What Is Timolol and How Does It Work?

Timolol is used to treat hypertension (high blood pressure). Timolol is a prescription drug in a group of drugs called beta-blockers. Beta-blockers affect the heart and circulation (blood flow through arteries and veins).

Timolol is available under the following different brand names: Blocadren and Timol.

Dosages of Timolol

Adult and Pediatric Dosages:


  • 5 mg
  • 10 mg
  • 20 mg

Dosage Considerations – Should be Given as Follows:


Adult and Geriatric:

  • 10-30 mg orally every 12 hours
  • Maintenance: 20-40 mg/day
  • No more than 60 mg/day

Acute Myocardial Infarction

Adult and Geriatric:

  • 10 mg orally every 12 hours

Angina (Off-label)

Adult and Geriatric:

  • 15-45 mg/day orally divided every 6-8 hours

Migraine, Prophylaxis

Adult and Geriatric:

  • Initial: 10 mg orally every 12 hours
  • Titrate to 10-30 mg/day


  • Children under 18 years old: safety and efficacy not established

Additional information

Less effective than thiazide diuretics in black and geriatric patients

Shown to decrease mortality in hypertension and post-myocardial infarction

Other Indications and Uses

Off-label: angina pectoris

What Are Side Effects Associated with Using Timolol?

Common side effects of timolol include:

  • allergic reactions (hives, difficulty breathing, swelling of your face, lips, tongue or throat)
  • anxiety
  • chest pain
  • clay-colored stools
  • cold feeling in your hands and feet (Raynaud's phenomenon)
  • dark urine
  • decreased exercise tolerance
  • decreased HDL levels (high density lipoprotein or cholesterol)
  • decreased sex drive
  • depression
  • fatigue
  • feeling tired
  • headache
  • impotence or difficulty having an orgasm
  • increased insulin resistance
  • increased triglyceride levels
  • irregular or abnormal heartbeats
  • lightheadedness, fainting
  • loss of appetite
  • low fever
  • nausea
  • nervousness
  • numbness and tingling
  • rattling sound when breathing
  • shortness of breath
  • sleep problems (insomnia)
  • slow heartbeat
  • stomach pain
  • sudden difficulty breathing
  • swelling
  • swelling of your ankles or feet
  • yellowing of the skin or eyes (jaundice)

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Timolol?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first.

  • Timolol has no known severe interactions with other drugs.
  • Timolol has serious interactions with 29 different drugs.
  • Timolol has moderate interactions with 231 different drugs.
  • Timolol has minor interactions with 30 different drugs.

This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns or for more information about this medicine.

What Are Warnings and Precautions for Timolol?


May exacerbate ischemic heart disease following abrupt withdrawal.

Hypersensitivity to catecholamines has been observed during withdrawal.

Exacerbation of angina and, in some cases, heart attack (myocardial infarction) occurrence after abrupt discontinuation.

When discontinuing chronically administered beta-blockers (particularly with ischemic heart disease) gradually reduce dose over 1-2 week and carefully monitor.

If angina markedly worsens or acute coronary insufficiency develops, reinstate beta-blocker administration promptly, at least temporarily (in addition to other measures appropriate for unstable angina).

Warn patients against interruption or discontinuation of beta-blocker without physician advice.

Because coronary artery disease is common and may be unrecognized, slowly discontinue beta-blocker therapy, even in patients treated only for hypertension.

This medication contains timolol. Do not take Blocadren or Timol if you are allergic to timolol or any ingredients contained in this drug.

Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.


Effects of Drug Abuse

  • None

Short-Term Effects

  • See "What Are Side Effects Associated with Using Timolol?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Timolol?"


Pregnancy and Lactation

  • Use timolol with caution during pregnancy if benefits outweigh risks. Animal studies show risk and human studies are not available or neither animal nor human studies were done.
  • Timolol is excreted in breast milk; the manufacturer recommends avoid breastfeeding. The American Academy of Pediatrics Committee states timolol is compatible with nursing. Consult your physician if breastfeeding.

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