Timolol

What is Timolol?

• Timolol (Blocadren) is a nonselective beta-adrenergic receptor blocking agent used for the therapy of hypertension, angina pectoris and prevention of vascular headaches.
• In addition, timolol is available in an ophthalmic formulation for therapy of ocular hypertension and glaucoma.

Timolol structure

Timolol

Timolol ball-and-stick

What are the uses of this medicine?

Timolol (Blocadren) is used for:

• the treatment of hypertension. They may be used alone or in combination with other antihypertensive agents, especially thiazide-type diuretics.
• Myocardial Infarction. Timolol is indicated in patients who have survived the acute phase of myocardial infarction, and are clinically stable, to reduce cardiovascular mortality and the risk of reinfarction.
• the prophylaxis of migraine headache.

How does this medicine work?

• Timolol (tim' oh lol) is a nonselective beta-blocker, acting on both beta-1 and beta-2 adrenergic receptors.
• Timolol competitively binds to beta 1 adrenergic receptors in the heart and vascular smooth muscle and beta 2 receptors in the bronchial and vascular smooth muscle, resulting in a decrease in beta adrenergic stimulation.
• Beta 1 receptor blockade results in a decrease in resting and exercise heart rate and cardiac output, a decrease in both systolic and diastolic blood pressure, and, possibly, a reduction in reflex orthostatic hypotension.
• Beta 2 blockade results in an increase in peripheral vascular resistance.
• The ultimate results include vasodilation, and negative chronotropic and inotropic effects.

Who Should Not Use this medicine ?

This medicine cannot be used in patients with:

• bronchial asthma or with a history of bronchial asthma
• severe chronic obstructive pulmonary disease
• sinus bradycardia
• second- and third-degree atrioventricular block
• overt cardiac failure
• cardiogenic shock
• hypersensitivity to this product

What drug interactions can this medicine cause?

• Tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take.

Be sure to mention any of the following:

• aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) and naproxen (Aleve, Naprosyn)
• clonidine (Catapres, Kapvay, in Clorpres)
• digoxin (Lanoxin)
• diltiazem (Cardizem, Cartia XT, Dilacor, Tiazac, others)
• medications for glaucoma
• nifedipine (Adalat, Afeditab CR, Procardia)
• other medications for heart disease or high blood pressure, quinidine, reserpine , and verapamil (Calan, Covera, Verelan)

Is this medicine FDA approved?

• Timolol was approved for use in the United States in 1995 and is still in wide use.
• Timolol is available in tablets of 5, 10 and 20 mg in generic forms and formerly under the trade name Blocadren.
• In addition, timolol is available in an ophthalmic formulation for therapy of ocular hypertension and glaucoma.

How should this medicine be used?

Recommended dosage: Hypertension:

• The usual initial dosage of timolol maleate is 10 mg twice a day, whether used alone or added to diuretic therapy.
• Dosage may be increased or decreased depending on heart rate and blood pressure response.
• The usual total maintenance dosage is 20 to 40 mg per day.
• Increases in dosage to a maximum of 60 mg per day divided into two doses may be necessary.

Myocardial Infarction:

• The recommended dosage for long-term prophylactic use in patients who have survived the acute phase of a myocardial infarction is 10 mg given twice daily.

Migraine:

• The usual initial dosage of timolol maleate is 10 mg twice a day.
• During maintenance therapy the 20 mg daily dosage may be administered as a single dose.
• Total daily dosage may be increased to a maximum of 30 mg, given in divided doses, or decreased to 10 mg once per day, depending on clinical response and tolerability.

Administration:

• Timolol comes as a tablet to take by mouth.
• It is usually taken one or two times a day.
• To help you remember to take timolol, take it around the same time every day.
• Timolol helps control your condition but will not cure it.
• Continue to take timolol even if you feel well.
• Do not stop taking timolol without talking to your doctor.

What are the dosage forms and brand names of this medicine?

This medicine is available in fallowing doasage form:

• As tablets containing 5 mg, 10 mg and 20 mg timolol maleate for oral administration.

This medicine is available in fallowing brand namesː

• Blocadren

What side effects can this medication cause?

The most common side effects of this medicine include:

• fatigue/tiredness
• headache
• chest pain
• asthenia
• bradycardia
• arrhythmia
• syncope
• edema
• dyspepsia
• nausea
• pruritus
• dizziness
• vertigo
• paresthesia
• decreased libido
• dyspnea
• bronchial spasm
• rales
• eye irritation
• tinnitus

• Less commonly severe hypotension, heart failure and bronchospasm. As with all beta-blockers, sudden withdrawal can trigger rebound hypertension.

What special precautions should I follow?

• Continued depression of the myocardium with beta-blocking agents over a period of time can, in some cases, lead to cardiac failure. At the first sign or symptom of cardiac failure, patients receiving timolol should be digitalized and/or be given a diuretic, and the response observed closely.
• Exacerbation of angina and, in some cases, myocardial infarction have occurred after abrupt discontinuation of such therapy. When discontinuing chronically administered timolol maleate, particularly in patients with ischemic heart disease, the dosage should be gradually reduced over a period of one to two weeks and the patient should be carefully monitored.
• The necessity or desirability of withdrawal of beta-blocking therapy prior to major surgery is controversial. For these reasons, in patients undergoing elective surgery, some authorities recommend gradual withdrawal of beta-adrenergic receptor blocking agents.
• Beta-adrenergic receptor blocking agents may mask the signs and symptoms of acute hypoglycemia. Timolol should be administered with caution in patients subject to spontaneous hypoglycemia or to diabetic patients.
• Beta-adrenergic blockade may mask certain clinical signs (e.g., tachycardia) of hyperthyroidism. Patients suspected of developing thyrotoxicosis should be managed carefully to avoid abrupt withdrawal of beta-blockade which might precipitate a thyroid storm.
• Beta-adrenergic blockade has been reported to potentiate muscle weakness consistent with certain myasthenic symptoms. Timolol has been reported rarely to increase muscle weakness in some patients with myasthenia gravis or myasthenic symptoms.
• If you are having surgery, including dental surgery, tell the doctor or dentist that you are taking timolol.
• You should know that Timolol may make you drowsy. Do not drive a car or operate machinery until you know how this medication affects you.
• Remember that alcohol can add to the drowsiness caused by Timolol.
• Timolol has yet to be convincingly associated with clinically apparent liver injury and is often used in patients with liver disease and cirrhosis.

What to do in case of emergency/overdose?

Symptoms of overdosage may include:

• irregular heart beat, hypertension, dizziness, tinnitus, faintness, increased pulse rate and borderline first degree heart block

The most common signs and symptoms to be expected with overdosage with a beta-adrenergic receptor blocking agent are symptomatic bradycardia, hypotension, bronchospasm, and acute cardiac failure.

Management of overdosage: Therapy with timolol should be discontinued and the patient observed closely.

The following additional therapeutic measures should be considered:

• Gastric lavage
• Use atropine sulfate intravenously in a dosage of 0.25 mg to 2 mg to induce vagal blockade. If bradycardia persists, intravenous isoproterenol hydrochloride should be administered cautiously
• For hypotension use sympathomimetic pressor drug therapy, such as dopamine, dobutamine or norepinephrine. In refractory cases the use of glucagon hydrochloride has been reported to be useful.
• For Bronchospasm use isoproterenol hydrochloride. Additional therapy with aminophylline may be considered.
• For Acute cardiac failure conventional therapy with digitalis, diuretics, and oxygen should be instituted immediately. In refractory cases the use of intravenous aminophylline is suggested.
• For heart block (second- or third-degree) use isoproterenol hydrochloride or a transvenous cardiac pacemaker.

Can this medicine be used in pregnancy?

There are no adequate and well controlled studies in pregnant women.

• Timolol should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Can this medicine be used in children?

• Safety and effectiveness in pediatric patients have not been established.

What are the active and inactive ingredients in this medicine?

Active ingredient:

• TIMOLOL MALEATE

Inactive ingredients:

• SILICON DIOXIDE
• CROSCARMELLOSE SODIUM
• MAGNESIUM STEARATE
• MICROCRYSTALLINE CELLULOSE
• STARCH, CORN
• SODIUM LAURYL SULFATE
• FD&C BLUE NO. 2
• D&C YELLOW NO. 10

Who manufactures and distributes this medicine?

• Mylan Pharmaceuticals Inc.
• Morgantown, WV

What should I know about storage and disposal of this medication?

• Store at 20° to 25°C (68° to 77°F).
• Protect from light.

Antihypertensive agents

• Dailymed label info on Timolol
• FDA Timolol

Timolol Resources
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