My wife is having continuous stomach cramps for about 4 hrs. she has used pepto bismol (bismuth subsalicylate) without success. she has not vomited. she is not nauseous.

This : This question is under the "obstetrics" division, is she pregnant? If she is pregnant she needs to be seen immediately. If she is having continued cramping or pain, vomiting, or fever then she needs an emergency evaluation.

Cramps: Usually diarrhea follows abdominal cramping. Absence of abdominal distension and vomiting is somewhat reassuring. A specific area of abdominal tenderness would be concerning. If cramping persists I recommend being evaluated in the hospital emergency room. If no serious findings noted, then a prescription for an antispasmodic can be obtained.