Indications
Betaxolol is a beta blocker. As eye drops it is used to lower raised pressure inside the eye in open-angle glaucoma and ocular hypertension, conditions that can slowly damage the optic nerve and sight if not treated. Tablets of betaxolol are also used in some countries to treat high blood pressure.
How It Works
Betaxolol selectively blocks beta-1 adrenergic receptors. In the eye, this reduces the amount of fluid (aqueous humour) produced, which lowers eye pressure. Because it acts mainly on beta-1 receptors, it is less likely than non-selective beta blockers to tighten the airways. As a tablet it slows the heart and lowers blood pressure.
Dosage and Administration
Eye drops (0.25% suspension or 0.5% solution): usually 1 drop into the affected eye(s) twice a day, or as prescribed. Shake the suspension well before use. Wash your hands, pull down the lower eyelid, put in the drop without touching the eye with the tip, then close the eye and press gently on the inner corner for 1 to 2 minutes to reduce absorption into the body. Remove soft contact lenses before use and wait 15 minutes before reinserting. Tablets for blood pressure: take as prescribed. Use it every day; glaucoma usually has no symptoms, so keep using it even when you feel well.
Interactions
- Oral beta blockers (such as Atenolol or Propranolol): added effects on the heart and eye pressure.
- Verapamil, Diltiazem, Digoxin and Amiodarone: slow heart rate or heart block.
- Insulin and medicines for diabetes: may hide warning signs of low blood sugar.
- Clonidine: rebound high blood pressure if Clonidine is stopped suddenly.
- Other eye drops: leave at least 5 minutes between them.
Contraindications
Do not use if you have a very slow heart rate, certain heart blocks (second or third degree), heart failure that is not controlled, cardiogenic shock, or allergy to betaxolol. Use only with great caution and specialist advice in asthma or severe chronic lung disease.
Side Effects
- Brief stinging, burning or discomfort in the eye after use.
- Watering, itching, redness or blurred vision for a short time.
- Dry eyes or sensitivity to light.
- Slow heartbeat, tiredness, dizziness or cold hands, as some medicine reaches the blood.
Get urgent medical help for wheezing or difficulty breathing, fainting, a very slow or irregular heartbeat, chest pain, swelling of the face or throat, or sudden loss of vision or severe eye pain.
Pregnancy and Lactation
Use in pregnancy only if your doctor decides the benefit is greater than the risk, as beta blockers may slow the baby’s heart rate and growth. Small amounts may pass into breast milk; ask your doctor before use while breastfeeding.
Precautions and Warnings
Tell your doctor if you have asthma or other lung disease, heart disease, diabetes, an overactive thyroid, myasthenia gravis or poor circulation. Tell the surgeon or anaesthetist before any operation. Blurred vision may affect driving. Do not stop tablets suddenly. Have regular eye checks.
Overdose
Too much may cause slow heartbeat, low blood pressure, dizziness and breathing problems. If drops are swallowed or too many are used, seek medical help. If too much gets in the eye, rinse with warm water.
Therapeutic Class
Selective beta-1 blocker; antiglaucoma agent.
Storage
Store below 30°C, do not freeze, keep the bottle tightly closed and away from light, and out of the reach of children. Discard eye drops 4 weeks after opening.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.