Blinding design

Discussion An initial effort to study group behavior when different drugs were present. In a three session double-blind design, each man in rotation received a small dose of BZ, LSD or atropine and the effect on their interactions and performance of simple military tasks was observed, but not scored. It was possible to distinguish which drug each subject had received by clinical examination. This was a pilot study, intended primarily to test the feasibility of using ... 

Qinical trials in which it would be unethical to use a double-blind design... 

Is the study valid Did the investigators use a randomized, controlled, blinded design in which all the patients were followed up at the end Apart from intrinsic differences in the treatments themselves, were all the patients treated the same way Without affirming these relatively straightforward parameters, it is impossible to know whether differences in the outcome reflect true differences in the impact of the treatments or some other characteristic of the study. 

Devanand et al. (1989) studied the effects of haloperidol (3 mg/day) in a group of patients with AD who presented with delusions and hallucinations. With a double-blind design, these researchers showed that haloperidol was... 

Studies have been carried out with antidepressants, and trazodone is probably the most studied. These studies contained small samples, and no double-blind design was applied. The general conclusion of these works (Pinner and Rich 1988 D. M. Simpson and Foster 1986) is that trazodone at high doses (200-500 mg/day) helps to control disruptive behaviors. Slight improvement with buspirone was obtained in two studies carried out in small samples of patients with dementia and dismptive behavior (N. Hermann and Eryavec 1993 Sakauye et al. 1993). 

In another study, 118 children with IQs ranging from 35 to 84 who demonstrated conduct disorder were randomized to risperidone (at a mean dose of 1.23 mg/day) versus placebo in a double-blind design (96). In comparison with placebo, risperidone produced a statistically significant reduction in insecure/anxious behavior, hyperactivity, self-injurious/stereotyped behavior, irritability, and aggressive/destructive behavior, as well as an increase in adaptive social behavior. The latter is important because it shows that the changes are not due to sedation, although more somnolence was apparent with risperidone. 

Controlled trials. Table 10-4 summarizes the results from four of the five well-controlled, albeit small, trials comparing lithium with an antipsychotic in classic manic patients. These studies presented their data in a way that allowed for inclusion in a meta-analysis. Each study was a well-controlled, double-blind design, finding lithium superior to an antipsychotic, and the meta-anaiysis of the combined studies demonstrated this difference to be highly statistically significant. 

First, in a study by Pope et al. (131), 36 previously lithium-resistant (i.e., nonresponsive and/or nontolerant) patients were treated for 3 weeks with DVPX or placebo in a random-assignment, double-blind design. DVPX was significantly more effective than placebo, with 12 of 17 patients responding to this agent, versus only six of 19... 

What is the impact of this more complex model on drug testing and submissions The current causality model assumes that randomly dividing disease victims into two (or more) groups and administering a therapy in a double blind design will determine whether or not the therapy is effective. But if the... 

The MORE study (Multiple Outcomes of Raloxifene Evaluation) was a multicenter, randomized, double-blind design which followed 7,705 postmenopausal... 

The study had a single-center, single- and repeated-dose, single-trial period, and double-blind design. 

Tezosentan has been studied in single intravenous doses of 5, 20, 50, 100, 200, 400, and 600 mg for 1 hour in sequential groups of six men in a randomized, placebo-controlled, double-blind design (2). Headache was the most frequently reported adverse event and it was more common than with placebo at doses of 100 mg and over. There were no clinically important changes in vital signs, electrocardiography, or clinical laboratory tests. The volume of distribution at steady state, about 16 liters, and the clearance, 30 1/hour, were independent of dose. Endothelin-1 concentrations increased dose- and concen-tration-dependently and returned slowly to basehne after the end of the infusion. 

In less well controlled studies topical theophylline, with or without topical dibutyryl cyclic AMP or a cyclic AMP analog, has shown modest efficacy in psoriasis.29,30 An uncontrolled clinical trial of oral theophylline is said to have demonstrated beneficial results in psoriasis.31 In two uncontrolled clinical studies of intramuscular dibutyryl cyclic AMP, studies inspired by our earlier biochemical studies on cyclic nucleotides in psoriasis,Chinese physicians in Shanghai considered the drug effective in 80% of 69 patients treated.32,33 in the Chinese studies, reported side effects were insignificant and thus it should be possible to duplicate their study but using a double blind design. In view of the excellent re-... 

Clinical trials in which it would be unethical to use a double-blind design Some large, multicentre postmarketing surveillance studies, in which a comparison of the newly marketed drug and standard therapy is made... 

Experimenter expectancy Researchers beliefs affect outcome Pygmalion effect Double-blind design... 

Eg, AZT trials. Assume double-blind design. Group A receives AZT for 3 months, Group B is control. For second 3 months, Group B receives AZT and Group A is control... 

The preparation of study medications or devices for clinical studies is a time-consuming process and often rate-limiting in initiating the study, particularly with double-blind designs. Requisition, labeling and packaging are some of the important considerations. 

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