Timolol Side Effects

It is possible that some side effects of timolol may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

For the Consumer

Applies to timolol: oral tablet

As well as its needed effects, timolol may cause unwanted side effects that require medical attention.

If any of the following side effects occur while taking timolol, check with your doctor immediately:

More common
  • Chest pain or discomfort
  • lightheadedness, dizziness, or fainting
  • shortness of breath
  • slow or irregular heartbeat
  • unusual tiredness
Less common
  • Difficult or labored breathing
  • fast heartbeat
  • tightness in chest
  • wheezing
  • Noisy breathing
  • small clicking, bubbling, or rattling sounds in the lung when listening with a stethoscope
  • swelling of hands, ankles, feet, or lower legs

If any of the following symptoms of overdose occur while taking timolol, get emergency help immediately:

Symptoms of overdose
  • Blurred vision
  • continuing ringing or buzzing or other unexplained noise in ears
  • headache
  • hearing loss
  • nervousness
  • pounding in the ears
  • sweating

Some timolol side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:

Less common
  • Itching skin
  • red, sore eyes
  • Acid or sour stomach
  • belching
  • burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • decreased interest in sexual intercourse
  • feeling of constant movement of self or surroundings
  • heartburn
  • inability to have or keep an erection
  • indigestion
  • lack or loss of strength
  • loss in sexual ability, desire, drive, or performance
  • nausea
  • sensation of spinning
  • stomach discomfort, upset, or pain

For Healthcare Professionals

Applies to timolol: compounding powder, oral tablet


Cardiovascular side effects are the most common. Sinus bradycardia is reported in 9% of patients. Atrioventricular conduction disturbances, hypotension, and exacerbation of congestive heart failure are reported in less than 1% of patients.


Alternative therapy should be considered in patients with reactive airways disease. Cases of fatal respiratory arrest are reported in patients with asthma, even after topically administered timolol.

Respiratory problems associated with timolol, like with other beta antagonists, include bronchial constriction in susceptible patients. Dyspnea is reported in 6% of patients.

Nervous system

A case of amaurosis fugax is associated with timolol. However, the patient involved had underlying cerebrovascular disease, autonomic dysfunction, and an arrhythmia.

Nervous system side effects include fatigue in 6%, headache in 4%, and dizziness in 6% of treated patients. Cases of visual hallucinations, insomnia and depression have been reported rarely. Timolol may worsen myasthenia gravis.


Endocrinologic side effects of timolol include masking the signs and symptoms and blunting the normal physiologic response to hypoglycemia. Timolol may cause an increase in serum triglycerides, LDL cholesterol, and VLDL cholesterol, and a decrease in HDL cholesterol.

Alternative therapy should be considered in patients with diabetes mellitus who are prone to hypoglycemia.


Psychiatric side effects, such as confusion, depression (including acute suicidal ideation), vivid and frightening dreams, and visual hallucinations are reported in rare cases.

Sexual dysfunction is reported from questionnaires, although the questions may have biased the data since the responses were not spontaneous.


Gastrointestinal complaints of general abdominal pain, nausea, constipation, or diarrhea are reported in 1% to 5% of patients.


Dermatologic side effects are unusual. Rare cases of generalized psoriasis and hyperpigmented nailbeds are reported.


Genitourinary complaints of impotence and decreased libido are rare.


Musculoskeletal side effects are rare. Timolol may worsen myasthenia gravis.


General side effects including decreased exercise tolerance, extremity pain, weight loss and fever have been reported.


Hypersensitivity reactions including anaphylaxis have been reported in clinical experience with timolol.

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