Magnesium sulfate - oral

Patient Medicine Information
Why do I need this medicine?
Magnesium sulfate or Epsom salt helps to relieve occasional constipation and maintain regularity of bowel movement.

This medicine belongs to a group of medicines called osmotic laxatives. These laxatives work by increasing water in the bowel, which makes the stools softer so they move out of the body more easily.

Magnesium sulfate may be used to empty bowel before a certain diagnostic procedure (together with other medicine).
How do I take this medicine?
Take Magnesium sulfate exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.

If you are taking the powder form, dissolve the contents of the sachet in water.

Magnesium sulfate may be mixed with fruit juice, water or milk to improve taste.
What should I do if I have forgotten to take this medicine?
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.

DO NOT double a dose under any circumstances.
When should I not use this medicine?
Do not take the medicine if you have the following conditions:
  • blocked bowel caused by by factors other than normal constipation
  • kidney problems
  • severe stomach pain
as Magnesium sulfate may not be suitable for you.
What should I take note of while taking this medicine?
Let your doctor know if you are pregnant or breastfeeding.

Do not take Magnesium sulfate for more than a week unless directed by a doctor.

Be sure to check with your doctor or pharmacist before giving this medicine to an elderly person.

What lifestyle changes can I make to prevent constipation?

You can adopt some of the following lifestyle changes to help prevent constipation:
  • Include high-fibre foods such as fruits, vegetables, beans, and whole-grain cereals and breads in your diet. Add fibre to your diet gradually to help reduce gas and bloating.
  • Drink plenty of liquids. Limit caffeine intake, which may worsen symptoms of constipation by causing dehydration.
  • Be active and exercise regularly.
  • Do not ignore the urge to have a bowel movement.
What side effects could I experience?
Magnesium sulfate may cause any of the following side effects: abdominal discomfort, stomach cramps and watery stool.

Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Can I take this with other medicines?
Inform your doctor and pharmacist if you are taking any of these medicines:
  • medicines that reduce stomach acid production
  • medicines for high blood pressure e.g. captopril
  • antibiotic e.g. azithromycin 
  • medicine to treat fungal infection e.g. itraconazole
  • medicine to treat viral infection e.g. atazanavir
  • medicine for cold or allergy e.g. fexofenadine
  • medicine for epilepsy or seizure (fits) e.g. gabapentin
  • medicine for stomach ulcer e.g. lansoprazole
  • medicine for thyroid disease e.g. levothyroxine
Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements and medicines that you buy without a prescription.
What special dietary instructions should I follow?
Avoid alcohol.
How should I store this medicine?
Store in a cool, dry place away from the reach of children.

Do not refrigerate or freeze.

Medicines must not be used past the expiry date.
This information is independently developed by MIMS based on magnesium sulfate - oral and is provided for your reference only. It is not a replacement for and should only be used in conjunction with full consultation with a licensed healthcare professional, the information provided by your pharmacist and/or the manufacturer of the medication. It may not contain all the available information you require and cannot substitute professional medical care, nor does it take into account all individual circumstances. Although great effort has been made to ensure content accuracy, we shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2021 MIMS. All rights reserved. Powered by
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