Laxatives are a type of medication that cause you to pass stools (poo) more often. You may need laxatives if you have constipation, meaning you are passing stools less than three times a week, having to strain to poo or passing hard or small pellet-like poo.
Constipation can happen to anyone. For some people it just happens a few times in their life, for others it can be an on-going chronic condition.
There are a number of things that can cause constipation. One of the most common is not having enough water in your poo, making it become hard and difficult to move through your bowel, which could also cause stomach pain, bloating and excess gas. Not having enough water in your poo could be because you aren’t drinking enough, or because your large bowel (colon) is absorbing more water than it should.
Factors that can contribute to constipation include:
Not eating enough, or eating a low fibre diet
Not drinking enough fluids
Not moving around enough
Taking certain medicines, including antidepressants, antidiarrhoeals, some supplements and painkillers
Underlying diseases or conditions
There are a few different types of laxatives and they work in different ways:
By drawing moisture into your bowel
By softening your poo
By lubricating your bowel
By stimulating the muscles in your bowels, encouraging your poo to move along
Laxatives are often used if lifestyle changes, such as drinking more fluids, increasing the amount of fibre in your diet, and getting more exercise have not helped to relieve constipation.
Some laxatives are available over-the-counter without a prescription, others are prescribed by a doctor.
Laxatives are a symptomatic medicine, which means they are used to help ease symptoms rather than treat the underlying cause of symptoms. They are intended to be taken short term, so if constipation persists, you should speak to your doctor.
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Why might I use laxatives for inflammatory bowel disease (IBD)?
Proctitis (inflammation of your rectum) - If your rectum is inflamed, but the rest of your colon is unaffected and still absorbing water normally (so you don’t have diarrhoea), formed poo may not be able to pass through your rectum easily, resulting in constipation. This is called proximal constipation.
Diet - Fibre helps your poo pass through your bowel. Some people with IBD are placed on low fibre/low residue diets, and some choose to avoid or restrict their intake of high fibre foods, such as raw fruits, vegetables, nuts and seeds. This can reduce bulk in the intestine, causing slower gut motility and constipation.
Dehydration - If you have diarrhoea, you are also more likely to become dehydrated which can result in hard, dry poo which is more difficult to pass.
Medicines - Some medicines and supplements used in IBD can cause constipation, such as antidiarrheals, iron supplements and certain painkillers, such as tramadol and cocodamol.
Some laxatives are available to buy over-the-counter without a prescription. However you should always speak to your IBD team before taking one of these medicines, in case it is not suitable for you, or might interact with other medicines you are taking.
Symptomatic medicines do not treat the underlying cause of symptoms, and so should not be a replacement for your IBD treatment.
It is also important to ensure that by taking laxatives you aren’t masking symptoms that indicate increased disease activity or complications, such as blockages or obstruction of your intestine (stricture).
Laxatives for bowel preparation in inflammatory bowel disease
You will be prescribed laxatives to prepare your bowel for bowel surgeries, endoscopies and some other types of investigation. They will usually be strong osmotic laxatives, which draw fluid into your bowel to soften your poo, such as:
Sometimes you will be given senna laxatives as well, which will stimulate contractions in your bowel, encouraging you to poo.
Bowel cleansing treatments are not treatments for constipation.
What types of laxatives are there?
As mentioned before, different types of laxatives work in different ways, and the effectiveness of each type varies from person to person.
Laxatives are commonly available as
Tablets and capsules
Sachets of powder you mix with water and drink
Syrups or liquid medicine
Suppositories you put inside your bottom
Enemas, liquids or gels you put inside your bottom
Some laxatives can work quickly, within an hour of taking them, whereas some can take up to a week to take effect. It is recommended some laxatives are taken at certain times of day, such as first thing in the morning or last thing at night.
There are four main types of laxative...
This type of laxative works by increasing the amount of water in your large bowel (colon) by drawing fluid from your body into your bowel. This softens your poo and makes it easier to pass. Osmotic laxatives (containing magrocols) are commonly used by people who have IBD and require laxatives.
It is a slow acting type of laxative, taking two to three days to take full effect, and has a relatively low risk of side effects. It is important to drink plenty of fluids whilst taking this laxative, to avoid dehydration.
These types of laxative contain water-absorbent plant fibres, such as bran, ispaghula, sterculia and methylcellulose. These absorb water and swell, helping to soften hard poo. They are also used to treat diarrhoea, by thickening it in the bowel. This provides bulk which is needed to encourage your bowel to work more normally.
Bulk-forming laxatives are considered the gentlest laxatives on your body, and so the safest to use longer term. They are generally safe to use if you have IBD, except if you have a stricture (narrowing) of your bowel.
They can take up to three days to act, and it is important to drink plenty of fluids whilst taking them, to avoid your intestines getting blocked.
Commonly used bulk-forming laxative brands include:
Stimulant laxatives increase movement (motility) in your gut by stimulating contractions of your intestinal muscles, encouraging you to poo.
Stimulant laxatives work quickly, generally within six to 12 hours. Suppositories can work even faster, often within minutes. It is recommended stimulant laxatives are only used under supervision of your doctor, and if other types of laxative have been ineffective. This is because your body can become dependent on them in order for your bowels to work normally.
Stool softeners work by allowing more water and fat to be absorbed into your poo, softening them and making them easier to pass without straining.
Most stool softeners contain the active ingredient docusate sodium. Some are available as enemas that contain arachis oil (peanut oil), which lubricate and soften your poo. Arachis oil enemas are not suitable for people with a nut allergy.
Stool softeners are considered to be a gentle form of laxative, and can take up to three days to have an effect. However stool softener enemas can work quickly, within a few minutes.
Commonly used stool softener brands include:
Docusate sodium: Dulcoease, Dioctyl, Norgalax
Other types of laxative
There are a number of newer laxatives available, used for more severe or chronic constipation.
Linaclotide is a guanylate cyclase-C receptor agonist and is used to treat moderate to severe irritable bowel syndrome (IBS), and works by increasing intestinal fluid secretion, and lessening visceral pain (internal pain that is not localised).
Prucalopride is a selective serotonin receptor agonist which stimulates the muscles in the intestinal wall, encouraging you to poo.
Lubiprostone is a chloride channel activator which helps to increase secretion of fluid into the bowel.
What side effects might I have when taking laxatives?
Like all medicines, laxatives can cause side effects, however they are usually mild and should pass once you stop taking the laxative. Any side effects you experience will depend on the type of laxative you take. You can read the patient information leaflet that comes with the medicine for details, and also for information on how to take them.
Common side effects include:
Discomfort and cramps in your tummy
Dehydration - you might feel lightheaded, have headaches and your wee might be darker coloured than normal
Some laxatives can interfere with your body’s absorption of medicines or nutrients, and with prolonged use can lead to an electrolyte imbalance (which can make you very unwell).
You can become laxative dependent - if you take some laxatives long term, it can decrease your colon’s ability to function well on it’s own.
Young children and pregnant women should always speak to their doctor before taking laxatives.