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Overview: Timolol is used to treat high blood pressure, lower the risk of a repeat heart attack, and help prevent migraine headaches. It works by blocking receptors in your heart, which slows your heart rate and helps it work more efficiently. Common side effects include feeling weak or tired, a slow heartbeat, and dizziness. Call your health care provider right away if you have trouble breathing, wheezing, or feel lightheaded. 

Uses

What is timolol used for?

Timolol is commonly used for the following conditions.

  • To lower high blood pressure (hypertension) 
  • To lower the risk of heart attack and death in people who have recently had a heart attack
  • To help prevent migraine headaches 

Timolol may also be used for other conditions as determined by your health care provider.

Other forms of timolol are available for use in the eyes. See timolol ophthalmic for more information.

How does timolol work (mechanism of action)?

Timolol blocks beta receptors in your heart. These receptors normally bind to hormones called catecholamines. When catecholamines bind to these receptors, it causes your heart to beat harder and faster. Blocking these receptors helps your heart beat more slowly. These effects can help your heart work better, lower blood pressure, and may reduce your risk for heart attack and stroke. 

It is not clear how timolol helps prevent migraine headaches.

How is timolol supplied (dosage forms)?

Brands and other names

  • Blocadren

Dosage forms and strengths

  • 5 mg oral tablets
  • 10 mg oral tablets
  • 20 mg oral tablets

How should I store timolol?

Timolol should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C), for shorter periods of time, such as when transporting it. Store in a cool, dry place, in a tightly closed container. Protect from light. 

Side Effects

What are the most common side effects of timolol?

The most common side effects of timolol are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Feeling unusually weak or tired 
  • Slow heartbeat
  • Dizziness

There may be other side effects of timolol that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of timolol?

While less common, the most serious side effects of timolol are described below, along with what to do if they happen.

Heart Rate Changes. Timolol can make your heart beat slower than normal (bradycardia). Call your health care provider right away if you have any of the following symptoms of bradycardia. 

  • Feeling lightheaded, dizziness, or fainting
  • Confusion
  • Feeling weak or easily tired 
  • Chest pain
  • Shortness of breath

Decreased Blood Pressure (Hypotension). Timolol may cause low blood pressure. If you feel faint or dizzy, lie down. Tell your health care provider right away if you have any of the following symptoms of low blood pressure.

  • Dizziness, feeling lightheaded, or fainting
  • Confusion
  • Feeling weak or tired

New or Worsening Heart Failure. Timolol may worsen existing heart failure or cause fluid buildup in your body. For individuals with underlying heart disease or heart damage, timolol can potentially lead to heart failure over time. Tell your health care provider right away if you have any of the following symptoms.

  • Shortness of breath or trouble breathing, especially while lying down
  • Swelling in your feet, ankles, or legs
  • Unusually fast weight gain
  • Unusual tiredness

Breathing Problems. Timolol may cause the muscles around the airways to tighten (bronchospasm) instead of relaxing, which can be serious. Stop taking timolol and contact your health care provider right away if you have trouble breathing.

Severe Allergic Reactions. Timolol may cause allergic reactions, which can be serious. Stop taking timolol and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching or skin rash
  • Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Warnings & Precautions

Who should not use timolol?

Allergies to Ingredients. People who are allergic to any of the following should not use timolol.

  • Blocadren
  • Timolol
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific timolol products they stock.

Breathing Problems. Timolol should not be used by those with asthma or chronic obstructive pulmonary disease (COPD).

Bradycardia. Timolol should not be used if your heart is beating too slow (bradycardia).

Heart Block. Timolol should not be used if the electrical signals in your heart move too slow (heart block).

Severe or Worsening Heart Failure. Timolol should not be used if your heart failure is severe or getting worse, causing you to feel very tired, have trouble breathing, or swelling in your legs. 

Cardiogenic Shock. Timolol should not be used if you have a life-threatening condition called cardiogenic shock where your heart cannot pump enough blood to the rest of your body.

What should I know about timolol before using it?

Do not take timolol unless it has been prescribed to you by a health care provider. Take it as prescribed.

Do not share timolol with other people, even if they have the same condition as you. It may harm them.

Keep timolol out of the reach of children.

Timolol can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how timolol affects you.

Stopping timolol suddenly may lead to chest pain, heart attack or dangerous heart rhythms in people with heart disease. Do not stop taking this medicine without talking to your health care provider first. 

What should I tell my health care provider before using timolol?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if timolol is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

  • Heart or circulation problems
  • Breathing problems
  • Kidney problems
  • Liver problems
  • Thyroid problems

Diabetes. Timolol can decrease early signs of low blood sugar, such as fast heartbeat, and make it more likely for the low blood sugar to be serious, especially for people with diabetes.

Pregnancy. It is not known if or how timolol could affect pregnancy or harm a fetus. Tell your health care provider if you are or plan to become pregnant.

Breastfeeding. Timolol passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should stop breastfeeding or stop timolol.

Interactions

Does timolol interact with foods or drinks?

There are no known interactions between timolol and foods or drinks.

It is unknown if drinking alcohol will affect timolol. The risk of dizziness may be increased if you drink alcohol while taking timolol.

Does timolol interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking timolol.

  • Diltiazem and verapamil, which are medicines used to treat chest pain and high blood pressure
  • A nonsteroidal anti-inflammatory drug (NSAID), such as ibuprofen, naproxen, and others, which are contained in many prescription and OTC products for pain, swelling, and fever
  • Clonidine, which is a medicine used to treat high blood pressure and attention deficit hyperactivity disorder (ADHD)
  • Any medicine for irregular heart rate or rhythm
  • Any medicine for high blood pressure 
  • Any medicine for diabetes

This may not be a complete list of medicines that can interact with timolol. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much timolol?

If you or someone else has used too much timolol, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of timolol?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.