As such, they are hybrids of the RCT methodology and naturalistic designs and are therefore termed “practical clinical trials.” 8 They are intentionally designed to evaluate the effectiveness of the treatments under real-world conditions and in patient samples representative of everydayclinical practice (Table I). They can be performed as RCTs,

but less demanding designs are also possible. If they use even a blind9 or double-blind10 Inhibitors,research,lifescience,medical RCT approach they come close to phase III trials considering design aspects, with the only difference being that patient selection is not that restrictive and that, eg, comorbidity or comedication are allowed. Table I. Some characteristics of clinical trials of “efficacy” vs trials Inhibitors,research,lifescience,medical of “effectiveness.” In order to avoid guidelines completely losing their relationship with clinical reality by preferring study types with too little generalizability, greater emphasis should be placed on other empirical research approaches. A drug that has been evaluated in placebo-controlled studies with the selection problems described above should also be tested in studies with less restrictive Inhibitors,research,lifescience,medical methodology, eg, randomized

control-group studies versus a standard drug; the results should at least show a tendency towards consistency. The 3-arm study design recommended Inhibitors,research,lifescience,medical by the European regulatory authority, EMEA/CPMP,11 in which the experimental substance is compared with placebo and a standard drug, delivers more meaningful results but cannot avoid the problems associated with the extensive selection of patients since it still has a placebo group. Therefore, other types of studies traditionally considered to be phase IV should be part of the

evaluation process. It should be remembered that, traditionally, Inhibitors,research,lifescience,medical there was a demand for a psych opharmaceutical drug to be clinically evaluated in a phase model at various methodological levels of empirical research and with approaches of different methodological stringency. This means that evidence for efficacy and toierabiiity should additionally be obtained from phase IV Levetiracetam studies, which are more closely oriented towards routine clinical care,12-17 to complement the results of phase III studies with their strict methodology. In such a phase model of clinical/pharmacological evaluation, the evidence from each phase is seen to be complementary and part of the overall evidence. This idea can no longer be found in the systems currently used in guidelines to assess evidence, since evidence is rated according to the study design with the most demanding methodology for the respective therapy (eg, placebo-controlled studies) selleck chemicals llc without ascertaining whether consistent results are available from less restrictive but more generalizable study types.