Long-term past laxative abuse can lead to chronic constipation as well as damaging the colonic muscle wall. It can also drain the body of water, vitamins and minerals.
To determine if any permanent damage has been done, the colonoscopy/upper endoscopy would be the most comprehensive next step.
Certainly the past laxative abuse may have lead to the IBS-like symptoms. Discussing this with your personal physician is the appropriate next step.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
Medical Weblog:
kevinmd_b