Diabete Medicne Substitut. Control!

I Got To Know I Am a Diabetic in January 2016. I Was Put On Istamet 50/500 (Sitagliptin 50 Mg +Metformin 500 Mg) Twice Day by my Doctor. Since This Drug Is Expensive Rs 359 I Started Taking Its Substitute Zitamet 50 /500 by Glenmark Which Cost Rs 160. Then in one month My Sugar level Came under Control and Thus I Started Taking Zitamaet 50/1000 One a day instead of taking 50/500 twice a day . Presently I am taking zitamet 50/1000 mg once a day. Now This Affordable Drug Zitamet 50/1000 Is Not Available and I have been told production has been stopped.. Istamet 50/1000 and Its Substitutes Are All Very Expensive costing Rs 350 and above.. My Question Is Can I Switch Onto To Zomelis Met 50/1000 (vidagliptin 50 mg+ metformin 100 mg) Which Is Comparatively Cheaper Costing Around Rs 220 . And Also Zomelis 50/1000 Is Being Taken By My Wife and Thus We Can Share the Same and It Becomes Convenient For Both of Us. Currently my sugar levels are absolutely under control