PHARMACOLOGY

 OPEN TRIAL ::

In an open trial the researcher knows the full details of the treatment and so does the patient These trials are open to challenge for bias and they do nothing to reduce the placebo effect However sometimes they are unavoidable particularly in relation to surgical techniques where it may not be possible or ethical to hide from the patient which treatment he or she received Usually this kind of study design is used in bioequivalence studies 

Single-blind trial ::

Here the researcher knows the details of the treatment but the patient does not Because the patient does not know which treatment is being administered (the new treatment or another treatment ) there should be no placebo effect In practice since the researcher knows it is possible for them to treat the patient differently or to subconsciously hint to the patient important treatment -related details thus influencing the outcome of the study 

Double -blind trial ::

Here trial one researcher allocates a series of numbers to new treatment or old treatment The second researcher is told the numbers but not what they have been allocated to Since the second researcher does not know they cannot possibly tell patient directly or otherwise and cannot give in to patient pressure to give them the new treatment In this system there is also often a more realistic distribution of sexes and ages of patients Therefore double -blind (or randomized ) trials are preferred as they tend to give the most accurate results 

Triple-blind trial ::

Some randomized controlled trials are considered triple-blinded although the meaning of this may vary according to the exact study design The most common meaning is that the subject researcher and person administering the treatment (often a pharmacist ) are blinded to what is being given Alternately it may mean that the patient researcher and statistician are blinded These additional precautions are often in place with the more commonly accepted term double blind trials and thus the term triple-blinded is infrequently used however it connotes an additional layer of security to prevent undue influence of study results by anyone directly involved with the study