I've managed to get myself to down to a Prilosec 20mg dose from Nexium 40mg (with much suffering) but it still is not working that great. I was taking 2 Prilosec OTC and that worked well by day 10 for heartburn but then I started to experience severe Vertigo. I thought I was dying. So I stopped Prilosec altogther and that horrible dizziness went away. In desperation I went back to it after 4 days but only took 20mg and suffered a lot before it finally calmed down. Now I'm at 20 but it really isn't working that great and after building back up on 20mg (this drug works very slow) I'm getting dizziness again. it is not as severe as before but I can definitely feel it throughout the day. I do not like it and do not think I can live with it. I'm thinking of trying Prevacid next but I'm not sure if 15mg is the same as 20mg Prilosec. I see on some sites that it is but others say 30mg equals 20mg Prilosec. Does anyone know for sure what amount of prevacid would just about equal 20mg of prilosec? Thank you so much.