Kliničko ispitivanje lijekova složen je i dugotrajan proces koji osim znanja zahtijeva i velika novčana sredstva. Postupak provođenja kliničkog pokusa uređen je odgovarajućim zakonskim propisima i međunarodnim smjernicama. Kliničko ispitivanje novog lijeka tradicionalno je podijeljeno u četiri faze, a prve tri faze provode prije procesa registracije regulatorna tijela. Klinički pokus može se oblikovati na različite načine, no idealnim kliničkim pokusom danas se smatra onaj koji je kontroliran, randomiziran, dvostruko slijep. Tehnike randomizacije i maskiranja (sljepo}a) smatraju se najznačajnijima za izbjegavanje pristranosti u provo|enju, evaluaciji i interpretaciji rezultata kliničkog pokusa. Dva u praksi najčešće provođena oblika kliničkog terapijskog pokusa, a s obzirom na tip terapijske usporedbe, paralelni su grupni pokus i križani pokus. Provođenje kliničkih pokusa jedini je način dobivanja pouzdanih podataka o novom lijeku s grupnom usporedbom, ali i novih podataka o bolesti koju liječimo te je preduvjet za registraciju novog lijeka. Ispitivanje provedeno u skladu s pravilima dobre kliničke prakse korisno je i za bolesnike i za liječnike određene sredine, koji su na taj način najkvalitetnije uključeni u najnovije medicinske spoznaje. široj društvenoj zajednici kliničko ispitivanje lijekova koristi i s financijskog aspekta jer omogućava uštedu sredstava za liječenje određenih bolestiClinical drug investigation is a complex and long-lasting process demanding knowledge and large financial funds. The procedure of conducting a clinical trial is regulated by appropriate legislative regulations and international guidelines. The clinical trial of a new drug has been traditionally divided into four phases, and the first three ones are carried out before the drug approval from regulatory authorities. It is possible to design a clinical trial in different ways, but an ideal clinical trial today is considered to be that one which is controlled, randomized and double blind. The randomization and masking (blinding) strategies are considered to be the most important in avoiding bias when running, evaluating and interpreting the results of clinical trials. Two of the most frequent types of clinical trial design, concerning the therapeutic control, are a parallel group design and a crossover design. Clinical trials are essential for obtaining relevant data about a new drug compared with a control group, but also new data about the disorder being treated. This is a precondition for the approval of a new drug. The study conducted in accordance with the good clinical practice guidelines is therefore desirable not only for patients but also for physicians, i.e. for the medical level of a specific area which is so best included into the most recent global knowledge of medicine. Clinical trials are also of interest for the community because they are also useful from the financial aspect in saving money for treating specific disorder
