What are the side effects of Timolol (beta blocker) eye drops?

From the Guidelines

Timolol eye drops can cause significant side effects, including bradycardia, which may require pacemaker implantation in some patients, especially the elderly, due to additive effects with systemic beta-blockers 1. When considering the use of timolol eye drops, it is essential to weigh the benefits of reduced intraocular pressure against the potential risks of systemic side effects.

• Common local side effects include eye irritation, burning, stinging, redness, and dry eyes.
• Systemic side effects can occur due to absorption of the medication, including lowered heart rate (bradycardia), reduced blood pressure, breathing difficulties, fatigue, dizziness, and headaches.
• More serious but less common side effects include depression, confusion, memory problems, sexual dysfunction, and allergic reactions. The mechanism of action of timolol, blocking beta-adrenergic receptors, not only reduces aqueous humor production in the eye but can also affect heart rate and other bodily functions when absorbed systemically 1. Key considerations for patients using timolol eye drops include monitoring for signs of bradycardia and other systemic effects, especially in the elderly or those with pre-existing heart conditions, and reporting any persistent or severe side effects to their healthcare provider immediately.
• Patients with diabetes should also be cautious, as timolol can mask symptoms of hypoglycemia, requiring careful monitoring of blood glucose levels.
• The potential for additive effects with oral beta-blockers, which are sometimes co-administered, especially in the elderly, underscores the need for careful management and monitoring of patients on timolol eye drops 1.

From the FDA Drug Label

ADVERSE REACTIONS The most frequently reported adverse experiences have been burning and stinging upon instillation (approximately one in eight patients). The following additional adverse experiences have been reported less frequently with ocular administration of this or other timolol maleate formulations: Body as a Whole Headache, asthenia/fatigue, and chest pain Cardiovascular Bradycardia, arrhythmia, hypotension, hypertension, 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, nightmares, 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 anaphylaxis, angioedema, urticaria, and localized and generalized rash. Respiratory Bronchospasm (predominantly in patients with preexisting 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; pseudopemphigoid; choroidal detachment following filtration surgery [see PRECAUTIONS, General]; and tinnitus. Urogenital Retroperitoneal fibrosis, decreased libido, impotence, and Peyronie's disease 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 pigmentation, 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

The side effects of Timolol eye drops include:

• Ocular irritation: burning, stinging, conjunctivitis, blepharitis, keratitis, ocular pain, discharge, foreign body sensation, itching, tearing, and dry eyes
• Cardiovascular effects: bradycardia, arrhythmia, hypotension, hypertension, syncope, heart block, cerebral vascular accident, cardiac failure
• Respiratory effects: bronchospasm, respiratory failure, dyspnea, nasal congestion, cough, and upper respiratory infections
• Nervous System/Psychiatric effects: dizziness, increase in signs and symptoms of myasthenia gravis, paresthesia, somnolence, insomnia, nightmares, behavioral changes, and psychic disturbances
• Other effects: headache, asthenia/fatigue, chest pain, nausea, diarrhea, dyspepsia, anorexia, dry mouth, alopecia, and psoriasiform rash or exacerbation of psoriasis 2

From the Research

Systemic Side Effects of Timolol Eye Drops

• Respiratory distress, particularly in patients with underlying restrictive airway disease 3
• Cardiovascular effects, including decreased resting pulse rate, bradycardia, and heart failure 3
• Central nervous system effects, such as fatigue, confusion, depression, and hallucinations 3
• Other systemic effects have also been reported, highlighting the need for caution when administering ophthalmic timolol to elderly patients or those with contraindications to systemic beta-blockers 3

Local Side Effects of Timolol Eye Drops

• Conjunctival hyperaemia, which may be more common with certain prostaglandin analogues, such as bimatoprost, when used in combination with timolol 4
• Eye irritation and corneal effects, although the differences between fixed combinations and prostaglandin analog monotherapy are not statistically significant 5
• Hyperaemia, which may be lessened by the addition of timolol to prostaglandin analogues 4

Special Considerations

• Inadvertent overdosing, particularly in elderly patients with impaired vision, can lead to significant and potentially dangerous side effects 6
• The use of a simple dropper that withdraws and delivers only one drop may help resolve this issue 6
• Long-term assessment of prostaglandin analogs and timolol fixed combinations versus prostaglandin analog monotherapy has shown that the fixed combinations may have a slightly greater efficacy in lowering intraocular pressure, but the differences in safety outcomes are not statistically significant 5