Betagan Ophthalmic

Beta-adrenergic blockers are commonly used in ophthalmology to treat glaucoma. They decrease the production of aqueous humor resulting in decrease intraocular pressure.

Thus, glaucoma is relieved. Topical beta-adrenergic blocking agents have been the first line drugs till recently.

In contrast to the miotics, the beta-blockers do not affect pupil size, the tone of ciliary muscle or outflow facility, but lower intraocular tension by reducing aqueous formation.

This probably results from down-regulation of adenylyl cyclase due to beta-2 receptor blockade in the ciliary epithelium. A secondary effect is also gained due to a reduction in ocular blood flow.

They are as effective as miotics and produce less ocular side effects.

Glaucoma is a group of diseases characterized by a progressive form of optic nerve damage.

This is generally but not necessarily associated with raised (>21 mm Hg) intraocular tension (i.o.t), but the etiology is unknown and there are many risk factors.

The chief therapeutic measure is to lower i.o.t either by reducing secretion of aqueous humor or by promoting its drainage.

On the contrary, ocular beta-blockers are lipophilic with high ocular capture to reduce systemic effects and have no/weak local anesthetic activity to avoid corneal hypoesthesia and damage.

If you are about to start a drug therapy, the risks, and benefits ratio of taking the medicine should be considered. This is a decision that your doctor will make with your active participation.

For this medicine, certain factors that may alter the drug action should be considered.

Present and past illness, drug interactions, hypersensitivity reactions, pregnancy, lactation and metabolic impairments should be considered cautiously.

Always try to answer each question appropriately asked by your physician. If you have had any allergic reaction to such medications or any other medicines, tell your doctor about that.

This is the medicine which is used irrespective of age and sex. Animal studies have shown an adverse effect but there are no adequate studies in pregnancy and lactation.

Hence, potential benefits may warrant use of the drug in pregnant women despite potential risks

Medicines should be used following the directions were given by a doctor. The dose of this medicine will vary according to patient’s condition or requirements.

You should follow the doctor's directions and advice. The amount of medicine that you take must not exceed the maximum therapeutic dose.

Also, the frequency of your daily drug administration and the duration of drug therapy depend on the particular medical problem for which you are taking the medicine.

Certain ocular beta-blockers are widely used in both chronic simple (wide angle) glaucoma and angle closure (narrow-angle) glaucoma. They are:

Timolol: it is the prototype of ocular beta-blockers which is non-selective and has no local anesthetic or intrinsic sympathomimetic activity.

The ocular hypotensive action becomes evident within 1 hour and lasts for ~12 hours. After chronic dosing, the action is smooth and well sustained.

You should start with 0.25% drops twice in a day in case of open-angle glaucoma which can be changed to 0.5% drops in case of inadequate response.

Additionally, topical beta-blocker such as timolol 0.5% is instilled 12 hourly as an adjuvant in angle closure glaucoma.

Betaxolol: it is beta-1 selective blocker offering the advantage of less bronchopulmonary and probably less cardiac, central and metabolic side effects.

In addition, it appears to exert a protective effect on retinal neurons. 0.5% eye drops are usually used in open-angle glaucoma. One drop should be instilled in each eye twice daily.

Levobunolol:  it has been introduced as a once-daily alternative to timolol. The ocular and systemic effects are very similar to timolol except for the longer duration of action.

Other ocular beta-blockers: Carteolol and metipranolol.

Always try to take your medicine in time. If you miss any dose of this medicine, you should take it as soon as possible.

But when it is time for your next dose, then skip the missed dose and go back to your regular dosing schedule.

You should store the medicine in a closed container at room temperature away from heat, moisture, and direct light.

All kinds of medicines should be kept out of the reach of children. Outdated medicine must be disposed of by an appropriate way.

Some important measures should be taken if you feel any discomfort following any drug therapy.

In the case of such drug therapy, you may not need to discontinue the therapy as there are least chances of drug toxicity.

But you should not delay consulting with your physician in case of extreme unwanted effects.

Systemic adverse effects can be minimized by applying mild pressure on the inner canthus of the eye for about 5 min. after instilling the eye drop to prevent entry of the drug into the naso-lacrimal duct from where it is mainly absorbed.

Actually, there are some unwanted side-effects associated with each drug that usually do not need medical attention.

These side-effects usually go away during the treatment episode as your body adjusts to the medicine.

Additionally, your health care professional may advise you about the ways how to prevent or reduce those unwanted side-effects.

Sometimes you may need to consult with the doctor if you feel any serious discomfort.

The following side effects may warrant medical care immediately:

Ocular side effects are generally mild and infrequent and they are stinging, redness and dryness of the eye, corneal hypoesthesia, allergic blepharoconjunctivitis and blurred vision.

Systemic adverse effects are the major limitations in the use of ocular beta-blockers and occur due to absorption through nasolacrimal duct.

Life-threatening bronchospasm has been reported in asthmatic and COPD patients. Bradycardia, accentuation of heart block and CHF are likely, especially in the elderly.