Help with my RX

Patient: Dear DoctorMy name is Nandus. I am a 19 year old South African student.I have been on Ritalin LA 20mg’s for about a year and a half. The Ritalin only lasts about 3 hours. Our family doctor does not want to give me a higher dose of the Ritalin, and he does not want to put me on another drug like concerta or vyvanse. I have read that those last longer. When I take the Ritalin My heart beats very fast, and my muscles jump like craze. I really need to concentrate on my school work, because I want to study medicine after school. But I have stopped taking the Ritalin because it is really expensive and it does not seem to work.Any advice on getting my doctor to see some sense in this situation.Thank you very much.Nandus Pieterse

Symptoms: Fast heartbeat motor tics