- Patients should not be scheduled to receive laxatives or stool softeners prophylactically to prevent constipation, as the prevention of neuro-constipation will be evaluated in this study; however, when patients show signs of developing constipation while on chemotherapy, as determined by the treating physician, they may be treated with laxatives or stool softeners at the clinician's discretion. Use of laxatives or stool softeners will be documented on the concomitant medication log.