Betimol - Use | Dosage | Side Effects
Betimol as an active substance contains timolol which belongs to the non-selective beta blockers. When administered locally, it reduces the production of aqueous humor, and leads to the reduction of intraocular pressure. Betimol eye drops are used for the local treatment of the following conditions:
- Chronic open-angle glaucoma
- Secondary glaucoma
- Aphakic glaucoma
- Ocular hypertension
Contraindications and precautions
Betimol is contraindicated in the following conditions:
- Second or third-degree atrioventricular (AV) block. Betimol is a beta blocker and slows the heart rate. Therefore, the use of this drug in patients with AV block should be avoided because it can lead to serious complications (e.g. cardiac arrest).
- Cardiogenic shock
- Sinus bradycardia
- Bronchial asthma. Betimol is a non-selective beta blocker which means that it blocks beta receptors on the airway smooth muscles and leads to the bronchoconstriction, which can trigger an asthma attack.
- Decompensated heart failure. Betimol exhibit negative inotropic effect, which means that it decreases contractile force of the heart muscle and this may exacerbate the condition in patients suffering from this disease.
Like other eye drops Betimol may also diffuse from the eye surface into the systemic circulation where it may exhibit systemic side effects. Therefore, Betimol should be avoided in patients who are already being treated with an oral beta-blocker.
Betimol, pregnancy and breastfeeding
Since Betimol may diffuse into systemic circulation and pass through the placental barrier, Betimol should be avoided during pregnancy. Beta blockers can cause bradycardia, hypotension and hypoglycemia in the babies after delivery.
AU TGA and FDA category: C. Animal studies have revealed / proven toxicity of this drug on the fetus, but there are no studies on humans.
Betimol passes into breast milk and your physician needs to evaluate the benefit / risk ratio of discontinuation of the breastfeeding or the Betimol therapy.
How to apply Betimol?
Betimol exists in the form of eye drops and is available in two different doses: 0.25% and 0.5%.
The recommended dosage is given in the table below:
|One drop of Betimol 0.25% in the affected eye two times a day. In severe conditions, the dose may be increased to one drop of Betimol 0.5% in the affected eye two times a day.|
The safety and efficacy of this drug in children younger than 12 years have not been established and is not recommended.
This drug works quickly, and reduces intraocular pressure within 15-25 minutes after topical application. Maximum reduction of intraocular pressure occurs 1-2 hours after topical application and lasts 12 to 24 hours.
A few tips for using Betimol eye drops:
- Before applying the medicine you need to wash your hands, because of the risk of developing an eye infection
- If you wear soft lenses, you must remove them before applying the drops and you can put them back after 20-30 minutes.
- Tilt your head back, pull down your lower eyelid with your finger to create a "pocket"
- Grab a medicine bottle between thumb and index finger and gently squeeze one drop into the inner corner of the eye ("pocket").
- Do not touch the surface of the eye with the tip of the bottle because it increases the risk of developing an eye infection.
- After the application, close your eyes and press on the inner corner of the eye with your fingertips and hold your eyes closed for 2 minutes.
- After the application, promptly return the medicine bottle in a box and take care not to touch the dirty surfaces.
Betimol can interact with the following medications:
- Beta-agonists, such as: salmeterol, albuterol and formoterol. These drugs are used to treat asthma. Concomitant administration with Betimol eye drops can reduce the effects of these drugs.
- Epinephrine (adrenaline), a drug used to treat severe allergic reactions. Betimol can reduce the effectiveness of epinephrine.
- Aminophylline, oxtriphylline, dyphylline and theophylline (medications used to treat asthma). These drugs reduce the effectiveness of the Betimol.
- Methyldopa (a drug used for hypertension treatment).
- Calcium antagonists (verapamil and diltiazem). Concomitant use with these drugs increases the risk of bradycardia.
- Clonidine and reserpine (medicines used to control high blood pressure). Concomitant use with these drugs increases the risk of hypotension.
- Thiazide diuretics (e.g. hydrochlorothiazide).
Betimol may cause the following side effects:
- Decreased corneal sensitivity
- Vasoconstriction and hypertension
- Loss of appetite