Constipation is caused by slow intestinal motility or insufficient water content, which makes stool too hard and blocks the intestinal tract. When diagnosing and treating patients, doctors usually recommend adjusting diet or lifestyle habits, and sometimes prescribe “laxatives” to treat symptoms. What exactly are laxatives? Why can they be used to solve constipation problems? And how should they be taken most effectively? Here is an introduction to the types of laxatives, correct treatment methods, and precautions.
- Dietary Fiber, Fiber Supplements, and Bulk-Forming Laxatives (e.g., Normacol Granules 7g/Pack): The main ingredients include psyllium, methylcellulose, calcium polycarbophil, and wheat dextrin. The entire packet of powder or tablets must be swallowed with a small amount of water, followed by a large amount of fluid. By absorbing water and expanding in the intestinal tract, they promote bowel motility, increase stool volume, and soften stool to achieve a bowel movement effect. Because they are simple and safe to take, this is the treatment method most consistent with physiological digestive processes. However, patients with impaired renal function who need to restrict fluid intake are not suitable for this type of laxative. The general recommended amount of dietary fiber is 20 to 35 grams per day. It is recommended to start with a small amount and slowly increase fiber intake to adjust, which can reduce abdominal bloating. Natural grains, wheat bran, citrus fruits, and legumes also have similar effects. In addition to fiber-rich foods, the sugar components (sorbitol and fructose) in foods such as apples, peaches, pears, cherries, raisins, grapes, and nuts also help relieve constipation.
- Surfactants: Also known as stool softeners, their purpose is to lower the surface tension of stool, making it easier for water to penetrate the stool. Although there are very few side effects, their efficacy is inferior to other laxatives.
- Non-absorbable Sugars (polyethylene glycol, lactulose, sorbitol) (e.g., Lactulose Syrup 300mL/Bot) and Osmotic Agents (salts) (milk of magnesia, magnesium citrate, magnesium sulfate): They promote water secretion in the intestinal tract, thereby increasing the frequency of bowel movements. Overuse can easily affect electrolyte balance and increase fluid volume, potentially placing a burden on patients with poor heart and kidney function. Magnesium Oxide Tablets 250mg/Tab have an acid-suppressing effect, which can simultaneously relieve stomach discomfort, a burning sensation, or indigestion, but patients with renal failure should be cautious of hypermagnesemia.
- Stimulant Laxatives (e.g., Bisacodyl Enteric-Coated Tablets 5mg/Tab, Sennosides Tablets 20mg/Tab): They mainly promote bowel motility by altering the electrolyte transport of the intestinal mucosa. Among them, Bisacodyl has a gastric-irritating effect, so it is manufactured as an enteric-released dosage form and needs to be swallowed whole. Sennosides tablets contain senna glycosides, a traditional Chinese medicine component, which can be ground into powder for administration. Long-term continuous use of these drugs may be associated with hypokalemia, protein-losing enteropathy, and salt overload. However, long-term use of stimulant laxatives does not cause structural or functional damage to the colon, nor does it increase the risk of colorectal cancer or other tumors.
- Mineral Oil, Fast-Acting Enemas (Glycerin Ball 20ml/Ball) or Suppositories (Bisacodyl 10mg/Supp), Water-Soluble Contrast Enemas (Gastrografin or Hypaque): Usually used for severe constipation, they can effectively soften stool, provide intestinal lubrication, and eliminate fecal impruction obstructions. Sodium phosphate enemas may cause hypotension, hyperphosphatemia, hypokalemia or hyperkalemia, metabolic acidosis, severe hypocalcemia, renal failure, and electrocardiogram changes (QT interval prolongation). It is recommended that patients with impaired renal function and the elderly avoid using them.
- Compound Preparations (e.g., Conslife Sugar-Coated Tablets): Contain surfactants, Sennosides, and Bisacodyl simultaneously, which can enhance therapeutic efficacy and reduce side effects. However, patients suspected of having acute abdominal symptoms, spastic constipation, severe hard fecal impactions, anal fissures, or ulcerative hemorrhoids must not use them.