Timolol is a beta-blocker used to treat high blood pressure and prevent complications after a heart attack. It's also used to prevent migraines. The medication comes as tablets that you typically take by mouth twice daily. Timolol can interact with other medications and make side effects worse, so make sure your prescriber knows everything that you're taking. Although the brand Blocadren is discontinued, the generic versions are still available. Common side effects include slow heart rate, tiredness, and dizziness.
Prevent complications after a heart attack
Migraine prevention
Timolol is a beta blocker. It slows your heart rate and relaxes blood vessels, which lowers blood pressure and makes it easier for the heart to pump blood throughout the body. It's not entirely clear how the medication prevents migraines, but it's thought to work in the brain by affecting nerve cell communication.
Source:Â DailyMed
Along with its needed effects, a medicine 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:
More common
Chest pain or discomfort
lightheadedness, dizziness, or fainting
shortness of breath
slow or irregular heartbeat
unusual tiredness
Rare
Noisy breathing
small clicking, bubbling, or rattling sounds in the lung when listening with a stethoscope
swelling of hands, ankles, feet, or lower legs
Get emergency help immediately if any of the following symptoms of overdose occur:
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 side effects 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:
Rare
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
inability to have or keep an erection
indigestion
lack or loss of strength
loss in sexual ability, desire, drive, or performance
sensation of spinning
stomach discomfort, upset, or pain
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Lowers the risk of death in people who recently had a heart attack
Can take with other medications that lower blood pressure
Taken twice a day, and some people might be able to take it once a day
First-choice treatment option to prevent migraines
Can worsen breathing problems in people with asthma or COPD
Won't stop a migraine if it has already started
Not known if it's safe for children
Not a first-choice treatment option for high blood pressure
Take timolol by mouth at the same time every day without skipping doses. Don't suddenly stop taking this medication because doing so can cause or worsen heart problems like chest pain and heart attack. Speak to your prescriber if you have questions about stopping this medication.
Timolol can hide symptoms of low blood sugar, which can be dangerous for people with diabetes. But a symptom of low blood pressure it doesn't affect is sweating. So if you notice you're sweating, it's a good idea to check your blood sugar and treat it if it's low.
Timolol can lead to or worsen heart failure. Contact your prescriber right away if you notice new or worsening symptoms, such as swelling in your legs, shortness of breath, or sudden weight gain.
If you're taking timolol for migraine prevention and it's been over 6 to 8 weeks with no improvement, follow up with your prescriber. You might need to take a different medication.
Timolol can interact with many medications. Let your prescriber know about everything that you're taking before starting this medication.
Timolol can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: Suddenly stopping timolol | Coronary artery disease
Don't stop taking timolol suddenly, as it can cause an irregular or fast heartbeat, high blood pressure, poor blood flow to your heart, or raise your risk of chest pain or a heart attack. If you need to stop taking this medication, work with your prescriber to lower your dose slowly over a period of one to two weeks.
Risk factors: History of heart failure
Though timolol is commonly used to treat heart failure, it can sometimes worsen symptoms. In rare cases, this medication can even cause heart failure in people without a history of it. Talk to your healthcare team if you think your heart failure is getting worse or if you notice symptoms like shortness of breath, sudden weight gain, or swelling in the legs after taking timolol.
Risk factors: Breathing conditions like asthma, COPD, or emphysema
If you have certain breathing conditions like asthma, chronic obstructive pulmonary disease (COPD), or emphysema, taking timolol can make your breathing worse. Timolol can narrow your airways and cause wheezing or difficulty breathing. That's why it's usually not recommended for people with these conditions. Let your prescriber know about any breathing conditions before starting this medication. If you notice trouble breathing, chest tightness, or wheezing while taking it, contact them right away.
Risk factors: Diabetes
If you have diabetes, timolol can make it harder to notice some signs of low blood sugar, like a fast heartbeat. But you might be able to still experience symptoms like sweating, which can help alert you to low blood sugar. Know how to check your blood sugar levels while taking this medication and when to treat it.
Risk factors: Hyperthyroidism
Because timolol lowers your heart rate, it might be harder to notice heart-related symptoms that are caused by an overactive thyroid (hyperthyroidism). If you have this condition, don't suddenly stop taking timolol since this can worsen thyroid problems.
High blood pressure: The typical starting dose is 10 mg by mouth twice a day. Your prescriber will adjust your dose based on your heart rate and blood pressure. Most people take 20 to 40 mg total a day. The maximum dose is 60 mg total a day.
Heart attack: The typical dose is 10 mg by mouth twice a day.
Migraine prevention: The typical starting dose is 10 mg by mouth twice a day. Once you get used to the medication, you can take 20 mg once a day. Your prescriber will adjust your dose based on how you respond. The maximum dose is 30 mg total per day.
Prevent complications after a heart attack
Migraine prevention
High blood pressure
Chest pain (angina)
Lower the risk of hospitalization and death in heart failure
Chronic chest pain
Atrial fibrillation (A.Fib)
Heart protection after a heart attack
Tremors
Pheochromocytoma (a rare tumor of the adrenal gland)
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Athem LLC. (2022). Timolol maleate tablet [package insert]. DailyMed.
Modi, S., et al. (2006). Medications for migraine prophylaxis. American Family Physician.
National Heart, Lung, and Blood Institute. (2022).
Pratt, N. L., et al. (2015). Association between ophthalmic timolol and hospitalisation for bradycardia. Journal of Ophthalmology.
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