8 Tips To Avoid Vomiting & Nausea During Colonoscopy Prep. [Dr. Farahat]


✅ Evidence-Based.

✅ By Dr. Farahat.

Quick insights on how to avoid vomiting during colonoscopy prep.

  • Start with a small test dose of 30 to 60 mL of your colon prep.
  • Gradually increasing the dose of your colon prep. AVOID drinking too much prep too fast.
  • Take a 30-60 minutes break if you are already vomiting.
  • Try to refrigerate your colon prep. This helps to reduce nausea and vomiting.
  • Avoid too much moving and activities.
  • Try a simple slow-deep breathing exercise.
  • Take over-The-Counter Anti-emetic or anti Nausea Medication if you don’t have contraindications.
  • Ask your doctor if there is no response or you have severe vomiting.

(1) Start Low.

The ultimate way to prevent nausea and vomiting during colonoscopy prep. is to avoid Drinking too much colon prep. too fast.

you should try a “test drink” of your colon prep liquid. If you can tolerate it then start increasing the second dose.

Most colon prep. doses are usually about 2- 4 liters. and you can drink it in 2 sessions (1-2 Litre/session).

We recommend you to start as low as one or two Fl. Oz. (30-60 mL) as a test dose, if no nausea or vomiting, you can drink a bigger amount 15-20 minutes later.

(2) Go slow

Don’ t consume the whole dose of your colon prep. solution as a single dose. rather split them into 2 doses:

  • The first dose: the night before colonoscopy.
  • the second dose: 4-5 hours Before colonoscopy.

For each dose, you can expand the time of drinking. For example. instead of drinking your first dose over 15-30 minutes, try to drink smaller amounts over a longer period over 1-2 hours) [ref]


(3) Already vomiting? take a break.

you can take 30-60 minutes to break if you’re vomiting.

A Break will help your stomach to calm down. Also, nausea will decrease with time.

A good sign for re-drinking your colon prep. is to want for nausea to decrease. Also, taking a break to avoid vomiting gives you a time to chill your colon prep. (see next tip).


(4) chill your colon prep.

Refrigerating your colon prep and drinking it helps. chilling or cooling is known to help with nausea and vomiting. [ref]

Aso, you can drink “cold water” along with your colon prep. If you experienced vomiting before, you can consider putting your colon prep. in the refrigerator during The break we mentioned before.

frequent drinking of small amounts of cold water helps you stay hydrated and increases the efficacy of your colon prep.

(5) Avoid too much moving.

If you feel nauseous or about to vomit try to avoid physical activities such as:

– walking, running.

– Bending.

– Regular housework such as cooking or cleaning.

Nausea & vomiting are induced by moderate to severe forms of physical activity [ref]

Instead, Try to lie comfortably. Better in a semi-setting position until nausea & vomiting resolves.

By staying still, you are keeping your vestibular system and vomiting Centre (inside your brain) from being triggered. 

Also, no. problem with light activities (such as moving from a room to another or using the toilet). the point is to restrict your movement when nausea is severe.

After 30-60 minutes from the last drink of colon prep, you can safely regain your physical activity.

(7) Try Over-The-Counter Antiemetic drugs.

Two main types of antiemetic medications are available over the counter:

  • Bismuth subsalicylate (Brand names: Kaopectate, Pepto-Bismol).
  • Antihistamines: Dimenhydrinate (Dramamine) and Meclizine (Dramamine Less Drowsy).

DO NOT use Beptobismol for vomiting or nausea as it may interfere with your colonoscopy procedure (causes black stool) [ref]

You can try either Dramatine or Dramamine Less Drowsy if you don’t have contraindications.

Tips on taking OTC anti-emetics to stop vomiting during colon prep: –

  • Take them only if you have vomiting or severe nausea (don’t take them for mild symptoms).
  • Use only antihistamines (not Pepto-Bismol).
  • Carefully read the drug directions on the drug facts label
  • DO NOT Use more than one antiemetic at the same time.
  • DO NOT take them if you are taking any prescription medication (unless you talk to your doctor). This is especially with: –
    • Blood-Thinning medicines.
    • gout & arthritis medicines.
    • anti-diabetes made cones.
  • DO NOT take them if you have certain medical conditions (unless you talk to you, doctor):
    • Heart diseases & high blood pressure.
    • Thyroid diseases.
    • Glaucoma
    • Benign prostatic hypertrophy.
    • Chest diseases such as Bronchial asthma.
  • If you are older than60, DO NOT take them unless you talk to your doctor.
  • Start with a low-dose tablet (50mg), you can repeat the dose 4-6 hours later.

(8) when to call your doctor?

Some conditions & signs that you need to call your doctor about colon prep. & vomiting:

  • No response to the above remedies and otc medications.
  • severe vomiting persistent severe vomiting attacks.
  • your age is older than 60 and you think you need an otc antiemetic.
  • Any complications related to vomiting such as aspiration into airways or v vomiting of blood.
  • you think vomiting will prevent adequate colonoscopy preparation. (this is necessary to avoid failure of colonoscopy and re-colonoscopy).


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