Side effects from laxatives include gastrointestinal issues, discolored urine and rectal irritation, depending on the type. Some laxatives also may interfere with the absorption of nutrients and medications, leading to seizures, heart arrhythmias and confusion, as stated by Mayo Clinic.
Different types of laxatives use distinct bodily functions to facilitate the passage of stool. Oral osmotics bring water into the colon from surrounding tissues to soften the stool and allow it to pass. These laxatives can cause increased thirst as well as gas, nausea, diarrhea, cramping and bloating. Oral bulk formers absorb water to bulk up and soften the stool, helping the intestinal muscles contract normally, and these laxatives can cause bloating, cramping, gas and even more constipation if the patient does not hydrate properly, notes Mayo Clinic.
Oral stool softeners bring moisture to the stool but can throw electrolytes out of balance with extended use. This sort of imbalance can lead to seizures, confusion, weakness and anomalous heart rhythms. Oral stimulants cause the intestinal muscles to move, pushing stool out, and these laxatives can cause discolored urine as well as nausea, diarrhea, cramping and belching. Rectal stimulants seek the same response as oral stimulants but are inserted through the rectum. These laxatives can cause cramping, stomach upset and rectal irritation, according to Mayo Clinic.