Read the warning on the label about driving and drowsiness,as if something occurrs on the roads whilst you are on that leave yourself open to possibly driving without due care or worst, and at the worst drive whilst over the limit with a prescribed drug new section 5a RTA law back in march 2015.
If I were you tell your gaffer that you are on it and let them check with DVLA etc,probably not what you want to hear but its always better to check prior to anything happening than after.
Stefluc