Cost-Effectiveness of Rate- and Rhythm-Control Drugs for Treating Atrial Fibrillation in Korea

PURPOSE: Although the economic and mortality burden of atrial fibrillation (AF) is substantial, it remains unclear which treatment strategies for rate and rhythm control are most cost-effective. Consequently, economic factors can play an adjunctive role in guiding treatment selection. MATERIALS AND METHODS: We built a Markov chain Monte Carlo model using the Korean Health Insurance Review & Assessment Service database. Drugs for rate control and rhythm control in AF were analyzed. Cost-effective therapies were selected using a cost-effectiveness ratio, calculated by net cost and quality-adjusted life years (QALY). RESULTS: In the National Health Insurance Service data, 268149 patients with prevalent AF (age ≥18 years) were identified between January 1, 2013 and December 31, 2015. Among them, 212459 and 55690 patients were taking drugs for rate and rhythm control, respectively. Atenolol cost $714/QALY. Among the rate-control medications, the cost of propranolol was lowest at $487/QALY, while that of carvedilol was highest at $1363/QALY. Among the rhythm-control medications, the cost of pilsicainide was lowest at $638/QALY, while that of amiodarone was highest at $986/QALY. Flecainide and propafenone cost $834 and $830/QALY, respectively. The cost-effectiveness threshold of all drugs was lower than $30000/QALY. Compared with atenolol, the rate-control drugs propranolol, betaxolol, bevantolol, bisoprolol, diltiazem, and verapamil, as well as the rhythm-control drugs sotalol, pilsicainide, flecainide, propafenone, and dronedarone, showed better incremental cost-effectiveness ratios. CONCLUSION: Propranolol and pilsicainide appear to be cost-effective in patients with AF in Korea assuming that drug usage or compliance is the same.

Neuroprotective Effects of Betaxolol Mediated by Heme Oxygenase-1 Induction in RGC-5

PURPOSE: To evaluate the neuroprotective effects of betaxolol (betaxolol hydrochloride) under hypoxic conditions using retinal ganglion cells (RGC-5) and determine whether heme oxygenase-1 (HO-1) expression exerts cytoprotective effects. METHODS: In this study, cultured RGC-5 cells were incubated with different concentrations of betaxolol hydrochloride (0.1 microM, 1 microM or 5 microM) and with 10 microM zinc protoporphyrin (ZnPP), in a hypoxia incubator (1% O2, 5% CO2, 94% N2) for 48 hours and the cell viability of each group was determined. Additionally, cell viability was measured after RGC-5 cells were incubated with 5 microM of brinzolamide (Azopt(R)), brimonidine tartrate (Alphagan(R)) or travoprost (Travatan(R)). RGC-5 cells were divided into three groups and incubated under three different conditions, normoxia group (20% O2, 5% CO2), hypoxia group (1% O2, 5% CO2) and the group with 5 microM of Betoptic S(R) treated under hypoxic conditions (hypoxia, Betoptic S(R)). After incubation for 4, 8, 12 and 24 hours, HO-1 expression was analyzed using Western blotting. RESULTS: Cell viability significantly increased in RGC-5 cells treated with Betoptic S(R) compared with other antiglaucoma agents. Increased levels of HO-1 expression indicate its relevance in cell viability. Furthermore, increased RGC-5 cell viability by Betoptic S(R) was significantly reduced in the HO-1 inhibitor ZnPP-treated group. CONCLUSIONS: We reaffirmed the known cytoprotective effects of Betoptic S(R) and the results suggests that HO-1 expression exerts cytoprotective effects against hypoxia.

Influence of Betaxolol on the Methamphetamine Dependence in Mice

OBJECTIVE: The noradrenaline system is involved in the reward effects of various kinds of abused drugs. Betaxolol (BTX) is a highly selective β1-antagonist. In the present study, we evaluated the effect of BTX on methamphetamine (MAP)-induced conditioned place preference (CPP) and hyperactivity in mice. METHODS: The mice (n=72) were treated with MAP or saline every other day for a total of 6 days (from day 3 to day 8; 3-times MAP and 3-times saline). Each mouse was given saline (1 mL/kg) or MAP (1 mg/kg, s.c.) or BTX (5 mg/kg, i.p.) or MAP with BTX (5 mg/kg, i.p.) 30 min prior to the administration of MAP (1 mg/kg, s.c.) every other day and paired with for 1 h (three-drug and three-saline sessions). We then compared the CPP score between the two groups. After the extinction of CPP, the mice were given BTX (5 mg/kg, i.p.) or saline (1 mL/kg) 24 h prior to a priming injection of MAP, and were then immediately tested to see whether the place preference was reinstated. RESULTS: The repeated administration of BTX 30 min prior to the exposure to MAP significantly reduced the development of MAP-induced CPP. When BTX was administered 24 h prior to the CPP-testing session on day 9, it also significantly attenuated the CPP, but did not result in any change of locomotor activity. In the drug-priming reinstatement study, the extinguished CPP was reinstated by a MAP (0.125 mg/kg, s.c.) injection and this was significantly attenuated by BTX. CONCLUSION: These findings suggest that BTX has a therapeutic and preventive effect on the development, expression, and drug-priming reinstatement of MAP-induced CPP.

effectiveness and safety profile of latanoprost in Libyan patients with primary open angle glaucoma

Latanoprost has proven to be an effective ocular hypotensive in healthy eyes and in eyes with elevated intraocular pressure. In this study the effect on intraocular pressure [IOP] and safety profile of topical applications of Latanoprost alone or combined with Betaxolol is investigated. A total of 25 eyes [25 patients] with open angle glaucoma were included in a 3 months prospective study. Mean age was 55.25 years [range 34-69]. They were allocated to a 4 weeks treatment with once daily administration of Latanoprost 0.005%, followed by 8 weeks' combination with Betoptic 0.5% topical drops twice daily therapy. The effect of Latanoprost alone reduced IOP from 26.48 [SD +/- 5.16] to 20.92 [SD +/- 3.8] mm Hg [p <0.005]. The addition of Betopic eye drops produced further reduction of IOP to 15.16 [SD +/- 2.81] mm Hg [p <0.005]. Latanoprost have a clinically significant IOP lowering effect. The effect of Xalatan on IOP is increased when combined with Betaxolol. No serious side effects were reported

[comparison of ocular hypotensive response to betaxolol and timolol and their topical and systemic side effects]

This is a study to compare the efficacy and side effects of betaxolol and timolol in lowering the IOP of primary open angle glaucoma or ocular hypertension. This Double-blind randomized cross-over clinical trial was conducted on 29 eyes of 20 patients with primary open angle glaucoma or ocular hypertension. Each patient received timolol 0.5% and betaxolol 0.5% [SINA DAROU] twice daily for four weeks in two phases. Before and between the two courses of treatment there was a wash-out period. At the end of the study the effect of these two drugs on intraocular pressure [lOP], mean arterial blood pressure, pulse rate, and basic tear secretion in addition to ocular symptoms were evaluated and statistically analyzed. The study was performed on 29 eyes of 20 patients with baseline IOP of 28,45 +/- 1.64 mmHg. After 4 weeks of treatment, timolol and betaxolol reduced IOP by 7.24 +/- 1.97 mmHg 25.36 +/- 1.22% and 3.55 +/- 1.18 mmHg 12.52 +/- 0.82%, respectively [P<0.001] and the difference between the two groups was also significant [P<0.001]. Mean arterial blood pressure was reduced with betaxolol and timolol by 6.37 +/- 3.96 mmHg [P<0.001], and 6.30 +/- 3.84 mmHg [P<0.001], respectively, but the difference between two groups was not statistically significant. Pulse rate was reduced with timolol and betaxolol by 7.37 +/- 3.22 beats /min, and 7.41 +/- 3.77 beats /min, respectively P>0.05. No significant difference was considered between two groups. Mean reduction in basic tear secretion with timolol and betaxolol was 1.31 +/- 0.66 mm/5min and 1.48 +/- 0.82 mm/5min, respectively; intergroup comparison was also not significant. Patients in 62.1% of the betaxolol group and 27.2% of the timolol group complained about eye burning. The differece between two groups was significant [P<0.01]. lacrimation-eye pruritis and bitter tastes was more in betaxolol group. Other symptoms were similar between two groups. Timolol is superior to betaxolol in treatment of early glaucoma or ocular hypertension, but both drugs should be used with caution in patients with cardiovascular compromise

Treatment of Normal-tension Glaucoma

Normal tension glaucoma (NTG) is a disorder showing the characteristic optic nerve head damage and visual field defect with a normal intraocular pressure (IOP) and open anterior chamber angle, without any other disorders that may induce a damage to the optic nerve head and visual field. A disturbance in the vascular supply to the optic nerve head is thought to be the main etiologic factor in this disorder. A thirty percent reduction of IOP from the baseline can delay or prevent the disease progress of glaucoma, and the treatment of NTG is focused on relieving any vascular disturbance to the optic nerve head and reducing IOP. The target pressure in NTG should be individualized in each patient by age, presence of any systemic vascular disorder, the degree of optic disc damage, and response to anti-glaucoma medications. It should also be carefully and regularly re-evaluated during follow-up. Since most patients with NTG are old, the selection of anti-glaucoma medication needs a careful consideration of the systemic status of the patient. Pilocarpine effectively reduces IOP, but has limitations from side effects including miosis. Nonselective beta-blocking agents may induce serious systemic side effects and can reduce the perfusion pressure to the optic nerve head. Brimonidine reduces the aqueous inflow, increases the uveoscleral outflow, and is known to have a potential neuroprotective effect. Betaxolol and dorzoldamide are known to increase the ocular blood flow and have a protective effect from optic nerve damage. Oral carbonic anhydrase inhibitor may be effective, if systemic adverse effects can be tolerated. Prostaglandins may reduce IOP below the level of episcleral venous pressure, but their long-term side effects have not been fully evaluated to date. Laser trabeculoplasty can reduce IOP, but not sufficiently in many instances. To reduce IOP sufficiently enough to halt the progression of glaucoma, filtering surgery assisted by mitomycin-C and 5-FU may be recommended, when the IOP reduction is not satisfactory with anti-glaucoma medications.

Efeito dos beta-bloqueadores na pressão intra-ocular e fluxo sangüíneo ocular pulsátil / The effect of beta-blockers on intraocular presure and pulsatile ocular blood flow

Avaliar a eficácia hipertensora de cinco drogas beta-bloqueadoras comumente prescritas no Brasil e avaliar a influência das mesmas no fluxo sangüíneo ocular pulsátil. Estudo prospectivo, randomizado, com 100 pacientes glaucomatosos ou hipertensos oculares sem tratamento prévio ou cirurgia intra-ocular. Pressão intra-ocular (Po), volume do pulso (VP), freqüência co pulso (FP) e fluxo sangüíneo ocular (FSO) foram avaliados com o medidor de fluxo sangüíneo (OBF laboratories, UK Ltda). Os pacientes foram randomizados a utilizar por 3 meses o betaxolol 0,5 por cento ou timolol 0,5 por cento ou metipranolol 0,3 por cento ou levobunolol 0,5 por cento na posologia de duas vezes ao dia e o timolol 0,1 por cento na posologia de uma vez ao dia (à noite), compondo um total de 20 pacientes para cada colírio. Po, PV, PR e FSO foram medidos às 11 horas tanto no início quanto no final de 3 meses. O betaxolol 0,5 por cento reduziu a Po em 2,1 mmHg (9,4 por cento), o timolol 0,5 por cento em 4 mmHg (18 por cento), o metipranolol 0,3 por cento em 2,7 mmHg (11,5por cento), o levobunolol 0,5 por cento em 5,1 mmHg (21,3 por cento) e o timolol 0,1 por centoem 3,1 mmHg (13 por cento). Com relação ao FSO o grupo do betaxolol 0,5 por cento apresentou aumento de 1,4 us/s (11por cento), o do timolol 0,5 por cento de 1,6 ul/s (12,2por cento), o do metipranolol 0,3 por centode 1,7 ul/s (5,2 por cento), o do levobunolol 0,5 por cento de 3,5 ul/s (23,8 por cento) e o do timolol 0,1 por cento de 2,3 ul/s (15,9 por cento). Houve redução significatica da Po nos quatro grupos, sendo a redução maior no grupo do timolol 0,5 por cento e levobunolol 0,5 por cento . Apenas o metipranolol 0,3 por cento não provocou aumento estatisticamente significativo no FSO. Houve aumento significativo no FSO no demais grupos, sendo que o aumento foi maior no grupos do levobunolol 0,5 por cento e timolol 0,1 por cento.

Blefaroconjuntivitis de contacto alérgica por timolol / Blepharoconjunctivitis: contact allergy to thymolol

Existen numerosas sustancias capaces de producir dermatitis de contacto alérgica en la zona de los párpados, llegando a ese lugar a través del aire, por medio de las manos o directamente por aplicación en el sitio. Tal es el caso de la dermatitis inducidas por medicaciones oftálmicas. Presentamos un paciente sensibilizado al timolol contenido en las gotas oftálmicas que utilizaba para controlar su glaucoma

Análise comparativa do fluxo sangüíneo ocular entre o cloridrato de betaxolol 0.5 porcento e o maleato de timolol 0.5 porcento: estudo prospectivo / Ocular blood flow comparative analysis between betaxolol 0.5 porcento and timolol 0.5 porcento: prospective study

Objetivo: Avaliar o efeito do cloridrato de betaxolol 0.5 porcento (betaxolol) e do maleato de timolol 0.5 porcento (timolol), no fluxo sangüíneo ocular, utilizando o medidor do fluxo sangüíneo ocular pulsátil (POBF). Material e Métodos: As observações foram realizadas envolvendo 30 olhos de 30 pacientes utilizando o POBF com o uso do timolol por 2 a 3 meses, suspensão do medicamento por 2 meses e uso do betaxolol por mais 2 a 3 meses. Os itens avaliados foram: pressão intra-ocular (Po), volume do pulso (VP), freqüência do pulso (FP) e o fluxo sangüíneo ocular pulsátil (FSOP). Resultados: A média inicial da Po, VP, FP e FSOP foi de 22.72mmHg com DP de +/- 3.33; 5.23 microlitros com DP de +/- 2.01; 69.3 bpm com DP de +/- 10.66 e 12.50 microlitros/segundo com DP de +/- 4.30. Após o uso do timolol os valores foram 18.51mmHg com DP de +/- 3.09; 6.68 microlitros/segundo com DP de +/- 2.40; 62.50 bpm com DP de +/- 8.68 e 13.84 microlitros/segundo com DP de +/- 3.28; 5.76 microlitros/segundo com DP de +/- 2.31; 68.66 bpm com DP de +/- 11.26 e 13.44 microlitros/segundo com DP de +/- 4.16. Ambas as drogas reduziram a Po, aumentaram o VP e o FSOP (p <0.01). O timolol apresentou uma maior redução da Po e do aumento do VP (p <0.01). Não houve diferença significativa do FSOP entre as medicações (p = 0.27). Conclusão: Ambas as drogas melhoram a hemodinâmica e a Po. Nossa pesquisa mostrou o timolol mais eficiente que o betaxolol no controle da Po e VP.

Unoprostone isopropyl compared with betaxolol in the treatment of open angle glaucoma

This study was carried out on 22 patients had bilateral open angle glaucoma divided randomly into two groups [11 patients each]; The first group [A] received unoprostone 0.12% eye drops twice daily every twelve hour and the second group [B] treated with betaxolol 0.50% eye drops in the same way. The patients had a periodic follow up every two weeks for two months where intraocular pressure was recorded and ophthalmologic examination was done for any adverse reaction and an assessment for the optic nerve head was also done. The results revealed that the mean baseline intraocular pressure in group A was 26.6 +/- 4.2 [23-36] mmHg and 26.4 +/- 4.4 [21-38] mmHg in group B. After three weeks of initiation of therapy, mean intraocular pressure was 21.8 +/- 3.2 mmHg in group A and 20.1 +/- 3.5 mmHg in group B. After two months, the mean intraocular pressure was 20.1 +/- 3.2 mmHg in group A and 19.8 +/- 3.8 mmHg in group B

The Acute Effect of Betaxolol and Difivefrin on Optic Nerve Head and Retinal Blood Flow in Normal Tension Glaucoma

The effect of betaxolol and dipivefrin on microcirculation of peripapil lary reina and optic disc in normal tension glaucoma was assessed. Betaxolol, selective beta-1 blocker, was known to improve the blood flow of retrobulbar arteries, and dipivefrin was known to decrease the flow of ciliary body. Total subjects were 29 normal tension glaucoma patients; 18 subjects with no previous IOP reducing eye drops during 4 weeks were assigned for betaxolol group, and 11 subjects with using timolol for dipivefrin group. The intraocular pressure was significantly reduced after instillation in betaxolol group(p<0.01), and in dipivefrin group(p<0.05). But systemic blood pressure and pulse rate were not changed after instillations in both groups. Blood flow, volume, velocity of optic disc and peripapillary retina of betaxolol group and dipivafrin group were not significantly changed. From the above results, we concluded that betaxolol and dipiverin with timolol did not influenced the microcirculation of peripapillary retina and opit disc.

Adverse drugs reactions associated with glaucoma medications

We undertook a non-concurrent prospective study of 191 Puerto Rican patients from August 1993 to April 1994. All patients had open angle glaucoma (OAG) (age ranged from 50 to 80 yrs; mean = 65 yrs). Patient's symptomatology associated to side effects of their glaucoma medicadons was reviewed. Incidence percent of ocular and/or systemic side effects per medication were: levobunolol 45.0; betaxolol 42.0; timolol 27.3; pilocarpine 100; dipivefrin 14.0; and acetazolamide 250 mg 64.1. Incidence percent of ocular and/or systemic side effects of topical beta-blockers used with concomittant medications were determined. Ocular side effects were more frequent in patients using levobunolol 44.2 than in those patients using betaxolol 42.0, 8.5 of patients using levobunolol did report systemic side effects. No systemic side effects were reported by patients using betaxolol. Ocular side effects in patients using pilocarpine were frequent (100); whereas the frequency of systemic side effects was low (6.1). Systemic side effects were common in patients using carbonic anhydrase inhibitors. These results suggest that non-selective and cardio-selective topical Beta-blockers, differ in their ocular or systemic side effects

Effect of topical antiglaucoma drugs on corneal epithelium wound healing in rabbits

Topical antiglaucoma drugs had been used frequently in treatment of different types of glaucoma. Some of these drugs cause inhibition of corneal epithelial wound healing. So, this study aimed to determine the toxic effect of topical antiglaucoma drugs on corneal epithelium of the rabbit. In the present study, seven antiglaucoma drugs [[1] Timolol maleate 0.5%; [2] Apraclonidine HCI 0.5%; [3] Dipvefrin HCI 0.1%; [4] Betoxolol HCI 0.5% [5] Levobunolol HCI 0.5%, [6] Befunolol HCI 0.5%, and [7] Pilocarpine HCI 2%] in their therapeutic concentrations were applied to the cornea of the rabbit which undergone mechanical removal of the epithelium 8 mm in diameter.The rate of healing of conreal wound in saline treated controls was found significant if compared with antiglaucoma drugs.Drugs 5,6,7 demonstrated more rapid healing than drugs 1, 2, 3, 4. In this study, anti glaucoma drugs appear to have toxic effect on the corneal epithelial wound healing specially drug 2 followed by drugs 1, 3, 4

The Acute Effects of Timolol and Betaxolol on the Peripapillary Retinal and Optic Nerve Head Microcirculation

We investigated the acute effects of timolol (beta-adrenergic non-selective) and betaxolol (beta1-adrenergic selective) on the retinal and optic nerve head (ONH) microcirculation in healthy subjects with Heidelberg Retina Flowmeter (HRF). Intraocular pressure (IOP), heart rate, blood pressure, and retinal and ONH microcirculation were measured in 7 healthy subjects (3 F/ 4 M; mean age=27.2 +/- 1.1 years) before and 90 minutes after instillation of each drug on separate occasions at 2 weeks apart. Volume, flow, and velocity of microcirculation in the peripapillary retina and neural rim of ONH were measured using HRF. Both drugs significantly reduced IOP (Wilcoxon signed rank test; p=.03) without affecting heart rate or blood pressure. It had no effect on the volume, flow, and velocity of blood flow in the peripapillary retina and ONH (Wilcoxon signed rank test; p>.1), From the above results, we concluded that both timolol and betaxolol did not alter retinal and ONH microcirculation.

Betaxolol a 0,25 por cento suspensäo iônica x betaxolol a 0,5 por cento: estudo comparativo / 0,25 betaxolol suspension x 0,5 por cento betaxolol: a double-masked comparison

Foram avaliados, comparativamente, em estudo duplo mascarado, o efeito dos colírios de betaxolol a 0,5 por cento e betaxolol a 0,25 por cento suspensäo iônica, sobre a pressäo ocular e a frequência do pulso arterial, assim como seus efeitos colaterais locais, em 24 indivíduos portadores de hipertensäo ocular ou glaucoma primário de ângulo aberto. Os resultados obtidos revelaram equipotência das duas apresentaçöes da droga como agentes hipotensores oculares, durante as 12 semanas de seguimento. Três indivíduos do grupo que instilou betaxolol a 0,5 por cento tiveram efeitos colaterais locais (sensaçäo de picada, 1; sensaçäo de queimaçäo, 1; ceratite puntata superficial, 1). Nos indivíduos que instilaram betaxolol a 0,25 por cento suspensäo iônica, näo foram verificados sinais ou sintomas de desconforto ocular. Quanto ao efeito das drogas sobre a frequência do pulso arterial, verificou-se que näo houve alteraçäo significante desse parâmetro, em nenhum dos grupos estudados, durante todo o tempo de seguimento

Açäo dos colírios de timolol a 0,5 por cento e betaxolol a 0,5 por cento sobre a concentraçäo protéica do humor aquoso pela laser "flare" fotometria em olhos normais e com glaucoma crônico simples / Effects of timolol 0,5 percent and betaxolol 0,5 percent on the aqueous humor protein concentration by laser flar photometry in normal and open angle glaucomatous eyes

Vários trabalhos na literatura associam o uso de maleato de timolol ao aumento da concentraçäo protéica do humor aquoso. Este estudo visa demonstrar o aumento da concentraçäo protéica através da laser flare fotometria, comparar duas medicaçöes beta-bloqueadoras (maleato de timolol e cloridato de betaxolol) em relaçäo a este aumento em 21 voluntários normais e 11 pacientes com glaucoma crônico simples, e associar a variaçäo do flare à variaçäo pressórica ocasionada pela medicaçäo. O estudo foi realizado antes e duas horas após a instilaçäo de uma gota de timolol 0,5 por cento no olho direito e uma gota de betaxolol 0,5 por cento no olho esquerdo. Os resultados demonstraram que, para o grupo de voluntários normais, tanto o timolol quanto o betaxolol aumentaram significativamente o flare näo foi significante em duas horas com nenhuma medicaçäo nos dois grupos, o timolol aumentou mais o flare em normais do que em glaucomatosos (p<0,05) enquanto o betaxolol näo apresentou diferença para os dois grupos. Näo foi possível associar as variaçöes do flare e da pressäo intra-ocular

Pars planite; consideraçöes sobre tratamento e relato de um caso / Pars planite; considerations about treatment and a case report

Os autores relatam um caso de uveíte intermediária (pars planite) num paciente de 10 anos de idade submetido a tratamento clínico (corticoterapia tópica e antiinflamatório näo hormonal tópico por 14 meses) que persistiu com a mesma acuidade visual inicial. Os autores ressaltam a importância do cuidado com o tratamento, no sentido de evitar catarata, glaucoma e outras complicaçöes devido ao uso abusivo de esteróides (fator iatrogênico)

Efeito colateral tardio de colírios de timolol e betaxolol em pai e filho / Systemy toxicity of Beta blokers

Relato breve de dois casos acerca dos beta-bloqueadores de açäo tópica ocular

Estudo da variaçäo do conteúdo protéico do humor aquoso após instilaçäo de colírio de pilocarpina, timolol e betaxolol avaliado pela laser flare fotometria / Human aqueous humor flare variation after instillation of pilocarpine, timolol and betaxolol by laser flare photometry

A variaçäo do flare doi estudada antes e 2 horas após a instilaçäo de 1 gota de timolol 0,5 por cento, pilocarpina 2 por cento e betaxolol 0,5 por cento em 26 voluntários, pela laser flare fotometria. Pilocarpina e timolol aumentaram as medidas do flare em média 143,7 por cento e 81,6 por cento acima dos valores iniciais, respectivamente para o primeiro grupo estudado (6 voluntários, 12 olhos). A diferença foi estatisticamente significante (P<0,05). Timolol e betaxolol aumentaram o flare respectivamente em 78,2 por cento e 33,2 por cento acima das leituras iniciais em média, para o segundo grupo estudado (20 voluntários, 40 olhos). Betaxolol induziu um aumento significativamente menor do flare quando comparado a pilocarpina e ao timolol (P<0.0l).

Betaxolol versus metoprolol: haemodynamic effects in experimental animals

The haemodynamic effects of the two cardioselective B- adrenoceptor blockers, betaxolol and metoprolol were studied in experimental animals both in vivo and in vitro. In Vitro studies; Betaxolol had 8 times the potency of metoprolol in suppression of isoprenaline chronotropic activity and 5 times its potency in inhibition of myocardial contractility in isolated rabbit heart. In addiotn, betaxolol had less antagonistic effect than metoprolol to the isoprenaline effect on isolated guinea pig tracheal spiral strips. In vivo studies, betaxolol had 4 times the potency of metoprolol in oppression of isoprenaline induced tachycarida in anaesthetized 'dogs. Both betaxolol and metoprolol had no intrinsic sympathomimetic effect as they failed to increase heart rate in reserpinized rats. The IV injection of betaxolol in small doses O.I mg/kg 0.1 mg to 0.4 mg / kg induced rapid significant reduction in the arterial blood pressure of anaesthetized dog while metoprolol up to 0.8 mg/kg intravenously did not produce acute effect on the blood pressure. Chronic administration of the two beta adrenoceptor blockers in oral doses of 2.5 and 5mg/kg for 4 weeks were able to attenuate the rise in the blood pressure in the two kidney one-clip adult hypertensive rats. However, betaxolol effect was more pronounced and early occurred. In conclusion, the new beta adrenoceptor blocker betaxolol had more beneficial haemodnamic effect than metoprolol by which betaxolol is suggested to be a useful addition to the beta adrenoceptor blacker family