Skip to content

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

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

Status
Completed
Phases
Phase 1
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT01906528
Enrollment
20
Registered
2013-07-24
Start date
2013-03-31
Completion date
2013-07-31
Last updated
2014-04-11

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Muscle Relaxation, Sex

Keywords

Nondepolarizing neuromuscular blocking drug, Mivacurium, Sensitivity, Sex

Brief 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.

Detailed 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.

Interventions

Effect of Mivacurium in males vs females

Sponsors

Oslo University Hospital
CollaboratorOTHER
University of California, San Francisco
Lead SponsorOTHER

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to 45 Years
Healthy volunteers
Yes

Inclusion criteria

Healthy individuals with no current medication -

Exclusion criteria

Previous complications during anesthesia, pregnancy, allergy to muscle relaxants, smoking, gastrointestinal reflux. \-

Design outcomes

Primary

MeasureTime frameDescription
Pharmacodynamics of Mivacurium6 monthsThe 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.

Secondary

MeasureTime frameDescription
Clearance of Mivacurium6 monthsClearance calculated as the relationship between steady-state infusion rate of Mivacurium and Mivacurium blood concentration.

Other

MeasureTime frameDescription
Relationship between thumb acceleration (TOF ratio) and handgrip strength in both sexes6 monthsThumb 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.

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026