Istalol (timolol) is an eye drop that's used to lower pressure within the eye and treat glaucoma. It belongs to the beta blocker drug class. This medication can be used by itself or together with other eye drops that aren't beta blockers. Istalol (timolol) is longer-acting than other timolol products, so the usual dosage is once daily in the morning. Common side effects include burning or stinging after you put in the eye drops, but it's generally a temporary feeling.
High pressure in the eye caused by ocular hypertension (high pressure inside the eye) or open-angle glaucoma (the most common type of glaucoma)
Istalol (timolol) is a beta blocker that lowers the amount of fluid in the eye. When there's less fluid inside the eye, the eye pressure goes down.
Source: 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.
Works well to treat high eye pressure
Used only once daily
Lower-cost generic available
Unknown if safe for use in children
Might cause more side effects than some other timolol eye medications
Wash your hands before placing Istalol (timolol) drops in your eyes. Avoid touching the dropper tip to your eye or any other surface. Don't touch the dropper tip with your hands. This helps prevent the eye drop solution from getting contaminated with germs and lower the risk for eye infections.
If you wear contact lenses, remove them before you place Istalol (timolol) into your eye(s). Wait 15 minutes before putting your lenses back in your eye(s).
After placing a drop of Istalol (timolol) in your eye, close your eye and gently press one finger to the inner corner of your eye by the nose for 1 minute. This helps your eye absorb the medication.
If you need to use Istalol (timolol) along with other eye drops or ointments, wait 5 minutes between using each product to give your eyes time to absorb each medication.
It's not easy to tell whether your eye pressure is improving at home. Use Istalol (timolol) as prescribed, even if you don't notice any differences in your symptoms or vision right away.
Istalol (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: Congestive heart failure | Second- or third-degree heart block
In rare cases, some people developed heart failure while they used beta-blocking medications like Istalol (timolol). People who already have heart failure might be at risk for worsening heart problems with this medication. Tell your healthcare team about your medical history. And talk to your primary care provider if you notice swelling in your feet or ankles, a fast or irregular pulse, or shortness of breath when you lie down or exercise. These might be signs of heart problems.
Risk factors: History of asthma | History of chronic obstructive pulmonary disease (COPD) | History of other lung problems
Beta blocker medications like Istalol (timolol) usually aren't recommended for people with lung problems, like asthma and COPD. This is because beta blockers can cause the airways to become narrower, which can make it harder to breathe. But the risk for breathing problems specifically with Istalol (timolol) isn't well known. Make sure your healthcare team knows if you have or have ever had any lung problems or conditions before you start using this medication to check whether it's safe for you.
Risk factors: Diabetes
Beta blockers can cause people with diabetes to not notice symptoms of low blood sugar, except for sweating and dizziness. It's possible for some Istalol (timolol) to be absorbed into your bloodstream and cause this effect. So though rare, it's important to be aware of this risk. Talk to your primary care provider to see whether you should check your blood sugar more often if you're using Istalol (timolol).
Beta blockers can cause people with an overactive thyroid to not recognize the signs of hyperthyroidism, such as a fast heart rate. It's possible for some Istalol (timolol) to get absorbed into your bloodstream and cause this effect. Although rare, it's good to be aware of this risk. Make sure your primary care provider knows that you're using Istalol (timolol) so they can monitor your thyroid problem more closely.
In some rare cases, Istalol (timolol) can worsen symptoms like muscle weakness in people who have myasthenia gravis. Watch out for worsening symptoms if you have myasthenia gravis and let your care team know if this happens to you.
The typical dose is 1 drop in the affected eye(s) once daily in the morning.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Asthma
Sinus bradycardia (slow heart rate)
Second- or third-degree heart block
High pressure in the eye caused by ocular hypertension (high pressure inside the eye) or open-angle glaucoma (the most common type of glaucoma)
High pressure in the eye caused by ocular hypertension (high pressure inside the eye) or open-angle glaucoma (the most common type of glaucoma)
High pressure in the eye caused by ocular hypertension (high blood pressure inside the eye) or open-angle glaucoma (the most common type of glaucoma)
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