Indications
Tinnevelly senna pods are the dried fruits of Cassia angustifolia (also called Senna alexandrina), named after the Tirunelveli region of southern India where the plant is widely grown. Senna is a well-known herbal laxative used for the short-term relief of occasional constipation, and sometimes to empty the bowel before examinations when a doctor directs it.
How It Works
Senna contains natural substances called sennosides. Bacteria in the large bowel turn them into active compounds that irritate the bowel lining gently, which makes the bowel muscles contract more strongly and draws water into the stool. This usually produces a bowel movement 6 to 12 hours after a dose, which is why it is often taken at bedtime.
Dosage and Administration
Take as directed on the label, usually once a day at bedtime, starting with the lowest suggested amount. Drink plenty of fluids. Do not use it for more than 1 week without medical advice. Children should only be given senna if a doctor advises it.
Interactions
Long or heavy use can lower blood potassium, which increases the risk of side effects from Digoxin, heart rhythm medicines, diuretics such as Furosemide or Hydrochlorothiazide, and steroids such as Prednisolone. Senna can also make other medicines pass through the gut faster and work less well. Licorice taken with senna can lower potassium further.
Contraindications
- Bowel blockage, or severe abdominal pain of unknown cause.
- Inflammatory bowel disease such as Crohn’s disease or ulcerative colitis, and appendicitis.
- Severe dehydration or low potassium.
- Children under 12 years, unless a doctor advises it.
Side Effects
Stomach cramps, colicky pain and loose stools are common. Urine may turn yellow-brown or reddish, which is harmless. Long-term use can lead to dependence on laxatives, low potassium, muscle weakness and darkening of the bowel lining.
Get urgent medical help if you have severe abdominal pain, bleeding from the back passage, severe or ongoing diarrhoea, signs of dehydration (dizziness, very little urine), muscle weakness or an irregular heartbeat.
Pregnancy and Lactation
Bulk-forming laxatives such as Ispaghula are preferred in pregnancy. Senna should only be used in pregnancy if a doctor advises it, for a short time. Small amounts pass into breast milk; occasional short-term use is generally considered acceptable while breastfeeding, but ask a doctor first.
Precautions and Warnings
Senna and other strong herbal laxatives are potent and should not be used regularly or for weight loss. Constipation that lasts more than 1 week, keeps returning, or comes with weight loss, blood in the stool or a change in bowel habit needs a doctor’s check. Increasing fibre, fluids and activity is the first step for ongoing constipation.
Overdose
Too much causes severe cramps, watery diarrhoea and loss of water and salts, which can be dangerous for children and older people. Drink fluids and get medical help if symptoms are severe or if a child has swallowed a large amount.
Therapeutic Class
Stimulant laxative (herbal, anthraquinone type).
Storage
Store below 30°C in a dry place, away from light and out of the reach of children. Keep the container tightly closed.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.