Source: Υπουργείο Υγείας (CY) Revision Year: 2019 Publisher: Medochemie Ltd., 1-10 Constantinoupoleos street, 3011 Limassol, Cyprus
Pharmacotherapeutic group: Beta blocking agents, selective, Beta blocking agents
ATC Code: C07AB05
Betaxolol HCl is a β1- selective adrenergic receptor blocking agent. Betaxolol has a strong beta-adrenolytic long-lasting effect. This effect is still detectable 24 hours after ingestion of 20 mg betaxolol. Following administration of therapeutic doses betaxolol causes a significant reduction in arterial blood pressure, heart rate and stroke volume. It has a weak membrane-stabilising activity and no intrinsic sympathomimetic activity. Betaxolol causes no reduction in natriuresis.
Betaxolol lowers plasma renin activity. The known effect of beta blockers on blood lipids is low for betaxolol. Blood pressure-lowering effect of 20 mg per 24 hours betaxolol is comparable to atenolol (100 mg/day) or propranolol (160-320 mg/day).
The anti-ischemic and anti-angina effect of betaxolol (20 mg single dose) is comparable.with other beta-blockers such as propranolol (160 mg, divided into several individual doses) or atenolol (100 mg single dose). The daily intake of 20 mg betaxolol as a single dose keeps an effect over 24 hours.
Side effects and discontinuation rate are similar to other beta-blockers.
A patient study (n= 4685) shows no significant change in following parameters:
Because of the small influence of the first pass, bioavailability of betaxolol fter oral administration is about 80%. Proteine binding is 50%. Betaxolol is lipo-soluble and distributed in the extracellular space. The distribution volume is about 6 l/kg;
85-90% of the administered dose is metabolised in the liver. Only one metabolite (2-3% of the administered dose), obtained after an aliphatic hydroxylation, has a maximum beta-blocking effect. This is selective and corresponds to about 50% betaxolol.
10-15% of the administered dose is excreted unchanged through the kidneys. The metabolites are mainly excreted by the kidney.
73-83% of dose is recovered in urine. Only 1-3% is excreted through the intestines. The peak plasma levels are at 2-4 hours after oral intake of 20 mg beatxolol and ranging from 30 to 60 ng/ml.
The intra- and inter-individual variation of the peak plasma levels or in the steady state are very low.
The plasma elimination half-life (16-20 h) enables a single daily dose. In elderly and in patients with renal insufficiency undergoing dialysis, the plasma elimination half-life is prolonged (24-30 h). In these cases, the dose should be reduced by half.
In case of liver insufficiency no significant changes in pharmacokinetic values were observed.
Chronic toxicity is based on rat and dog studies. Betaxolol was found to be relatively well tolerated. No unexpected findings were collected.
In vivo and in vitro tests revealed no mutagenic potential of the drug. Carcinogenicity studies (in mouse and rat) also provided no evidence for a carcinogenic potential.
So far there is no evidence of teratogenic effects in humans. Beta-blockers can lead to the placental blood flow reduction, resulting in intrauterine fetal death, miscarriage or premature birth. Furthermore, they can cause the occurrence of side effects (especially hypoglycaemia and bradycardia) in the fetus.
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