There is a lot of stigma, misinformation and misuse about the role of laxatives in managing constipation.⁠

I get that people want to try food first, but if you’re really struggling, properly using laxatives is SO beneficial – so let’s get into it!⁠

Table of Contents

  1. Bulk Forming
  2. Osmotic
  3. Stool Softeners
  4. Stimulants
  5. Prokinetics
  6. New Generation

What are bulk forming laxatives?⁠

Bulk forming laxatives are technically, fibre!

Certain fibres are excellent at absorbing & holding water in the stool, speeding up transit time (or how quickly things move through the gut) and providing a more bulky, soft stool to pass – leading to better poops!⁠

EMBARRASSING STORY TIME: when I got diagnosed with IBS, the doc said to try psyllium I kinda rolled my eyes since I ate a ton of fibre anyway.

I followed up to let him know my constipation wasn’t any better, and he said ‘ok, but how are you taking the psyllium?”

…. I turned bright red and had to admit I hadn’t. 🙊⁠

I then went on to ACTUALLY try (and understand!) how psyllium worked – and low and behold – it DID make a difference!

Common bulk forming laxatives include:

  • Psyllium (Metamucil)
  • Methylcellulose (Citrucel)⁠
  • FiberCon (Polycarbophil)⁠

Typically taken 1-3x per day (check the label), these fibre supplements are an inexpensive and easy way to soften and bulk your stool, improving regularity. They NEED to be taken with adequate fluid to work – so be sure to follow the directions.⁠

⁠They’re a go-to as we want patients to get relief FAST and help to improve satisfaction and sensation with a bowel movement.

What are osmotic laxatives? 🌊💩⁠⁠

Simply put, osmotic laxatives pull water into your bowels, softening stool, and speeding up how quickly things pass through your gut. ⁠⁠
These laxatives are not particularly well (if at all) absorbed, so work well to create an osmotic gradient for water to be pulled in.

Examples of osmotic laxatives:⁠⁠

  • Magnesium (typically doses >~400 mg, up to 2000 mg have a laxative effect)⁠⁠
  • PEG-3350 (aka restor-a-lax, lax-a-day, miralax – 17g or more if recommended by your health care team) ⁠⁠
  • Glycerin suppositories⁠⁠

Are laxatives habit forming?

Contrary to popular belief, not all laxatives are habit forming. Osmotic laxatives do not cause the bowel to rely on them, they can be used very safely over the long term – often a big concern of my patients when they’ve been suggested to try them. ⁠⁠
Typically for chronically constipated patients, using this on an as-need basis is often unsuccessful. Why? because it can take a few days to work its way through your gut, especially if you are FOS – full of stool! (exception being the suppository!) ⁠⁠
If you have more situational constipation (ie related to travel or cyclical hormone changes), using them as you expect the constipation to onset or if your gut starts to slow down and you’re missing bowel movements can help prevent or relieve constipation (I bring magnesium tablets with me when I travel for ease of use!) ⁠⁠

What are stool softener laxatives?

#glowup your stool with softeners? 💩⁠⁠
Or maybe not⁉️⁠⁠

⁠⁠What is colace?

Docusate, also known as colace, is a non-absorbable, non-habit forming laxative – you can kind of think of it as a moisturizer for your stool! ⁠⁠
It was SUPER popular, especially in hospitals, to manage constipation and is very low cost compared to other laxatives. When I worked in oncology or the ICU, you’d rarely find a patient NOT prescribed docusate. ⁠⁠
However – research shows that in acute care populations, docusate underperforms compared to bulk forming laxatives (covered in week 1) and osmotic laxatives (covered in week 2). In some studies, they’ve found it ineffective compared to placebo! ⁠⁠
In fact, it’s been recommended by several groups that due to lack of effectiveness, we stop using it entirely in favour of other choices.⁠⁠
Take colace and love it? Don’t panic. I have a couple patients with hemmorhoids and anal fissures that have always used and like docusate. Because of it’s favorable safety profile, if it works for you – thats cool! But if its NOT working for you, chat with your doctor because research shows there are far more effective laxatives available to us now! ⁠⁠

What are stimulant laxatives?

I find thoughts on stimulant laxatives fall into two categories:⁠⁠
1) Terrifying for people for being habit forming⁠⁠
2) accidentally misused/overused⁠⁠
How is it we seem to fall on either side of the two extremes?⁠⁠
Stimulant laxatives work by way of irritating the nerves in the gut, stimulating movement of the bowels. ⁠⁠
While often very effective, they are more likely to cause cramping and discomfort than some of their other laxative counterparts and are contraindicated for some individuals.⁠⁠

Examples of stimulant laxatives include:⁠⁠

  • Senna ⁠⁠
  • Bisacodyl⁠⁠
  • Cascara⁠⁠
  • Castor oil⁠⁠
  • Aloe latex⁠⁠
  • Rhubarb⁠⁠

Are natural laxatives safer?

🍃You’ll notice a lot of ‘natural’ or ‘plant based’ laxatives on that list! But just because somethings natural, doesn’t mean it’s SAFE! 🛑⁠⁠
This is how people end up in the accidental misuse category. They think ‘a natural laxative must be better’, do not seek medical advice when using, and can use it for longer or in higher doses than intended. ⁠⁠
Some research suggests that overuse, over a long period of time (years of use!) can result in damage to the nerves of the bowel, resulting in dependance on the laxative. ⁠⁠
This is with SIGNIFICANT overuse. Which leads me to my second category of person – those that are terrified to use them for fear of their habit forming nature!⁠⁠

Are laxatives habit forming?

As long as your doctor has reviewed your past medical history for safety, and suggests this as a strategy, these laxatives CAN be taken safely. ⁠⁠
While we lack data on exactly how often that is, working with your GI doc can help you to sort out what safe use would be for you.⁠⁠
They are more often used for ‘situational constipation’ rather than long term and daily, as we now have other options that have more favourable safety profiles for long term use. ⁠⁠
My ‘rule of thumb’ on when to consult the GI doc is if I see a patient is using stimulant laxatives >2-3x per week in addition to their other laxative regimens, their medical history, and any unwanted side effects. To me, that’s a sign to review and see if there are better long term options! ⁠⁠

What are prokinetic laxatives?

Slide right into a good bowel movement – that’s the dream right? 💩⁠⁠
Simply put, prokinetics help stimulate movement of the gut.⁠⁠
Prokinetics often get a bad wrap due to a history of adverse events, however, newer agents with better safety profiles ARE indicated as an option for use in IBS-C and chronic constipation when diet and lifestyle, in addition to the other laxatives we discussed, are inadequate. ⁠⁠
Some prokinetics, like alosetron and tegaserod did cause adverse events, including cardiac arrhythmia, and have been removed from the market in Canada (and other countries too).⁠⁠
Other prokinetics, like metoclopramide are safe for short term use, but do come with long term risks that need to be carefully weighed out with your physician.⁠⁠
What has been recognized since these drugs is the importance of targeted affinity – ensuring the drug only takes action where we want it to.⁠⁠

What about Prucalopride?

Since then, newer drugs like prucalopride have become available. Prucalopride is highly selective, meaning it only takes action where we want it to.⁠⁠
In large scale studies, prucalopride is highly effective in reducing constipation and improving quality of life in patients. That’s a HUGE win for patients – favourable safety profile, and effective, especially in patients who have failed other therapies.⁠⁠
Similar, targeted prokinetics are in trials now and I anticipate we will see more IBS specific research on them come out! ⁠⁠

  • 1 doi: 10.5056/jnm15094⁠⁠
  • 2 doi: 10.1111/nmo.14070⁠⁠
  • 3 doi: 10.1155/2017/8612189⁠⁠

What are new generation laxatives?

⁠⁠In Canada, we really only have access to linaclotide, though our US colleagues have access to lubiprostone which would fall into this ‘new’ category.⁠⁠
Linaclotide is a really neat medication. It is a guanylate cyclase-C agonist that does not have systemic action in the body, rather is localized to the gut.⁠⁠

How does Linaclotide work?

  • decrease transit time (speed up the bowels)⁠⁠
  • soften stool ⁠⁠
  • AND the best part – reduce visceral hypersensitivity – meaning less pain for IBS-C’ers!⁠⁠

What is fantastic about these new options is, when patients have exhausted all the ‘older generation’ laxatives, there’s an option that’s a ‘step up’, and has a variety of dosing options to see what works best for patients. ⁠⁠
In practice the major downside I see is it can soften stool too much, so talking with your doctor about what doses are available and knowing that you can switch between different doses is often VERY helpful!⁠⁠
As research continues, I assume we will have more of these targeted, effective laxatives in our toolkit, but for now in Canada, linaclotide is really the only one! ⁠⁠