From the Guidelines
Yes, senna is a stimulant laxative. It contains compounds called sennosides that work by irritating the lining of the bowel, which stimulates intestinal contractions and promotes bowel movements 1. Senna typically begins working within 6-12 hours after ingestion, making it useful for short-term relief of constipation. The typical adult dose ranges from 8.6–17.2 mg daily 1. However, senna should only be used short-term (less than 1 week) as prolonged use can lead to dependence, electrolyte imbalances, and potentially damage to the colon's nerve cells. Side effects may include abdominal cramping, diarrhea, and discoloration of urine.
Key Points
- Senna is a stimulant laxative that works by increasing intestinal motility and fluid secretion in the colon 1.
- The typical adult dose ranges from 8.6–17.2 mg daily 1.
- Senna should only be used short-term (less than 1 week) due to the risk of dependence, electrolyte imbalances, and potential damage to the colon's nerve cells.
- Side effects may include abdominal cramping, diarrhea, and discoloration of urine.
Mechanism of Action
Senna works because the sennosides are converted by gut bacteria into active compounds that increase intestinal motility and fluid secretion in the colon 1. This leads to an increase in bowel movements and relief of constipation.
Clinical Use
Senna is available over-the-counter in various forms, including tablets, capsules, and teas, under brand names like Senokot, Ex-Lax, and Fletcher's Castoria. It is recommended for short-term use or rescue therapy, with a recommended maximum dose of 4 tablets twice per day 1. However, the long-term safety and efficacy of senna are unknown.
From the FDA Drug Label
Active ingredient (in each 5 mL = 1 teaspoonful) Sennosides 8.8 mg The FDA drug label does not answer the question.
From the Research
Definition and Classification of Senna
- Senna, also known as Sennoside, is classified as a stimulant laxative 2, 3, 4, 5, 6.
- Stimulant laxatives work by increasing the amount of fluid in the intestines and stimulating the intestinal muscles to move stool through the digestive system more quickly 3, 4, 5.
Mechanism of Action
- Senna produces contractions that improve colonic motility without affecting the stool consistency 6.
- It is commonly used to treat constipation in children and adults 2, 4, 5, 6.
Efficacy and Safety
- Studies have shown that Senna is effective in treating constipation in children and adults 2, 4, 5, 6.
- Senna has been found to be safe for long-term use, with no evidence of tolerance or serious side effects 2, 3, 4, 5.
- Common side effects of Senna include abdominal cramping, vomiting, and diarrhea, which are usually mild and resolve on their own 2, 4, 5.