| Item |
Information |
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Drug Groups
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approved |
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Description
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A cardioselective beta-1-adrenergic antagonist with no partial agonist activity. [PubChem] |
| Indication |
For the management of hypertension. |
| Pharmacology |
Betaxolol is a competitive, beta(1)-selective (cardioselective) adrenergic antagonist. Betaxolol is used to treat hypertension, arrhythmias, coronary heart disease, glaucoma, and is also used to reduce non-fatal cardiac events in patients with heart failure. Activation of beta(1)-receptors (located mainly in the heart) by epinephrine increases the heart rate and the blood pressure, and the heart consumes more oxygen. Drugs such as betaxolol that block these receptors therefore have the reverse effect: they lower the heart rate and blood pressure and hence are used in conditions when the heart itself is deprived of oxygen. They are routinely prescribed in patients with ischemic heart disease. In addition, beta(1)-selective blockers prevent the release of renin, which is a hormone produced by the kidneys which leads to constriction of blood vessels. Betaxolol is lipophilic and exhibits no intrinsic sympathomimetic activity (ISA) or membrane stabilizing activity. |
| Toxicity |
Oral LD50s are 350 to 400 mg betaxolol/kg in mice and 860 to 980 mg/kg in rats. Predicted symptoms of overdose include bradycardia, congestive heart failure, hypotension, bronchospasm, and hypoglycemia. |
| Affected Organisms |
| • |
Humans and other mammals |
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| Biotransformation |
Primarily hepatic. Approximately 15% of the dose administered is excreted as unchanged drug, the remainder being metabolites whose contribution to the clinical effect is negligible. |
| Absorption |
Absorption of an oral dose is complete. There is a small and consistent first-pass effect resulting in an absolute bioavailability of 89% ± 5% that is unaffected by the concomitant ingestion of food or alcohol. |
| Half Life |
14-22 hours |
| Protein Binding |
50% |
| References |
| • |
Canotilho J, Castro RA: The structure of betaxolol studied by infrared spectroscopy and natural bond orbital theory. Spectrochim Acta A Mol Biomol Spectrosc. 2010 Aug;76(3-4):395-400. Epub 2010 Apr 4.
[Pubmed]
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| External Links |
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