By Dr. Anthony Feck
The drug Remimazolam (Byfavo) has recently achieved FDA approval for use as clinical trials continue to discover greater knowledge on the value of this drug.
While there have arguably been much higher profile drugs achieving FDA approval this year, remimazolam – a benzodiazepine indicated for the induction and maintenance of procedural sedation – received the green light in July for medical use in the United States.
Marketed as BYFAVO (Acacia Pharma Europe, licensed in the U.S. to Cosmo Technologies), remimazolam is similar to midazolam, which is widely used in intravenous (IV) sedation dentistry to decrease anxiety with minimal respiratory and cardiovascular concerns. Remimazolam, studies show, offers a shorter and more predictable duration and is designed for adult procedures such as colonoscopies that last 30 minutes or less.
The FDA approval for remimazolam followed three clinical trials and approximately 1,000 patients. As an ester-based drug, it hydrolyzes quickly for a more rapid onset and offset of sedation than other medications, including midazolam. The cardio-respiratory safety profile is good, and the potential for pharmacokinetic drug interactions is very minimal. Results show that body weight or BMI are factors that affect pharmacodynamics, and the drug worked similarly for those aged under and over 65.
Other pharmacokinetic facts include:
- Plasma protein binding over 91% due to serum albumin.
- Terminal elimination half-life of approximately 37-53 minutes.
- Mean distribution half-life of approximately 0.5-2 minutes.
- Approximately half of remimazolam is excreted in urine in the form of CNS7054, with a small fraction remaining unchanged.
The initial dose is administered intravenously as a 5 mg (2 mL) push injection over a 10-15 second time period. Supplemental doses of 2.5 mg (1 mL) may be administered as needed over 10-15 seconds; however, a minimum of 2 minutes must elapse prior to any supplemental dose.
With the recommended IV dosing, the median time to peak sedation is 3.0 - 3.5 minutes. Following the last dose of remimazolam, the median time to fully alert is 11.0 - 14.0 minutes. The medicated sedation is reversible with flumazenil.
The common side effects of remimazolam recorded were hypotension, hypertension, hypoxia, and tachycardia. It was shown that sedation tended to last longer with a slower recovery for subjects with liver related impairment compared to other subjects. Those with renal impairment did not require dose adjustments, as renal function did not influence the dynamics of the sedation drug.
The most serious side effects shown in the trials were severe or life-threatening allergic reactions and dangerous deep sedation if used with opiates. Remimazolam may cause sedation in newborns after being administered during pregnancy.
A Future in Sedation Dentistry?
It’s widely understood in the dentistry field that anxiety and phobia can deter patients from visiting the dentist and seeking the care they need. Procedural sedation in a wide variety of forms has proven to relieve anxiety and pain, thus aiding in the necessary treatment. Intravenous sedation is the most expedient and effective method for a trained sedation dentist.
Clinical trials are already under way in order to learn more of the potential value of remimazolam in sedation dentistry, and it will be interesting to see if it proves as efficient as midazolam has in many practices.
Author: Dr. Anthony Feck, DOCS Education Dean of Faculty, has authored 10 dentistry manuals and published 27 articles on dental topics. He is a nationally recognized educator and speaker, having personally given more than 300 courses to dentists and their teams. He has been published in several dental trade publications including AGD Impact, Dental Products Report, and Dental Economics.