A colonoscopy is an essential medical procedure that allows doctors to examine the inside of your colon and rectum for abnormalities, such as polyps or signs of colorectal cancer. One of the most important steps in preparing for a colonoscopy is ensuring that your colon is thoroughly cleared of stool and debris. A clean colon allows the doctor to have a clear view of the inside of your digestive tract, making the procedure more accurate and effective.
Miralax (polyethylene glycol 3350) is commonly used as a part of colonoscopy bowel prep. In many cases, the prep will involve a split-dose method, where the Miralax solution is taken in two separate doses—one the evening before the colonoscopy and the other on the morning of the procedure. This split-dose approach has been shown to improve the quality of bowel cleansing and provide better visibility during the exam.
In this blog, we will explain the Miralax colonoscopy prep process, what you can expect with the split-dose method, and tips to help you make the prep process as smooth and comfortable as possible.
What is Miralax and How Does It Work?
Miralax (polyethylene glycol 3350) is an over-the-counter laxative that works by drawing water into the colon to help soften the stool and stimulate bowel movements. When used for colonoscopy prep, Miralax is mixed with a large volume of clear liquids to cleanse the colon effectively.
Unlike stimulant laxatives, Miralax is not harsh on the stomach and does not typically cause cramps or sudden urgency. Instead, it works gradually over several hours to empty the bowel, making it a commonly recommended choice for colonoscopy preparation.
Why is Split-Dose Miralax Used for Colonoscopy Prep?
Split-dose prep refers to dividing the total amount of prep solution into two separate doses. The first dose is taken the evening before the colonoscopy, and the second dose is taken a few hours before the procedure, typically on the morning of the colonoscopy.
Research has shown that the split-dose method results in a cleaner colon and better visualization during the procedure. This is because taking the second dose on the morning of the colonoscopy ensures that the colon remains clear throughout the procedure. It also helps improve the accuracy of the exam by ensuring that the colon is still adequately cleansed during the examination.
How to Prepare with Miralax for Colonoscopy (Split Dose)
Your doctor will provide specific instructions on how to prepare for your colonoscopy, but the general process for Miralax bowel prep with the split-dose method involves the following steps:
- Dietary Restrictions
A few days before your colonoscopy, you will need to follow a clear liquid diet. This diet helps to ensure that your colon is free of solid food, which can interfere with the prep process. Clear liquids include:
- Water
- Broth (clear, without any solid pieces)
- Tea or coffee (without milk or cream)
- Clear juices (like apple or cranberry juice, without pulp)
- Sports drinks (without added red, purple, or orange coloring)
- Gelatin (without added fruit or toppings)
Avoid any food or drink that contains solid particles or colored liquids like red, purple, or orange.
- Preparing the Miralax Solution
The next step involves mixing the Miralax powder with a large quantity of clear liquid, usually 64 ounces (about 2 liters) of water or another approved beverage. You should mix the Miralax with water according to your doctor’s instructions, stirring until the powder is completely dissolved.
- First Dose (Evening Before the Colonoscopy)
You will begin by drinking the first dose of the Miralax solution in the evening before your colonoscopy. This typically involves drinking half of the solution (32 ounces or about 1 liter) over the course of 1 to 2 hours. To minimize nausea, you can drink the solution slowly, taking small sips.
- Timing: Make sure to start drinking the solution at least 4–6 hours before bedtime, so that you have enough time to finish the first dose and to allow the colon to begin emptying.
- Second Dose (Morning of the Colonoscopy)
On the morning of your colonoscopy, you will drink the second dose of the Miralax solution, usually about 4–6 hours before the scheduled procedure time. Like the first dose, you will consume the remaining 32 ounces (1 liter) of the solution over the course of 1–2 hours.
- Timing: It is essential to finish the second dose of the prep solution according to your doctor’s instructions. This ensures that your colon is completely cleansed by the time of the colonoscopy. If your procedure is in the morning, this will mean drinking the second dose early enough so that you finish it a few hours before the exam.
- Clear Liquids During the Prep Process
In addition to the Miralax solution, it is important to stay hydrated. You will need to drink plenty of clear liquids during the prep process to prevent dehydration. Water, broth, tea, or sports drinks are all great options. Avoid any liquids that are dark or opaque, as they may not be considered “clear” and could interfere with the prep process.
What to Expect During the Miralax Colonoscopy Prep
During the bowel prep with Miralax, you will experience frequent bowel movements as your colon empties. This is a normal part of the process, and you should stay close to a bathroom. Here is what you can expect:
- Frequent Bowel Movements: After drinking the first dose of Miralax, you will likely begin experiencing bowel movements within 1 to 3 hours. These will start as soft stools and become more watery as your colon clears.
- Cramping and Bloating: Mild abdominal cramping, bloating, and gurgling sounds in the stomach are common during bowel prep. These symptoms should subside as the colon empties.
- Clear Stool: By the time you finish the second dose of Miralax, your stool should be clear or light yellow in color. This indicates that your colon has been adequately cleansed and is ready for the colonoscopy.
- Hydration: Be sure to drink plenty of fluids during the prep process to stay hydrated. Dehydration can cause fatigue, dizziness, and other symptoms.
Tips to Make the Miralax Prep Easier
While colonoscopy prep with Miralax is generally well-tolerated, it can be uncomfortable. Here are some tips to make the process more manageable:
- Refrigerate the Solution: Many people find it easier to drink Miralax when it is cold. Refrigerating the solution can help make it more palatable.
- Drink Through a Straw: Using a straw can minimize the taste of the solution, making it easier to drink.
- Take Breaks Between Sips: If you have trouble drinking the full amount of solution at once, try drinking it slowly by taking breaks in between.
- Stay Close to a Bathroom: You’ll need to stay close to a bathroom as frequent bowel movements are expected. Consider spending time at home to avoid any inconvenience.
- Use Wet Wipes: Frequent bowel movements can cause irritation around the rectal area. Wet wipes are gentler than toilet paper and can reduce discomfort.
Possible Side Effects of Miralax
While Miralax is generally considered safe, some people may experience mild side effects, including:
- Nausea: Some people may feel nauseous after drinking the solution, especially if consumed too quickly. If nausea occurs, take a break and resume drinking the solution slowly.
- Abdominal Discomfort: Mild bloating or cramping is common as the colon is being cleansed.
- Dehydration: Since Miralax causes frequent bowel movements, staying hydrated is crucial to prevent dehydration.
When to Contact Your Doctor
If you experience severe side effects such as extreme abdominal pain, vomiting, or signs of dehydration (like dizziness, dry mouth, or dark urine), contact your healthcare provider immediately.
Conclusion
The split-dose Miralax colonoscopy prep is one of the most effective and widely recommended methods for preparing the colon for examination. While the process can be uncomfortable, following your doctor’s instructions carefully, staying hydrated, and using tips to ease the prep can help make the experience smoother. A well-prepared colon allows for a thorough and accurate colonoscopy, which is key to detecting any issues early and maintaining your digestive health. If you have any concerns or questions about the prep process, be sure to consult your healthcare provider for guidance and support.
