Skip to main content

Istalol Side Effects

Generic name: timolol ophthalmic

Medically reviewed by Drugs.com. Last updated on Mar 5, 2023.

Note: This document contains side effect information about timolol ophthalmic. Some dosage forms listed on this page may not apply to the brand name Istalol.

Applies to timolol ophthalmic: ophthalmic gel forming solution, ophthalmic solution.

Serious side effects of Istalol

Along with its needed effects, timolol ophthalmic (the active ingredient contained in Istalol) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking timolol ophthalmic:

More common

Less common

Other side effects of Istalol

Some side effects of timolol ophthalmic may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

For Healthcare Professionals

Applies to timolol ophthalmic: ophthalmic gel forming solution, ophthalmic solution.

General

Gel-forming Solution: The most commonly reported side effects were transient blurred vision, burning, and stinging.

Long-acting Solution: The most commonly reported side effects included burning and stinging on administration.

Ophthalmic Solution: The most commonly reported side effects included localized burning and stinging.[Ref]

Local

Gel:

Frequency not reported: Burning, itching, localized rash, redness, signs/symptoms of ocular irritation, stinging, tearing

Gel-forming Solution:

Very common (10% or more): Burning (up to 12.5%), stinging (up to 12.5%)

Common (1% to 10%): Crusting, discharge, itching, pain

Frequency not reported: local weakness, localized rash, signs/symptoms of ocular irritation

Long-acting Solution:

Very common (10% or more): Burning (up to 38%), stinging (up to 38%)

Common (1% to 10%): Itching

Frequency not reported: Crusting, discharge, localized rash, signs/symptoms of ocular irritation

Postmarketing reports: Local weakness

Ophthalmic Solution:

Very common (10% or more): Biting sensation (up to 13%), burning sensation (up to 13%)

Common (1% to 10%): Itching, secretion, signs/symptoms of ocular irritation, stinging

Rare (0.01% to 0.1%): Localized rash

Frequency not reported: Local weakness[Ref]

Ocular

Gel:

Frequency not reported: Blepharitis, blurred vision, choroidal detachment (following filtration surgery), conjunctival hyperemia, conjunctivitis, corneal erosion, decreased corneal sensitivity, dry eyes, keratitis, refractive changes

Gel-forming Solution:

Very common (10% or more): Transient blurred vision (up to 33%)

Common (1% to 10%): Blurred vision, conjunctival injection, conjunctivitis, foreign body sensation, tearing

Frequency not reported: Blepharitis, choroidal detachment (following filtration surgery) corneal erosion, cystoid macular edema, decreased corneal sensitivity, dry eyes, keratitis, redness, refractive changes, visual disturbances

Long-acting Solution:

Common (1% to 10%): Blurred vision, cataract, conjunctival injection, decreased visual acuity

Frequency not reported: Blepharitis, choroidal detachment (following filtration surgery), conjunctivitis, cystoid macular edema, decreased corneal sensitivity, dry eyes, foreign body sensation, keratitis, ocular pain, refractive changes, tearing, visual disturbances

Ophthalmic Solution:

Common (1% to 10%): Abnormal vision, blepharitis, blurred vision, cataract, conjunctival hyperemia, conjunctival injection, conjunctivitis, corneal fluorescein staining, decreased corneal sensitivity, dry eyes, epiphora, eye discomfort, eye pain, eyelid erythema, foreign body sensation, keratitis, photophobia

Rare (0.01% to 0.1%): Refractive changes, visual disturbance

Frequency not reported: Aphakic cystoid macular edema, choroidal detachment (following filtration surgery), corneal calcification, corneal erosion, crusting, cystoid macular edema, discharge, ocular pain, redness, retinal vascular disorder, tearing[Ref]

In some patients, refractive changes occurred as a result of mitotic therapy withdrawal.

Corneal calcification occurred with phosphate-containing drops in patients with significantly damaged corneas.[Ref]

Cardiovascular

Gel:

Frequency not reported: Arrhythmia, atrioventricular (AV) block, bradycardia, cardiac arrest, cardiac failure, chest pain, claudication, cold hands and feet, congestive heart failure, edema, hypotension, palpitations, Raynaud's phenomenon

Gel-forming Solution:

Frequency not reported: Arrhythmia, bradycardia, cardiac arrest, cardiac failure, chest pain, claudication, cold hands and feet, congestive heart failure, edema, heart block, hypertension, hypotension, palpitation, Raynaud's phenomenon, second-/third-degree AV block, sinoatrial block, vasodilation, worsening of angina pectoris, worsening of arterial insufficiency

Long-acting Solution:

Common (1% to 10%): Hypertension

Frequency not reported: Arrhythmia, bradycardia, cardiac arrest, cardiac failure, chest pain, claudication, cold hands and feet, edema, heart block, hypotension, palpitation, Raynaud's phenomenon, worsening of angina pectoris

Postmarketing reports: Vasodilation, worsening of arterial insufficiency

Ophthalmic Solution:

Common (1% to 10%): Hypertension, peripheral edema

Uncommon (0.1% to 1%): Bradycardia

Rare (0.01% to 0.1%): Arrhythmia, cardiac arrest, chest pain, claudication, cold hands and feet, congestive heart failure, edema, heart block, hypotension, palpitation, Raynaud's phenomenon

Frequency not reported: Cardiac failure, second-/third-degree AV block, sinoatrial block, vasodilation, worsening of angina pectoris, worsening of arterial insufficiency[Ref]

Nervous system

Gel:

Frequency not reported: Cerebral ischemia, cerebrovascular accident, diplopia, dizziness, dysgeusia, headache, increase in signs/symptoms of myasthenia gravis, memory loss, paresthesia, ptosis, syncope

Gel-forming Solution:

Common (1% to 10%): Dizziness, headache

Frequency not reported: Cerebral ischemia, cerebrovascular accident, diplopia, dysgeusia, increase in signs/symptoms of myasthenia gravis, memory loss, paresthesia, ptosis, slightly clouded sensorium, somnolence, syncope, vertigo

Long-acting Solution:

Common (1% to 10%): Headache

Frequency not reported: Cerebral ischemia, cerebrovascular accident, diplopia, dizziness, increase in signs/symptoms of myasthenia gravis, memory loss, paresthesia, ptosis, somnolence, syncope

Postmarketing reports: Slightly clouded sensorium, vertigo

Ophthalmic Solution:

Common (1% to 10%): Dizziness, headache

Uncommon (0.1% to 1%): Syncope

Rare (0.01% to 0.1%): Cerebral ischemia, cerebrovascular accident, diplopia, increase in signs/symptoms of myasthenia gravis, memory loss, paresthesia, ptosis

Frequency not reported: Blepharoptosis, central nervous system (CNS) effects, dysgeusia, increased dreaming, slightly clouded sensorium, somnolence, syncope, vertigo[Ref]

Respiratory

Gel:

Frequency not reported: Bronchospasm, cough, dyspnea

Gel-forming Solution:

Common (1% to 10%): Upper respiratory infections

Frequency not reported: Asthma exacerbation, bronchial obstruction, bronchospasm, cough, dyspnea, laryngospasm with respiratory distress, nasal congestion, pulmonary edema, rales, respiratory failure

Long-acting Solution:

Frequency not reported: Bronchospasm, cough, dyspnea, nasal congestion, pulmonary edema, respiratory failure, upper respiratory infections

Postmarketing reports: Bronchial obstruction, laryngospasm with respiratory distress, rales

Ophthalmic Solution:

Common (1% to 10%): Respiratory infection, sinusitis

Uncommon (0.1% to 1%): Dyspnea

Rare (0.01% to 0.1%): Bronchospasm, cough, respiratory failure

Frequency not reported: Asthma exacerbation, bronchial obstruction, laryngospasm with respiratory distress, nasal congestion, pulmonary edema, rales, upper respiratory infections[Ref]

Bronchospasm most commonly occurred in patients with preexisting bronchospastic disease.[Ref]

Gastrointestinal

Gel:

Frequency not reported: Abdominal pain, diarrhea, dry mouth, dyspepsia, nausea, vomiting

Gel-forming Solution:

Frequency not reported: Abdominal pain, diarrhea, dry mouth, dyspepsia, ischemic colitis, mesenteric arterial thrombosis, nausea, vomiting

Long-acting Solution:

Frequency not reported: Diarrhea, dry mouth, dyspepsia, nausea

Postmarketing reports: Gastrointestinal pain, ischemic colitis, mesenteric arterial thrombosis, vomiting

Ophthalmic Solution:

Common (1% to 10%): Dry mouth, nausea

Uncommon (0.1% to 1%): Dyspepsia

Rare (0.01% to 0.1%): Diarrhea

Frequency not reported: Abdominal pain, gastrointestinal pain, ischemic colitis, mesenteric arterial thrombosis, vomiting[Ref]

Immunologic

Gel:

Frequency not reported: Antinuclear antibodies positive, psoriasis exacerbation

Gel-forming Solution:

Frequency not reported: Psoriasis exacerbation, retroperitoneal fibrosis

Long-acting Solution:

Common (1% to 10%): Infection

Frequency not reported: Psoriasis exacerbation, retroperitoneal fibrosis

Ophthalmic Solution:

Common (1% to 10%): Common cold

Rare (0.01% to 0.1%): Psoriasis exacerbation

Frequency not reported: Retroperitoneal fibrosis[Ref]

Other

Gel:

Frequency not reported: Asthenia, fatigue

Gel-forming Solution:

Frequency not reported: Asthenia, decreased exercise tolerance, fatigue, fever combined with aching and sore throat, tinnitus

Long-acting Solution:

Frequency not reported: Asthenia, fatigue

Postmarketing reports: Decreased exercise tolerance, fever combined with aching and sore throat

Ophthalmic Solution:

Common (1% to 10%): Asthenia

Uncommon (0.1% to 1%): Fatigue

Rare (0.01% to 0.1%): Tinnitus

Frequency not reported: Decreased exercise tolerance, fever with aching and sore throat[Ref]

Hypersensitivity

Gel:

Frequency not reported: Anaphylactic reaction, angioedema, systemic allergic reactions

Gel-forming Solution:

Frequency not reported: Anaphylactic reaction, anaphylaxis, angioedema, exfoliative dermatitis, signs/symptoms of allergic reactions

Long-acting Solution:

Frequency not reported: Angioedema, signs/symptoms of systemic allergic reactions

Ophthalmic Solution:

Common (1% to 10%): Allergic reaction

Rare (0.01% to 0.1%): Anaphylaxis, angioedema, signs/symptoms of allergic reactions

Frequency not reported: Exfoliative dermatitis, hypersensitivity, signs/symptoms of systemic allergic reactions, systemic allergic reactions[Ref]

Psychiatric

Gel:

Frequency not reported: Decreased libido, depression, hallucination, insomnia, nightmares

Gel-forming Solution:

Frequency not reported: Acute reversible syndrome characterized by disorientation to time/place, anxiety, behavioral changes, confusion, decreased libido, decreased performance on neuropsychometrics, depression, diminished concentration, disorientation, emotional lability, hallucinations, increased dreaming, insomnia, nervousness, nightmares, psychic disturbances, reversible mental depression progressing to catatonia

Long-acting Solution:

Frequency not reported: Anxiety, behavioral changes, confusion, decreased libido, depression, disorientation, hallucinations, insomnia, nervousness, nightmares, psychic disturbances

Postmarketing reports: Acute reversible syndrome characterized by disorientation for time and place, decreased performance on neuropsychometrics, diminished concentration, emotional lability, reversible mental depression progression to catatonia

Ophthalmic Solution:

Uncommon (0.1% to 1%): Depression

Rare (0.01% to 0.1%): Decreased libido, insomnia, nightmares

Frequency not reported: Acute reversible syndrome characterized by disorientation for time and place, anxiety, behavioral changes, confusion, decreased/diminished concentration, decreased performance on neuropsychometrics, disorientation, emotional lability, hallucinations, nervousness, psychic disturbances, reversible mental depression progressing to catatonia[Ref]

Musculoskeletal

Gel:

Frequency not reported: Myalgia, systemic lupus erythematosus

Gel-forming Solution:

Frequency not reported: Arthralgia, extremity pain, myalgia, systemic lupus erythematosus

Long-acting Solution:

Frequency not reported: Systemic lupus erythematosus

Postmarketing reports: Arthralgia, extremity pain

Ophthalmic Solution:

Common (1% to 10%): Extremity pain

Rare (0.01% to 0.1%): Systemic lupus erythematosus

Frequency not reported: Arthralgia, myalgia[Ref]

Dermatologic

Gel:

Frequency not reported: Alopecia, generalized rash, pruritus, psoriasiform rash, skin rash, urticaria

Gel-forming Solution:

Frequency not reported: Alopecia, erythematous rash, generalized rash, increased pigmentation, nonthrombocytopenic purpura, pruritus, pseudopemphigoid, psoriasiform rash, skin irritation, skin rash, sweating, thrombocytopenic purpura, urticaria

Long-acting Solution:

Frequency not reported: Alopecia, generalized rash, pseudopemphigoid, psoriasiform rash, urticaria

Postmarketing reports: Erythematous rash, increased pigmentation, nonthrombocytopenic purpura, pruritus, skin irritation, sweating, thrombocytopenic purpura

Ophthalmic Solution:

Rare (0.01% to 0.1%): Alopecia, generalized rash, psoriasiform rash, urticaria

Frequency not reported: Erythematous rash, increased pigmentation, nonthrombocytopenic purpura, pruritus, pseudopemphigoid, skin irritation, skin rash, sweating, thrombocytopenic purpura[Ref]

Genitourinary

Gel:

Frequency not reported: Impotence, sexual dysfunction

Gel-forming Solution:

Frequency not reported: Impotence, micturition/urination difficulties, Peyronie's disease, sexual dysfunction

Long-acting Solution:

Frequency not reported: Impotence, Peyronie's disease

Postmarketing reports: Urination difficulties

Ophthalmic Solution:

Rare (0.01% to 0.1%): Peyronie's disease

Frequency not reported: Impotence, micturition difficulty, sexual dysfunction, urinary difficulties[Ref]

Metabolic

Gel:

Frequency not reported: Hypoglycemia

Gel-forming Solution:

Frequency not reported: Anorexia, high-density lipoprotein (HDL)-cholesterol slightly decreased, hyperglycemia, hypoglycemia, masked symptoms of hypoglycemia, serum potassium slightly increased, serum triglycerides slightly increased, serum uric acid slightly increased, weight loss

Long-acting Solution:

Frequency not reported: Anorexia, masked symptoms of hypoglycemia

Postmarketing reports: Hyperglycemia, hypoglycemia, weight loss

Ophthalmic Solution:

Frequency not reported: Anorexia, HDL-cholesterol slightly decreased, hyperglycemia, hypoglycemia, masked symptoms of hypoglycemia, serum potassium increased, serum triglycerides increased, serum uric acid increased, weight loss[Ref]

Masked hypoglycemia symptoms occurred in patients with diabetes.[Ref]

Hematologic

Gel-forming Solution:

Frequency not reported: Agranulocytosis, hematocrit slightly decreased, hemoglobin slightly decreased

Long-acting Solution:

Postmarketing reports: Agranulocytosis

Ophthalmic Solution:

Frequency not reported: Agranulocytosis, hematocrit slightly decreased, hemoglobin slightly decreased[Ref]

Hepatic

Gel-forming Solution:

Frequency not reported: Hepatomegaly

Long-acting Solution:

Postmarketing reports: Hepatomegaly

Ophthalmic Solution:

Frequency not reported: Hepatomegaly[Ref]

Renal

Gel-forming Solution:

Frequency not reported: Serum urea slightly increased

Ophthalmic Solution:

Frequency not reported: Increased blood urea nitrogen (BUN)[Ref]

References

1. Product Information. Timoptic (timolol ophthalmic). Merck & Co., Inc. 2001;PROD.

2. Product Information. Timolol Maleate, Ophthalmic (timolol ophthalmic). Bausch and Lomb Americas, Inc. 2005.

3. Cerner Multum, Inc. UK Summary of Product Characteristics.

4. Cerner Multum, Inc. Australian Product Information.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.