Disease relevance of Minipress

• Prazosin benefits severe congestive heart failure by inducing a sustained fall of both cardiac preload and impedance [1].
• To elucidate the hemodynamic effects of prazosin, an antihypertensive agent, in congestive heart failure, we studied 10 patients with ischemic cardiomyopathy and severe ventricular dysfunction [1].
• Prazosin-new hypertensive agent. A double-blind crossover study in the treatment of hypertension [2].
• The introduction of additional agents of this class with properties different from prazosin provides slower onset of action, which should reduce the degree of first-dose and postural hypotension and a longer duration of action, which allows for once-a-day dosage [3].
• Prazosin in the diagnosis and treatment of pheochromocytoma [4].

Psychiatry related information on Minipress

• Atropine, a central anticholinergic agent, but not methylatropine, a peripheral one, completely suppressed the prazosin effect, which suggests that adrenergic and cholinergic systems act sequentially and not independently to generate cataplexy [5].
• Subsequent studies showed that the beneficial effects of classical treatments of human narcolepsy (amphetamines and tricyclic antidepressants) are antagonized by prazosin, suggesting that these drugs are active through an indirect alpha-1 stimulation (via an increase of norepinephrine in the synaptic cleft) [5].
• Both the increases in extracellular DA levels and in locomotor activity were completely blocked by a pretreatment with prazosin, injected either systemically (0.5 mg/kg, i.p.) or locally and bilaterally into the prefrontal cortex (500 pmol/side) [6].
• The alpha 1-receptor antagonist prazosin (200 micrograms/kg) also prevented the behavioral effect of restraint, whereas the alpha 1-agonist phenylephrine (50 or 100 ng, i.c.v.) decreased exploratory behavior [7].
• Reduction of nightmares and other PTSD symptoms in combat veterans by prazosin: a placebo-controlled study [8].

High impact information on Minipress

• For various reasons, the alpha 1-receptor blocker prazosin has been used infrequently as initial therapy for hypertension [3].
• Prazosin treatment of ergotamine-induced peripheral ischemia [9].
• In a patient with paraganglioma, severe hypertension due to high levels of plasma norepinephrine was easily controlled with prazosin hydrochloride, 6 to 8 mg/day for 19 days before surgery [4].
• Responses were inhibited by the predominantly MT2-selective antagonist luzindole but not by prazosin, acting at MT3 receptors [10].
• Responsiveness of superficial hand veins to phenylephrine in essential hypertension. Alpha adrenergic blockade during prazosin therapy [11].

Chemical compound and disease context of Minipress

• BACKGROUND & AIMS: The association of prazosin to propranolol enhances the decrease in portal pressure but may cause hypotension and sodium retention [12].
• Combined prazosin and hydralazine in resistant hypertension [13].
• However, surgical management of the pheochromocytomas was inadequate with prazosin alone, and intravenous phentolamine was required to suppress the pressor surges generated by the tumor during surgical manipulation and excision [14].
• In patients with congestive heart failure, prazosin results in balanced venous and arterial dilation, similar to that produced by nitroprusside [15].
• Fifty patients with congestive heart failure received, by infusion, 15 ml/kg body weight water load, and systemic hemodynamic, renal function, and neurohumoral parameters values were measured before, 2 days, and 1 month after randomly allocating patients to prazosin or captopril therapy [16].

Biological context of Minipress

• When prazosin was added to beta blockade the average fall in mean blood-pressure, standing, was 16% [17].
• The patients' autoantibodies caused a decrease in tritiated prazosin binding sites and an increase in heart beating frequency of neonatal cultured rat cardiomyocytes; antibodies purified from the controls had no effect [18].
• Prazosin decreased the hepatic venous pressure gradient (HVPG) while increasing hepatic blood flow [19].
• CONCLUSIONS: In cirrhotic patients, continuous prazosin administration reduces portal pressure and improves liver perfusion and function but favors sodium and water retention [19].
• Prazosin increased hepatic blood flow and reduced hepatic vascular resistance at lower doses; these changes decreased as prazosin was increased [20].

Anatomical context of Minipress

• To ascertain whether increased sympathetic nervous system activity may contribute to the attenuation of prazosin's effect on congestive heart failure, we measured plasma norepinephrine levels in 10 patients with severe heart failure before and after chronic prazosin therapy [21].
• Prazosin (50 micrograms/kg IV) significantly attenuated the exercise-induced coronary artery constriction after endothelial denudation (+1.5 +/- 1.4% versus -4.6 +/- 1.0%) [22].
• Furthermore, nitrendipine (range 0.01 to 0.3 mg/kg) proved to be more effective (p less than .001) against exogenous norepinephrine than against electrical stimulation of the spinal cord, a behavior opposite that of selective alpha 1-blockade (prazosin) and directionally comparable to that of selective alpha 2-antagonism (rauwolscine) [23].
• The highly selective alpha 1-adrenergic receptor antagonist prazosin was used to identify binding sites having alpha-adrenergic specificity in rat hepatic plasma membranes [24].
• Treatment with prazosin was also able to suppress clinical and histological signs of EAE in animals sensitized by adoptive transfer with activated spleen or lymph node cells [25].

Associations of Minipress with other chemical compounds

• By contrast, prazosin HCl, an alpha 1-adrenergic blocking agent, and Cyclospasmol, a peripheral vasodilator, did not enhance the tumor perfusion and antitumor efficacy of 125I- or Ida-conjugated MAbs, and no vasoactive agent enhanced the antitumor effect of Ida when used alone [26].
• The aim of this study was to investigate the effects of continuous blockade of alpha-adrenoceptors with prazosin on hemodynamics, liver function, and renal function and whether the association of propranolol or furosemide enhances the portal pressure lowering effect of prazosin [19].
• Treating familial Mediterranean fever with prazosin hydrochloride [27].
• NE likewise increased the percentage of apoptotic cells with hypodiploid DNA content as assessed by flow cytometry from 7.8+/-0.7% to 16.7+/-2.2% (P<0.01; n=6), and this effect was abolished by propranolol but not prazosin [28].
• Norepinephrine (10(-6)M to 10(-3)M) appeared to produce a concentration-dependent reduction in membrane potential that was blocked by equimolar concentrations of prazosin but not of yohimbine [29].

Gene context of Minipress

• In this study, using [125I]iodoarylazidoprazosin ([125I]IAAP), a photoactive analog of prazosin, we have demonstrated the presence of two nonidentical drug-interaction sites within Pgp [30].
• P-gp had no effect on the brain transport of prazosin and mitoxantrone at the mouse BBB, but wild-type and P-gp-deficient mouse brains perfused with GF120918 or a high concentration of prazosin showed carrier-mediated effluxes of prazosin and mitoxantrone from the brain that did not involve P-gp [31].
• Prazosin enhanced the LS-induced increase of AT1A mRNA (P<.05) [32].
• Prazosin also enhanced the LS-induced increase in AT1B mRNA (P<.05) [32].
• Furthermore, in crude membrane preparations, neither the basal nor the prazosin-stimulated ( approximately 2-fold) ATPase activities of ABCG2 (N596Q) were affected compared to glycosylated ABCG2 [33].

Analytical, diagnostic and therapeutic context of Minipress

• Drug therapy. Prazosin [34].
• However, prazosin blunted the infarct size-limiting effect of ischemic preconditioning (infarct size: 42.8 +/- 3.7%) [35].
• Age, sex, presence of alcohol, and time of death to autopsy did not affect prazosin binding, in our sample, as measured by autoradiography [36].
• Phenylephrine (5 X 10(-8) M) at 2.7 mM [Ca2+]o rapidly restored membrane potential during reperfusion, an effect that was blocked by prazosin [37].
• Efficacy of ambulatory systemic vasodilator therapy with oral prazosin in chronic refractory heart failure. Concomitant relief of pulmonary congestion and elevation of pump output demonstrated by improvements in symptomatology, exercise tolerance, hemodynamics and echocardiography [38].

References