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Can I Continue Taking Montelukast, Zyrtec HTC, And Spironolactone Before My Colonoscopy?
I m scheduled for a colonoscopy this coming Friday (7 days away including today). My doctor hasn t contacted me with updated instructions or sent a pamphlet yet. I got most of the basic instructions over the phone. Can I continue taking hormone medication & allergy medication? (montelukast, zyrtec htc, spironolactone) I m allergic to everything that s on a standard blood allergy test + environmental (no joke).
posted on
Tue, 7 Nov 2023
Medically reviewed by
Ask A Doctor - 24x7 Medical Review Team
Mon, 17 Nov 2025
Answered on
Mon, 1 Dec 2025
Last reviewed on
Hello,
Most daily medications that are not blood thinners are usually safe to continue for a routine colonoscopy. From what you listed:
• Montelukast - is usually safe to continue. It does not impact bowel preparation, the risk of bleeding, or sedation.
• Zyrtec HCT (or any antihistamine combination)-also usually fine. Stopping allergy medication suddenly may actually make you more uncomfortable, especially if you have very strong environmental allergies, before the procedure.
• Spironolactone-this is usually OK, but I always tell patients to check with the gastroenterologist because it has the potential to mildly affect your electrolytes during bowel preparation.
Most still permit this medication; however, they would want you well hydrated during the prep day. Since your procedure is still seven days away, you have plenty of time to clarify. Every hospital or gastroenterology team sometimes has its own small variations in instruction, so it is best to get their final word once they send the prep sheet.
Nothing in what you are currently taking is a red flag for a colonoscopy, but please do not hesitate to call the clinic if the instructions do not arrive in the next day or two. It is completely reasonable for you to want written guidance.
Take care. Hope I have answered your question. If you have any further query I will be happy to help. Wish you good health.
Regards,
Dr. Usaid Yousuf
General and Family Physician
Most daily medications that are not blood thinners are usually safe to continue for a routine colonoscopy. From what you listed:
• Montelukast - is usually safe to continue. It does not impact bowel preparation, the risk of bleeding, or sedation.
• Zyrtec HCT (or any antihistamine combination)-also usually fine. Stopping allergy medication suddenly may actually make you more uncomfortable, especially if you have very strong environmental allergies, before the procedure.
• Spironolactone-this is usually OK, but I always tell patients to check with the gastroenterologist because it has the potential to mildly affect your electrolytes during bowel preparation.
Most still permit this medication; however, they would want you well hydrated during the prep day. Since your procedure is still seven days away, you have plenty of time to clarify. Every hospital or gastroenterology team sometimes has its own small variations in instruction, so it is best to get their final word once they send the prep sheet.
Nothing in what you are currently taking is a red flag for a colonoscopy, but please do not hesitate to call the clinic if the instructions do not arrive in the next day or two. It is completely reasonable for you to want written guidance.
Take care. Hope I have answered your question. If you have any further query I will be happy to help. Wish you good health.
Regards,
Dr. Usaid Yousuf
General and Family Physician
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