Sex-related Differences in the Response to the Muscle Relaxant Drug Mivacurium

Muscle Relaxation Clinical Trial

Official title:

The Pharmacodynamics of Mivacurium in Males and Females: A Study in Human Volunteers

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01906528
• Other study ID #: IRB11-07970
• Status: Completed
• Phase: Phase 1
• First received: July 17, 2013
• Last updated: April 9, 2014
• Start date: March 2013
• Est. completion date: July 2013

Study information

• Verified date: April 2014
• Source: University of California, San Francisco
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Institutional Review Board
• Study type: Interventional

Clinical Trial Summary

Muscle relaxants are drugs providing muscle relaxation during surgical treatment. Previous studies have shown that males and females respond differently to this kind of drug. Our hypothesis is that males are more sensitive to the effect of Mivacurium (a muscle relaxant) than females, meaning that males need a lower blood concentration of the drug than females in order to obtain a given effect.

Description:

Muscle relaxants are a type of drug used to provide muscle relaxation during induction of anesthesia and surgical treatment. Residual drug effect postoperatively (i.e. residual muscle relaxation) occurs frequently and studies have shown that this may be harmful in certain groups of patients. Of special concern is residual effect on upper airway and breathing muscles. A previous study has shown that males and females respond differently to the effect of this kind of drug. It appears that some muscle groups which are important for airway protection and breathing are more sensitive to the effect of muscle relaxants in males than females. Males may therefore be more susceptible to postoperative lung complications than females. In this study we try to determine what causes the observed sex-related difference in response to the muscle relaxant Mivacurium. We have previously shown that this sex-related difference cannot be explained by different pharmacokinetics (what the body does to the drug) in males and females. Our hypothesis is that a pharmacodynamic (what the drug does to the body) difference between sexes exists, i.e. that a lower blood concentration of Mivacurium is needed in males than females in order to obtain a predefined degree of muscle relaxation in certain muscle groups.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 20
• Est. completion date: July 2013
• Est. primary completion date: July 2013
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 18 Years to 45 Years

Eligibility

Inclusion Criteria: Healthy individuals with no current medication -

Exclusion Criteria: Previous complications during anesthesia, pregnancy, allergy to muscle relaxants, smoking, gastrointestinal reflux.

Study Design

Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Treatment

Related Conditions & MeSH terms

• Muscle Relaxation
• Sex

Intervention

Drug:
• Mivacurium
Effect of Mivacurium in males vs females

Locations

Country	Name	City	State
United States	University of California, UCSF	San Francisco	California

Sponsors (2)

Lead Sponsor	Collaborator
University of California, San Francisco	Oslo University Hospital

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Other	Relationship between thumb acceleration (TOF ratio) and handgrip strength in both sexes	Thumb acceleration secondary to nerve stimulation at the ulnar nerve (TOF ratio) is an objective way of monitoring the effect of muscle relaxants that is used frequently during clinical anesthesia. Handgrip strength will be monitored with a dynamometer.	6 months	No
Primary	Pharmacodynamics of Mivacurium	The mivacurium drug concentration in the blood associated with 50% of maximal drug effect at steady-state conditions (Css50) will be determined at the thumb and the handgrip muscles.	6 months	No
Secondary	Clearance of Mivacurium	Clearance calculated as the relationship between steady-state infusion rate of Mivacurium and Mivacurium blood concentration.	6 months	No