There may be different opinions among us, Doctors,  about prescribing a perticular drug  in generic name alone OR brand name with generic name OR brand name alone .These are some of my queries which many of You also may be having . Does a perticular drug ,say  an antibiotic , Manufactured or Marketed by an international brand differ in real in vivo efficacy from a low cost /  smaller manufacturer brand? Could there be difference between two batches of same medicines from same manufacturer in terms of quality?

W ill there be difference in quality between brands marketed by two different divisions of the same company? How to ensure quality of drug in real practice? Please provide your valuable inputs and share your experiences.