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

The following additional adverse experiences have been reported less frequently with ocular administration of this or other timolol maleate formulations:

Body As A Whole

Asthenia/fatigue and chest pain.

Cardiovascular

Bradycardia, arrhythmia, hypotension, syncope, heart block, cerebral vascular accident, cerebral ischemia, cardiac failure, worsening of angina pectoris, palpitation, cardiac arrest, pulmonary edema, edema, claudication, Raynaud's phenomenon, and cold hands and feet.

Digestive

Nausea, diarrhea, dyspepsia, anorexia, and dry mouth.

Immunologic

Systemic lupus erythematosus.

Nervous System/Psychiatric

Dizziness, increase in signs and symptoms of myasthenia gravis, paresthesia, somnolence, insomnia, night-mares, behavioral changes and psychic disturbances including depression, confusion, hallucinations, anxiety, disorientation, nervousness, and memory loss.

Skin

Alopecia and psoriasiform rash or exacerbation of psoriasis.

Hypersensitivity

Signs and symptoms of systemic allergic reactions, including angioedema, urticaria, and localized and generalized rash.

Respiratory

Bronchospasm (predominantly in patients with pre-existing bronchospastic disease), respiratory failure, dyspnea, nasal congestion, cough and upper respiratory infections.

Endocrine

Masked symptoms of hypoglycemia in diabetic patients (see WARNINGS).

Special Senses

Signs and symptoms of ocular irritation including conjunctivitis, blepharitis, keratitis, ocular pain, discharge (e.g., crusting), foreign body sensation, itching and tearing, and dry eyes; ptosis; decreased corneal sensitivity; cystoid macular edema; visual disturbances including refractive changes and diplopia; pseudopem-phigoid; choroidal detachment following filtration surgery (see PRECAUTIONS, General); and tinnitus.

Urogenital

Retroperitoneal fibrosis, decreased libido, impotence, and Peyronie's disease.

The following additional adverse effects 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: Extremity pain, decreased exercise tolerance, weight loss; Cardiovascular: Worsening of arterial insufficiency, vasodilatation; Digestive: Gastrointestinal pain, hepatomegaly, vomiting, mesenteric arterial thrombosis, ischemic colitis; Hematologic: Nonthrombocytopenic purpura; thrombocytopenic purpura, agranulocytosis; Endocrine: Hyperglycemia, hypoglycemia; Skin: Pruritus, skin irritation, increased pigmenta-tion, sweating; Musculoskeletal: Arthralgia; Nervous System/Psychiatric: Vertigo, local weakness, diminished concentration, reversible mental depression progressing to catatonia, an acute reversible syndrome characterized by disorientation for time and place, emotional lability, slightly clouded sensorium, and decreased performance on neuropsychometrics; Respiratory: Rales, bronchial obstruction; Urogenital: Urination difficulties.

Read the Istalol (timolol maleate ophthalmic solution) Side Effects Center for a complete guide to possible side effects »

Although ISTALOL (timolol maleate ophthalmic solution) used alone has little or no effect on pupil size, mydriasis resulting from concomitant therapy with ISTALOL (timolol maleate ophthalmic solution) and epinephrine has been reported occasionally.

Beta-adrenergic blocking agents

Patients who are receiving a beta-adrenergic blocking agent orally and ISTALOL (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.

Calcium antagonists

Caution should be used in the coadministration of beta-adrenergic blocking agents, such as ISTALOL (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, coadministration should be avoided.

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.

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.

Quinidine

Potentiated systemic beta-blockade (e.g., decreased heart rate) has been reported during combined treatment with quinidine and timolol, possibly because quinidine inhibits the metabolism of timolol via the P-450 enzyme, CYP2D6.

Clonidine

Oral beta-adrenergic blocking agents may exacerbate the rebound hypertension which can follow the withdrawal of clonidine. There have been no reports of exacerbation of rebound hypertension with ophthalmic timolol maleate.

Injectable epinephrine

(See PRECAUTIONS, General, Anaphylaxis)

Last reviewed on RxList: 3/27/2009
This monograph has been modified to include the generic and brand name in many instances.