I'm in mirt & cough medicine cause drowsiness today finish gym i feel dizzy and feel like almost fainted . is this effect of medicine ??

Could be...: Nearly passing out can be related to the medication; however, there can be quite a few other reasons too. If you are taking cough medicine, I imagine you aren't feeling well and it is possible that you overdid you workout for how your body is feeling. Dehydration could be another cause. I would rest, stop the cough medication and see how you feel. If persistent symptoms, be seen by your doctor

Dehydration.: Some cough meds contain drugs which cause drowsiness; the label might clarify this. After exercise, one can feel dizzy, or faint, due to dehydration with low blood pressure. One could check BP sitting and standing when such symptoms occur; a blood pressure of 85mm Hg or less (systolic, upper number) upon standing can be associated with symptoms. Keep well hydrated, especially prior to exercise.