Most of the time, you’ll need to start colonoscopy prep days in advance. However, your timeline will depend on your doctor’s recommendations.

Colonoscopies might not be the most exciting way to spend your day, but they’re vital diagnostic exams that are used to look for abnormalities such as ulcers, polyps, or even cancerous cells. While the procedure is straightforward, it does require preparation, which can be uncomfortable.

In particular, most people are familiar with the idea that a person must take laxatives to clear their bowels. This is because colonoscopies require using a colonoscope which is inserted inside the rectum and colon.

Timing the preparation period is critical to be ready for your colonoscopy. But if you forget to take the necessary medications, here’s what you need to know.

Whether you forgot to take the laxatives, didn’t follow the recommended cleanse schedule, or they just didn’t work, these things can and do happen.

In most cases, you’ll need to reschedule your colonoscopy procedure. If your bowels haven’t been properly cleared, it’s going to be difficult for your doctor to perform an effective diagnostic review of your colon.

Note that people are usually given a preparation schedule that can range from 5 to 7 days before the procedure. During this time, you’re encouraged to adjust your diet. And, within the 24 hours before the colonoscopy, you’re expected to take the laxatives — whether prescribed or purchased over the counter — to clear your bowels.

When to call your doctor to reschedule?

Guidelines can vary as some doctors will recommend a split-dose rather than a single-dose laxative.

This means that you might take half of the recommended amount 12 hours before the procedure and then complete the final portion anywhere from 5 to 7 hours before your colonoscopy is scheduled.

Regardless of the guidelines given to you, you should contact your doctor no later than 12 hours before your scheduled procedure time to request a new date if you haven’t cleansed your bowels.

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Whether or not you can take a laxative on the morning of your scheduled procedure is going to depend on the type of bowel preparation plan that your physician has given you and what time your procedure is scheduled for.

For people on a single-dose preparation plan, you’ll be expected to take a laxative only once. This will usually be planned for roughly 12 hours before your intended procedure.

If you have a split-dose preparation — meaning that you take half the laxative 12 hours before and the remainder roughly five to seven hours before your procedure, you might need to finish your laxative dosage in the morning.

How long does it take for Dulcolax to work before a colonoscopy?

How quickly a laxative works can depend on several factors. For example, a single-dose preparation might result in more forceful bowel movements that begin faster than a split-dose option.

In general, bowel preps for colonoscopies are typically designed to aid in bowel movements anywhere from an hour to 3 hours after consuming them. However, Dulcolax itself may take 6 to 12 hours to work. As usual, individual experiences can vary.

If you don’t experience any — or enough — bowel movements after taking a laxative, you’ll most likely need to contact your doctor to reschedule your colonoscopy.

Why is Dulcolax used for colonoscopies?

Dulcolax is just one of many types of laxatives that might be recommended. Dulcolax is an over-the-counter option that can be easier for people to find and is generally affordable.

But your doctor will likely also recommend a prescription-strength laxative which is much stronger and more likely to effectively empty your bowels. If you haven’t received a prescription for a laxative and are unsure of which one to use, always speak with your healthcare professional for recommendations before making a purchase.

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The goal of the bowel preparation stage is to ensure that your colon is empty so your doctor can perform an effective colonoscopy.

In most cases, a successful cleanse means that any bowel movements you have before the procedure should result in clear or yellow-tinged liquid.

If you’re still passing solid stools — even slightly watery ones — your cleanse was not effective, and you’ll need to reschedule your procedure. It’s best to contact your doctor’s office as soon as possible to avoid any rescheduling fees.

Preparing for a colonoscopy is far from the most enjoyable experience you’ll have in your life — but it’s a critical one. Taking a preventive approach to colon health is critical, especially if you’re at a higher risk of colon cancer or other bowel-related conditions.

But for this diagnostic procedure to be effective, you need to perform the recommended cleanse at least 12 hours in advance. If you’re not sure of what to do, speak with your healthcare professional for guidance.