Biomedical subjects

R C Schriver

Publications and source records attributed to R C Schriver.

3 recordsLinked to original sources

PubMed1987

p-value and power computations in multiple look trials.

This paper presents at an instructive level detailed design, decision and computational aspects of p-values and power for clinical trials in which interim looks at accumulating data are planned. Background theory and an application are presented. In addition, a definition of the term p-value, appropriate for a trial in which interim looks are planned is proposed. The definition is intuitively consistent with that for a fixed sample size trial. That is, the p-value reflects the strength of the data against the null hypothesis. For trials incorporating group sequential methods, the p-value at a particular look reflects the conditional nature of the data collected through that look on the data collected through earlier looks.

Clinical Trials as Topic↗

PubMed1985

Role of nocturnal acid suppression on the rate of duodenal ulcer healing: clinical dose-range trials with oxmetidine.

These studies represent the first attempt to compare, concurrently, several once or twice daily dosage regimens of an H2-receptor antagonist for ulcer-healing efficacy in the same national population within the same time period, using the same criteria for patient selection, duration of treatment, and end-point. Investigators from 66 centers entered 745 patients, 17-71 years of age, with endoscopically documented uncomplicated duodenal or pyloric channel ulcers, greater than or equal to 0.5 cm in the longest axis. Patients were randomly assigned to six regimens (five oxmetidine, one placebo) and were dosed once (bedtime) or twice (morning and bedtime) daily. Antacid use was restricted. Endoscopy was performed at wk 0 and 2, and at wk 4 in patients not healed at wk 2. Statistical analysis at wk 4 revealed the following healing rates with oxmetidine: 400 mg bid-73.3%; 600 hs-71%; 400 hs-68.6 and 61.6%; 200 mg bid-61.5%; and 200 hs-59.9%. All of the regimens except 200 hs were statistically significantly superior to placebo. The efficacy of the nocturnal 600-mg dose was comparable to that of 400 mg bid and the efficacy of the nocturnal 400-mg dose was comparable to that of 200 mg bid.

Adolescent↗

PubMedDate not supplied

Steady-state lithium blood level fluctuations in man following administration of a lithium carbonate conventional and controlled-release dosage form.

A controlled-release lithium carbonate tablet was compared to an immediate release lithium carbonate capsule in normal volunteers. These crossover studies at steady state showed that the tablet produced a smoother serum curve than the capsule with no loss of total bioavailability. Quantitatively, the capsule produced about 1.4 times more fluctuation in serum lithium values than the tablet.

Adult↗