Magnesium citrate is a saline laxative commonly used to cleanse the bowel before medical procedures like a colonoscopy. If you’ve been instructed to use magnesium citrate for colonoscopy preparation, you’re likely wondering: “How Long Does It Take For Magnesium Citrate To Work?” Understanding the expected timeframe and factors that influence its effectiveness is crucial for successful prep and a smooth procedure. This guide will provide you with a comprehensive overview of magnesium citrate’s onset of action, how to use it effectively for colonoscopy prep, and what to expect.
Understanding Magnesium Citrate and How It Works
Magnesium citrate is an over-the-counter laxative that works by drawing water into the intestines. This increased fluid in the bowel helps to soften the stool and increase its volume, stimulating bowel movements. As a saline laxative, it’s known for its relatively quick action compared to bulk-forming laxatives or stool softeners.
The Typical Onset Time of Magnesium Citrate
For most individuals, magnesium citrate typically starts to produce a bowel movement within 30 minutes to 3 hours after ingestion. However, the exact time frame can vary depending on several factors, including:
- Individual Metabolism: Metabolic rates differ from person to person, affecting how quickly the body processes and reacts to medications.
- Dosage: The amount of magnesium citrate consumed will influence the speed and intensity of its effect. Colonoscopy prep usually involves a specific dosage recommended by your doctor.
- Empty Stomach vs. Full Stomach: Taking magnesium citrate on an empty stomach may lead to faster results as there is less food to interfere with absorption and action.
- Hydration Levels: Adequate hydration is crucial for magnesium citrate to work effectively. It draws water into the intestines, so sufficient fluid intake is necessary.
- Bowel Content: If you have a significant amount of stool in your colon, it may take slightly longer for magnesium citrate to work initially.
It’s important to note that while you may experience initial bowel movements within a few hours, the complete cleansing of the colon required for a colonoscopy may take longer and involve multiple bowel movements over several hours.
Magnesium Citrate for Colonoscopy Preparation: A Step-by-Step Guide
Magnesium citrate is a common component of colonoscopy prep regimens. The goal is to completely empty the colon so that the doctor can clearly visualize the colon lining during the procedure. Here’s a general guideline based on the original instructions, always follow your doctor’s specific instructions as they may vary:
Days Before Your Colonoscopy
It’s crucial to start preparing several days before your scheduled colonoscopy. This often involves dietary adjustments and medication considerations.
- One week before the procedure: Stop taking iron supplements.
- Three (3) days before the procedure:
- Stop taking Vitamin E, Motrin, Advil, Aleve, ibuprofen, and similar NSAIDs (non-steroidal anti-inflammatory drugs). Aspirin may be continued if advised by your doctor.
- If approved by your physician, stop taking blood thinners like Coumadin, Warfarin, Plavix, or Pradaxa.
- Continue taking usual medications for chronic conditions like blood pressure, heart problems, or lung problems, unless specifically instructed otherwise by your doctor. Always clarify with your physician or the GI Endoscopy office at 860-679-3238 if you have any doubts about your medications.
- Purchase two (2) bottles of 10-ounce magnesium citrate (avoid cherry flavor) and one package of Dulcolax tablets. No prescription is usually needed.
The Day Before Your Colonoscopy
The day before your procedure is critical for bowel preparation.
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Morning Laxatives: Upon waking, take four (4) Dulcolax tablets with a large glass of water. Dulcolax is a stimulant laxative that will work in conjunction with the magnesium citrate to ensure thorough bowel cleansing.
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Clear Liquid Diet: Follow a strict clear liquid diet all day. This means no solid foods, milk, or milk products, and no red or purple liquids. Acceptable clear liquids include:
- Apple juice
- Sprite, Ginger ale, Fresca, or other clear sodas
- Tea and coffee (without milk or cream, sugar or sugar substitutes are okay)
- Jell-O (no red or purple)
- Popsicles (orange, lemon-lime)
- Vitamin Water or Gatorade (orange, lemon-lime)
- Clear soup, broth (vegetable, beef, or chicken)
- White grape juice
- Hard candy
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Evening Magnesium Citrate Dose: At 6 p.m., drink the entire contents of the first 10-ounce bottle of magnesium citrate. Follow it immediately with an 8-ounce glass of water.
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Continue Clear Liquids: Keep drinking clear liquids throughout the evening to stay hydrated and aid the bowel-cleansing process.
The Day of Your Colonoscopy
On the day of your colonoscopy, timing is crucial.
- Second Magnesium Citrate Dose: Five (5) hours before your scheduled arrival time at the procedure center, drink the entire contents of the second 10-ounce bottle of magnesium citrate, and another 8-ounce glass of water. Do not consume anything else to eat or drink after this second dose (except for essential medications with a small sip of water, if approved by your doctor). Again, clarify any medication concerns with your physician or the GI Endoscopy office at 860-679-3238.
- Transportation: Arrange for a friend or family member to drive you to and from the procedure, as you will likely be sedated and unable to drive yourself.
Additional Instructions for Afternoon Procedures
If your colonoscopy is scheduled for the afternoon (after 12 p.m.), you may have clear liquids for a bit longer:
- For procedures after 12 p.m.: You can drink clear liquids (black coffee or tea without milk or sugar, water, 7UP, ginger ale, or apple juice) until 6 hours before the start time of your procedure.
- No solid food after midnight the night before your procedure, regardless of appointment time.
Example Clear Liquid Schedule for Afternoon Procedures:
- Procedure at 1 p.m.: Clear liquids allowed until 7 a.m.
- Procedure at 2 p.m.: Clear liquids allowed until 8 a.m.
- Procedure at 3 p.m.: Clear liquids allowed until 9 a.m.
What to Expect After Taking Magnesium Citrate
After taking magnesium citrate, you should expect to experience bowel movements. Initially, these bowel movements may contain formed stool. As the magnesium citrate works to cleanse your colon, the bowel movements will become more liquid and frequent. The goal is to have clear, yellowish liquid stools, which indicates that your colon is sufficiently clean for the colonoscopy.
It is important to stay near a bathroom once you start taking magnesium citrate, as the urge to defecate can come on suddenly and frequently. You may experience some abdominal cramping or bloating, which is normal. Staying hydrated by drinking clear liquids is essential to replace fluids lost through bowel movements and to prevent dehydration.
When to Contact Your Doctor
While magnesium citrate is generally safe, it’s important to be aware of potential issues and know when to seek medical advice.
Contact your doctor or the GI Endoscopy office if you experience:
- Severe abdominal pain that is not relieved by bowel movements.
- Signs of dehydration, such as dizziness, lightheadedness, decreased urination, or excessive thirst.
- Vomiting or inability to keep down clear liquids.
- Rectal bleeding that is more than a small amount or persistent.
- If you do not have any bowel movements within 3 hours after taking magnesium citrate.
For UConn Health patients: If you have any problems or questions during weekday hours (8 a.m. to 4:30 p.m.), call 860-679-3238 and ask to speak with the GI nurse. For evening hours (after 4:30 p.m.) or weekends, call 860-679-2626 and ask for the GI fellow on call.
Conclusion
Magnesium citrate is an effective and relatively fast-acting laxative used for colonoscopy preparation. Knowing that it typically takes effect within 30 minutes to 3 hours can help you plan and feel more prepared for your colonoscopy prep. Remember to follow your doctor’s specific instructions carefully, maintain a clear liquid diet, stay hydrated, and contact your healthcare provider if you have any concerns. Proper colonoscopy preparation is essential for a successful procedure and accurate results.
