Coming to work drunk is an outright cause for disciplinary action. However, suggest keeping two aspects in mind before you initiate any action.
1. The employee concerned should be given a chance to give his version—however illogical it might sound in the face of the evidence you seem to have. Issue a Show Cause Notice with a specific timeframe for his response.
2. You mentioned that you used a Breath Analyzer for confirmation. This could be disputed. Is the Breath Analyzer verified/calibrated for correctness? I am not sure, but please check if such a facility/practice exists, like the Legal Metrology Department in any government certifying the accuracy of all the weights & measures used everywhere. This is just to ensure the employee isn't given a chance to take the stand: the Breath Analyzer is defective & readings are incorrect. Hope you get the point.
If you need the legal aspects (under which clauses of which act, etc.), please wait for the legal members to respond.
Regards, TS