This medication belongs to the family of medications called beta-blockers. Timolol eye drops are used to treat glaucoma and increased pressure in the eye. This medication works by reducing the production of fluid in the eye, thereby lowering the pressure in the eye. It may take up to 4 weeks for the eye drops to lower the pressure in the eye to a satisfactory level.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. As well, some forms of this medication may not be used for all of the conditions discussed here. If you have not discussed this with your doctor or are not sure why you are using this medication, speak to your doctor. Do not stop using this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to use this medication if their doctor has not prescribed it.

The usual dose is 1 drop of timolol solution in the affected eye(s) twice daily. 

Avoid touching the tip of the dispensing container to the eye or around the eye. Eye solutions, if handled improperly, can become contaminated by common bacteria known to cause eye infections. Serious damage to the eye and loss of vision may result from using contaminated solutions.

If more than 1 type of eye drop is being used, the different eye drops should be administered at least 10 minutes apart.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are using the medication without consulting your doctor.

It is important to use this medication exactly as prescribed by your doctor. If you miss a dose, use it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not instill a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and keep it out of the reach of children. Discard any solution remaining in the dropper bottle one month after the date on which the container is first opened.

Do not use this medication if you:

• are allergic to timolol or any ingredient of the medication
• are in overt heart failure or cardiogenic shock (shock due to heart-related causes)
• have an extremely slow heart rate or serious heart block
• have asthma or severe chronic obstructive pulmonary disease (e.g., emphysema, chronic bronchitis)

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who uses this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people using this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• abdominal pain
• blurred vision (temporary) after putting in the eye drop
• double vision
• nausea
• sensation of something in your eyes
• stinging of eye or other eye irritation (when medication is applied)
• vomiting

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• low blood pressure
• muscle pain
• shortness of breath
• slow or irregular heartbeat

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of an allergy such as swelling of the mouth, shortness of breath, hives, severe itching, and rash

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Blurred vision: Timolol eye drops may cause temporary blurred vision after putting them in your eyes. Avoid driving, operating machinery, or performing other hazardous tasks until you have determined how this medication affects you.

Breathing problems: Like other beta-adrenergic blockers, timolol can cause difficulty breathing for people with asthma and certain other breathing problems. If you have breathing problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking this medication.

Contact lenses: There are preservatives present in both formulations of timolol eye drops. These preservatives may be absorbed by soft contact lenses. Remove your contact lenses before using timolol drops and wait for at least 15 minutes after using the drops to put the contact lenses back in your eyes.

Diabetes: The signs of hypoglycemia (low blood sugar) may not be as noticeable when using timolol eye drops. People with diabetes who are prone to hypoglycemia or those who are receiving insulin or taking medications that can reduce blood sugar should monitor blood glucose regularly. If you have diabetes or are at risk for developing diabetes, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

General: As with other topically applied eye drops, this medication may be absorbed into the blood circulation. The same side effects reported with oral medications from the family known as beta-blockers (e.g., timolol, propranolol, metoprolol) may occur with the eye drops.

Heart failure: Beta blockers, such as timolol, can slow down the heart rate and may cause severely decreased blood pressure. These effects can make symptoms of heart failure worse. If you have heart disease such as angina, congestive heart failure, or arrhythmia, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Contact your doctor as soon as possible if you develop symptoms of heart problems such as shortness of breath, chest pain, rapid heartbeat, or swollen ankles.

People with heart failure should be carefully monitored by their doctors while using timolol eye drops.

Overactive thyroid: Timolol may mask the signs of overactive thyroid, such as rapid heartbeat. If you have been told that you have an overactive thyroid, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Pregnancy: Timolol has not been studied for use by pregnant women. This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication passes into breast milk. If you are a breast-feeding mother and are using timolol eye drops, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: Timolol eye drops are not currently recommended for use by children.

There may be an interaction between timolol and any of the following:

• acetylcholinesterase inhibitors (medications for Alzheimer's disease; e.g., donepezil, galantamine, rivastigmine)
• alpha agonists (e.g., clonidine, methyldopa)
• alpha blockers (e.g., alfuzosin, doxazosin, silodosin, tamsulosin)
• antiarrhythmics (e.g., amiodarone, disopyramide, flecainide, lidocaine, propafenone, quinidine)
• anti-psychotics (e.g., chlorpromazine, perphenazine, thioridazine)
• other beta-adrenergic blockers (e.g., atenolol, propranolol, sotalol)
• beta-2 agonists (e.g., salbutamol, formoterol, salmeterol, terbutaline)
• brimonidine
• bromocriptine
• bupropion
• calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
• ceritinib
• crizotinib
• diabetes medications (e.g., acarbose, canagliflozin,   glyburide, insulin, lixisenatide, metformin,  rosiglitazone, sitagliptin)
• digoxin
• dipyridamole
• diuretics (water pills; e.g., furosemide, hydrochlorothiazide, triamterene)
• ergot alkaloids (e.g., dihydroergotamine, ergonovine, ergotamine, methylergonovine)
• fluoxetine
• guanfacine
• ivabradine
• mefloquine
• other eye drops
• paroxetine
• sphingosine 1-phosphate receptor (S1P) receptor inhibitors (e.g., fingolimod, ponesimod, siponimod)
• somatostatin analogues (e.g., lanreotide, octreotide, pasireotide)
• thalidomide
• theophylline
• tipranavir
• tizanidine
• tofacitinib

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.