Left leg and left hand nerve numbness.

Am facing left hand and left leg numbness whenever am lying on bed. Am facing this issue for past six months. Doctor has prescribed Pregamec forte tablet for this issue before six months. Its almost six months am taking this tablet. After taking this tablet am not facing this issue much. This tablet helped me for this issue. Since am in hometown, am not able to consult that doctor which i supposed to visit him in january. In between, i stopped that tablet for few days and checked whether am facing that issue or not. After stopped that tablet, again i was facing numbness issue. Hence i started to take again. Please advise whether it is safe to continue this tablet for a long period. For how long is it advisable to take this tablet continuously? I took Brain MRI and Cervical Spine MRI, Nerve Conduction test, Sugar and Thyroid. Everything is Normal. Do I need to take any other test?