How does this medication work? What will it do for me?
Magnesium citrate belongs to a class of medications called osmotic laxatives and purgatives. It works by drawing and retaining water into the large colon. This softens the stool and stimulates the rhythmic movement of the muscles in the colon, leading to a bowel movement.
Magnesium citrate is used for the short-term of relief of constipation, and to cleanse the bowels prior to certain procedures, such as a colonoscopy. A bowel movement usually occurs between ½ hour to 6 hours after taking magnesium citrate.
This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.
Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.
Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.
What form(s) does this medication come in?
Each 300 mL bottle of lemon-flavoured, colourless solution contains anhydrous magnesium citrate 15 g. Nonmedicinal ingredients: citrus flavour, phosphoric acid, sodium benzoate, sodium saccharin, and water.
How should I use this medication?
If you are taking this medication to treat constipation, the usual adult dose is 75 mL to 150 mL daily, taken by mouth. Children should only use magnesium citrate after consulting with their doctor. For children less than 6 years of age, the dose is based on weight. Children 6 to 12 years of age should take 100 mL to 150 mL per day. For children over 12 years of age, the dose is 150 mL to 300 mL per day. After taking magnesium citrate, drink a full glass of water (250 mL).
This medication should be used only for short-term relief of constipation on an as-needed basis, once or twice daily at most, or as directed by your doctor. Do not take this medication for more than one week, unless directed by your doctor.
If you are taking this medication to cleanse your bowels prior to a medical procedure, the usual adult dose is 300 mL (1 full bottle) as a single dose. The dose for children is based on body weight and is usually 4 mL per kg, with a maximum of 300 mL per dose. Before taking magnesium citrate, drink a full glass of water (250 mL) each hour for 4 to 6 hours before. Drink a full glass of water every hour for another 3 hours after taking the medication.
Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.
It is important to use this medication exactly as recommended by your doctor.
This medication can be chilled in the refrigerator for better taste.
Stored this medication at 2°C to 30°C, and keep it out of the reach of children.
Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.
Who should NOT take this medication?
Do not take this medication if you:
- are allergic to magnesium citrate or any ingredients of this medication
- have heart block (a problem with the heart's electrical system affecting the rate and rhythm of heartbeats)
- have or are suspected to have intestinal obstruction
- have severely reduced kidney function
- have unexplained or undiagnosed abdominal pain, nausea, vomiting, bleeding, or fever
What side effects are possible with this medication?
Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.
The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.
The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.
Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.
- abdominal cramping
Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:
- decreased blood pressure
- irregular heartbeat
- loss of tendon reflexes
- muscle weakness
- rectal bleeding
- trouble breathing
Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.
Are there any other precautions or warnings for this medication?
Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Dehydration: You should not use osmotic laxatives frequently or for extended periods of time as it can result in dehydration, especially if they are not taken with sufficient amounts of fluids.
Frequent or prolonged use: Use this medication only when you need it or as recommended by your doctor. Avoid using this medication repeatedly at short intervals, and do not use it for more than 1 week unless directed by your doctor. Frequent and long-term use of this medication can lead to your body depending on this medication for bowel movements. Taking this medication too often can also lead to diarrhea, as well as problems with the electrolyte and fluid levels in your body.
Gastrointestinal: You should not use magnesium citrate if you are experiencing acute abdominal pain, nausea, vomiting, or other symptoms of appendicitis or undiagnosed abdominal pain. It should also not be used if you have ileostomies or colostomies.
Heart block: Hypermagnesemia (high levels of magnesium in the body) can cause heart block. If you have heart block, do not take this medication. Talk to your doctor or pharmacist for advice.
Low sodium diet or kidney problems: If you are on a low sodium diet or have severely reduced kidney function, your doctor should closely monitor your magnesium levels while you are taking magnesium citrate, as you may be at an increased risk for hypermagnesemia.
Neuromuscular disease: If you have myasthenia gravis or other neuromuscular diseases, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Pregnancy: Occasional use of magnesium citrate as a laxative is considered safe in pregnancy. If you have any questions, talk to your doctor.
Breast-feeding: Magnesium citrate is considered safe in breast-feeding.
Children: Magnesium citrate should only be used in children on the advice of a doctor.
Seniors: As kidney function declines with age, your doctor should closely monitor your magnesium levels while you are taking magnesium citrate, as you may be at an increased risk for hypermagnesemia.
What other drugs could interact with this medication?
There may be an interaction between magnesium citrate and any of the following:
If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:
- stop taking one of the medications,
- change one of the medications to another,
- change how you are taking one or both of the medications, or
- leave everything as is.
An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.
Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.