http://www.medications.com/effect/view/41469 Muscle /joint pain, Chest pain, vivid nightmares, have had an ablation to cure high speed heart rhythm. Stopped taking Omeprazole as I was having excessive pain though the arthritic swelling was almost zero. Now feel MUCH! better N. K. Wiltshire Thu, 14 May 2009 05:38:23 -0400 http://www.medications.com/effect/view/41469?item=19823 I don't think nightmares would be the side effect of Omeprazole. You can find them at http://www.internationaldrugmart.com/prilosec.html http://www.medications.com/effect/view/41469?item=19823