Senna (Cassia senna)
Overview
Senna (Senna alexandrina, syn. Cassia senna) is a small shrub about 3 ft (1 m) tall, with yellow, pea-like flowers and pods containing seeds. One of the most renowned herbal laxatives, senna’s anthraquinone glycosides (sennosides) cause strong bowel stimulation.
Traditional uses & properties
Stimulating Laxative (Cathartic): Clears constipation by irritating the large intestine lining; expect a bowel movement 8–10 hours after a dose. Carminative Additions: Usually combined with aromatic herbs (like ginger or fennel) to reduce colic and griping. Occasional Constipation Remedy: Effective short-term solution; caution against frequent use. Pods vs. Leaves: Pods are milder; leaves are stronger and more likely to cause cramping.
Preparations & dosage
½–1 cup daily
100–500 mg, 1–2 times daily
Dried leaf (1:5, 50% alcohol); 10 drops to 2 ml (0.4 tsp.) 1–2 times daily
Safety & precautions
Children Under 12: Not advisable. Short-Term Use: Prolonged use (beyond 10 days) can weaken the bowels and cause dependency. Pregnancy: Consult a professional. Gastrointestinal Sensitivity: May cause cramping and discomfort.
Drug & food interactions
Although senna has been predicted to interact with a number of drugs that lower potassium (such as the corticosteroids and potassium-depleting diuretics), or drugs where the effects become potentially harmful when potassium is lowered (such as digoxin), there appears to be little or no direct evidence that this occurs in practice. Senna may slightly reduce quinidine levels.
The information regarding the use of senna with paracetamol is based on experimental evidence only. No interactions found.
The information regarding the use of senna with propranolol is based on experimental evidence only. No interactions found.
Theoretically, patients taking potassium-depleting diuretics could experience excessive potassium loss if they also regularly use, or abuse, anthraquinone-containing substances such as senna.
The interaction between senna and ketoprofen is based on experimental evidence only. No interactions found.
Senna does not appear to affect the pharmacokinetics of estradiol. In a clinical study in 19 women, the maximum daily tolerated dose of senna tablets (Senokot) was taken for 10 to 12 days with a single 1.5-mg dose of estradiol glucuronide given 4 days before the end of the assessment period. Senna had no significant effect on the median AUC of estradiol or estrone.
The information regarding the use of senna with verapamil is based on experimental evidence only. No interactions found.
No interactions found.
Quinidine plasma levels can be reduced by the anthraquinonecontaining laxative senna. In a study in 7 patients with cardiac arrhythmias taking sustainedrelease quinidine bisulfate 500mg every 12 hours, senna reduced plasma quinidine levels, measured 12 hours after the last dose of quinidine, by about 25%.
Theoretically, digitalis toxicity could develop if patients regularly use, or abuse, anthraquinone-containing substances such as senna.
Theoretically, the risk of hypokalaemia might be increased in patients taking corticosteroids, who also regularly use, or abuse, anthraquinone-containing substances such as senna. Chronic diarrhoea as a result of long-term use, or abuse, of stimulant laxatives such as senna can cause excessive water and potassium loss; one paper (cited as an example) describes a number of cases of this.1 Systemic corticosteroids with mineralocorticoid effects can cause water retention and potassium loss. The effect of senna over-use combined with systemic corticosteroids is not known, but, theoretically at least, the risk of hypokalaemia might be increased. Although this is mentioned in some reviews on herbal interactions2 there do not appear to be any case reports of such an interaction. It has also been suggested that senna, by increasing gastrointestinal transit times, might theoretically reduce the absorption of oral corticosteroids.2 However, there appears to be no published clinical data suggesting that that the absorption of corticosteroids is affected by senna or other drugs that alter gastrointestinal transit time, such as metoclopramide or loperamide.
Habitat
Primarily native to tropical Africa, senna is cultivated in many tropical regions. Leaves can be picked before or during flowering; pods are collected fully ripe in autumn.
Traditionally used for
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