In short
Alfentanil is a fast-acting opioid analgesic belonging to the class of medicines that relieve pain and reduce awareness. It is being studied in two Phase 3 clinical trials as part of sedation for colonoscopy, where it is given by injection alongside sedative medicines. One trial has 1 planned participant and the other 175 participants, both authorised but not yet recruiting.
Key points
- Alfentanil is an opioid analgesic used in sedation for procedures such as colonoscopy.
- Two Phase 3 trials are authorised, with 1 and 175 planned participants.
- One trial studies patient-controlled sedation with remimazolam; the other compares patient-controlled propofol sedation with standard sedation.
- Alfentanil is given as a solution for injection, in strengths of 1 mg/2 mL and 5 mg/1 mL.
- The trials measure patient satisfaction and a composite of procedure success, adverse events, discharge without delay and satisfaction.
- Both trials are authorised but not yet recruiting.
What is alfentanil?
Alfentanil is an opioid analgesic, a medicine that relieves pain and reduces awareness during medical procedures. It is listed in the NHS Highland formulary under anaesthesia as a sedative and analgesic peri-operative drug. The NHS dm+d browser records alfentanil as an ingredient with SNOMED codes 387560008 and 3510511000001102, and notes that there are currently no virtual medicinal products for this ingredient. In the clinical trials listed here, alfentanil is used as part of sedation for colonoscopy, rather than as a treatment for a disease itself.
How does alfentanil work?
Alfentanil is an opioid analgesic. Opioids work by acting on specific receptors in the brain and spinal cord to reduce the sensation of pain and to produce a calming effect. In the context of the trials listed on this page, alfentanil is given together with sedative medicines to help keep a person comfortable during a colonoscopy. The supplementary sources provided do not describe the molecular target of alfentanil in more detail.
Which conditions is alfentanil used or studied for?
Alfentanil is not studied as a treatment for a disease in the trials listed here. Instead, it is used as part of the sedation given during a diagnostic or therapeutic procedure:
- Colonoscopy sedation — one trial studies sedation related to colonoscopy and states that it is not concerned with the underlying medical condition leading to the colonoscopy.
- Adenoma — the other trial is carried out in people undergoing diagnostic and therapeutic colonoscopies, with adenoma listed as the condition.
How is alfentanil given?
Alfentanil is given by injection. The NHS Highland formulary lists two formulations: a solution for injection of 1 mg/2 mL and an intensive care solution for injection of 5 mg/1 mL, both classified as CD schedule 2 controlled drugs. In the clinical trials, alfentanil is given intravenously: one trial uses a 5 mg injection and the other a 1 mg intravenous dose.
What do the clinical trials show?
Two Phase 3 clinical trials involving alfentanil are listed in the registries. Both are authorised but not yet recruiting. One trial, 2026-525809-13-00, has a planned enrolment of 1 participant and studies whether patient-controlled sedation with remimazolam is safer and gives greater patient satisfaction than physician-controlled sedation with remimazolam or midazolam. The other trial, NCT07637279, has a planned enrolment of 175 participants and compares patient-controlled propofol sedation with standard sedation during diagnostic and therapeutic colonoscopies.
The primary outcome in the first trial is a composite of four parameters: procedure success, no moderate or severe adverse events, discharge without delay and high patient satisfaction. The second trial measures patient satisfaction using a validated questionnaire.
Both trials are interventional studies in which alfentanil is given as one of the drugs in the sedation regimen. The first trial also includes midazolam and remimazolam, and the second includes propofol and midazolam.
What side effects are known?
The supplementary sources provided do not describe side effects of alfentanil. The NHS Highland formulary notes an MHRA alert from March 2020 reminding of the risk of potentially fatal respiratory depression with benzodiazepines and opioids, which includes alfentanil as an opioid. No further side effect information is available from the sources on this page.