Betaxolol

Betaxolol is a beta blocker used in the treatment of hypertension and angina.
It acts as a selective β₁-adrenergic receptor antagonist.
The drug was patented in 1975 and approved for medical use in 1983.

Medical uses

Hypertension

Betaxolol is most commonly ingested orally alone or with other medications for the management of essential hypertension. It is a cardioselective beta blocker, targeting beta-1 adrenergic receptors found in the cardiac muscle. Blood pressure is decreased by the mechanism of blood vessels relaxing and improving the flow of blood.

Glaucoma

Ophthalmic betaxolol is an available treatment for primary open angle glaucoma and optical hypertension. Betaxolol effectively prevents the increase of intracellular calcium, which leads to increased production of the aqueous humor. In the context of open angle glaucoma, increased aqueous humor produced by ciliary bodies increases intraocular pressure, causing degeneration of retinal ganglion cells and the optic nerve.
Furthermore, betaxolol is additionally able to protect retinal neurones following topical application from excitotoxicity or ischemia-reperfusion, providing a neuroprotective effect. This is thought to be attributed to its capacity to attenuate neuronal calcium and sodium influx. Betaxolol is also an effective treatment for Intraocular pressure

Other uses

Betaxolol has been used to treat anxiety as well.
One study showed that topical betaxolol can be used in treating relapsed paronychia.

Contraindications

Hypersensitivity to the drug
Patients with sinus bradycardia, heart block greater than first degree, cardiogenic shock, and overt cardiac failure

Side effects

The adverse side effects of betaxolol can be categorized into local and systemic effects. The local effects include:

transient irritation
burning
pruritus, or general itching
punctate keratitis
blurry vision

Systemically, patients taking betaxolol might experience:

bradycardia
hypotension
fatigue
sexual impotence
hair loss
confusion
headache
dizziness
bronchospasm at higher doses
cardiac problems such as arrhythmia, bundle branch block, myocardial infarction, sinus arrest, and congestive heart failure
mental effects such as depression, disorientation, vertigo, sleepwalking, rhinitis
dysuria
metabolic side effects such as an increase in LDL cholesterol levels
can mask the symptoms of hypoglycemia diabetic patients

Pharmacology

Pharmacodynamics

Betaxolol is a beta blocker and acts specifically as a selective β₁-adrenergic receptor antagonist. It has no partial agonist action and shows minimal membrane-stabilizing activity. Being selective for beta₁ receptors, it typically has fewer systemic side effects than non-selective beta-blockers, for example, not causing bronchospasm as timolol may. Betaxolol also shows greater affinity for beta₁ receptors than metoprolol. In addition to its effect on the heart, betaxolol reduces the pressure within the eye. This effect is thought to be caused by reducing the production of the liquid 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.

Chemistry

The experimental log P of betaxolol is 2.4 to 2.81.

History

Betaxolol was approved by the U.S. Food and Drug Administration for ocular use as a 0.5% solution in 1985 and as a 0.25% solution in 1989.

Society and culture

Brand names

Brand names include Betoptic, Betoptic S, Lokren, Kerlone.