Common name: Senna
Parts used: Leaves, pod
Constituents: Anthraquinone glycosides (sennosides and their aglycones), naphthalene glycosides, misc. mucilage, flavonoids, volatile oil, sugars, resins.
Medicinal actions: Stimulant laxative, cathartic (direct stimulation of a bowel movement)
Medicinal use: The anthraquinones are absorbed into the blood, re-secreted into the colon as active anthraquinones where they stimulate smooth muscle contraction. Atonic constipation, or until the cause of constipation is discovered. It is best to combine Senna with carminative herbs to reduce gripping.
Pharmacy: Infusion: 4-12 dried pods steeped in cold or hot water for 6-12 hours. Tincture (1:5, 45%), 2-4 ml QD. Dried pods (powdered or whole): 0.6–2.0 g QD.
Toxicity: Use > 10 days consequtively frequently exacerbates atonicity of the colon and can lead to dependence on laxatives for a bowel movement to occur. Recurrent use or abuse can lead to electrolyte imbalances (particularly hypokalemia), dehydration, and muscle and kidney destruction with hematuria and albuminuria. Can provoke reflex contractions in the uterus when taken during pregnancy, leading to miscarriage. Adverse effects: acute intestinal pain and cramping (colic) (can often be offset with carminatives). Harmless reddish discolouration of urine and feces may occur. Pseudomelanosis coli (PMC) reversible deposition of active anthraquinone glycosides in the colon wall occurs frequently, but is not associated with any toxicity.
Contraindications: Use > 10 days, intestinal obstruction, spastic constipation, acute intestinal inflammation, abdominal pain of unknown origin, children <12 years old, pregnancy. Safe in lactation.
Interactions: Due to dramatic decrease in transit time, can interfere with absorption of practically any drug. Drugs that cause hypokalemia should not be combined with.