Senna
Scientific names: Cassia acutifolia and Cassia angustifolia.
C. acutifolia (Alexandria senna) is native to Egypt and the Sudan while C. angustifolia (Tinnevally senna) is native to Somalia, the Middle East, and India. The top parts are harvested, dried, and graded. There are more than 400 known species of Cassia. Wild sennas (C. hebecarpa and C. marilandica) grow on moist banks and woods in the eastern United States, but are not used commercially. Cassia is also a common name for cinnamon, but that is a different plant. The plant derives its name from the Arabic “sena” and from the Hebrew word “cassia,” which means “peeled back,” a reference to its peelable bark.
Traditional/Ethnobotanical uses
Senna first was used by Arabian physicians as far back as the 9th century AD. It has long been used in traditional Arabic and European medicine as well, primarily as a laxative. The leaves have been brewed and the tea administered for its strong laxative effect. Because it often is difficult to control the concentration of the active ingredients in the tea, an unpredictable effect may be obtained. Therefore, standardized commercial dosage forms have been developed, and these concentrates are available as liquids, powders, and tablets in OTC laxatives.
General uses
Senna is most commonly used as a laxative.
What is the dosage of Senna?
Senna leaves or pods have been used as a laxative at doses of 0.6 to 2 g/day, with a daily dose of sennoside B from 20 to 30 mg. The brand Senokot is available in 8.6 and 17.2 mg tablets. A bitter tea can be made containing senna 0.5 to 2 g (ie, ½ to 1 teaspoon). Senna should not be used at higher doses or for extended periods of time.
Is Senna safe?
Contraindications
Senna is contraindicated in patients with intestinal obstruction, ulcerative colitis, appendicitis, and Crohn disease. Senna is not recommended for children younger than 2 years of age.
Pregnancy/nursing
Use with caution until more definitive information is known. Some data suggest stimulation of the uterus, mutations, and other gene damage with senna usage, while other sources suggest it is the laxative drug of choice in pregnancy.
Interactions
Use of senna with drugs known to deplete potassium, such as diuretics, should be limited or avoided. Because senna may cause diarrhea, caution is warranted in patients receiving warfarin, because diarrhea can reduce the absorption of vitamin K and increase the risk of bleeding.
Side Effects
Senna may cause diarrhea, loss of fluids, high blood potassium, and abdominal pain or cramping. The long-term use of senna has resulted in pigmentation of the colon, reversible finger clubbing, wasting, and dependence on the laxative. Children, particularly those wearing diapers, may experience severe diaper rash, blister formation, and skin sloughing. Case reports indicate a possible association between long-term administration of senna and liver damage.
Toxicities
Case reports of senna toxicity are available and include coma and nerve damage after ingestion of a senna-combination laxative, as well as liver damage after long-term use of the plant.
References
Senna. Review of Natural Products. Facts & Comparisons [database online]. St. Louis, MO: Wolters Kluwer Health, Inc; December 2010.