What is Senna-S (senna)?

What is Senna-S?

Senna-S is a natural stimulant laxative derived from the senna plant, containing sennosides A and B that are metabolized by gut microbiota to active compounds that stimulate colonic peristalsis and increase water content in the intestines, making it an effective treatment for constipation. 1, 2

Mechanism of Action

• Sennosides A and B are metabolized by gut bacteria to active metabolites (rheinanthrone and rhein) that stimulate prostaglandin E2 production and chloride ion secretion 2
• These active metabolites increase colonic peristalsis and luminal water content, facilitating bowel movements 1
• Over 90% of sennosides and their metabolites are excreted in feces 1
• Antibiotics may decrease senna's efficacy by affecting the colonic bacteria that produce the active metabolites 2

Formulations and Dosing

• Available as tablets (typically containing 8-9 mg sennosides per tablet), syrup (8.8 mg/5 mL or 26.4 mg/15 mL), and in laxative teas 2, 3
• Recommended initial dose for adults is 8.6-17.2 mg daily, with dose adjustments based on symptom response 2
• Clinical trials used higher doses (1 g daily) than typically used in practice, with 83% of participants reducing their dose during trials due to side effects 1
• Onset of action is typically 6-12 hours after oral administration 1

Efficacy

• Significantly increases complete spontaneous bowel movements (CSBMs) per week compared to placebo (MD 7.60,95% CI 5.90–9.30) 1
• Higher response rates compared to placebo (RR 5.25,95% CI 2.05–13.47) 1
• May improve quality-of-life scores compared to placebo (MD 7.80,95% CI 1.40–14.20) 1
• The American Gastroenterological Association suggests senna over no treatment for chronic idiopathic constipation (conditional recommendation, low certainty of evidence) 1

Side Effects and Precautions

• Common side effects include abdominal cramping, diarrhea, and abdominal pain, particularly at higher doses 1, 2
• Not recommended during pregnancy due to potential weak genotoxic effects observed in animal studies 1
• Contraindicated in individuals with ileus, intestinal obstruction, severe dehydration, or acute inflammatory conditions in the bowel 1
• Perineal blistering has been reported in rare cases, particularly with higher doses and prolonged skin contact with stool 4

Special Considerations

• In children, senna is generally considered safe for constipation treatment, though skin blistering can occur with higher doses and prolonged stool-to-skin contact 4
• In palliative care settings for patients with limited life expectancy, higher doses may be used 2
• While clinical trials were conducted for 4 weeks, longer-term use is probably appropriate, though data on long-term tolerance and side effects are limited 1
• No evidence of tolerance to senna has been found in pediatric populations 4

Clinical Implications

• The combination of efficacy, impact on quality of life, over-the-counter availability, and low cost makes senna an attractive first-line option for individuals with chronic idiopathic constipation 1
• Consider starting at a lower dose and increasing if there is no response, as higher doses are associated with more side effects 1
• May be particularly effective in patients with anorectal malformations and constipation due to its stimulation of colonic propulsion waves 5