BMA Concise Guide to Medicine & Drugs

Timolol

Brand names Betim, Nyogel, Timoptol, Timoptol LA

Used in the following combined preparations Combigan, Cosopt, DuoTrav, Ganfort, Prestim, Xalacom

QUICK REFERENCE

Drug group Beta blocker and drug for glaucoma

Overdose danger rating High

Dependence rating Low

Prescription needed Yes

Available as generic Yes

GENERAL INFORMATION

Timolol is a non-cardioselective beta blocker used to treat angina. It may be given after a heart attack to prevent further damage to the heart. Timolol is also used to treat hypertension (high blood pressure), but is not usually used to initiate treatment. It is also commonly given as eye drops to people with certain types of glaucoma and is occasionally given to prevent migraine. Timolol can occasionally cause breathing difficulties, especially in people with respiratory diseases; this is more likely with the tablets, but it can also occur in people using the eye drops. Timolol may also mask the body’s response to low blood sugar and, for that reason, is prescribed with caution to diabetics on insulin.

INFORMATION FOR USERS

Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.

How taken/used Tablets, eye drops.

Frequency and timing of doses 1–3 x daily.

Adult dosage range By mouth 10–60mg daily (hypertension); 10–60mg daily (angina/hypertension); 10–20mg daily (after a heart attack); 10–20mg daily (migraine prevention).

Onset of effect Within 30 minutes (by mouth); 15–20 minutes (eye drops).

Duration of action Up to 24 hours.

Diet advice None.

Storage Keep in original container at room temperature out of the reach of children.

Missed dose Take as soon as you remember. If your next dose is due within 3 hours, take a single dose now and skip the next.

Stopping the drug Do not stop taking the drug without consulting your doctor; stopping the drug may lead to worsening of the underlying condition.

OVERDOSE ACTION

Seek immediate medical advice in all cases of overdose by mouth. Take emergency action if breathing difficulties, palpitations, or loss of consciousness occur.

POSSIBLE ADVERSE EFFECTS

Eye drops commonly cause only irritation of the eyes, which, if severe, should be discussed with your doctor. Rarely, the drug may be absorbed from the eyes into the body and cause the systemic side effects that may occur with oral use. All systemic adverse effects should be reported to your doctor. The most common systemic effects are lethargy, fatigue, and cold hands and feet. Nausea and vomiting are less common. Also uncommon are vivid dreams or nightmares, rash, dry eyes, and visual disturbances; you should stop taking the drug if any of these occur. Timolol can also occasionally provoke or worsen heart problems and asthma. If you experience fainting or palpitations (which may be a sign that the drug has slowed the heartbeat or lowered blood pressure excessively), breathlessness, or wheezing, you should stop taking the drug and contact your doctor immediately.

INTERACTIONS

Calcium channel blockers may cause low blood pressure, a slow heartbeat, and heart failure if used with timolol.

Cardiac glycosides (e.g. digoxin) may increase the heart-slowing effect of timolol.

Antihypertensive drugs Timolol may enhance the blood-pressure-lowering effect.

Drugs for asthma (e.g. salbutamol, salmeterol, and other beta agonists) The effects of these drugs may be reduced by timolol.

SPECIAL PRECAUTIONS

Be sure to tell your doctor if:

· You have heart problems.

· You have kidney or liver problems.

· You have a lung disorder such as asthma, bronchitis, or emphysema.

· You have diabetes.

· You have psoriasis.

· You are taking other medicines.

Pregnancy Safety in pregnancy not established. Discuss with your doctor.

Breast-feeding The drug passes into the breast milk, but at normal doses adverse effects on the baby are unlikely. Discuss with your doctor.

Infants and children Not usually prescribed.

Over 60 Reduced dose may be necessary.

Driving and hazardous work Avoid such activities until you have learned how timolol affects you because the tablets may cause dizziness or fatigue, and the eye drops may cause blurred vision.

Alcohol Avoid excessive intake. Alcohol may increase the blood-pressure-lowering effects of timolol.

Surgery and general anaesthetics Occasionally, timolol eye drops may need to be stopped before you have a general anaesthetic, but only do this after discussion with your doctor or dentist.

PROLONGED USE

No problems expected.