My doctor suggested 8 grams of powdered inositol daily for anxiety. can i take this with minocin (minocycline) and ativan? should i start on a smaller dose?

Yes you can, BUT: Please don't rely solely on Ativan (lorazepam) or even inositol to deal with your anxiety. If you haven't already, please get a comprehensive evaluation of your anxiety by a psychiatrist and psychologist who knows cbt and other talk therapies well. If meds are needed, ssri's will help anxiety without exposing you to habit-forming meds like ativan (lorazepam). http://www.ncbi.nlm.nih.gov/pubmed/9169302.