Prescription Drugs to Treat Constipation. Chronic constipation is often cured by natural remedies: A diet with natural fiber from fruits and vegetables, at least eight cups of water a day, and exercise -- plus maybe an occasional laxative from the drug store.ere are prescription drugs used for the treatment of chronic constipation: ... When you have EPI, you don't get the nutrition you need because your body can't digest and then absorb fats, starches, proteins, and some vitamins and minerals from foods.