**5. Dysbiosis**

Dysbiosis is a term used to describe any quantitative and/or qualitative imbalance, dysfunction or disturbance of the gut microbiota and microbiome as an indicator of disease or poor health status [23], and may be caused by a number of risk factors, including medications. Drugs and microbiota have a two-way relationship: drugs exert a significant impact on organs and tissues through their effect on gut microbiota, but in the other hand, microbiota metabolic capacity may affect stability, metabolite production, availability, absorption and thus, increase or decrease efficacy and/or toxicity of different medications [24–26]. A number of drugs have been described to alter the composition
