摘要:

Propranolol kinetics was studied in six hyperthyroid and six hypothyroid patients who received single oral and intravenous doses of propranolol when they had thyroid dysfunction and again when they had become euthyroid. Change in thyroid status from hyperthyroid to euthyroid produced no change in the elimination half‐life (t½) of oral propranolol (3.2 ± 0.5 to 4.1 ± 0.7 hr), the oral clearance (38.4 ± 7.3 to 27.4 ± 2.4 ml/min/kg), the elimination t½ of intravenous propranolol (2.5 ± 0.3 to 3.5 ±0.7 hr), and the apparent volume of distribution (4.8 ± 0.4 to 3.8 ± 0.5 l/kg). The systemic clearance of propranolol, however, was greater when the patients were hyperthyroid (20.8 ±2.5 ml/min/kg) than when they had become euthyroid (11.7 ± 1.7 ml/min/kg). The elimination t½ after oral propranolol was longer in the hypothyroid (3.7 ± 0.5 hr) than in the euthyroid state (2.0 ±0.1 hr). No other changes were observed in the kinetic parameters measured when these hypothyroid patients had become euthyroid. Adequate β‐adrenoceptor blockade in hyperthyroid patients may require higher propranolol dosage than expected.Clinical Pharmacology and Therapeutics(1980)28,565–574; doi

ISSN:0009-9236    

DOI:10.1038/clpt.1980.204

年代:1980

数据来源: WILEY

摘要:

Because beta blockers have been shown to reduce glomerular filtration rate (GFR), the renal effect of intravenous and prolonged oral administration of pindolol was examined in 10 patients with essential hypertension. Intravenous pindolol decreased inulin clearance from 99 to 94 ml/min/1.73 m2(p<0.005), and pulse rate from 75 to 69/min (p<0.005). Blood pressure and filtration fraction were not changed. Oral pindolol (10 to 20 mg/day) for a mean of 6 mo resulted in a decrease in mean blood pressure from 124 to 111 mm Hg (p<0.001), in mean pulse rate from 76 to 69/min (p<0.005), and in mean plasma renin activity (PRA) from 0.9 to 0.29 ng/ml/hr (p<0.05). Inulin clearance and filtration fraction did not change. At the end of oral therapy, intravenous pindolol induced a greater reduction in inulin clearance than in the first study. These observations indicate that intravenous pindolol induces a decrease in GFR probably secondary to hemodynamic effects. On the other hand, prolonged oral pindolol has no effect on GFR despite decreases in blood pressure, pulse rate, and PRA.Clinical Pharmacology and Therapeutics(1980)28,575–580; doi:10.1038/clpt.1980.2

ISSN:0009-9236    

DOI:10.1038/clpt.1980.205

年代:1980

数据来源: WILEY

摘要:

The antihypertensive effects of a clonidine‐chlorthalidone combination (Combipres) as a single daily dose at bedtime and the same amount in twice‐daily doses were compared in an open‐label, crossover study in 14 patients. An analysis of the blood pressure and pulse data in nine patients who completed the study revealed no statistically significant differences between the two regimens, and no difference in the incidence of side effects was noted.Clinical Pharmacology and Therapeutics(1980)28,581–586; doi:10.1038/clpt.

ISSN:0009-9236    

DOI:10.1038/clpt.1980.206

年代:1980

数据来源: WILEY

摘要:

The correlation between hydralazine‐induced tachycardia and overall cardiovascular reactivity to sympathetic stimulation was explored in 50 normal subjects. Blood pressure and heart rate changes after standing, immersion of a hand in cold water, the Valsalva maneuver, and moderate exercise were compared with pressure and rate responses to 20 mg oral hydralazine. The drug did not modify blood pressure but increased heart rate, mainly in the standing position. Because plotting the magnitude of this response suggested a two‐population distribution, subjects were divided into hyporeactor and hyperreactor groups. Reactivity did not appear to be related to acetylator phenotype. The magnitude of the cardiac response correlated with heart rate responses to standing and to the Valsalva maneuver; when analyzed separately from hyporeactors, correlation was greater among hyperreactors. Because the orthostatic and Valsalva responses are reflex in nature, these results suggest that hydralazine tachycardia is also reflexly induced, that its magnitude depends on individual baroreceptor sensitivity, which is distributed nonnormally, and that it can be predicted by suitable tests of sympathetic responsiveness.Clinical Pharmacology and Therapeutics(1980)28,587–591; doi:10.1038/clpt.19

ISSN:0009-9236    

DOI:10.1038/clpt.1980.207

年代:1980

数据来源: WILEY

摘要:

The hemodynamic effects of the converting enzyme inhibitor teprotide (SQ 20881) were investigated in five patients with normal plasma renin activity who were normotensive during the study (group I), in five patients with hypertension and normal plasma renin activity (group II), and in five patients with hypertension and high plasma renin activity (group III). No significant hemodynamic changes were observed during teprotide administration in group I. In group II there was a decrease in mean arterial pressure by 10 ± 2% (p<0.005) that was associated with a decrease by 16 ± 7% (p<0.05) in stroke volume and cardiac output, possibly due to venodilatation and without a concurrent change in total peripheral resistance. In group III the larger decrease of 19 ± 4% (p<0.005) in mean arterial pressure was due to a decrease by 30 ± 3% (p<0.005) in peripheral resistance. In this group stroke volume and cardiac output increased by 13 ± 2% (p<0.025). There were no compensatory changes in heart rate despite the decrease in mean arterial pressure and vasodilatation. These results indicate that teprotide decreases arterial pressure by a dual hemodynamic mechanism. Cardiac output is increased by teprotide in patients with high‐renin hypertension who exhibit the greatest decrements in peripheral resistance.Clinical Pharmacology and Therapeutics(1980)28,592–601; doi:10.1038/clpt

ISSN:0009-9236    

DOI:10.1038/clpt.1980.208

年代:1980

数据来源: WILEY

摘要:

The treatment of endometriosis with danazol or lynestrenol decreased cholesterol content of plasma high‐density lipoproteins by 50% and 32%. There were simultaneous increases in low‐density lipoprotein cholesterol content of 51% and 19%. We suggest that changes induced by lynestrenol are due to progestational activity, while in the case of danazol both antigonadotropic and androgenic activities are involved.Clinical Pharmacology and Therapeutics(1980)28,602–604; doi:10.1038/clpt.19

ISSN:0009-9236    

DOI:10.1038/clpt.1980.209

年代:1980

数据来源: WILEY

摘要:

The possibility that clonidine might exert some of its effects via opiate or histamine H2receptors has been suggested from observations in animals and man. We undertook a double‐blind, randomized study in six normal subjects, comparing the effects of 0.2 mg intravenous clonidine after pretreatment with 300 mg cimetidine, 0.8 mg naloxone, and saline. There was no attenuation of the hypotension, bradycardia, sedation, inhibition of salivary flow, or reduction in plasma catecholamines after cimetidine and naloxone, but the fall in plasma catecholamines after clonidine correlated with blood pressure, sedation, and salivary flow, suggesting a central adrenergic mechanism for these effects. It is not known whether cimetidine can cross the blood‐brain barrier after short‐term dosing. We conclude that in normotensive subjects the short‐term effects of intravenous clonidine are probably not mediated by an action at peripheral histamine H2or central opiate receptors.Clinical Pharmacology and Therapeutics(1980)28,605–610; doi:10.1038/clp

ISSN:0009-9236    

DOI:10.1038/clpt.1980.210

年代:1980

数据来源: WILEY

摘要:

A double‐blind crossover comparison was made in 18 nonedematous hypertensive subjects with glomerular filtration rates exceeding 70 ml/min/1.73 m2of the effects of 5 mg metolazone and 5 mg bendroflumethiazide on blood pressure and metabolic parameters. After a 4‐wk run‐in placebo period, patients received either metolazone or bendroflumethiazide for 6 wk in a crossover fashion with an intervening washout period of 4 wk. Metolazone induced a more sustained and greater blood pressure response than bendroflumethiazide. Changes in plasma potassium, urate, bicarbonate, renin, and angiotensin II occurred during treatment with both metolazone and bendroflumethiazide; the only significant difference, however, was in changes in plasma bicarbonate. Total body potassium (TBK), measured by whole‐body monitor, did not fall outside the normal range with either metolazone or bendroflumethiazide, although metolazone induced a greater reduction in TBK (6.2 gm, 5.5% of TBK) than bendroflumethiazide (1.2 gm, 1.1% of TBK, p<0.05). Our results suggest that metolazone is a more effective antihypertensive and induces similar but greater metabolic changes than bendroflumethiazide. The results of our comparison suggest that although changes in plasma potassium and TBK are minor, they are greater with metolazone, and potassium supplements may not be necessary in nonedematous hypertensive patients with normal renal function.Clinical Pharmacology and Therapeutics(1980)28,611–618; doi:10.1038/clp

ISSN:0009-9236    

DOI:10.1038/clpt.1980.211

年代:1980

数据来源: WILEY

摘要:

Total body clearance (ClT) of theophylline was examined in 12 markedly obese patients and related to total body weight (TBW) and ideal body weight (IBW). Patients were infused with aminophylline continuously and evaluated at steady state. Total body clearances of theophylline were 29.5 ± 7.8 ml/hr/kg TBW and 58.8 ± 15.9 ml/hr/kg IBW. In patients with congestive heart failure (CHF) (N = 4) theophylline ClTwas 19.7 ± 1.9 ml/hr/kg TBW or 47.7 ± 8.3 ml/hr/kg IBW while in those with no CHF (N = 8) clearance was 34.5 ± 3.5 ml/hr/kg TBW or 64.3 ± 16.2 ml/hr/kg IBW. Acute renal failure did not appear to alter theophylline ClTin two patients (one with and one without CHF). Mean theophylline ClTclosely approximated that of a normal population when corrected for IBW, but there was a much stronger correlation between theophylline ClTand weight when corrected for TBW. Our data suggest that maintenance doses of theophylline in markedly obese patients with CHF should be based on a theophylline ClTof 19.7 ml/hr/kg TBW and of 34.5 ml/hr/kg TBW in those with no CHF.Clinical Pharmacology and Therapeutics(1980)28,619–623; doi:10.1038/clpt.

ISSN:0009-9236    

DOI:10.1038/clpt.1980.212

年代:1980

数据来源: WILEY

摘要:

The disposition of lidocaine and penicillin was studied in normal subjects before and after 7 days of total recumbency. Penicillin (1,000,000 U) and lidocaine (100 mg) were adminstered intravenously. Lidocaine protein binding was also followed. Total body clearance, elimination half‐life, and volume of distribution were calculated. There were no statistically significant differences in these disposition parameters before and after 7 days of recumbency. The binding of lidocaine also was not changed after bed rest. We conclude that the physiologic changes that occur during prolonged bed rest do not affect distribution or elimination of lidocaine or pencillin.Clinical Pharmacology and Therapeutics(1980)28,624–628; doi:10.1038/clpt.1980

ISSN:0009-9236    

DOI:10.1038/clpt.1980.213

年代:1980

数据来源: WILEY