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Results for “randomized crossover trial”

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PubMed1988

Alteration of methyldopa absorption, metabolism, and blood pressure control caused by ferrous sulfate and ferrous gluconate.

This study examined the effect of two widely used iron treatments on methyldopa absorption, metabolism, and blood pressure control. A 500 mg tablet of methyldopa (2.37 mmol) was taken with and without ferrous sulfate (325 mg) by 12 normal subjects in a randomized crossover trial. When ferrous sulfate was taken with methyldopa there was a decrease in the proportion of methyldopa excreted as "free" methyldopa (49.5% +/- 12.4% vs 21.1% +/- 4.77%; p less than 0.01), a significant increase in the proportion excreted as methyldopa sulfate (37.8% +/- 12.3% vs 65.8% +/- 10.5%; p less than 0.01), and a decrease in the percentage of methyldopa absorbed (29.1% +/- 12.5% vs 7.88% +/- 4.14%; p less than 0.01). These factors resulted in an 88% reduction in the quantity of "free" methyldopa excreted. To determine if an iron preparation without sulfate produced the same effect, the study was repeated with ferrous gluconate (600 mg) with similar results. The clinical consequences of the methyldopa-ferrous sulfate interaction was determined in five hypertensive subjects receiving chronic methyldopa therapy. The subjects took ferrous sulfate for 2 weeks. There was an increase in both systolic and diastolic blood pressure in four patients and a decrease in blood pressure in all patients after ferrous sulfate was discontinued. The increases in blood pressure were substantial in three of the patients.

Administration, Oral↗

PubMed1994

The efficacy and relative bioavailability of diclofenac resinate in rheumatoid arthritis patients.

The pharmacodynamics and pharmacokinetics of 75 mg resin-bound diclofenac (resinate) were compared with enteric-coated tablets containing 75 mg of diclofenac in a double-blind randomized crossover trial in 16 patients suffering from rheumatoid arthritis. Diclofenac was significantly faster absorbed from the resinate than from the enteric coated formulation (tlag = 0.454 h vs. 0.998 h, tmax = 1.41 h vs. 2.56 h) and reached lower peak concentrations (Cmax = 1.64 micrograms/ml vs. 2.59 micrograms/ml). No significant differences were found concerning the area under the plasma level-time curves and the mean residence times. Smaller variances were found for the tmax and the mean residence times in the group treated with diclofenac resinate. Onset and duration of analgesia, as assessed by visual analogue scales were similar in both treatment groups, but did not correlate with the plasma concentrations. Four patients experienced adverse effects including gastric pain, transaminase increases, proteinuria and plasma creatinin increase. No uncommon adverse effects were observed with the new preparation.

Absorption↗

PubMed1982

Rationale for the choice of calcium antagonists in chronic stable angina. An objective double-blind placebo-controlled comparison of nifedipine and verapamil.

The effectiveness and safety of verapamil, nifedipine, and placebo in patients with chronic stable angina pectoris were evaluated and compared in two double-blind randomized crossover trials. In the first study, nifedipine (10 mg 3 times daily) was compared with placebo in 24 patients with chronic effort-related angina pectoris; no significant differences in exercise performance were observed with nifedipine compared with placebo. In the second study, the effects of verapamil (120 mg 3 times daily), nifedipine (20 mg 3 times daily), and placebo were compared in 32 patients with chronic stable angina using a double-blind crossover study design. Compared with placebo, both nifedipine and verapamil prolonged exercise duration (5.7 +/- 0.3 minutes with placebo, 7.9 +/- 0.5 minutes with nifedipine [p less than 0.001], and 10.0 +/- 0.7 minutes with verapamil [p less than 0.001]), but the improvement with verapamil was greater than that seen with nifedipine (p less than 0.01). Seven patients had increasing angina with nifedipine, none did with verapamil; the exacerbation of angina during nifedipine therapy appeared related to our observation that, compared with placebo, patients receiving nifedipine had higher heart rates, while patients receiving verapamil had slower heart rates. This study indicates that, at the doses used, verapamil was more effective and better tolerated than nifedipine in patients with chronic stable angina pectoris.

Adult↗

PubMed1986

Ketanserin and prazosin: a comparison of antihypertensive and biochemical effects.

A randomized crossover trial was conducted in 15 patients with essential hypertension to compare the actions of prazosin, a specific alpha 1-adrenoceptor blocker, and ketanserin, an antagonist at alpha 1-adrenergic and serotonin receptors. After placebo dosing for 2 weeks, active drug was given double-blind in two 4-week phases. Satisfactory control of supine blood pressure was obtained in nine of the 12 subjects who completed the prazosin phase and 11 of the 15 subjects who completed the ketanserin phase. Whether comparison was based on supine, erect, postexercise, or ambulatory values, the blood pressure responses to prazosin (2 or 4 mg/day) and ketanserin (40 or 80 mg/day) were closely similar. Neither of the drugs significantly altered supine or erect pulse rates, body weight, serum triglyceride concentrations, plasma renin activity, or urinary aldosterone excretion, and their side effect profiles were similar. The serum cholesterol concentration was lowered by prazosin but was not affected by ketanserin. However, no other features were observed that distinguished the clinical effects of ketanserin from those of prazosin.

Adult↗

PubMed2001

Comparison of methylene blue-directed biopsies and conventional biopsies in the detection of intestinal metaplasia and dysplasia in Barrett's esophagus: a preliminary study.

BACKGROUND: The diagnostic advantage of methylene blue (MB) chromoendoscopy in Barrett's esophagus is unclear. METHODS: Patients with columnar-lined esophagus (CLE) were enrolled into a prospective, randomized crossover trial of MB-directed biopsy versus conventional biopsy. RESULTS: Forty-seven patients (19 long-segment CLE; 28 short-segment CLE) were enrolled and underwent MB-directed biopsy. Sensitivity and specificity of MB for specialized intestinal metaplasia were 53% and 51%, respectively. Sensitivity and specificity of MB for dysplasia were 51% and 48%, respectively. Thirty-five patients (15 long-segment CLE; 20 short-segment CLE) completed the crossover trial. Relative frequencies for specialized intestinal metaplasia were 73% and 71% from MB-directed and conventional biopsy specimens, respectively (p = 0.73). Relative frequencies for dysplasia were 20% and 18% from MB-directed and conventional biopsy specimens, respectively (p = 0.65). In patients with long-segment CLE, dysplasia was diagnosed in 10 patients with MB and 7 patients with conventional biopsy methods (p = 0.25). The number of biopsy specimens per EGD was greater with MB, which may have influenced the diagnosis. Histologically, the grade of dysplasia was indefinite/low in nearly all of the dysplastic specimens. CONCLUSIONS: Results of MB-directed biopsy were similar to conventional biopsy in detecting specialized intestinal metaplasia and indefinite/low-grade dysplasia. MB was not useful in short-segment Barrett's esophagus.

Barrett Esophagus↗

PubMed2001

Flaxseed consumption influences endogenous hormone concentrations in postmenopausal women.

Lignans, similar in structure to endogenous sex steroid hormones, may act in vivo to alter hormone metabolism and subsequent cancer risk. The objective of this study was to examine effects of dietary intake of a lignan-rich plant food (flaxseed) on serum concentrations of endogenous hormones and binding proteins (estrone, estrone sulfate, 17 beta-estradiol, sex hormone-binding globulin, progesterone, prolactin, dehydroepiandrosterone sulfate, dehydroepiandrosterone, androstenedione, testosterone, and free testosterone) in postmenopausal women. This randomized, crossover trial consisted of three seven-week feeding periods, during which 28 postmenopausal women, aged 52-82 yr, consumed their habitual diets plus 0, 5, or 10 g of ground flaxseed. Serum samples collected during the last week of each feeding period were analyzed for serum hormones using standard diagnostic kits. The flaxseed diets significantly reduced serum concentrations of 17 beta-estradiol by 3.26 pg/ml (12.06 pmol/l) and estrone sulfate by 0.09 ng/ml (0.42 nmol/l) and increased prolactin by 1.92 micrograms/l (0.05 IU/ml). Serum concentrations of androstenedione, estrone, sex hormone-binding globulin, progesterone, testosterone, free testosterone, dehydroepiandrosterone, and dehydroepiandrosterone sulfate were not altered with flaxseed feeding. In this group of postmenopausal women, consuming flaxseed in addition to their habitual diets influenced their endogenous hormone metabolism by decreasing serum 17 beta-estradiol and estrone sulfate and increasing serum prolactin concentrations.

Aged↗

PubMed2005

A comparison of spinergy versus standard steel-spoke wheelchair wheels.

OBJECTIVES: To compare the energy efficiency of straight-line wheeling using Spinergy wheels as compared with standard steel-spoke wheels, and to assess the 2 wheels in terms of user comfort and wheeling preference during a wheeling course with multiple turns and surfaces. DESIGN: Nonblinded randomized crossover trial. SETTING: Rehabilitation center. PARTICIPANTS: Twenty persons with paraplegia (neurologic level T6 and below). INTERVENTION: Wheeling a straight line and obstacle course with Spinergy or standard spoke wheelchair wheels. MAIN OUTCOME MEASURES: Velocity and Physiological Cost Index (PCI) while wheeling over ground at a self-selected pace, and the User Preference Questionnaire after wheeling an obstacle course, using Spinergy or standard spoke wheelchair wheels. RESULTS: There was no significant difference in wheeling energy efficiency between the Spinergy and the steel-spoke wheels as measured by PCI ( P =.975). When rated for overall comfort, the Spinergy wheels were preferred over steel-spoke wheels ( P =.002). CONCLUSIONS: Spinergy wheels provided a more comfortable ride, but did not differ from standard steel-spoked wheels in terms of energy efficiency. The increased comfort may have important implications in patient management of pain and spasticity.

Activities of Daily Living↗

PubMed2026

Virtual Reality Education for Hospitalized Pediatric Patients Improves Intrinsic Motivation: A Prospective, Randomized Crossover Study.

Hospitalized children experience educational disruption and reduced motivation during prolonged admissions. Despite the availability of in-hospital schools, many cannot participate due to illness severity or isolation precautions. This pragmatic, randomized crossover trial evaluated whether bedside virtual reality (VR) lessons improve intrinsic motivation among inpatients aged 5 to 25 years unable to attend the hospital school. Participants completed both VR-based educational sessions and standard of care (SOC) conditions on consecutive days. The primary outcome was intrinsic motivation, with secondary outcomes including educational self-efficacy, well-being, self-esteem, and parental experience. Of 156 enrolled patients, 100 were analyzed (mean age 11.5 [SD = 4.1 years]; 43.9% female). Intrinsic motivation scores were higher in the VR condition than SOC (P = .0048), and parental satisfaction was also greater (P = .0008). Bedside VR education represents a feasible, acceptable, and scalable adjunct to inpatient learning, supporting intrinsic motivation and caregiver satisfaction during hospitalization.Trial Registration: ClinicalTrials.gov NCT05725395, date first registered November 22, 2022.

Humans↗

PubMed1988

The combination of prazosin and verapamil in the treatment of essential hypertension.

An exaggerated fall in blood pressure has been reported with the combination of an alpha 1-blocker and a calcium antagonist. This study investigated, in a placebo-controlled, randomized crossover trial, the clinical usefulness of the combination of prazosin (2 mg b.i.d.) and verapamil (160 mg b.i.d.). Therapeutic efficacy was monitored at regular outpatient visits: average supine and erect blood pressures were, respectively, 175/99 and 176/103 mm Hg with placebo, 160/91 and 164/96 mm Hg with single drug treatment, and 152/84 and 152/89 mm Hg with combination therapy. This significant and clinically useful reduction in blood pressure had an overall magnitude of approximately 28/18 mm Hg (supine) and 29/19 mm Hg (erect). Further measurements were made during a series of intensive study days, and the most important additional finding was a pharmacokinetic interaction that resulted in increased peak concentrations and bioavailability of prazosin. In conclusion, the combination of prazosin and verapamil proved effective in the treatment of 12 patients with essential hypertension who had been poorly responsive to conventional treatment with a beta-blocker and thiazide diuretic.

Adult↗

PubMed2005

Effects of expiratory rib-cage compression on oxygenation, ventilation, and airway-secretion removal in patients receiving mechanical ventilation.

BACKGROUND: Expiratory rib-cage compression, a chest physiotherapy technique, is well known as the "squeezing" technique in Japan. OBJECTIVE: To determine the effects of rib-cage compression on airway-secretion removal, oxygenation, and ventilation in patients receiving mechanical ventilation. SETTING: An intensive care unit of an emergency and critical care center at a tertiary-care teaching hospital in Tokyo, Japan. METHODS: Thirty-one intubated, mechanically ventilated patients in an intensive care unit were studied in a randomized, crossover trial. The patients received endotracheal suctioning with or without rib-cage compression, with a minimum 3-hour interval between the 2 interventions. Rib-cage compression was performed for 5 min before endotracheal suctioning. Arterial blood gas and respiratory mechanics were measured 5 min before endotracheal suctioning (baseline) and 25 min after suctioning. The 2 measurement periods were carried out on the same day. RESULTS: There were no significant differences in the ratio of arterial partial pressure of oxygen to fraction of inspired oxygen, P(aCO2), or dynamic compliance of the respiratory system between the 2 periods (before and after endotracheal suctioning). Moreover, there were no significant differences in airway-secretion removal between the 2 periods. CONCLUSIONS: This study suggests that rib-cage compression prior to endotracheal suctioning does not improve airway-secretion removal, oxygenation, or ventilation after endotracheal suctioning in this unselected population of mechanically ventilated patients.

Combined Modality Therapy↗

PubMed1986

Bambuterol: dose response study of a new terbutaline prodrug in asthma.

The bronchodilator activity and side-effects of treatment for 4 days with either 0.085, 0.170 or 0.34 mg/kg bambuterol b.i.d. (a prodrug of terbutaline) or 0.071 mg/kg terbutaline t.i.d. have been evaluated over 12 h, in a double-blind, randomized crossover trial in 19 asthmatic out-patients. Plasma terbutaline concentrations after bambuterol administration were smoother, with a ratio between the maximum and minimum values of about 1.4 compared to 2.6 for terbutaline. The plasma terbutaline level rose with dose, but by less than the increase in dose. The bronchodilator effect was related to the plasma terbutaline concentration in each treatment group, so bambuterol produced more prolonged bronchodilatation than treatment with terbutaline. Tremor and cardiac side-effects were most pronounced after administration of bambuterol 0.34 mg/kg. No severe side-effects were seen. Bambuterol produced stable plasma levels of terbutaline, indicating that as a prodrug of terbutaline it might possibly be administered once daily with good antiasthmatic effect.

Adult↗

PubMed1991

Bioequivalence between two furosemide-spironolactone formulations: a pharmacokinetic and pharmacodynamic approach.

Two formulations of the drug combination furosemide (20 mg)-spironolactone (100 mg) were tested for bioequivalence in a randomized crossover trial in 12 healthy volunteers. By comparing the AUC values derived from drug serum concentrations, bioequivalence was only achieved for canrenone, the main metabolite of spironolactone, but not for furosemide. A significant difference in the tmax values indicates sustained release of furosemide from one of the formulations. By contrast, bioequivalence was achieved if pharmacodynamic criteria, such as urine volume and Na+ and Cl- excretion over a period of 12 hours, were used. Fractional measurements of urinary volume and electrolyte excretion (0 to 3 h, 3 to 6 h, 6 to 12 h) correlated with the different tmax values for both formulations. These data indicate that bioequivalence is more conclusively verified on the basis of pharmacodynamic parameters than on the basis of pharmacokinetic parameters. These considerations are applicable in particular to drugs displaying large inter-individual variations in serum levels and/or a poor correlation between serum levels and effect.

Adult↗

PubMed1993

Fish oil in lupus nephritis: clinical findings and methodological implications.

Our objective was to determine the effects of fish oil on renal function, symptoms, and serum lipids in patients with lupus nephritis. A double-blind, randomized crossover trial of fish oil versus placebo (olive oil) was done on 26 patients with confirmed systemic lupus; 21 completed the study. Intervention was fish oil or placebo, 15 g/day, for one year followed by a 10 week wash-out period, and then the reverse treatment for one year. At baseline and six month intervals, we measured platelet membrane fatty acids, indices of renal function, a disease activity index, serum lipid levels, blood pressure, serum viscosity and red cell flexibility. We found that platelet membrane phospholipids were uniformly affected by fish oil supplementation (P < 0.001) but with significant carry-over effects despite a 10 week wash-out period. Glomerular filtration rate and serum creatinine were not affected. A non-significant reduction in mean (SE) 24-hour proteinuria occurred, from 1424.1 mg (442.7) on placebo to 896.7 mg (352.2) on fish oil (P = 0.21). Fish oil lowered serum triglycerides from 1.89 (0.25) mmol/liter to 1.02 (0.11) mmol/liter (P = 0.004). VLDL cholesterol decreased markedly whether patients initially received fish oil or placebo (P = 0.004). The size of the reduction was affected by the order of treatment (P = 0.03), but parallel comparisons were significant before the crossover (P = 0.0006). With the possible exception of bleeding time, no other treatment effects were shown with fish oil. However, treatment order effects were seen in urinary IgG excretion (P = 0.03), whole blood viscosity (P < 0.0001), red cell flexibility (P = 0.004), and bleeding time (P = 0.06). In conclusion, one year of dietary supplementation with fish oil in patients with stable lupus nephritis did not improve renal function or reduce disease activity, but did alter some lipid parameters. Hitherto unreported carry-over effects and treatment order effects caused by the olive oil created a risk of type II error, and bear methodologic consideration in the design of future studies.

Adult↗

PubMed1982

Acceleration of the body clearance of phenobarbital by oral activated charcoal.

We investigated the effect of multiple oral doses of activated charcoal on the pharmacokinetics of intravenously administered phenobarbital in a randomized crossover trial. Six healthy men volunteered to take 200 mg of phenobarbital sodium per 70 kg of body weight intravenously on two separate occasions. On one occasion, each subject received oral activated charcoal (180 g) in divided doses over three days after the infusion of phenobarbital. Serum levels of phenobarbital were measured in all subjects up to 96 hours after the infusion, and urinary excretion of phenobarbital was measured in two subjects 24 to 96 hours after the infusion. A pharmacokinetic analysis showed that the charcoal decreased the serum half-life of phenobarbital form 110 +/- 8 to 45 +/- 6 hours (S.E.M.) (P less than 0.01), increased the total body clearance of phenobarbital from 4.4 +/- 0.2 to 12.0 +/- 1.6 ml per kilogram per hour (P less than 0.01), and increased the nonrenal clearance from 52 to 80 per cent of the total body clearance. We conclude that oral administration of activated charcoal enhances the nonrenal clearance of phenobarbital.

Administration, Oral↗

PubMed1995

Alterations in gastric acidity in patients infected with human immunodeficiency virus.

In a randomized crossover trial, gastric acidity and gastric microbial colonization in 19 men infected with human immunodeficiency virus (HIV) (of whom nine had AIDS) were assessed. Gastric acidity was assessed during a baseline period and following pentagastrin or glutamic acid administration. Only two (22.2%) of the nine patients with AIDS and none of the non-AIDS patients were hypochlorhydric, as determined by maximal acid output. However, 60% and 67% of patients in the HIV-infected and AIDS groups, respectively, had persistently elevated gastric pH values during the baseline period. Both pentagastrin and glutamic acid significantly increased gastric acidity. Gastric colonization with Candida albicans and gram-positive mouth flora was common. Overall, this study demonstrates that many HIV-infected patients have elevated gastric pH values that may lead to alteration in drug absorption. The large degree of intrasubject and intersubject variability observed in gastric pH suggests that, unfortunately, one cannot predict which patients will have elevated gastric pH values.

AIDS-Related Opportunistic Infections↗

PubMed2006

Safety of reduced-antigen-content tetanus-diphtheria-acellular pertussis vaccine in adolescents as a sixth consecutive dose of acellular pertussis-containing vaccine.

OBJECTIVE: The safety of a booster dose of a reduced-antigen-content tetanus-diphtheria-acellular pertussis (Tdap) vaccine was evaluated in adolescents previously vaccinated with five doses of acellular pertussis-containing vaccine. STUDY DESIGN: Adolescents (n = 319) previously vaccinated with either 5 doses of diphtheria-tetanus-acellular pertussis (DTaP) (n = 193) or 4 doses of DTaP plus another acellular pertussis-containing vaccine received one dose each of Tdap and hepatitis A vaccine in a double-blinded, randomized, crossover trial. Rates of adverse events (AEs) after vaccination with Tdap versus hepatitis A and rates of local AEs among adolescents vaccinated with Tdap (sixth acellular pertussis-containing vaccine dose) versus rates in these same individuals after vaccination with their fifth DTaP dose were assessed. RESULTS: After Tdap, pain (63.6%), redness (51.7%), and swelling (41.4%) were the most frequently reported AEs. Large injection site swelling (swelling > 100 mm, arm circumference increase > 50 mm or diffuse swelling interfering with daily activities) occurred in three adolescents and resolved without sequelae. After the sixth dose of acellular pertussis-containing vaccine, adolescents reported more pain and less redness and swelling compared with incidences of these AEs reported when these same individuals received their fifth DTaP dose. CONCLUSIONS: These results suggest that Tdap is well tolerated as a sixth consecutive dose of acellular pertussis-containing vaccine.

Adolescent↗

PubMed1993

Lack of effect of magnesium-aluminium hydroxide on the absorption of theophylline given as a pH-dependent sustained release preparation.

Antacids can modify the pharmacokinetic parameters of sustained-release preparations of theophylline by changing the gastric pH. Though this has been studied with various theophylline/antacid combinations, the specific preparations investigated here have not previously been tested. The objective of the study was to assess any change in the availability of theophylline from a sustained-release preparation (SR), induced by the coadministration with an antacid. The study was designed as a double-blind randomized crossover trial in the Pneumology Departments of three general hospitals. Fifteen patients were studied. They all had stable asthma treated with theophylline and no major organ failure or gastro-intestinal lesions requiring the use of antacids. The antacid (aluminium hydroxide 800 mg and magnesium hydroxide 800 mg), or placebo, tid, was added to a stable regimen of theophylline SR bid, for 4 days, in crossover fashion. Plasma theophylline concentrations were measured before and 1, 2, 3, 4, 6, 8, 10, 12, 16 and 24 h after the morning dose of Armophylline on the fourth day of each treatment period; the maximum plasma concentration (Cmax), and time to Cmax (tmax) were noted, and the area under the 24-h time-concentration curve (AUC0-24) and mean plasma concentration (Cmean) were computed. Peak expiratory flows on the same day, before and 3, 6 and 12 h after the morning dose of Armophylline were also measured. There was no change in any of the parameters studied. The addition of the antacid to theophylline, each given according to standard clinical practice, did not modify the pharmacokinetics of the latter.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Diuretic and non-diuretic actions of furosemide: effects of probenecid.

Furosemide causes not only natriuresis, but a rapid (5-10 min) increase in plasma renin activity. The latter has been attributed both to the release of eicosanoids from renal blood vessels and to changes in sodium delivery to the macula densa. Drugs like indomethacin abolish the renin increment and could potentially affect both mechanisms: they inhibit cyclooxygenase but could also compete with furosemide for transport into the tubular lumen, reducing furosemide concentration at its site of action. We studied the effects of probenecid, a weak acid without cyclooxygenase activity, on the responses to furosemide in 20 healthy young men. Each received placebo and low (1000 mg/d) or high (2000 mg/d) doses of probenecid for one week in double-blind, randomized trials, crossover fashion. One hour after the last dose, all participants were given furosemide 0.5 mg/kg intravenously. Probenecid reduced serum uric acid in a dose-dependent manner but did not change platelet thromboxane B2 production. Similarly, there was no change in urine excretion rates of thromboxane B2 or 6ketoprostaglandin F1 alpha, or in baseline or stimulated plasma renin activity. The total natriuresis in 4 h was also unchanged. By contrast, the sodium excretion rate in the first 30 min was reduced after both probenecid regimens while that of later periods was increased. These findings are consistent with the proposed effect of probenecid as reducing furosemide secretion in the proximal tubule, which reduces its concentration at the lumenal surface of the thick ascending limb of Henle's loop, but also prevents its excretion from the body.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗