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Istalol Side Effects

Generic Name: timolol ophthalmic

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

For the Consumer

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

In addition to its needed effects, some unwanted effects may be caused by timolol ophthalmic (the active ingredient contained in Istalol). In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when taking timolol ophthalmic:

More common:
  • Blurred vision
  • burning or stinging in eye
Less common:
  • Arm, back, or jaw pain
  • blisters, hives, welts, or itching
  • blue lips, fingernails, or skin
  • burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • change in vision
  • chest pain or discomfort
  • chest tightness or heaviness
  • confusion about identity, place, and time
  • continuing ringing or buzzing or other unexplained noise in ears
  • coughing that sometimes produces a pink frothy sputum
  • depression
  • difficult, fast, noisy breathing, sometimes with wheezing
  • difficulty in chewing, swallowing, or talking
  • dilated neck veins
  • discharge, excessive tearing
  • disturbed color perception
  • dizziness, faintness, or lightheadedness when getting up from a lying or sitting position suddenly
  • double vision
  • drooping eyelids
  • dry or itching eyes
  • extreme fatigue
  • false sense of well-being
  • fast, slow, irregular, pounding, or racing heartbeat or pulse
  • fear, nervousness
  • feeling of having something in the eye
  • fever and chills
  • flashes of light, floaters in vision
  • general feeling of discomfort or illness
  • hair loss
  • halos around lights
  • headaches
  • inability to speak
  • increased sweating
  • irregular, fast or slow, or shallow breathing
  • large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • lightheadedness, dizziness, or fainting
  • loss of vision
  • memory loss
  • mood swings
  • muscle or joint pain
  • muscle weakness
  • nausea
  • night blindness
  • no blood pressure or pulse
  • overbright appearance of lights
  • pain, tension, and weakness upon walking that subsides during periods of rest
  • pale skin
  • paleness or cold feeling in fingertips, toes, hands, and feet
  • personality changes
  • pounding in the ears
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • redness of skin
  • redness, pain, swelling or irritation of eye, eyelid, or inner lining of eyelid
  • seeing double
  • seeing, hearing, or feeling things that are not there
  • seizures
  • severe numbness, especially on one side of the face or body
  • severe or sudden headache
  • severe tiredness
  • shortness of breath or troubled breathing
  • skin irritation or rash, including rash that looks like psoriasis
  • slurred speech
  • sore throat
  • stopping of heart
  • sweating
  • swelling of face, fingers, feet, lower legs, and ankles
  • swollen glands
  • temporary blindness
  • tingling or pain in fingers or toes when exposed to cold
  • tunnel vision
  • unconsciousness
  • unusual tiredness or weakness
  • weakness in arm and/or leg on one side of the body, sudden and severe
  • weight gain
  • wheezing

Minor Side Effects

Some of the side effects that can occur with timolol ophthalmic may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

Less common:
  • Acid or sour stomach
  • belching
  • body aches or pain
  • diarrhea
  • dry mouth
  • ear congestion
  • hearing loss
  • heartburn
  • indigestion
  • lack or loss of strength
  • loss of appetite
  • loss of voice
  • nightmares
  • runny nose
  • sleepiness or unusual drowsiness
  • sleeplessness
  • sneezing
  • stomach discomfort, upset, or pain
  • stuffy nose
  • trouble sleeping
  • unable to sleep
  • weight loss

For Healthcare Professionals

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


The most commonly reported side effects were burning/stinging sensation, blurred vision, and abnormal vision.[Ref]


Very common (10% or more): Burning/stinging sensation (up to 38%), blurred/abnormal vision (up to 25%)
Common (1% to 10%): Conjunctival hyperemia, foreign body sensation, keratitis, conjunctivitis, cataract, decreased visual acuity
Frequency not reported: Itching, tearing, redness, blepharitis, dry eyes, decreased corneal sensitivity, corneal erosion, refractive changes (due to withdrawal of miotic therapy in some cases), diplopia, ptosis and choroidal detachment following filtration surgery, discharge (e.g., crusting), foreign body sensation, cystoid macular edema, pseudopemphigoid[Ref]


Common (1% to 10%): Hypertension
Frequency not reported: Bradycardia, chest pain, arrhythmia, heart block, congestive heart failure, palpitations, cardiac arrest, atrioventricular block, cardiac failure, edema; AV block (second- or third-degree), sino-atrial block, worsening of arterial insufficiency, worsening of angina pectoris, vasodilation, claudication, hypotension, syncope, Raynaud's phenomenon, cold hands and feet[Ref]


Frequency not reported: Pulmonary edema, bronchospasm (predominantly in patients with pre-existing bronchospastic disease), respiratory failure, dyspnea, cough, rales, sore throat, laryngospasm, respiratory distress
Postmarketing reports: Bronchial obstruction[Ref]

Nervous system

Common (1% to 10%): Headache
Frequency not reported: Tinnitus, memory loss, diminished concentration, increased dreaming, cerebrovascular accident, cerebral ischemia, dizziness, increase in signs and symptoms of myasthenia gravis, paresthesia, vertigo, local weakness[Ref]


Frequency not reported: Depression, insomnia, nightmares, catatonia[Ref]


Frequency not reported: Alopecia, psoriasiform rash or exacerbation of psoriasis, skin rash, sweating, exfoliative dermatitis[Ref]


Frequency not reported: Nausea, diarrhea, dyspepsia, dry mouth, dysgeusia, abdominal pain, vomiting, mesenteric artery thrombosis, ischemic colitis[Ref]


Frequency not reported: Systemic lupus erythematosus[Ref]


Frequency not reported: Anaphylaxis, angioedema, urticaria, localized/generalized rash, anaphylactic reaction
Postmarketing reports: Erythematous rash[Ref]


Frequency not reported: Decreased libido, Peyronie's disease, impotence, micturition difficulties, retroperitoneal fibrosis[Ref]


Frequency not reported: Asthenia, fatigue, extremity pain, decreased exercise tolerance, fever[Ref]


Frequency not reported: Non-thrombocytopenic purpura, thrombocytopenic purpura, agranulocytosis[Ref]


Frequency not reported: Myalgia, arthralgia[Ref]


Postmarketing reports: Hepatomegaly[Ref]


Frequency not reported: Hypoglycemia, hyperglycemia, anorexia[Ref]


1. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

2. "Product Information. Timolol Maleate, Ophthalmic (timolol ophthalmic)." Bausch and Lomb, Rochester, NY.

3. "Product Information. Timoptic (timolol ophthalmic)." Merck & Co, Inc, West Point, PA.

4. Cerner Multum, Inc. "Australian Product Information." O 0

Not all side effects for Istalol may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.