia, rash, rhinitis, sinus infection, sinusitis, superficial punctate keratopathy, tearing, upper respiratory symptoms, visual field defect, vitreous detachment, vitreous disorder, vitreous floaters, and worsened visual acuity. Timolol (Ocular Administration) Body as a whole : chest pain Cardiovascular: Arrhythmia, bradycardia, cardiac arrest, cardiac failure, cerebral ischemia, cerebral vascular accident, claudication, cold hands and feet, edema, heart block, palpitation, pulmonary edema, Raynaud’s phenomenon, syncope, and worsening of angina pectoris Digestive: anorexia, diarrhea, nausea Immunologic: Systemic lupus erythematosus Nervous System/Psychiatric: Increase in signs and symptoms of myasthenia gravis, insomnia, nightmares, paresthesia, behavioral changes and psychic disturbances including confusion, hallucinations, anxiety, disorientation, nervousness, and memory loss Skin: Alopecia, psoriasiform rash or exacerbation of psoriasis Hypersensitivity: Signs and symptoms of systemic allergic reactions, including anaphylaxis, angioedema, urticaria, and generalized and localized rash Respiratory: Bronchospasm (predominantly in patients with pre-existing bronchospastic disease) [see Contraindications ( 4.1 )] , dyspnea, nasal congestion, respiratory failure, upper respiratory infections Endocrine: Masked symptoms of hypoglycemia in diabetes patients [see Warnings and Precautions ( 5.7 )] Special Senses: diplopia, choroidal detachment following filtration surgery, cystoid macular edema, decreased corneal sensitivity, pseudopemphigoid, ptosis, refractive changes, tinnitus Urogenital: Decreased libido, impotence, Peyronie’s disease, retroperitoneal fibrosis

6.2 Postmarketing Experience The following reactions have been identified during postapproval use of brimonidine tartrate ophthalmic solutions, timolol ophthalmic solutions, or both in combination, in clinical practice. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Bradycardia, eyelid erythema extending to the cheek or forehead, hypersensitivity, iritis, keratoconjunctivitis sicca, miosis, nausea, skin reactions (including erythema, rash, and vasodilation), syncope, and tachycardia. Apnea, coma, hypotension, hypothermia, hypotonia, lethargy, pallor, respiratory depression, and somnolence have been reported in infants receiving brimonidine tartrate ophthalmic solutions [see Contraindications ( 4.3 ) and Use in Specific Populations ( 8.4 )] . Oral Timolol/Oral Beta-blockers The following additional adverse reactions have been reported in clinical experience with ORAL timolol maleate or other ORAL beta-blocking agents and may be considered potential effects of ophthalmic timolol maleate: Allergic: Erythematous rash, fever combined with aching and sore throat, laryngospasm with respiratory distress Body as a whole: Decreased exercise tolerance, extremity pain, weight loss Cardiovascular: Vasodilatation, worsening of arterial insufficiency Digestive: Gastrointestinal pain, hepatomegaly, ischemic colitis, mesenteric arterial thrombosis, vomiting Hematologic: Agranulocytosis, nonthrombocytopenic purpura, thrombocytopenic purpura Endocrine: Hyperglycemia, hypoglycemia; Skin: Increased pigmentation, pruritus, skin irritation, sweating Musculoskeletal: Arthralgia Nervous System/Psychiatric: An acute reversible syndrome characterized by disorientation for time and place, decreased performance on neuropsychometrics, diminished concentration, emotional lability, local weakness, reversible mental depression progressing to catatonia, slightly clouded sensorium, vertigo Respiratory: Bronchial obstruction, rales Urogenital: Urination difficulties.

Antihypertensives/cardiac glycosides may lower blood pressure. ( 7.1 ) Concomitant use with systemic beta-blockers may potentiate systemic beta-blockade. ( 7.2 ) Oral or intravenous calcium antagonists may cause atrioventricular conduction disturbances, left ventricular failure, and hypotension. ( 7.3 ) Catecholamine-depleting drugs may have additive effects and produce hypotension and/or marked bradycardia. ( 7.4 ) Use with CNS depressants may result in an additive or potentiating effect. ( 7.5 ) Digitalis and calcium antagonists may have additive effects in prolonging atrioventricular conduction time. ( 7.6 ) CYP2D6 inhibitors may potentiate systemic beta-blockade. ( 7.7 ) Tricyclic antidepressants may potentially blunt the hypotensive effect of systemic clonidine. ( 7.8 ) Monoamine oxidase inhibitors may result in increased hypotension. ( 7.9 )

7.1 Antihypertensives/Cardiac Glycosides Because brimonidine tartrate/timolol maleate ophthalmic solution may reduce blood pressure, caution in using drugs such as antihypertensives and/or cardiac glycosides with brimonidine tartrate/timolol maleate ophthalmic solution is advised.

7.2 Beta-adrenergic Blocking Agents Patients who are receiving a beta-adrenergic blocking agent either orally or intravenously and brimonidine tartrate/timolol maleate ophthalmic solution should be observed for potential additive effects of beta-blockade, both systemic and on intraocular pressure. The concomitant use of two topical beta-adrenergic blocking agents is not recommended.

7.3 Calcium Antagonists Caution should be used in the co-administration of beta-adrenergic blocking agents, such as brimonidine tartrate/timolol maleate ophthalmic solution, and oral or intravenous calcium antagonists because of possible atrioventricular conduction disturbances, left ventricular failure, and hypotension. In patients with impaired cardiac function, co-administration should be avoided.

7.4 Catecholamine-depleting Drugs Close observation of the patient is recommended when a beta blocker is administered to patients receiving catecholamine-depleting drugs such as reserpine, because of possible additive effects and the production of hypotension and/or marked bradycardia, which may result in vertigo, syncope, or postural hypotension. 7.5 CNS Depressants Although specific drug interaction studies have not been conducted with brimonidine tartrate/timolol maleate ophthalmic solution, the possibility of an additive or potentiating effect with CNS depressants (alcohol, barbiturates, opiates, sedatives, or anesthetics) should be considered.

7.6 Digitalis and Calcium Antagonists The concomitant use of beta-adrenergic blocking agents with digitalis and calcium antagonists may have additive effects in prolonging atrioventricular conduction time. 7.7 CYP2D6 Inhibitors Potentiated systemic beta-blockade (e.g., decreased heart rate, depression) has been reported during combined treatment with CYP2D6 inhibitors (e.g., quinidine, SSRIs) and timolol.

7.8 Tricyclic Antidepressants Tricyclic antidepressants have been reported to blunt the hypotensive effect of systemic clonidine. It is not known whether the concurrent use of these agents with brimonidine tartrate/timolol maleate ophthalmic solution in humans can lead to resulting interference with the IOP-lowering effect. Caution, however, is advised in patients taking tricyclic antidepressants which can affect the metabolism and uptake of circulating amines.

7.9 Monoamine Oxidase Inhibitors Monoamine oxidase (MAO) inhibitors may theoretically interfere with the metabolism of brimonidine and potentially result in an increased systemic side effect such as hypotension. Caution, however, is advised in patients taking MAO inhibitors which can affect the metabolism and uptake of circulating amines.

Use with caution in pediatric patients aged 2 years and older. ( 8.4 )

8.1 Pregnancy Risk Summary There are no adequate and well-controlled studies with brimonidine tartrate/timolol maleate ophthalmic solution in pregnant women. Limited available data from postmarketing safety reports and published literature reviews with brimonidine tartrate/timolol maleate ophthalmic solution use in pregnant women are insufficient to establish a drug-associated risk of major birth defects, miscarriage or other adverse maternal or fetal outcomes (see Data) . In animal studies, brimonidine crossed the placenta and entered into the fetal circulation to a limited extent. Oral administration of brimonidine tartrate or timolol maleate to pregnant rats and rabbits during organogenesis at dose exposures 580 and 37 times the recommended human ophthalmic dose (RHOD) resulted in no adverse developmental effects (see Data) . Oral administration of timolol maleate to mice, rats, and rabbits during organogenesis at dose exposures up to 4,200 times the RHOD resulted in no evidence of fetal malformations (see Data) . The estimated background risk of major birth defects and miscarriage for the indicated population(s) is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. Data Human Data Limited available data from postmarketing safety reports and published literature with topical use of brimonidine ophthalmic solution in pregnant women are insufficient to inform a drug-associated risk of pregnancy-related adverse outcomes including miscarriage, stillbirth, congenital anomaly, and events experienced by the breastfed infant. Animal Data Embryo fetal development studies were conducted with oral administration of brimonidine tartrate during organogenesis in rats (gestation days 6 to 15) and rabbits (gestation days 6 to 18). No adverse developmental effects were observed in rats up to 2.5 mg/kg/day and rabbits up to 5 mg/kg/day. These doses represent exposures 580 and 37 times higher, respectively, than the recommended human ophthalmic dose (RHOD) of brimonidine tartrate/timolol maleate ophthalmic solution at 1 drop in both eyes twice daily. Orally administered brimonidine crossed the placenta in pregnant rats and entered the fetal circulation to a limited extent. Embryofetal development studies conducted with timolol during organogenesis in mice, rats, and rabbits at oral doses up to 50 mg/kg/day [4,200 times the maximum recommended human ophthalmic dose of 0.012 mg/kg/day on a mg/kg basis (MRHOD)] demonstrated no evidence of fetal malformations. Although delayed fetal ossification was observed at this dose in rats, there were no adverse effects on postnatal development of offspring. Doses of 1,000 mg/kg/day (83,000 times the MRHOD) were maternotoxic in mice and resulted in an increased number of fetal resorptions. Increased fetal resorptions were also seen in rabbits at doses 8,300 times the MRHOD without apparent maternotoxicity.

8.2 Lactation Risk Summary Timolol has been detected in human milk following oral and ophthalmic drug administration. It is not known whether brimonidine tartrate is excreted in human milk. In animal studies, brimonidine tartrate has been shown to be excreted in breast milk. Because of the potential for serious adverse reactions in the breastfed infant, including central nervous system depression and apnea, brimonidine tartrate/timolol maleate ophthalmic solution is not recommended for use during lactation. Data Animal Data After a single oral dose of 14 C-labeled brimonidine tartrate to lactating rats, brimonidine tartrate and trace metabolites were detected in milk after 30 minutes. There was 30% higher milk concentration compared to maternal plasma concentration 30 minutes after dosing and a 10-fold higher milk concentration compared to maternal plasma concentration 8 hours after dosing. No radiolabeled brimonidine tartrate or metabolites were detectable in milk 24 hours after dosing.

8.4 Pediatric Use Brimonidine tartrate/timolol maleate ophthalmic solution is contraindicated in pediatric patients younger than 2 years old [see Contraindications ( 4.3 )] . During post-marketing surveillance, apnea, bradycardia, coma, hypotension, hypothermia, hypotonia, lethargy, pallor, respiratory depression, and somnolence have been reported in infants receiving brimonidine. The safety and effectiveness of brimonidine tartrate/timolol maleate ophthalmic solution 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 have been established in pediatric patients aged 2 years and older. Use of brimonidine tartrate/timolol maleate ophthalmic solution for this indication is supported by evidence from adequate and well-controlled studies of brimonidine tartrate/timolol maleate ophthalmic solution in adults with additional data from a study of the concomitant use of brimonidine tartrate ophthalmic solution 0.2% and timolol maleate ophthalmic solution in pediatric glaucoma patients (ages 2 to 7 years). In this well-controlled clinical study, brimonidine tartrate ophthalmic solution 0.2% was dosed three times a day as adjunctive therapy to beta-blockers. The most commonly observed adverse reactions were somnolence (50% to 83% in patients 2 to 6 years) and decreased alertness. In pediatric patients 7 years of age or older (>20 kg), somnolence appears to occur less frequently (25%). Approximately 16% of patients on brimonidine tartrate ophthalmic solution discontinued from the study due to somnolence.

8.5 Geriatric Use No overall differences in safety or effectiveness have been observed between elderly and other adult patients.

Brimonidine tartrate/timolol maleate ophthalmic solution is comprised of two components: brimonidine tartrate and timolol. Each of these two components decreases elevated intraocular pressure, whether or not associated with glaucoma. Elevated intraocular pressure is a major risk factor in the pathogenesis of optic nerve damage and glaucomatous visual field loss. The higher the level of intraocular pressure, the greater the likelihood of glaucomatous field loss and optic nerve damage. Brimonidine tartrate/timolol maleate ophthalmic solution is a relatively selective alpha-2 adrenergic receptor agonist with a non-selective beta-adrenergic receptor inhibitor. Both brimonidine and timolol have a rapid onset of action, with peak ocular hypotensive effect seen at two hours post-dosing for brimonidine and one to two hours for timolol. Fluorophotometric studies in animals and humans suggest that brimonidine tartrate has a dual mechanism of action by reducing aqueous humor production and increasing uveoscleral outflow. Timolol maleate is a beta 1 and beta 2 adrenergic receptor inhibitor that does not have significant intrinsic sympathomimetic, direct myocardial depressant, or local anesthetic (membrane-stabilizing) activity.