I've been taking Zantac as an H2 blocker to address what I think are mast cell issues. I hope to be seen by a specialist eventually but right now I just take Allegra at night and was taking Zantac twice a day but I can't tolerate it well. Are there other H2 blockers that might not have this effect? I saw there's Pepcid etc but it also has fatigue as a potential side effect. I could take Zantac before bed but since a lot of my symptoms flare with eating I think it's most effective taking it before lunch and dinner but I can't tolerate being that drowsy throughout the day and evening.