Skip to content
Clinical Trials – home

Rare diseases

Investigational molecules

Locations

Our offerNewsroom

Not yet recruiting

Patient‑controlled remimazolam, alfentanil and midazolam sedation for outpatients undergoing colonoscopy: safety, efficacy and satisfaction study

Verified siteRegistered drugNo placebo
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

What is this trial about?

A plain-language summary of the goals, design and what participants do

The study focuses on the use of medication to keep patients relaxed and comfortable during a colonoscopy, a procedure that looks inside the large intestine with a thin tube. The medicines being compared are an injectable form of remimazolam, an injectable form of midazolam, and a background medication called alfentanil. All three drugs are given by injection and work by calming the brain so the procedure can be performed without pain or distress.

The purpose of the study is to find out if letting patients control their own sedation with remimazolam is safer and leads to higher satisfaction than when the doctor controls the sedation using either remimazolam or midazolam. Participants will be randomly assigned to one of the three groups, receive the assigned medication through an injection, and either manage the dose themselves using a simple device or have the dose given by the physician. The study follows each person through the colonoscopy, monitors for any moderate or severe side effects (known as adverse events), records how quickly they can leave the clinic (discharge), and asks about their overall experience to measure satisfaction.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Randomization

    After joining the study you are assigned to one of three groups: patient‑controlled sedation with remimazolam, physician‑controlled sedation with remimazolam, or physician‑controlled sedation with midazolam. the assignment is done by the study system and you are not required to choose.

  2. Step 2

    Background medication

    You receive an alfentanil injection of 5 mg. alfentanil is an opioid medication that helps control pain during the procedure.

  3. Step 3

    Sedation administration

    Depending on the group to which you were assigned, one of the following occurs:

    patient‑controlled sedation with remimazolam: you use a handheld device to give yourself a 50 mg injection of remimazolam as needed during the colonoscopy.

    physician‑controlled sedation with remimazolam: the physician gives you a single 50 mg injection of remimazolam at the start of the procedure.

    Comparator group (physician‑controlled midazolam): the physician gives you a single 10 mg injection of midazolam at the start of the procedure.

    The dose is administered as a single injection before the colonoscopy begins; additional doses may be given only if required by the physician.

  4. Step 4

    Colonoscopy procedure

    You lie on a table while the endoscopist performs the colonoscopy. the sedation you received keeps you comfortable and may cause limited awareness.

  5. Step 5

    Monitoring for safety

    Clinical staff continuously monitor your heart rate, breathing, and level of consciousness throughout the procedure.

    They watch for any moderate or severe adverse events (undesired medical problems) and are prepared to intervene if needed.

  6. Step 6

    Recovery and discharge

    After the colonoscopy you are moved to a recovery area where you are observed until you meet the criteria for safe discharge (stable vital signs, ability to sit up, and clear thinking).

    The goal is to achieve discharge without unnecessary delay.

  7. Step 7

    Satisfaction questionnaire

    Once you are ready to leave, you complete a short questionnaire that measures your overall satisfaction with the sedation experience.

Who can join the trial?

5 criteria

  • Age: You must be 18 years old or older.
  • ASA 1‑3: Your overall health must be rated as ASA class 1, 2, or 3, which means you are generally healthy or have only mild to moderate medical problems.
  • Patient‑controlled sedation (PCS) device use: You need to understand the instructions, have good hand coordination, and be fluent in Danish so you can safely operate the device yourself.
  • Colonoscopy requirement: You must be scheduled for a diagnostic colonoscopy that aims to reach the caecum (the start of the large intestine) and may include removal of polyps using a cold snare polypectomy (a technique that cuts polyps without heat).
  • Both men and women are eligible to participate.

Who cannot join the trial?

8 criteria

  • You are planned to receive general anaesthesia or a type of sedation called NAAP/NAPS, which are not allowed in this study.
  • You have an allergy to medicines such as midazolam, remimazolam, any opioids, or any ingredient listed in the drug’s official information sheet (the SmPC).
  • You have a medical reason that makes using midazolam, remimazolam or alfentanil unsafe (this is called a contraindication).
  • You are having a therapeutic colonoscopy that is not a simple cold snare removal of a polyp (cold snare polypectomy).
  • You are currently pregnant or are breastfeeding.
  • You use benzodiazepines, opioids or medicines that act like opioids every day.
  • You have sleep apnoea, a condition where breathing stops briefly during sleep.
  • You drink more than 10 standard alcoholic drinks each week (a standard drink is about one small glass of wine, one bottle of beer, or one shot of spirits).
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

We usually reply within a few days

Verified sites

All sites with verified contact details – recruitment status may not be available; ask directly

Trial locations

Where you can join this trial

Countries are shaded by recruitment status. Click a recruiting country to ask about joining there.

Not yet recruiting
Not finding your country?

Not sure what to do next?

Joining a clinical trial can seem overwhelming. We guide you step by step, so you know exactly what to expect and how we support you through the process.

See the full process and FAQ

Investigated drugs

  • Midazolam

    is a medication that helps people relax and feel sleepy. In this study it was used as the standard treatment that doctors control, so researchers could compare it with the new method of giving sedation.

  • Alfentanil

    is a strong pain‑relieving drug that works quickly. It was given to all participants in the background to keep them comfortable while the sedative medicines were being used.

  • Remimazolam

    is a newer medicine that also makes people relaxed and sleepy. The trial tested this drug in two ways: one where the patient could control the amount they received, and another where the doctor controlled the dose. This allowed researchers to see if patient‑controlled use was safer and gave higher satisfaction compared with the doctor‑controlled approach.

What is already known about the treatment

  • MIDAZOLAM

    This medication is given by injection and is used to put patients into a calm, sleepy state before procedures. It is a well‑known drug that has been used for many years and is described in many medical studies. Midazolam is mainly used for procedural sedation and to reduce anxiety. It works by enhancing the activity of a natural brain chemical called GABA, which slows down nerve signals, and it belongs to the short‑acting benzodiazepine class.

  • ALFENTANIL

    Alfentanil is also administered by injection and provides fast‑acting pain relief during medical procedures. It is an established opioid that has been studied extensively in anesthesia practice. The drug is mainly used to control pain when a patient is being sedated. It acts by binding to mu‑opioid receptors in the brain, which lowers the perception of pain, and it is classified as a short‑acting synthetic opioid analgesic.

  • REMIMAZOLAM

    Remimazolam is given by injection and is used to create a quick, controllable sedation for procedures such as colonoscopy. It is a newer medication that has recently received approval and is being discussed in current medical literature. The main use is procedural sedation with a focus on fast recovery. Like other benzodiazepines, it enhances GABA activity to calm brain activity, and it is placed in the short‑acting benzodiazepine class.

Investigated diseases

Colorectal disease - A range of conditions affecting the colon and rectum, such as polyps, inflammatory bowel disease, or cancer, that may be evaluated with colonoscopy. These conditions develop gradually as abnormal cells grow or inflammation persists, leading to larger lesions that can be detected during the procedure. Over time, the affected area may enlarge or change in appearance, prompting further clinical observation.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2026-525809-13-00Protocol codeHERLEV-PCS-2026-01Estimated enrolment1 patientSponsorRegion Hovedstaden

sourced from the EU Clinical Trials Register and site verification

Want to learn more about this trial or check if you can participate?

Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.