Evidence for the involvement of peripheral -adrenoceptors in delayed liquid gastric emptying induced by dipyrone, 4-aminoantipyrine, and antipyrine in rats

Dipyrone (Dp), 4-aminoantipyrine (AA), and antipyrine (At) delay liquid gastric emptying (GE) in rats. We evaluated adrenergic participation in this phenomenon in a study in male Wistar rats (250-300 g) pretreated subcutaneously with guanethidine (GUA), 100 mg·kg−1·day−1, or vehicle (V) for 2 days before experimental treatments. Other groups of animals were pretreated intravenously (iv) 15 min before treatment with V, prazosin (PRA; 1 mg/kg), yohimbine (YOH; 3 mg/kg), or propranolol (PRO; 4 mg/kg), or with intracerebroventricular (icv) administration of 25 µg PRO or V. The groups were treated iv with saline or with 240 µmol/kg Dp, AA, or At. GE was determined 10 min later by measuring the percentage of gastric retention (%GR) of saline labeled with phenol red 10 min after gavage. %GR (mean±SE, n=8) indicated that GUA abolished the effect of Dp (GUA vs V=31.7±1.6 vs 47.1±2.3%) and of At (33.2±2.3 vs 54.7±3.6%) on GE and significantly reduced the effect of AA (48.1±3.2 vs 67.2±3.1%). PRA and YOH did not modify the effect of the drugs. %GR (mean±SE, n=8) indicated that iv, but not icv, PRO abolished the effect of Dp (PRO vs V=29.1±1.7 vs 46.9±2.7%) and At (30.5±1.7 vs 49±3.2%) and significantly reduced the effect of AA (48.4±2.6 vs 59.5±3.1%). These data suggest activation of peripheral β-adrenoceptors in the delayed GE induced by phenylpyrazolone derivatives.

Impacts of the Quinazoline-Based Alpha1-Antagonist, Terazosin, and of the Sulfonamide Derivative, Tamsulosin, on Serum Prostate-Specific Antigen and Prostate Volume

The aim of this study was to compare the impacts of terazosin and tamsulosin, on prostate activity, i.e., serum prostate-specific antigen, total prostate volume (TPV), and transition zone volume (TZV). A total of 90 patients who presented with lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH), ranging in age from 52 to 83 yr (median 65 yr), were included in the study. Patients were given 0.2 mg tamsulosin, 2 mg terazosin, or 4 mg terazosin once daily for an average of 14 months (range, 6-56 months). Subjective (International Prostate Symptom Scores, I-PSS) and objective (maximal flow rate and post-void residual) parameters were assessed both at baseline and at treatment cessation. Serum prostatespecific antigen (PSA) levels were found to be unaffected by treatment (1.2 and 1.3 ng/mL). In total patients, multivariate analysis showed that baseline TPV was the only independent predictor of treatment-related TPV reduction. Moreover, baseline TPV > or =30 g was found to be associated with a higher likelihood of TPV reduction (odds ratio [OR], 3.939; 95% confidence interval [CI], 1.506-10.304; p=0.005), and a baseline TZV of > or =10 g was associated with a 7.1-times greater chance of TZV reduction (OR, 7.100; 95% CI, 2.428-20.763; p<0.001). The same model showed that patients on 2 mg terazosin had a 10.8-fold greater likelihood (OR, 10.770; 95% CI, 1.409-82.323; p=0.022) and that those on 4 mg terazosin had a 9.0-fold greater likelihood (OR, 9.001; 95% CI, 1.724-46.995; p=0.009) of a TZV reduction than those on 0.2 mg tamsulosin. In addition, symptoms improved regardless of prostate activity after taking alpha1-blockers. Our findings suggest that terazosin reduces TZV and demonstrate that the relief of symptoms associated with BPH may not be due to a prostate activity reduction induced by apoptosis in the prostate gland.

Effects of alpha-1 adrenergic receptor antagonist, terazosin, on cardiovascular functions in anaesthetised dogs.

Initially a dose-response curve of phenylephrine was constructed at dose strengths of 1-16 microg/kg in a cumulative manner. Phenylephrine caused a significant rise in the mean arterial pressure, left ventricular systolic pressure, left ventricular contractility, stroke volume and a significant decline in the heart rate. Terazosin was administered in three selected doses of 10, 100 and 300 microg/kg. Following each dose of terazosin, dose-response curve of phenylephrine was constructed. Terazosin, per se, decreased the basal mean arterial pressure, left ventricular systolic pressure, left ventricular contractility and stroke volume significantly in a dose dependent manner with an increase in the heart rate with no significant change in the cardiac output. The baroreflex sensitivity at all the three doses remained unchanged. In conclusion, the present findings support the view that terazosin reduces the blood pressure in a physiologically more favorable manner by maintaining the neural integrity of the cardiovascular system.

Clinical profile of severe scorpion envenomation in children at rural setting.

he present study is an attempt to evaluate the clinical manifestations of severe scorpion sting in children and their management at a rural setting. Twelve patients with severe scorpion sting referred from primary health center are presented in this report. Eight children had pulmonary edema and hypotension; two had pulmonary edema and hypertension while one each presented with hypertension and tachycardia in isolation. Oral prazosin, dobutamine infusion and sodium nitroprusside drip (SNP) were used as therapeutic options based on the symptomatology. Two children died of massive pulmonary edema despite use of SNP and dopamine drip. Anti scorpion venom did not prevent the cardiovascular manifestations of severe scorpion sting. Early administration of prazosin alleviated the severity of scorpion envenomation

Enhancer aided in vitro permeation of atenolol and prazosin hydrochloride through mice skin.

Effect of penetration enhancers were studied on the permeation of antihypertensive drugs prazosin hydrochloride and atenolol through full thickness skin of swiss albino mice. Atenolol was delivered to skin from saturated alcoholic solution containing 5% of 1-decanol and alcohol alone, while prazosin hydrochloride was saturated in dimethyl formamide(DMF, 5% v/v in water) and dimethyl sulfoxide(DMSO, 5% v/v in water). Atenolol permeation was augmented significantly in decanolic solution and also in pure alcohol. In case of prazosin hydrochloride, significant enhancement of permeation was shown by DMSO but not by DMF.

Effect of prazosin GITS, atenolol, nifedipine SR, and enalapril on ADP-induced platelet aggregation.

A randomized, observer-blind, parallel-group study was carried out to compare the effect of prazosin GITS, atenolol, nifedipine SR, and enalapril on platelet aggregation, measured at a time expected to coincide with trough plasma levels of these drugs. 24 patients (age-30 to 60 yrs) with uncomplicated mild to moderate hypertension who completed a placebo run-in phase successfully were recruited in this study. They were randomly allocated to one of the 4 treatments: prazosin GITS 2.5 mg OD (Group 1), atenolol 50 mg OD (Group II), nifedipine SR 20 mg BD (Group III), and enalapril 5 mg OD (Group IV). All the drugs were given for 7 days, and blood samples were collected at 0 hr on day 1 (pre-treatment) and day 8 (post-treatment). Based on the dose (incremental concentrations of ADP)--response (% maximum aggregation) curve obtained, 2.5 microM/L of ADP was used to compare % inhibition of platelet aggregation among the 4 groups. We found that prazosin GITS inhibited % maximum aggregation significantly (p = 0.02) at 2.5 microM/L of ADP. Such inhibitory effect was not seen in any of the other groups. The inhibition produced by prazosin GITS differed significantly from the action of the other 3 drugs (p < 0.05). This antiplatelet effect of prazosin GITS bears more clinical relevance in view of the fact that it was seen at a time which is expected to coincide with the trough plasma levels of prazosin.

Prazosin GITS vs sustained release nifedipine in patients with hypertension and abnormal lipid profile: a randomized, controlled, multicenter study. Madras Hypertension Study Group.

OBJECTIVE: To compare the long-term antihypertensive efficacy, tolerability, and metabolic effects of prazosin GITS and a sustained release (SR) preparation of nifedipine. DESIGN: Randomized, controlled, multicenter study of 26 weeks duration. SETTING: Office practices of 24 physicians in Chennai, Tamil Nadu, India. PATIENTS: Males and females, aged 30 to 70 yrs, with hypertension of JNC V stage 1 or 2 at the end of a 2-week placebo run-in period, and an abnormal lipid profile. Sufficient number of patients recruited so that at least 60 complete the entire study. INTERVENTIONS: Prazosin GITS (Minipress XL, 2.5-5 mg once daily) or sustained release nifedipine (Nicardia Retard 10-20 mg twice daily) for upto 6 weeks, continued upto 24 weeks in those showing a pre-defined response (SBP and/or DBP normalized, or DBP fall of at least 10 mm Hg with actual value of DBP < 95 mm Hg). Patients allocated to either of the two interventions by randomization. OUTCOME MEASURES: Percent patients showing pre-defined BP response at week 6; percent patients with DBP < 90 mm Hg, SBP < 140 mm Hg, and both; percent patients with DBP fall > or = 10 mm Hg; mean fall in BP among those receiving treatment for 24 weeks; mean change in blood glucose and serum lipids at the end of weeks 8, 16, and 24 of treatment; frequency and intensity of adverse events judged probably or definitely related to the drug. RESULTS: 54 patients randomized to prazosin GITS group and 52 to nifedipine SR group. Of these, 39 in prazosin GITS group (M 23, F 16; mean age-50. 6 yr, SEM 1.66) and 36 in nifedipine SR group (M 20, F 16; mean age-52.3 yr, SEM 1.71) completed the study. Percent patients with DBP < 90 mm Hg at 24 weeks: prazosin GITS--100%, nifedipine SR--100%; SBP < 140 mm Hg: prazosin GITS--94.9%, nifedipine SR--91.7%; both DBP < 90 mm Hg and SBP < 140 mm Hg: prazosin GITS--92.3%, nifedipine SR--91.7%; percent patients with DBP fall of 10 mm Hg or more at 24 weeks: prazosin GITS--76.9%, nifedipine SR--83.3%. The mean fall in the systolic and diastolic blood pressure from the end-of-placebo-phase values to all the other time points was comparable in the 2 groups. Treatment with prazosin GITS did not produce any statistically or clinically significant change in the metabolic parameters at the end of 24 weeks, while with nifedipine SR there was a significant increase in the serum LDL values at 24 weeks (p = 0.009). Adverse events probably or definitely related to the drug: prazosin GITS--1.9%, nifedipine SR--2.1%. CONCLUSION: Both drugs were equally effective and well tolerated. While prazosin GITS was neutral on serum lipids, use of nifedipine SR was associated with a significant increase in serum LDL cholesterol at the end of 24 weeks.

A randomized, controlled, multicenter study to compare prazosin GITS with enalapril in hypertensive patients with diabetes mellitus. Bombay Hypertension Study Group.

OBJECTIVE: To compare the long-term antihypertensive efficacy, tolerability, and metabolic effects of prazosin GITS and enalapril. DESIGN: Randomized, controlled, multicenter study of 26 weeks duration. SETTING: Office practices of 20 physicians in Mumbai, India. PATIENTS: Males and females, aged 30 to 70 yrs, with hypertension of JNC V stage 1 or 2 at the end of a 2-week placebo run-in period, and diabetes mellitus with at least acceptable glycaemic control (FBS < or = 140 mg/dl, 2-hr PMBS < or = 200 mg/dl, and glycosylated hemoglobin < or = 9.5%). Sufficient number of patients recruited so that at least 60 complete the entire study. INTERVENTIONS: Prazosin GITS (Minipress XL, 2.5-5 mg once daily) or enalapril (Enam, 5-10 mg once daily) for upto 6 weeks; continued upto 24 weeks in those showing a pre-defined response (SBP and/or DBP normalized, or DBP fall of at least 10 mm Hg with actual value of DBP < 95 mm Hg). Patients allocated to either of the two interventions by randomization. OUTCOME MEASURES: Percent patients showing pre-defined BP response at week 6; percent patients with DBP < 90 mm Hg, SBP < 140 mm Hg, and both; percent patients with DBP fall > or = 10 mm Hg; mean fall in BP among those receiving treatment for 24 weeks; mean change in serum lipids at the end of weeks 8, 16, and 24 of treatment; mean change in blood sugar and glycosylated hemoglobin at the end of weeks 8, 16, and 24 of treatment; mean change in 12-hr urinary microalbuminuria and laboratory parameters for safety at the end of week 24; frequency and intensity of adverse events judged probably or definitely related to the drug. RESULTS: Forty-Eight patients randomized to prazosin GITS group and 41 to enalapril group. Of these, 31 in prazosin GITS group (M 19, F 12; mean age-53.4 yr, SEM 1.68) and 29 in enalapril group (M17, F 12; mean age-54.7 yr, SEM 1.64) completed the entire study. Percent patients with DBP < 90 mm Hg at 24 weeks: prazosin GITS--71.0%, enalapril--72.4%; SBP < 140 mm Hg: prazosin GITS--54.8%, enalapril--55.2; both DBP < 90 mm Hg and SBP < 140 mm Hg: prazosin GITS--54.8%, enalapril--44.8%; percent patients with DBP fall of 10 mm Hg or more at 24 weeks: prazosin GITS--77.4%, enalapril--72.4%. The mean fall in the systolic and diastolic blood pressure from the end-of-placebo-phase values to all the other time points was comparable in the two groups. Treatment with prazosin GITS resulted in a favourable effect on serum triglycerides at the end of 8 weeks (p = 0.017) and 16 weeks (p = 0.011), and no detrimental effect or a marginal beneficial effect on total cholesterol, HDL cholesterol, and LDL cholesterol. Enalapril group, on the other hand, showed a significant increase in LDL cholesterol at the end of 24 weeks (p = 0.018), and a marginal increase in total cholesterol, but a beneficial effect on triglycerides at the end of 16 weeks (p = 0.015). Neither drug had any effect on glycosylated hemoglobin and 12-hr urinary microalbuminuria. Treatment with both drugs was associated with an increase in FBS and 2-hr PMBS, but this rise reached statistical significance only in prazosin GITS group. Adverse events probably or definitely related to the drug: prazosin GITS--2 of 44 patients (4.5%), enalapril--6 of 39 patients (15.4%). CONCLUSION: 1. In the doses used, prazosin GITS showed comparable antihypertensive efficacy to enalapril. 2. While enalapril had variable effect, prazosin GITS showed a consistent beneficial effect on some of the serum lipid fractions. 3. The 3-fold difference in the incidence of side effects, although not statistically significant for the available sample size, may be clinically relevant.

Prazosin GITS vs atenolol in patients with hypertension and normal lipid profile: a randomized, controlled multicenter study. Hyderabad Hypertension Study Group.

OBJECTIVE: To compare the long-term antihypertensive efficacy, tolerability, and metabolic effects of prazosin GITS and atenolol. DESIGN: Randomized, controlled, multicenter study of 26 weeks duration. SETTING: Office practices of 24 physicians in Hyderabad, Andhra Pradesh, India. PATIENTS: Males and females, aged 30 to 70 yrs, with hypertension of JNC V stage 1 or 2 at the end of a 2-week placebo run-in period, and a normal lipid profile. Sufficient number of patients recruited so that at least 60 complete the entire study. INTERVENTIONS: Prazosin GITS (Minipress XL, 2.5-5 mg once daily) or atenolol (Tenormin 50-100 mg once daily) for upto 6 weeks, continued upto 24 weeks in those showing a pre-defined response (SBP and/or DBP normalized, or DBP fall of at least 10 mm Hg with actual value of DBP < 95 mm Hg). Patients allocated to either of the two interventions by randomization. OUTCOME MEASURES: Percent patients showing pre-defined BP response at week 6; percent patients with DBP < 90 mm Hg, SBP < 140 mm Hg, and both; percent patients with DBP fall > or = 10 mm Hg; mean fall in BP among those receiving treatment for 24 weeks; mean change in serum lipids at the end of weeks 8, 16, and 24 of treatment; mean change in laboratory parameters for safety at the end of week 24; frequency and intensity of adverse events judged probably or definitely related to the drug. RESULTS: 62 patients randomized to prazosin GITS group and 60 to atenolol group. Of these, 39 in prazosin GITS group (M 23, F 16; mean age-48.4 yr, SEM 1.60) and 39 in atenolol group (M 24, F 15; mean age-42.9 yr, SEM 1.48) completed the entire study. Percent patients with DBP < 90 mm Hg at 24 weeks: prazosin GITS--92.3%, atenolol--92.3%; SBP < 140 mm Hg: prazosin GITS--89.7% atenolol--94.9% both DBP < 90 mm Hg and SBP < 140 mm Hg: prazosin GITS--87.2%, atenolol--89.7%; percent patients with DBP fall of 10 mm Hg or more at 24 weeks: prazosin GITS--92.3%, atenolol--100%. The mean fall in the systolic and diastolic blood pressure from the end-of-placebo-phase values to all the other time points was comparable in the 2 groups, except at week 2, when the fall was greater for atenolol (8.8 mm Hg vs 11.4 mm Hg, p = 0.05). Treatment with prazosin GITS resulted in a favourable effect on the serum lipid profile at the end of 24 weeks (p = 0.02 for total cholesterol, p = 0.015 for the ratio of total to HDL cholesterol, p = 0.04 for LDL cholesterol). Atenolol, on the other hand, did not produce any significant change in the metabolic parameters at the end of 24 weeks. Adverse events probably or definitely related to the drug: prazosin GITS--in 10.3% patients, atenolol--in 16.7% patients. CONCLUSION: In the doses used, both prazosin GITS and atenolol had comparable efficacy and tolerability. While atenolol was neutral on serum lipids, prazosin GITS showed a beneficial effect at the end of 24 weeks.

Ruta diagnóstica y tratamiento del feocromocitoma. Presentación de dos casos clínicos / The treatment and diagnosis of pheochromocytoma. Report two cases

Se presentan dos casos de feocromocitoma. La sospecha se hace cuando presentan hipertensión arterial, sintomatología adrenérgica o hipotensión, el diagnóstico se realizó bajo sospecha clínica, bioquímicamente encontrando niveles de adrenalina y noradrenalina cuarenta y tres veces mayores a lo normal, la localización se realizó por ultrasonido, TAC, y rastreo con metayodobencilguanidina, los dos pacientes recibieron tratamiento médico a base de bloqueadores de canales de calcio, prazosín, Tratamiento definitivo resección quirúrgica, los dos pacientes actualmente se encuentran sanos sin tratamiento médico

Hypotensive effect of intracerebroventricular injection of norepinephrine and its modulation by alpha and beta adrenergic blockers in conscious rabbits.

The present study was designed to investigate the role of central adrenoceptors in the hypotensive effect of intracerebroventricular (ICV) injection of norepinephrine (NE) in conscious rabbits. Experiments were carried out on 19 adult rabbits (oryctolagus cuniculus) of either sex. A dose-dependent hypotensive response to ICV injection of NE was observed with no significant change in heart rate. The hypotensive response of NE was blocked 74.2 +/- 0.7% by yohimbine (alpha-2 adrenergic blocker), and 25.0 +/- 0.5% by metoprolol (beta-1 adrenergic blocker). NE response was not affected either by prazosin or butoxamine (alpha-1 and beta-2 adrenergic blockers respectively). The results suggest that the dose-dependent hypotensive response of ICV administered NE is mediated through alpha-2 and beta-1 central adrenoceptors.

Eficácia anti-hipertensiva e tolerabilidade do cloridrato de prazosina de liberaçäo lenta. Estudo multicêntrico brasileiro / Anti-hypertensive efficacy and tolerability of sustained-release prazosin hydrochloride. A Brazilian multicenter study

Objetivo: Avaliar o efeito anti-hipertensivo e a tolerabilidade de dose única diária de cloridrato de prazosina de liberaçäo lenta (SR). Casuística e Métodos: 1393 portadores de hipertensäo arterial sistêmica primária (HAS) leve (644 pacientes e moderada (749 pacientes), com média etária de 47,63 anos, sendo 745 (53,52%) do sexo masculino, 1011 (72,84%) brancos e 279 (20,1%) negros. De acordo com protocolo multicêntrico aberto näo comparativo, os pacientes receberam cloridrato de prozosina SR em dose inicial de 1 mg, ajustada até máximo de 6 mg, de acordo com a resposta (objetivo = pressäo arterial diastólica (PAD) < ou = 90 mmHg), por prazo de 4 semanas. Resultados: A dose média diária foi de 2,08 mg, em tomada única. Ao final do estudo, 1274 (91,46%) pacientes atingiram PAD < ou = 90 mmHg, sendo 624 do grupo HAS leve e 650 do HAS moderada. O número de pacientes sob controle nas 3 primeiras semanas foi de 426 (1ª semana), 844 (2ª semana) e 1147 (3ª semana). APAD reduziu-se da média de 104 ñ 5 mmHg para a de 88 ñ 8 mmHg (p < 0,05). A freqüência cardíaca variou da média de 82 ñ 9 bpm pré-tratametno para 80 ñ 8 bpm na 4ª semana. Reaçöes adversas foram reconhecidas em 377 (27,06%) pacientes, total de 444 eventos, sendo mais freqüente a associaçäo de vertigem, tontura e lipotímia. Apenas 8 (2,12%) pacientes necessitaram reduzir as doses de cloridrato de prazosina SR e 5 (1,32%) tiveram de abandonar o estudo pelos efeitos indesejáveis da droga. Conclusäo: Cloridrato de prazosina SR em tomada única diária parece ser real avanço no tratamento da HAS leve e moderada, facilitando-o sem perda da eficácia e com boa tolerabilidade

Purpose: To evaluate the efficacy and tolerability of a single daily dose of sustained-release (SR) formulation of prazosin hydrocloride. Patients and Methods: 1393 outpatients in a multicenter open comparative trial. 644 patients had mild hypertension and 749 patients had moderate hypertension. The mean age was 47.63 years, 745 (53.52%) were male, 1011 (72.84%) white and 279 (20.1%) black. The patients received prazosin hydrocloride SR during 4 weeks in an initial dose of 1 mg, adjusted to a maximum of 6 mg in order to decrease the diastolic blood pressure (DBP) to 90 mmHg or less. Results: The mean daily dose was 2.08 mg. At the end of the study, 1274 (91.46%) patients had DBP £ 90 mmHg or less. 624 patients were in the mild hypertension group and 650 patients were in the moderate hypertension group. The number of patients under DBP control in the first three weeks was 426 (first week), 844 (second week) and 1147 (third week). The DBP decreased from the mean value of 104 ± 5 mmHg to 88 ± 8 mmHg (p < 0.05)’. The mean heart rate ranged from 82 ± 9 beats/min (pre-treatment) to 80 8 beats/min (fourth week). Adverse effects were identified in 377 (27.06%) patients, total of 444 episodes, the more frequent being dizziness. Only 8 (2.12%) patients had to reduce the doses of prazosin hydrocloride SR and 5 (1.32% ) had to discontinue the treatment on account of the adverse effects of the drug. Conclusion: Prazosin hydrocloride SR in a single daily dose seems to be an advance in the treatment of patients with mild and moderate hypertension.

Efecto antihipertensivo de la prazosina en pacientes con hipertesnión arterial esencial, estudio multicentrico en el Perú / Effect antihypertensive of the prozosina in patients with arterial hypertension essential, multicenter study in Perú

Se estudió la eficacia y tolerancia del clorhidrato de prazosina en 192 pacientes, 90 hombres, 102 mujeres cuyas edades variaron entre 29 y 65 años portadores de HAE en 10 hospitales de Lima metropolitana y 1 de provincias agrupados en 3 categorías según los criterios de la OMS - 1962. Después de 1 semana de placebo se hicieron controles de presión arterial (PA) supina cardíaca (FC) al finalizar la 1ra., 2da., 4ta., 6ta., 8va. semana. La dosis fue de 0.5 mg b.i.d. tomando la primera al acostarse. A juicio del investigador y a partir de la 6ta. semana se añadió un diurético (52 casos la mayoría usó clortalidona, o hidroclorotiazida y sólo 4 casos furosemida. al finalizar la 8va. semana se encontró una respuesta "normalizada" (PAD 90 mmHg) en 100% de los hipertensos leves, 85% de los moderados y 60% de los severos, y una respuesta "satisfactoria" (PAD 100 mmHg) en 98% de los hipertensos moderados y en 90% de severos. Los efectos más frecuentes fueron: cefalea, mares y palpitaciones. No se observó ningún caso de "fenómeno de la primera dosis". De acuerdo al estudio, la prazosina es una droga útil en el tratamiento de la HAE cualquiera sea su severidad, teniendo en cuenta su baja toxicidad, su amplio rango de sodificación y su potenciación combinada con diuréticos. Si a esto le agregamos su carencia de "fenómeno de rebote" y de efectos sobre la líbido, así como su favorable acción sobre las dislipoproteinas al elevar el HDL. Se concluye que la prazosina es una droga con amplias ventajas en el manejo de los hipertensos

Prazosin como medicamento inicial en el tratamiento de la hipertension / Prazosin as initial medication in treatment of hypertension

Valoracion de la eficacia del prazosin como farmaco de primer paso en pacientes con hipertension arterial leve a moderada; tambien se intento valorar su efecto farmacologico sobre los lipidos sericos

Avaliação comparativa, aberta e randomizada da atividade anti-hipertensiva da nifedipinina e de cloridrato de prazosin / Comparative open and randomized evaluation of the antihypertensive activity of nifedipine and prazosin hydrochloride

Trinta portadores de hipertensäo leve ou moderada foram submetidos a uma avaliaçäo comparativa, aberta e "randomizada" de 12 semanas, durante a qual as doses diárias de nifedipina (em nova formulaçäo retard) e de cloridrato de prazozin foram tateadas, com o objetivo de reduzir a pressäo diastólica a um valor igual ou inferior a 90 mm Hg. Concomitante ao uso de ambas as substâncias, observou-se diminuiçäo significativa (p < 0,001) das pressöes sistólica e diastólica, assim como da freqüência cardíaca. O efeito anti-hipertensivo da nifedipina mostrou-se mais precoce (p < 0,05) e superior (p < 0,02) ao do cloridrato de prazosin. Esta substância mostrou-se de difícil manuseio, pois a dose ótima para a maioria dos pacientes foi alcançada no fim da observaçäo e o ajuste da dose individual foi acompanhado de freqüentes hipotensöes. Ambas as substâncias foram bem toleradas, porém, um paciente teve sua terapia com nifedipina interrompida em virtude de "flush" e edema de membros inferiores, apesar de importante efeito anti-hipertensivo