In my experience as a medically complicated person, generics generally work, but may have different side effects, both in scale and style. One of the worst was a duloxetine generic that came on so hard and strong that I felt serontoninised.

My friend the John the Pharmacist explained that the binders etc can accelerate absorption. His advice was be careful the first two days of a new generic formulation.

I would assume the NHS (like the TGA here in Oz) looks _very_ carefully at the side-affect profile before they buy any particular generic. Government agencies tend to try not to poison voters.