Remimazolam vs Midazolam Cognitive and Motor Recovery After Intravenous Conscious Sedation for Dental Extractions.

The study is looking to see if a new drug (remimazolam) that is used to sedate and relax adults (aged 18-59 years) having dental treatment is better than the current drug in use (midozolam). Intravenous sedation is where a drug is injected into a patient's hand or arm. The drug stops them feeling worried, and helps them relax. After sedation, patients wait in a recovery area until they are safe to walk but the side effects of the drug can last until the next day. A new drug has been developed that has the same sedation effect and safety, but the recovery is much quicker. The investigators think that the side effects from the new drug will have worn off by the time patients are ready to leave the hospital. Patients who are coming to Guy's Hospital to have their wisdom tooth extracted under sedation will be asked if they want to be included in the research. Patients will be randomised to receive either remimazolam of standard of care midazolam. The sedation and dental treatment will be carried out in the normal way.

The patients will be asked to do will be some questionnaires and some tests which are as follows:

1. Patients are asked to listen to some words and repeat them back. This tests how well they can remember new information
2. Reaction test - Patients are asked to rest their fingers on a keypad and move their fingers when lights come on above them. This tests how quick their reactions are.
3. Symbol test- Patients are asked to draw small shapes that are linked to numbers. This tests how well they can process information.
4. Standing test- Patients are asked to stand on a platform that measures how much they are swaying back and forth. This tests how stable they are to walk.

By testing people before and after the sedation the investigators can see how they recovered and compare the two drugs. The research will take place during the day case visit and involve 2 x 30 mins research assessments (before sedation and post sedation). After the post-sedation tests, participants will be discharged, followed by a telephone review 3-10 days post procedure.

This study will be performed as a prospective, randomised, triple blind, active controlled, parallel group, single centre study design assessing enhanced cognitive recovery in patients having third molar wisdom tooth extraction under intravenous conscious sedation with remimazolam. An active control group has been chosen using intravenous midazolam which is the current standard of care in Dentistry. 128 patients will be randomised, of which n=64 will receive remimazolam, and n=64 in the midazolam group.

Eligibility Criteria:
Inclusion Criteria:

* Patients who are scheduled to have mandibular third molar removal with intravenous conscious sedation.
* Male and female patients, aged ≥18 to ≤59 years old.
* American Society of Anesthesiologists (ASA-PS) grade I or II.
* English as their first or main language for 5+ years. The primary outcome measure (HVLT) is a cognitive test to remember English words and validated on this basis.
* A patient who has given informed written consent for inclusion to the study.
* Patients who are willing and able to comply with study requirements.

Exclusion Criteria:

* Any surgical risk factor which, in the opinion of the study surgeon, can lead to increased procedure complexity (for example high risk of inferior alveolar nerve damage)
* A known sensitivity to benzodiazepines or a medical condition such that these agents are contraindicated as per the SmPC, for example unstable myasthenia gravis, hepatic impairment, acute respiratory depression, and severe respiratory failure.
* Any neurological deficit where cognitive tests will be impaired (for example dementia).
* A patient with known difficult airway/ mask ventilation or who has increased risk factors recorded by the clinical team at assessment.
* A patient who reports hypersensitive gag reflex.
* Body mass index \>34.9 kg/m or weight \<50kg or \>130kg.
* Dental or needle phobia identified by a modified dental anxiety score ≥19 (MDAS questionnaire).
* High Hospital Anxiety and Depression Score (HADS) \>12.
* Chronic use of benzodiazepines or opioids for any indication.
* Use of medications known to interact with IMP or comparator as listed in the SmPC.
* All female patients with a positive urine pregnancy test within 8 hours before IMP administration. Female patients who are permanently sterile are not required to have a urine test. Permanent sterilisation methods include hysterectomy, bilateral salpingectomy and bilateral oophorectomy.
* Lactating female patients currently breastfeeding.
* Patients who self-report illicit drug use in the last 4 weeks. Patients who self-report alcohol abuse (AUDIT-C Scores \> 7) or history of abuse within the past 5 years.
* Patients who self-report a history of illicit drug abuse within the past 5 years or any history of benzodiazepine dependence.
* Inclusion in a study of an IMP in the previous 4 weeks or less than seven half-lives (whichever is the longer).
* Hypersensitivity to the IMP or to any of the excipients.
* Patients who are unable to stand unassisted.