I'm not a doctor either, but I take omeprazole (Prilosec). The PPI action treats acid reflux in the stomach. What does this have to do with IBS, which is generally lower intestine?!?
Please take her to the doctor to adjust dosage of medication, don't mess with it yourself. Besides, wouldn't she be more willing to give up the pills if that advice came from her doctor?
5'0" female, 45 years old. Started Primal October 31, 2011, at a skinny fat 111.5 lbs. Low weight: 99.5 lb on a fast. Gained back to 115(!) on SAD chocolate, potato chips, and stress. Currently 111.