Laxatives for adults

Drink plenty of water:

• When taking laxatives, you should try to drink at least 8 to 10 cups of water a day.
• This is because laxatives, especially an osmotic laxative, can make you dehydrated.
• If you take a bulk-forming laxative and you don't drink enough fluid this can cause a blockage in the gut as the poo may become dry and difficult to pass.

Use laxatives only for short periods of time:

• Long-term use can make your body dependent on them, so your bowel no longer works normally without them. 
• Generally, it's recommended that you don't take laxatives for more than 5 to 7 days in a row.
• If you still have constipation after taking laxatives for several days contact your healthcare provider for advice.

Bulk-forming laxatives are high in fibre which adds bulk to the poo. The bulky size stimulates the bowel muscles, causing poo to move along, leading to an easier bowel movement.

• They usually take 2 to 3 days to cause a bowel movement.
• Bulk-forming laxatives may be useful in people with haemorrhoids, anal fissure, chronic diarrhoea associated with diverticular disease and irritable bowel syndrome.
• They're not recommended for constipation caused by opioids, or in people unable to maintain adequate fluid intake, at risk of dehydration or with problems swallowing.
• It's important to drink enough fluids when using bulk-forming laxatives – not drinking enough fluids can cause blockage of the gut. 

Examples include:

• unprocessed bran or oat bran
• psyllium (Konsyl D®, Mucilax®, Metamucil®, Bonvit®)
• sterculia (Normacol®, Normafibe®)

Read more about bulk-forming laxatives.

These laxatives soften the poo.

• The oral softeners usually cause a bowel movement after 12 to 72 hours.
• The rectal softeners (enema) usually cause a bowel motion within 30 minutes.

Examples include:

• Tablets and drops:
  • Docusate (Laxofast capsule, Coloxyl tablet).
  • Coloxyl drops.
• Enema:
  • Docusate (Coloxyl enema).

Osmotic laxatives draw water into the bowel. The bowel becomes filled (distended) with extra fluid, and this stimulates the muscles of the walls of the bowels to contract and squeeze the bowel movement along.

• The oral liquids usually take 1 to 3 days to cause a bowel motion.
• The rectal osmotic laxatives (enema) usually cause a bowel motion within 30 minutes.

Examples include:

• Syrup:
  • Lactulose (Laevolac).
• Powder (to be mixed with water):
  • Movicol.
  • Lax-Sachets.
  • Molaxole.
• Enema:
  • Fleet enema.
  • Micolette enema.
  • Microlax enema.

Stimulant laxatives stimulate the nerves in the bowel, causing muscle contractions and in this way gets the bowel moving.

• The tablets or capsules usually cause a bowel movement after 8 to 12 hours. A bedtime dose is recommended, so you're likely to feel the urge to go to the toilet sometime the next morning. 
• The rectal stimulant laxatives (suppositories or enemas) are quick acting and cause a bowel movement after 15 minutes but may take up to 1 hour.
• Stimulant laxatives are used for constipation caused by opioids or when complete emptying of the bowel is required such as before surgery (operation).

Examples include:

• Tablets:
  • Bisacodyl (Dulcolax tablet).
  • Sennoside B (Senokot tablet).
• Suppositories:
  • Bisacodyl (Dulcolax suppository, Lax-Suppositories®).
  • Gylcerol suppositories.

Like all medicines, laxatives can cause side effects, although not everybody gets them. The common side effects of laxatives are stomach pain or cramps, bloating, gas in the tummy, flatulence or 'farting'. Other side effects include:

• Constipation: Ongoing use of laxatives can cause constipation because the bowel loses muscle and nerve response and can no longer move poo out. This results in dependency on the laxative, so that higher doses are needed to poo.
• Diarrhoea and dehydration: Taking too much of some laxatives can lead to diarrhoea and losing too much salt from the body. 

Read more about medicines and side effects and reporting a reaction you think might be a side effect.