Senna, or also known as sennosides, is an over-the-counter (OTC) laxative medication that's used to help with occasional constipation. It can work faster than some other alternatives, like docusate (Colace), but it can also cause stomach cramps as a side effect. This medication comes as tablets and liquids that are taken by mouth once or twice a day, depending on your needs. Senna is sold under many different brand names and lower-cost generic versions.
Occasional constipation
Senna is a stimulant laxative. It stimulates the muscles in your intestines (gut). It helps your gut move so that your body can have a bowel movement.
Source: DailyMed
Side effects that you should report to your care team as soon as possible:
Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):
Available over the counter, so you don't need a prescription
Safe to use in children
Works faster than stool softeners, like docusate (Colace)
Might cause stomach cramps or electrolyte changes
Not for long-term use (longer than 1 week)
Can use with other types of laxatives, if senna isn't working well on its own
Before taking laxatives like senna, go over the medications you're taking with your provider or pharmacist. One of your medications might be causing your constipation. If this is the case, you can discuss with your provider about the best way to manage your constipation, such as a change in treatment or taking a particular laxative as needed.
Before using senna, contact your provider if you have stomach pain, nausea, or vomiting. Also ask your provider before using this medication if you've noticed sudden changes in your bowel movement patterns for more than 2 weeks. There might be a more serious problem going on that your provider should check out.
Your provider might recommend that you take your first dose of senna at bedtime. This might help you to have a bowel movement the following morning.
Stay hydrated and eat foods that are high in fiber, like fruits, beans, and nuts. This helps your body have regular bowel movements.
Contact your provider if you need to use senna to help with constipation for more than 1 week. This could be a sign of a more serious problem.
The active ingredient "senna" can be found in combination medications and herbal teas. Always check your medications and teas to make sure you aren't doubling up on senna. Taking too much senna can raise your risk of side effects.
For the senna liquid or syrup: Shake the bottle well before using. Always use the measuring device given to you by your provider or pharmacist to measure out your dose. Don't use kitchen spoons or measuring spoons since these might not be accurate.
Senna can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: Misuse of senna | Taking senna longer than recommended | Taking higher than recommended doses
Only take senna as directed by your provider or according to the manufacturer's label. The risk of side effects from senna is low if you take it as directed. But some people who took senna at a higher dose or for a longer time than recommended have experienced low potassium levels and changes in their electrolyte levels. Low potassium levels can cause muscle weakness or twitching, more constipation, a numbing or tingling sensation, or more seriously irregular heartbeat. If you experience any of these symptoms after you take senna, contact your provider.
Adults and children age 12 and older: The typical starting dose is 2 tablets by mouth once a day. The maximum dose is 4 tablets twice a day.
Children age 6 to 11 years: The typical starting dose is 1 tablet by mouth once a day. The maximum dose is 2 tablets twice a day.
Children age 2 to 5 years: The typical starting dose is one-half tablet by mouth once a day. The maximum dose is 1 tablet twice a day.
Children under 2 years of age: Senna isn't recommended for this age group. Ask your child's provider for appropriate treatment.
Adults and children age 12 and older: The typical starting dose is 10 mL to 15 mL by mouth once a day at bedtime. The maximum dose is 15 mL in the morning and at bedtime.
Children under 12 years of age: The oral liquid isn't recommended for this age group. Ask your child's provider for appropriate treatment.
Occasional constipation and irregular bowel movements
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Atlantis Consumer Healthcare, Inc. (2023). SENOKOT- standardized senna concentrate tablet. DailyMed.
Centers for Disease Control and Prevention. (2020). Spoons are for soup, milliliters are for medicine.
Duboc, H., et al. (2020). Disruption of circadian rhythms and gut mobility. Journal of Clinical Gastroenterology.
Khan, S., et al. (2020). Adverse drug event of hypokalaemia-induced cardiotoxicity secondary to the use of laxatives: A systematic review of case reports. Journal of Clinical Pharmacy and Therapeutics.
National Eating Disorder Association. (n.d.). Laxative abuse.
National Institute of Diabetes and Digestive and Kidney Diseases. (2012). Senna. LiverTox.
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