The application scenarios of Pursennid laxatives in preoperative bowel cleansing and treatment of refractory constipation need to be strictly distinguished, and their dosage regimen needs to be personalized according to the patient's age, degree of constipation, and type of surgery. The following will explain from three aspects: differences in indications, dosage recommendations, and risk control.

1. Application standards for preoperative bowel cleansing

(1) Applicable scenario: Only recommended for preoperative preparation such as colonoscopy that requires moderate bowel cleansing.

(2) Standard dose: Adults take 4 tablets orally 18 hours before surgery (each containing 12mg of sennoside), and add 2 tablets 6 hours later.

(3) Contraindications: This regimen is contraindicated for patients with gastrointestinal obstruction, inflammatory bowel disease, and dehydration.

2. Treatment plan for stubborn constipation

(1) Initial dose: Take 1-2 tablets per day before bedtime for adults, and reduce to the lowest effective dose (usually 0.5-1 tablet/day) after taking effect.

(2) Course control: Continuous use should not exceed 7 days, and annual cumulative medication should be limited to 4 courses.

(3) Combination therapy: It is recommended to alternate with osmotic laxatives to reduce the risk of dependence.

3. Dose adjustment for special populations

(1) Elderly individuals: preoperative bowel cleansing dose should be reduced by 25%, and the maintenance dose for refractory constipation should not exceed 0.5 tablets per day.

(2) Children: For those over 12 years old, an adult dose of 50% can be used before surgery. For stubborn constipation, it should be calculated at 0.3 tablets/20kg.

(3) Renal insufficiency: Patients with creatinine clearance rate<30ml/min should not use preoperative bowel cleansing regimen.

4. Risk warning measures

(1) Electrolyte monitoring: Blood potassium levels should be checked before and after surgery, and electrolytes should be rechecked monthly for patients with refractory constipation.

(2) Medication discontinuation indication: If severe abdominal pain or watery stools occur more than 3 times per day, medication should be immediately discontinued.

(3) Transitional management: After preoperative medication, 500ml of electrolyte solution should be supplemented to prevent dehydration.