A double-blind comparison of indoramin and propranolol in the treatment of moderate to severe essential hypertension

Antani, J. A.; Buckle, J. W.; Turner, J. Rick; Cohen, Michael N.

doi:10.1185/03007998309109805

Cited by 2 publications

(1 citation statement)

References 26 publications

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“…In contrast to the non-selective aadrenoceptor blockers phentolamine and phenoxybenzamine, the vasodilatation evoked by the selective ml-adrenoceptor blocker indoramin is not accompanied by a tachycardia in either animals or man (Baum et al, 1973;Carballo et al, 1974;Antani et al, 1983).…”

Section: Introductionmentioning

confidence: 99%

Investigation into the cardioregulatory properties of the α₁‐adrenoceptor blocker indoramin

Pierce

Shepperson

Todd

et al. 1986

British J Pharmacology

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1 The cardioregulatory properties of the a1-adrenoceptor blocker indoramin have been compared with those of prazosin in the anaesthetized rat. The effects of autonomic blockade on heart rate responses evoked by these two agents and their effects on blood pressure and heart rate after peripheral or central administration have been compared. 2 Cumulative administration of indoramin (0.8-25.6 mg kg-' i.v.) evoked significant decreases in arterial blood pressure and a concomitant bradycardia. Pithing or autonomic blockade, by pretreatment with a combination of practolol and bilateral vagotomy, prevented the bradycardia evoked by indoramin (0.8-3.2 mg kg-' i.v.). Atropine sulphate pretreatment abolished the bradycardia until a cumulative dose of 25.6 mg kg-' (i.v.) of indoramin had been reached. Bilateral vagotomy, intravenous administration of atropine methylnitrate or practolol pretreatment attenuated the bradycardia. 3 Prazosin (0.02-0.64mg kg-i.v.) evoked a fall in arterial blood pressure of similar magnitude to that observed following indoramin. A bradycardia was evoked only at a relatively high dose (0.64mg kg-' i.v.). 4 Intracisternal injection of indoramin or prazosin evoked bradycardia and hypotension at a dose which had no effect after intravenous injection (25 Jpg). Intracerebroventricular injection ofindoramin (25 gtg) had no significant effect on heart rate or blood pressure compared to control values, whereas prazosin (25 jig) evoked a significant tachycardia and hypotension.5 It is concluded that the bradycardia evoked by indoramin in the rat is not due to a direct action on the heart except possibly at high doses. Central c~,-adrenoceptor blockade, possibly in the brainstem region, results in a bradycardia and this may explain the lack of reflex tachycardia following the administration of indoramin.

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Section: Introductionmentioning

confidence: 99%

Investigation into the cardioregulatory properties of the α₁‐adrenoceptor blocker indoramin

Pierce

Shepperson

Todd

et al. 1986

British J Pharmacology

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Indoramin

Holmes¹,

Sorkin²

1986

Drugs

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Indoramin is a postsynaptic selective alpha 1-adrenoceptor antagonist used in the treatment of hypertension. In contrast to some other alpha-blockers, animal studies suggest that its blood pressure lowering effect results from relaxation of peripheral arterioles as a consequence of blockade of postsynaptic alpha 1-adrenoceptors. Furthermore, unlike some other alpha-blockers, this lowering of blood pressure is rarely associated with reflex tachycardia or postural hypotension. Therapeutic trials have shown indoramin to be effective in lowering blood pressure in all grades of hypertension: mild and moderate hypertension when used alone, but generally in combination with a thiazide diuretic, and in moderate to moderately severe hypertension when used in combination with a beta-blocker and diuretic. In a few small comparative studies, no significant difference was found in the blood pressure lowering effects between indoramin and methyldopa, propranolol and prazosin. Side effects were similar for indoramin, propranolol and methyldopa; however in the 1 comparative study with prazosin, prazosin produced a lower incidence of sedation. Indeed, the most common side effect with indoramin therapy has been sedation of a mild to moderate and/or transient nature, reported in about 19% of cases. Other side effects which have sometimes led to a withdrawal of indoramin treatment have been dry mouth, dizziness, and in males, failure of ejaculation; however, side effects may be reduced by starting therapy with smaller doses and titrating more gradually.

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A double-blind comparison of indoramin and propranolol in the treatment of moderate to severe essential hypertension

Cited by 2 publications

References 26 publications

Investigation into the cardioregulatory properties of the α₁‐adrenoceptor blocker indoramin

Investigation into the cardioregulatory properties of the α₁‐adrenoceptor blocker indoramin

Indoramin

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A double-blind comparison of indoramin and propranolol in the treatment of moderate to severe essential hypertension

Cited by 2 publications

References 26 publications

Investigation into the cardioregulatory properties of the α1‐adrenoceptor blocker indoramin

Investigation into the cardioregulatory properties of the α1‐adrenoceptor blocker indoramin

Indoramin

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Investigation into the cardioregulatory properties of the α₁‐adrenoceptor blocker indoramin

Investigation into the cardioregulatory properties of the α₁‐adrenoceptor blocker indoramin