Did your doctor give you a reason for changing your medication? (assuming you asked why). I don't take medications; just insulin, but I've experienced the same thing - doctor suggesting a change in medication when I've been doing fine on the old one. And, my mother's doctor changed her BP medication, even though she was doing fine on her old one. She had several bad side effects with the new one & I had to take her to the ER three times. She was one of those "He's the doctor & he knows what's best" patients, so talking to her didn't help.
At my recent Dr. visit (only because they won't refill insulin Rx without a visit), my doctor tried to sell me on a new inhaled insulin. I had heard about it, but it's still in the "experimental" stages. Coincidentally, when I was signing out after the visit, a Drug Co. Rep. (wearing the name tag: "Merck") was at the counter, trying to pick up the receptionist.
Before a drug company can profit on a new drug, they have to recoup the millions of $$$$ they spent on research, testing, studies, marketing, advertising. They do that by visiting doctors & offering them HUGE perks to prescribe the new medication.
If you were doing OK on your usual medication, ask your doctor WHY he/she wants to change it, & I suggest you don't accept a B.S. answer, like, "It's better for you."
Medical practice is more about business than patient care.