- What is timolol and how does it work (mechanism of action)?
- What are the uses for timolol?
- What are the side effects of timolol?
- What is the dosage for timolol?
- Which drugs or supplements interact with timolol?
- Is timolol safe to take if I'm pregnant or breastfeeding?
- What else should I know about timolol?
What is timolol and how does it work (mechanism of action)?
Timolol GFS 0.25% and 0.5% are indicated for the treatment of elevated intraocular pressure in patients with ocular hypertension or open-angle glaucoma.
Timolol maleate is a beta1 and beta2 (nonselective) adrenergic receptor inhibitor that does not have significant intrinsic sympathomimetic, direct myocardial depressant, or local anesthetic (membrane-stabilizing) activity. Timolol GFS, when applied topically to the eye, has the action of reducing elevated, as well as normal, intraocular pressure, whether or not accompanied by glaucoma.
Elevated intraocular pressure is a major risk factor in the pathogenesis of glaucomatous visual field loss and optic nerve damage. The precise mechanism of the ocular hypotensive action of Timolol GFS is not clearly established at this time.
Is timolol available as a generic drug?
Yes
Do I need a prescription for timolol?
Yes
What are the uses for timolol?
- Timolol is prescribed to lower blood pressure in patients with high blood pressure (hypertension).
- It also is used to reduce angina (heart pain), and to stabilize irregular heartbeats (arrhythmias) and prevent migraine headaches. Off label uses include the treatment of hypertrophic cardiomyopathy and mitral valve prolapse.
What are the side effects of timolol?
Minor side effects of timolol include:
Major side effects include:
- depression,
- vivid dreams,
- memory loss,
- fever,
- impotence,
- lightheadedness,
- slow heart rate,
- low blood pressure,
- numbness,
- tingling,
- cramps,
- blueness of the hands or feet,
- sore throat,
- shortness of breath, or
- wheezing.

QUESTION
In the U.S., 1 in every 4 deaths is caused by heart disease. See AnswerWhich drugs or supplements interact with timolol?
- The concurrent use of timolol and clonidine (Catapres), may cause rebound hypertension upon abrupt discontinuation of clonidine. It is advisable, therefore, to stop the beta adrenergic blocking drug by several days before gradually withdrawing clonidine.
- Fenoldopam (Corlopam), which is used for the treatment of severe hypertension should not be taken together with timolol as the combination may increase the risk of hypotension due to additive effects of the two drugs in lowering blood pressure.
- Close observation should be carried out when timolol is administered to patients receiving catecholamine-depleting drugs such as reserpine (Harmonyl) because of possible additive effects and the production of hypotension and/or a markedly slow heartbeat, which may produce dizziness, syncope, or postural hypotension (dizziness upon standing).
- Concurrent use of NSAIDs with timolol may cause the antihypertensive action of beta-blockers to be decreased. This occurs because prostaglandins are important in controlling blood pressure.
Is timolol safe to take if I'm pregnant or breastfeeding?
- There are no adequate studies in pregnant women. Timolol should be used during pregnancy only if the potential benefit justifies the potential risk.
- Timolol has been detected in human milk and has a potential for adverse events in infants.
Summary
Timolol (Betimol) is a first-generation beta-blocker drug. Timolol is prescribed for the treatment of high blood pressure, angina, heart attacks, and migraine headache prevention. Off label uses include treatment for cardiomyopathy and mitral valve prolapse. Side effects include fatigue, insomnia, nausea, vomiting, diarrhea, abdominal cramps. Drug interactions, warnings and precautions, and pregnancy and breastfeeding safety information should be reviewed prior to taking this medication.
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High Blood Pressure (Hypertension)
High blood pressure (hypertension) is a disease in which pressure within the arteries of the body is elevated. About 75 million people in the US have hypertension (1 in 3 adults), and only half of them are able to manage it. Many people do not know that they have high blood pressure because it often has no has no warning signs or symptoms. Systolic and diastolic are the two readings in which blood pressure is measured. The American College of Cardiology released new guidelines for high blood pressure in 2017. The guidelines now state that blood normal blood pressure is 120/80 mmHg. If either one of those numbers is higher, you have high blood pressure. The American Academy of Cardiology defines high blood pressure slightly differently. The AAC considers 130/80 mm Hg. or greater (either number) stage 1 hypertension. Stage 2 hypertension is considered 140/90 mm Hg. or greater. If you have high blood pressure you are at risk of developing life threatening diseases like stroke and heart attack.REFERENCE: CDC. High Blood Pressure. Updated: Nov 13, 2017.
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How the Heart Works
The heart is a very important organ in the body. It is responsible for continuously pumping oxygen and nutrient-rich blood throughout your body to sustain life. It is a fist-sized muscle that beats (expands and contracts) 100,000 times per day, pumping a total of five or six quarts of blood each minute, or about 2,000 gallons per day.
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Arrhythmias (Abnormal Heart Rhythms)
Heart rhythm disorders vary from minor palpitations, premature atrial contractions (PACs), premature ventricular contractions (PVCs), sinus tachycardia, and sinus bradycardia, to abnormal heart rhythms such as tachycardia, ventricular fibrillation, ventricular flutter, atrial fibrillation, atrial flutter, paroxysmal supraventricular tachycardia (PSVT), Wolf-Parkinson-White syndrome, brachycardia, or heart blocks. Treatment is dependent upon the type of heart rhythm disorder.
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Migraine Headache
Migraine headache is a type of headache associated with a sensitivity to light, smells, or sounds, eye pain, severe pounding on one side of the head, and sometimes nausea and vomiting. The exact cause of migraine headaches is not known. Triggers for migraine headaches include certain foods, stress, hormonal changes, strong stimuli (loud noises), and oversleeping. Treatment guidelines for migraines include medicine, pain management, diet changes, avoiding foods that trigger migraines, staying hydrated, getting adequate sleep, and exercising regularly. Prevention of migraine triggers include getting regular exercise, drinking water daily, reducing stress, and avoiding trigger foods.
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Heart Disease
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Atrial Fibrillation (AFib) Treatment Drugs
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Angina
Angina is chest pain due to inadequate blood supply to the heart. Angina symptoms may include chest tightness, burning, squeezing, and aching. Coronary artery disease is the main cause of angina but there are other causes. Angina is diagnosed by taking the patient's medical history and performing tests such as an electrocardiogram (EKG), blood test, stress test, echocardiogram, cardiac CT scan, and heart catheterization. Treatment of angina usually includes lifestyle modification, medication, and sometimes, surgery. The risk of angina can be reduced by following a heart healthy lifestyle.
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Things to Know About High Blood Pressure Treatment
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Mitral Valve Prolapse
Mitral valve prolapse (MVP), also called "click murmur syndrome" and "Barlow's syndrome," is the most common type of heart valve abnormality. Usually, people with mitral valve prolapse have no signs and symptoms; however, if the prolapsed valve is severe, symptoms may appear. When symptoms of severe mitral valve prolapse do appear, they may include, fatigue, palpitations, chest pain, anxiety, migraine headaches, and pulmonary edema. Echocardiography is the most useful test for mitral valve prolapse. Most people with mitral valve prolapse need no treatment. However, if the valve prolapse is severe, treatment medications or surgery may be necessary to repair the heart valve.
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Heart Attack Treatment
A heart attack involves damage or death of part of the heart muscle due to a blood clot. The aim of heart attack treatment is to prevent or stop this damage to the heart muscle. Heart attack treatments included medications, procedures, and surgeries to protect the heart muscle against injury.
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Dilated Cardiomyopathy
Dilated cardiomyopathy causes the heart muscles to progressively enlarge and weaken, reducing the ability of the heart to pump enough blood. Check out the center below for more medical references on heart disease, including multimedia (slideshows, images, and quizzes), related diseases, treatment, diagnosis, medications, and prevention or wellness.
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Heart Disease in Women
Heart disease in women has somewhat different symptoms, risk factors, and treatment compared to heart disease in men. Many women and health professionals are not aware of the risk factors for heart disease in women and may delay diagnosis and treatment. Lifestyle factors such as diet, exercise, tobacco use, overweight/obesity, stress, alcohol consumption, and depression influence heart disease risk in women. High blood pressure, high cholesterol, and diabetes also increase women's risk of heart disease. Electrocardiogram (EKG or ECG), stress-ECG, endothelial testing, ankle-brachial index (ABI), echocardiogram, nuclear imaging, electron beam CT, and lab tests to assess blood lipids and biomarkers of inflammation are used to diagnose heart disease. Early diagnosis and treatment of heart disease in women saves lives. Heart disease can be prevented and reversed with lifestyle changes.
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Cardiomyopathy (Restrictive)
Restrictive cardiomyopathy, the rarest form of cardiomyopathy, is a condition in which the walls of the lower chambers of the heart (the ventricles) are abnormally rigid and lack the flexibility to expand as the ventricles fill with blood. The pumping or systolic function of the ventricle may be normal but the diastolic function (the ability of the heart to fill with blood) is abnormal. Therefore, it is harder for the ventricles to fill with blood, and with time, the heart loses the ability to pump blood properly, leading to heart failure.
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Heart Disease Treatment in Women
Heart disease treatment in women should take into account female-specific guidelines that were developed by the American Heart Association. Risk factors and symptoms of heart disease in women differ from those in men. Treatment may include lifestyle modification (diet, exercise, weight management, smoking cessation, stress reduction), medications, percutaneous intervention procedure (PCI), and coronary artery bypass grafting (CABG). Heart disease is reversible with treatment.
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- Beta Blockers
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- Beta Blocker Side Effects (Adverse Effects)
- propranolol, Inderal, Inderal LA, Innopran XL
- metoprolol
- atenolol
- bisoprolol (Zebeta)
- timolol ophthalmic solution (Timoptic)
- bisoprolol and hydrochlorothiazide (Ziac)
- nadolol (Corgard)
- Sectral (acebutolol)
Prevention & Wellness

Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.