Stimulant laxatives

Stimulant laxatives are turned into their active forms in the gut and act directly on the lining of the large bowel. They set off propulsive contractions of the colon and make it secrete water and salts while absorbing less, so stool arrives sooner and softer: about 6 to 12 hours after a tablet, and within an hour after a bisacodyl suppository.

• SennaA plant-derived stimulant laxative (sennosides) for short-term relief of constipation, usually taken at night.
• BisacodylA stimulant laxative given as tablets or suppositories for constipation and to empty the bowel before procedures.

• Short-term relief of constipation
• Emptying the bowel before surgery or examinations

• Abdominal cramps and painKnown for
• Low potassium with overuseKnown forSerious
• Diarrhea
• Nausea
• DehydrationSerious
• Sluggish, laxative-dependent bowel after long overuse
• Allergic reactions, such as rash and itching

What the class has in common. Each drug's card has its own, and Known for marks what an exam expects you to know.

• Contraindicated with bowel obstruction, appendicitis, acute inflammatory bowel disease or unexplained abdominal pain.
• Daily use beyond about a week (5 days for bisacodyl) calls for finding the cause of the constipation.
• Low potassium from overuse strengthens digoxin's effects; diuretics, corticosteroids and licorice add to potassium loss.

Written for biofideX in plain words, after checking these references:

• Laxative (NCI Thesaurus)
• Bisacodyl 5mg tablets: SmPC (eMC)
• Sennosides 7.5 mg tablets: SmPC (eMC)
• Senna (NHS)
• About bisacodyl (NHS)

For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.