CompletedPhase IInterventional

Buccal naloxone testing in healthy volunteers

This study is looking at a new type of naloxone, a wafer you place in your cheek, to see how quickly it gets into the body compared to current naloxone options like injections or nasal sprays. Naloxone is a vital medicine that rapidly reverses the effects of opioid overdose, preventing deaths. The aim is to create a small, portable form of naloxone that people can easily carry, like in a wallet, making it more available during an emergency. Healthy volunteers will take part, undergoing medical checks and blood tests over several visits. This research helps improve overdose prevention and access to life-saving medication, with minimal risks involved.

At a glance

Status

Completed

Phase

Phase I

Enrolment target

Start

15 Dec 2025

Estimated completion

01 Feb 2026

Opioid overdose

What is this study about?

This study is all about improving how we deliver naloxone, a crucial medicine that can quickly reverse an opioid overdose and save lives. Right now, naloxone is usually given as an injection or a nasal spray. However, these methods can have problems. For example, nasal sprays might not work well if someone has a blocked nose or is vomiting. Also, people don't always have these larger forms of naloxone with them when an emergency happens.

That's why researchers are testing a brand-new approach: a very small naloxone wafer you place inside your cheek. Imagine something as easy to carry as a credit card or a mobile phone! The idea is that if naloxone is super portable, more people will carry it, making it much more likely to be available when someone needs it most during an overdose. This could make a big difference in how quickly help can be given, potentially preventing more deaths.

This early stage study, called a Phase I trial, will compare the new cheek wafer with existing naloxone treatments. Researchers want to see if the wafer gets the medicine into the body just as quickly and effectively. By testing this in healthy volunteers, they can carefully measure how the medicine is absorbed and find the best way to use this new, convenient form of naloxone to help tackle opioid overdoses.

Key takeaways

New study testing a small, portable naloxone wafer for opioid overdose.
Compares absorption speed with existing naloxone treatments.
Involves healthy volunteers aged 18-60.
Requires 5 visits over 3 weeks with blood sampling.
Aims to improve access to life-saving overdose medication.
Risks are minimal; confidentiality is a priority.

Who may be eligible?

To join this study, you need to be a healthy volunteer aged between 18 and 60 years old. You'll have a thorough medical check-up, including blood and urine tests, to make sure you're fit enough for the study. You also need to be willing to have small tubes (cannulas) inserted into your veins for blood samples during your visits.

There are certain reasons why you might not be able to take part. For instance, if you have any serious or long-term health conditions that could affect the study results or put your safety at risk, such as heart problems, diabetes, or kidney issues. Also, if you've had major surgery recently that might affect how medicines are absorbed, or if you've lost a lot of blood recently (for example, by donating blood).

If you're currently taking any prescribed medications (other than contraception), or if you've used certain pain relievers containing opioids or illicit opioids in the last two weeks (or longer for some types of opioids), you won't be able to join. Your doctor will discuss all these points with you to ensure it's safe and appropriate for you to participate.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you between 18 and 60 years old?
Are you generally healthy and don't have any serious ongoing health conditions?
Are you willing to have blood tests and small tubes put in your arm?
Are you able to attend five study visits over about three weeks?
Are you not currently taking any prescribed medicines (other than contraception) or certain pain relievers (opioids)?

Answer every question to see your result.

What does participation involve?

If you decide to take part, you'll first have an initial visit at King's College Hospital. During this visit, a doctor will interview you, give you a health check, and you'll have blood and urine tests.

Over the next three weeks, you'll need to attend five experimental visits. Each visit will involve regular health checks, and importantly, intensive blood sampling. This means small tubes (cannulas) will be placed in your arm, and blood samples will be taken frequently to see how quickly the different naloxone formulations are absorbed by your body. Medical and nursing staff will be on hand throughout to support you. The total duration of your active participation will be around three weeks.

Potential risks and benefits

Participants might find the experience of being involved in medical research interesting and will be paid for their time. Your contribution will be very valuable in helping improve life-saving treatments for opioid overdose. The risks connected with this study are considered very small. Naloxone is generally safe when used correctly, and its main job is to reverse an overdose. You might feel a little pain or discomfort when the small tubes are put in your arm for blood tests, but experienced nurses will do their best to make this as comfortable as possible. Confidentiality is taken very seriously, and your personal information will be kept safe and anonymous. While pregnant, naloxone is considered safe, women who could become pregnant will need to use effective contraception during and for a period after the study. You are free to withdraw from the study at any time without giving a reason.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

King’s College Hospital NHS Foundation Trust
City only
London, England

Common questions

What is naloxone used for?

Naloxone is a medicine that quickly reverses the effects of an opioid (like heroin or strong painkillers) overdose, helping someone to breathe again.

Why is a new form of naloxone being developed?

The new wafer form aims to be smaller and easier to carry than current options, making it more likely people will have it with them during an emergency.

Will I be given opioids during this study?

No, this study is testing naloxone in healthy volunteers and you will not be given opioids.

How long will each visit take?

The study aims to minimise the time you spend, but each experimental visit will involve several hours due to intensive blood sampling.

Will my privacy be protected?

Absolutely. Your personal information will be kept separate and confidential, and you will be given an anonymous ID number for the study.

How to find out more

Sophie Espinoza

sophie.espinoza@kcl.ac.uk +44 (0)20 1885732 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.