Are there any meds I can use chronically to prevent anaphylaxis?

Anahylaxis. Depending on the cause of your anaphylaxis, you should avoid the trigger. You need to see an allergist and get tested. If your anaphylaxis is adiopathic, as determined by an allergist, then a daily antihistamine may keep things somewhat under control. If you have not seen one yet, you should consult an allergist.
Yes, Many different combinations of medications have been studied. Antihistamines (Histamine 1 blockers), Histamine 2 blockers (ranitidine, cimetidine or famotidine) some will also add anti leukotrienes (montelukast, Zafirlucast) Keep your epinephrine injector close by. If you qualify, the NIH is studyingAnaphylaxis http://www.niaid.nih.gov/volunteer/idiopathicanaphylaxis/Pages/default.aspx.