Pharmacy Corner
Constipation: Time Goes Slow When You Can’t Go What medications can be used for constipation?

If you are constipated you should always try to change your lifestyle first. If this does not help with your constipation, there are laxatives that you are able to buy without a prescription at your local pharmacy.



Even if you are taking a laxative for your constipation, you should still do the lifestyle changes. Both will work together to help with your constipation.

What over-the-counter medications can I use for constipation? What are the common side effects?

There are a couple of non-prescription medications available for constipation. Before selecting a medication, you should speak to a pharmacist or doctor. There are many options to choose from and they can help select the best option for you.

Bulking agents – holds water and adds extra bulk to the stool4

  • Examples: Metamucil® (psyllium), Prodiem® caplets (polycarbophil calcium)
  • Common side effects: bloating and gassiness.4 To prevent this from happening, start with a small amount and slowly increase
  • Bulking agents contain fibre, they may take a couple of days to work and they are safe for long term use6


It is important to drink plenty of fluids if you are taking bulking agents. If you are unable to drink a lot of fluids, this option may not be the best for you. Speak to your pharmacist or doctor for more information.

Osmotic Laxatives– Pulls water into the colon3

  • Examples: Lax-A-Day® (polyethylene glycol 3350 or PEG-3350), lactulose, Milk of Magnesia® (magnesium hydroxide)
  • Common side effects: bloating, gassiness, cramps, nausea6
  • If fibre or fibre supplements don’t work or do not work fast enough, these laxatives may be an option for you
  • PEG-3350 has been shown to be effective for long-term use in chronic constipation7


Some osmotic laxatives such as Milk of Magnesia® and Citro-Mag® should be avoided if you have kidney problems because they can be high in salt and magnesium which can either cause you to swell or cause your magnesium levels to go high in the body.

Stimulants – Stimulates movement in the intestines4

  • Examples: Senokot® (senna), Dulcolax® (bisacodyl)
  • Common side effects: cramping, diarrhea6
  • Can be used for occasional constipation or rescue therapy in chronic constipation.7, 14

Stool Softeners – Makes stool softer by allowing more water to enter and mix with stool more readily3

  • Examples: Colace® (docusate sodium), docusate calcium
  • Stool softeners have very little side effects
  • They don’t work well on their own to help with constipation, but it can soften the stool which can help with straining4
  • Reduced straining can be helpful, especially if you have certain conditions such as hemorrhoids or angina4

Suppositories and enemas work quicker compared to pills and liquids.6 Usually these options are only used short term. There are different suppositories and enemas available. Speak to your pharmacist for more information.



Before choosing a medication, speak to a pharmacist or doctor to make sure it is the best medication for you.

Are there prescription medications for constipation?

There are prescription medications available for chronic constipation. Lifestyle changes and laxatives you can buy from the pharmacy should be tried before prescription medications. If you find that the non-prescription laxatives are not giving you constipation relief, speak to your doctor.