摘要:

The Aspirin Myocardial Infarction Study (AMIS) was a double‐blind placebo‐controlled trial to test the effect of aspirin on the survival of 4524 people who had experienced a prior heart attack. Shortly before their closeout visits, 400 of the participants were randomly selected to be interviewed concerning their perceptions of their treatment assignments; 380 were actually interviewed. A bare majority (52%) correctly identified their study therapy, 28% mistakenly named the alternative treatment, 13% declined to guess, and 7% specified extraneous substances. According to the proposed formula for evaluating the patient blind, only 24% of the sample made “informed” guesses regarding their therapy, while the remainder guessed in an uninformed way or not at all. Those who tested their capsules (usually by taste) showed proportionately more correct responses than the nontesters. Correctness also varied with the reasons for the subjects guesses (e.g., side effects). Among the sample as a whole, most people were only moderately or less than moderately certain their guess was correct. Even among those who were in fact correct, only 18% were absolutely certain of their choice.Clinical Pharmacology and Therapeutics(1982)32,543–553; doi:10.1038/clp

ISSN:0009-9236    

DOI:10.1038/clpt.1982.201

年代:1982

数据来源: WILEY

摘要:

The effectiveness and safety of oral flecainide for suppression of complex ventricular arrhythmias was tested in nine patients in a short‐term (4 wk), single‐blind, placebo‐controlled experiment. The prevalence of multiform premature ventricular complexes (PVCs), couplets, and nonsustained ventricular tachycardia (VT) (>3 PVCs at rate>100/min) was determined by 48‐hr Holter monitoring on placebo and flecainide (200 to 300 mg b.i.d.) therapy. Multiform PVCs/hr were reduced by 96% in eight of nine patients (P<0.001). Couplets per 24‐hr period were suppressed entirely in six patients (P<0.001) and reduced by 92% in the remaining two patients. VT runs per 24 hr were abolished in six patients (P<0.02) and reduced by 91% in one. As a group the frequency of PVCs per hour, couplets per 24 hr and VT per 24 hr was reduced by 96% (P<0.01) over that in the preceding placebo period. Flecainide (P<0.02) slowed heart rate by 10% and prolonged PR, QRS, and QTCintervals by 31%, 47% and 6%. No hematologic, hepatic, or renal abnormalities were found. Side effects were mild, transient, and central nervous system related; blurring of vision was the most frequent effect and was reported in four patients.Clinical Pharmacology and Therapeutics(1982)32,554–561; doi:10.1038/c

ISSN:0009-9236    

DOI:10.1038/clpt.1982.202

年代:1982

数据来源: WILEY

摘要:

Verapamil has been shown to reduce total‐body digoxin clearance by 35% due to impairments of both renal and extrarenal clearances. Our study was undertaken to evaluate the influence of the related calcium antagonist nifedipine on single‐dose digoxin kinetics. Nifedipine increased extrarenal clearance of digoxin from 1.09 ± 0.30(SD) to 1.45 ± 0.23 ml/min/kg (P<0.05) and reduced the total urinary recovery of the drug from 69.2% ± 5.9(SD) to 64.3% ± 5.2 (P<0.05). There were no significant changes in renal digoxin clearance, distribution, or biological half‐life or in digoxin distribution volumes during nifedipine coadministration.Clinical Pharmacology and Therapeutics(1982)32,562–565; doi:10.1038/c

ISSN:0009-9236    

DOI:10.1038/clpt.1982.203

年代:1982

数据来源: WILEY

摘要:

To investigate the effect of glucocorticoids on β‐agonist‐induced desensitization, we studied the effect of a single intravenous dose of methylprednisolone (2 mg/kg) on β‐receptor density and affinity in lymphocytes from four normal and four mildly asthmatic subjects at the end of 3 to 5 wk of terbutaline therapy and from four normal subjects taking no other drug. Terbutaline decreased (‐) [3H]‐dihydroalprenolol binding sites by 53% in normal and by 42% in asthmatic subjects. Methylprednisolone restored the number of binding sites to levels statistically indistinguishable from the preterbutaline values in both groups of subjects. In subjects not exposed to terbutaline beforehand there was no significant alteration in receptor density after methylprednisolone, nor in normal lymphocytes incubated in vitro for 90 min with hydrocortisone (10−5M). No significant change in the dissociation constant was observed in any situation. A single intravenous dose of methylprednisolone reverses terbutaline‐induced down‐regulation of β‐adrenoceptors. This may provide a mechanism for the beneficial effect of steroids in restoring catecholamine responsiveness in asthmatic subjects.Clinical Pharmacology and Therapeutics(1982)32,566–571; do

ISSN:0009-9236    

DOI:10.1038/clpt.1982.204

年代:1982

数据来源: WILEY

摘要:

The effects on blood pressure and renal function of a single 20‐mg sublingual dose of nifedipine were investigated in 10 patients with mild to moderate arterial hypertension insufficiently treated on beta‐blocker monotherapy. Nifedipine induced a prompt and marked reduction of both systolic and diastolic blood pressure (average maximal reduction 30/22 mm Hg, P<0.001). Despite the beta blockade, heart rate rose 25%. Only insignificant increments of glomerular filtration rate and renal plasma flow were registered, whereas calculated renal vascular resistance (RVR) was markedly reduced (P<0.001). Urinary excretion rate of albumin and beta‐2 microglobulin rose after nifedipine, reflecting changes in glomerular as well as tubular function. Mean blood pressure seemed to be a major determinant of the excretion of proteins. There was a marked increase in the excretion of sodium after nifedipine and urine volume rose from a mean of 8.2 ± 1.3 to 12.5 ± 1.8 ml/min (P<0.01). The changes in sodium excretion rate correlated with the renal hemodynamic changes. Uric acid excretion rate rose remarkably after nifedipine and the magnitude of the changes seemed intimately related to the basal level of RVR. The results indicate that nifedipine therapy may be advantageous in patients whose hypertension is insufficiently controlled with beta blockers alone. Renal blood flow is maintained and there is a desirable diuretic action and enhancement of uric acid excretion.Clinical Pharmacology and Therapeutics(1982)32,572–576; doi:10.1038/clp

ISSN:0009-9236    

DOI:10.1038/clpt.1982.205

年代:1982

数据来源: WILEY

摘要:

The effectiveness and tolerance of a centrally acting antihypertensive agent (Clonidine) was compared to that of a diuretic (hydrochlorothiazide) in treatment of adolescents with essential hypertension. After a phase on placebo 29 adolescents with fixed primary hypertension were randomly assigned, double blind, to one of two treatment groups. Active therapy was initiated at a low dose (0.1 mg Clonidine b.i.d. or 25 mg hydrochlorothiazide b.i.d.) for 12 wk. In those in whom treatment goals for blood pressure control had not been reached, the dose was increased (Clonidine to 0.2 mg and hydrochlorothiazide to 50 mg) for 12 wk. In the clonidine‐treated group there was a reduction during low‐do se therapy in systolic (P<0.05) and diastolic pressure (P<0.01) and heart rate (P<0.01). With low‐dose diuretic therapy there was a reduction in systolic pressure only (P<0.05). Linear growth patterns were normal for both groups, but there was a reduction in serum potassium in the diuretic group (P<0.001). Of the two drugs investigated the centrally acting Clonidine was more effective in blood pressure control (85%) than the diuretic (40%).Clinical Pharmacology and Therapeutics(1982)32,577–583; doi:10.1038/clpt.

ISSN:0009-9236    

DOI:10.1038/clpt.1982.206

年代:1982

数据来源: WILEY

摘要:

Bioavailability and dynamics of a sustained‐release preparation of furosemide (FR, 60 mg) were compared with those of a conventional tablet (F, 40 mg). The preparations were given to 12 healthy subjects in a study of crossover randomized design once daily for a week. FR absorption was substantially delayed and the uptake of furosemide was about 75 % of that from F, despite the larger dose administered. F induced a brief, intense diuresis and excretion of Na+, K+, and Cl−, both during short‐ and long‐term administration. There was no such peak after FR. Total diuretic and saluretic effects did not differ between the two preparations, despite the lower bioavailability of FR. It is suggested that this discrepancy might be caused by transient supramaximal urinary levels of furosemide after F, whereby not all of the drug can exert an effect.Clinical Pharmacology and Therapeutics(1982)32,584–591; doi:10.1038/clp

ISSN:0009-9236    

DOI:10.1038/clpt.1982.207

年代:1982

数据来源: WILEY

摘要:

Interruption of the renin‐aldosterone system with angiotensin‐converting enzyme inhibitors (CEI) should result in a low aldosterone secretion, but most investigators have measured aldosterone production only indirectly by plasma aldosterone (PA) levels or urinary metabolites. We evaluated the effects of CEI of the aldosterone secretion rate (ASR) and compared them with PA, urinary tetrahydroaldosterone (THA), plasma renin activity (PRA), and electrolyte balance in six normotensive subjects in a metabolic unit during a control period (5 days) and during administration of 10 mglday enalapril for 28 days. Our results demonstrated that (1) the ASR did not decline until after 1 wk of CEI therapy and this was reflected by a corresponding decline in the urine potassium:sodium ratio, (2) upright PA levels at day 1 declined, but supine PA levels were unchanged, (3) THA excretion remained essentially unchanged and the THA:ASR ratio rose progressively during therapy, (4) PRA rose and was maximal on day 3, but subsequently declined. In conclusion, enalapril‐induced hypoaldosteronism required several days to become demonstrable and this was not accurately assessed by PA or THA — possibly due, in part, to altered aldosterone metabolism. The simultaneous decline in both PRA and ASR could be due to a decrease in renin substrate. Caution is therefore warranted when assessing aldosterone secretion indirectly by either PA levels or urinary metabolites during CEI therapy.Clinical Pharmacology and Therapeutics(1982)32,592–598; doi:10.1038/clp

ISSN:0009-9236    

DOI:10.1038/clpt.1982.208

年代:1982

数据来源: WILEY

摘要:

Using isotope technique, the serum binding of amitriptyline (AT), nortriptyline (NT), and quinidine (Q) was measured by equilibrium dialysis in sera containing varying amounts of lipoproteins. Sera were obtained from 10 fasting subjects with normal to grossly elevated levels of cholesterol, triglycerides, or both. When the lipoproteins were removed from eight of the sera by a standard ultracentrifugation technique, the ratio bound/unbound (B/F) AT decreased an average of 47% (range 30% to 68%), NT an average of 54% (range 39% to 67%), and Q an average of 6% (range 0 to 16%). This decrease in the ratio B/F correlated linearly with the sum of serum concentrations of cholesterol and triglycerides for AT (r = 0.88) and NT (r = 0.82), but not for Q (r = 0.15). In three lipoprotein‐depleted sera resuspended with lipoproteins at eight different concentrations ranging from 0 to 100% of the original content, there was a linear correlation between the ratio B/F for AT and NT and the lipoproteins, as evidenced by cholesterol or triglycerides concentrations (r = 0.97 to 0.99), but not for Q (r = ‐0.17 to 0.36). Finally, in the original 10 serum samples, there was a linear correlation between the ratio B/F and the serum lipoproteins (sum of cholesterol and triglycerides) for AT (r = 0.89) and NT (r = 0.68), whereas there was no such relationship for Q (r = ‐0.15). These data indicate that basic drugs differ in binding characteristics (probably depending on lipophility).Clinical Pharmacology and Therapeutics(1982)32,599–606; doi:10.1038/clpt.

ISSN:0009-9236    

DOI:10.1038/clpt.1982.209

年代:1982

数据来源: WILEY

摘要:

Procainamide kinetics were studied in six children after a single intravenous dose. Two‐compartment kinetic analysis of serum concentration‐time curves of five children, who received a dose of 5.5 ± 0.9 mg/kg (mean ± SD), revealed the following values for kinetic parameters: distribution half‐life, 10.3 ±3.4 min; elimination half‐life, 1.7 ±0.1 hr; elimination constant, 1.2 ± 0.3 hr−1; plasma clearance 19.4 ± 2.0 ml/min/kg, and steady‐state volume of distribution, 2.2 ± 0.3 l/kg. A sixth patient, who received an accidental overdose of 28 mg/kg, had altered elimination kinetics due to drug‐induced hypotension.N‐acetylprocainamide (NAPA) was detected in serum samples obtained soon after procainamide dosing and peak concentrations were attained at 1 to 2 hr. NAPA levels were lower than corresponding procainamide concentrations at most sampling periods. The findings of short elimination half‐life and rapid plasma clearance of procainamide in children suggest that continuous intravenous infusion may be necessary to maintain therapeutically effective plasma concentrations in these patients.Clinical Pharmacology and Therapeutics(1982)32,607–611

ISSN:0009-9236    

DOI:10.1038/clpt.1982.210

年代:1982

数据来源: WILEY