Betaxolol
Encyclopedia
Betaxolol is a selective beta1 receptor blocker
used in the treatment of hypertension
and glaucoma
. Being selective for beta1 receptors, it typically has fewer systemic side effect
s than non-selective beta-blockers, for example, not causing bronchospasm
(mediated by beta2 receptors) as timolol
may. Betaxolol also shows greater affininty for beta1 receptors than metoprolol
. In addition to its effect on the heart, betaxolol reduces the pressure within the eye (intraocular pressure
). This effect is thought to be caused by reducing the production of the liquid (which is called the aqueous humor) within the eye. The precise mechanism of this effect is not known. The reduction in intraocular pressure reduces the risk of damage to the optic nerve
and loss of vision in patients with elevated intraocular pressure due to glaucoma
.
Betaxolol was approved by the U.S. Food and Drug Administration
(FDA) for ocular use as a 0.5% solution (Betoptic) in 1985 and as a 0.25% solution (Betoptic S) in 1989.
Beta blocker
Beta blockers or beta-adrenergic blocking agents, beta-adrenergic antagonists, beta-adrenoreceptor antagonists or beta antagonists, are a class of drugs used for various indications. They are particularly for the management of cardiac arrhythmias, cardioprotection after myocardial infarction ,...
used in the treatment of hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
and glaucoma
Glaucoma
Glaucoma is an eye disorder in which the optic nerve suffers damage, permanently damaging vision in the affected eye and progressing to complete blindness if untreated. It is often, but not always, associated with increased pressure of the fluid in the eye...
. Being selective for beta1 receptors, it typically has fewer systemic side effect
Adverse drug reaction
An adverse drug reaction is an expression that describes harm associated with the use of given medications at a normal dosage. ADRs may occur following a single dose or prolonged administration of a drug or result from the combination of two or more drugs...
s than non-selective beta-blockers, for example, not causing bronchospasm
Bronchospasm
Bronchospasm or a bronchial spasm is a sudden constriction of the muscles in the walls of the bronchioles. It is caused by the release of substances from mast cells or basophils under the influence of anaphylatoxins...
(mediated by beta2 receptors) as timolol
Timolol
Timolol maleate is a non-selective beta-adrenergic receptor blocker.-Uses:In its oral form , it is used:* to treat high blood pressure* to prevent heart attacks* to prevent migraine headaches...
may. Betaxolol also shows greater affininty for beta1 receptors than metoprolol
Metoprolol
Metoprolol is a selective β1 receptor blocker used in treatment of several diseases of the cardiovascular system, especially hypertension. The active substance metoprolol is employed either as metoprolol succinate or metoprolol tartrate...
. In addition to its effect on the heart, betaxolol reduces the pressure within the eye (intraocular pressure
Intraocular pressure
Intraocular pressure is the fluid pressure inside the eye. Tonometry is the method eye care professionals use to determine this. IOP is an important aspect in the evaluation of patients at risk from glaucoma...
). This effect is thought to be caused by reducing the production of the liquid (which is called the aqueous humor) within the eye. The precise mechanism of this effect is not known. The reduction in intraocular pressure reduces the risk of damage to the optic nerve
Optic nerve
The optic nerve, also called cranial nerve 2, transmits visual information from the retina to the brain. Derived from the embryonic retinal ganglion cell, a diverticulum located in the diencephalon, the optic nerve doesn't regenerate after transection.-Anatomy:The optic nerve is the second of...
and loss of vision in patients with elevated intraocular pressure due to glaucoma
Glaucoma
Glaucoma is an eye disorder in which the optic nerve suffers damage, permanently damaging vision in the affected eye and progressing to complete blindness if untreated. It is often, but not always, associated with increased pressure of the fluid in the eye...
.
Betaxolol was approved by the U.S. Food and Drug Administration
Food and Drug Administration
The Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...
(FDA) for ocular use as a 0.5% solution (Betoptic) in 1985 and as a 0.25% solution (Betoptic S) in 1989.
Clinical uses
- Oral: for the management of hypertension
- Ophthalmic: for the management of glaucoma
- the drug seems to have an effect of neuroprotection in glaucoma treatment
Dosage
- Oral: The initial dose in hypertension is ordinarily 10 mg once daily either alone or added to diuretic therapy.
- Ophthalmic: The recommended dose one to two drops in the affected eye(s) twice daily.
Contraindications
- Hypersensitivity to the drug
- Patients with sinus bradycardia, heart block greater than first degree, cardiogenic shock, and overt cardiac failure