Comprehensive Guide to Colonoscopy Bowel Preparation Types of Drugs, Instructions, Effectiveness, an

Author : Leena Shedmake | Published On : 22 Feb 2024

Colonoscopy is a common medical procedure performed to examine the inner walls of the large intestine (colon) for any signs of abnormality or disease. Like any other medical or surgical procedure, proper preparation is required before a colonoscopy to get accurate results. This preparation involves consuming specific medications known as bowel preparation drugs a day before the procedure to cleanse the colon by inducing multiple bowel movements. These drugs are essential to flush out waste from the colon and allow clear visibility of the colonic mucosa during the procedure. This article provides an overview of commonly used colonoscopy bowel preparation drugs, their mechanism of action, instructions for use, effectiveness, and side effects.

 

Types of Bowel Preparation Drugs

 

There are two main categories of medications used for colonoscopy bowel preparation - oral sodium phosphate solutions and polyethylene glycol (PEG)-based solutions.

 

Oral Sodium Phosphate Solutions

 

Oral sodium phosphate solutions like Visicol and OsmoPrep contain phosphate salts that pull water into the intestinal contents, softening the stool and inducing bowel movements. These solutions come as tablets or powders that need to be dissolved in water as per instructions. They work faster than PEG solutions within 6-12 hours but are associated with more side effects like nausea, vomiting, dehydration and electrolyte imbalance. Due to safety concerns, the FDA issued warnings against their use in 2011.

 

Polyethylene Glycol (PEG)-based Solutions

 

Colonoscopy Bowel Preparation Drugs PEG-based solutions like Golytely and Colyte contain large molecules of PEG that are not well absorbed from the digestive tract and remain in the colon, drawing water into the stool and facilitating multiple bowel movements. They come as clear liquids that need to be diluted as per package insert and consumed throughout the day before the procedure. PEG solutions are better tolerated than phosphate solutions but may require a longer preparation time of 6-12 hours.

 

Instructions for Use

 

Bowel preparation drugs come with clear instructions on when to start and complete the medication based on the timing of the colonoscopy.

 

- Start the solution the night before or early morning on the day before the procedure.

 

- Drink an specified volume of the solution over hours, usually completing it within 4-6 hours.

 

- Drinking clear fluids along with the preparation helps improve tolerance.

 

- Avoid solid foods and restrict dairy/red products after starting the preparation.

 

- Expect multiple bowel movements that produce clear or light yellow fluid to signify adequate cleansing.

 

- Discard any remaining solution after completing preparation.

 

- Follow post-preparation diet restrictions advised by the doctor.

 

Effectiveness

 

When taken as prescribed under medical guidance, colonoscopy bowel preparation drugs are usually highly effective in cleansing the colon. PEG-based solutions are more effective than phosphate solutions as they require a longer preparation time to fully evacuate the colon. An adequately prepared colon allows the endoscopist to visualize the entire length of the colon mucosa and detect most colon polyps or cancers larger than 5 mm. Inadequate preparation may require repeating the entire colonoscopy at additional risk, discomfort and cost to the patient. Proper hydration and following instructions carefully maximizes the cleansing effectiveness of these drugs.

 

Side Effects

 

While bowel preparation drugs effectively cleanse the colon, they may cause temporary side effects like:

 

- Nausea/Vomiting: Occurs in 10-30% patients especially with phosphate solutions. Staying well hydrated helps minimize it.

 

- Abdominal Cramping: Mild to moderate cramps are common until the colon is emptied.

 

- Bloating: Caused due to gas buildup from solution ingestion. It subsides after bowel movements.

 

- Dizziness: May occur in elderly or dehydrated patients from electrolyte imbalance.

 

- Anal Discomfort: Passing frequent liquid stools may cause anal discomfort. Use soothing creams.

 

- Sleep Disturbance: Frequent toilet trips during night may disrupt sleep before procedure.

 

Side effects are usually mild to moderate and subside within few hours after completion of preparation. Drinking clear fluids, staying close to a toilet and resting help tolerate these temporary side effects better. Serious complications are rare if consuming as directed.

 

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