Table 1.

Stages for including articles into the review.

Stage	Action	Results
I	Key words (‘gastrectomy’, ‘gastric bypass’, ‘bariatric surgery’ AND ‘pharmacokinetic’, ‚absorption’ and ‚bioavailability) Databases: Cochrane, PubMed, Scopus	814
II	Due to the small number of studies in recent years, the time criterion has not been applied	383
III	Clinical trial	383
IV	Independent verification and inclusion of research by two authors inclusion criteria: The groups of drugs selected by the authors: Antibiotics, Analgesic drugs, Antidepressants, Anticoagulant drugs, Immunosuppressants, Thyroid hormones, Antidiabetic drugs, Loop diuretics, Proton-pump inhibitors, Vitamins, Mineral elements	34