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Potency and maintenance requirement of atracurium and vecuronium given alone or together
P Rautoma1, O Erkola, O A Meretoja
1Maria Hospital, University of Helsinki, Finland.
Insights
Combining atracurium and vecuronium muscle relaxants in adults demonstrates significant potentiation, reducing overall drug consumption by approximately 30%. This combination offers an intermediate-acting effect for neuromuscular blockade maintenance during anesthesia.
Area of Science:
- Anesthesiology
- Pharmacology
- Neuromuscular Blockade
Background:
- Synergistic effects are known for some competitive muscle relaxants.
- Previous studies on muscle relaxant combinations primarily focused on pediatric patients.
Purpose of the Study:
- To evaluate the maintenance requirement and synergistic effects of combining atracurium and vecuronium in adult surgical patients.
- To determine the dose-response relationship and potential drug savings with a combined agent.
Main Methods:
- 45 adult surgical patients (ASA I-II) received propofol-alfentanyl-N2O-O2 anesthesia.
- Individual dose-response curves were established for atracurium and vecuronium in 30 patients.
- 15 patients received a combination of atracurium and vecuronium (cAV) in equipotent ratios.
Main Results:
- ED95 values were 260 ± 9 µg/kg for atracurium and 59 ± 3 µg/kg for vecuronium.
- The combination (cAV) showed significant potentiation (P = 0.0001), with an ED95 of 94 ± 7 µg/kg atracurium and 21 ± 2 µg/kg vecuronium.
- Maintenance requirements for cAV were 120 µg/kg/h atracurium and 27 µg/kg/h vecuronium, a 30% reduction in drug consumption.
Conclusions:
- Atracurium and vecuronium exhibit significant synergism in adult patients, maintaining potentiation throughout anesthesia.
- The combination acts as an intermediate-acting muscle relaxant.
- Using the atracurium-vecuronium combination can reduce overall drug consumption by approximately 30%.
Abstract:
A synergism exists between some competitive muscle relaxants. However, maintenance requirement of a combination of muscle relaxants has been evaluated only in paediatric patients. We studied 45 elective adult surgical patients (ASA I-II) during propofol-alfentanyl-N2O-O2-anaesthesia. The first 30 patients were randomized to receive either atracurium or vecuronium to create individual dose-response curves for these muscle relaxants. ED95-values for atracurium and vecuronium were 260 +/- 9 and 59 +/- 3 micrograms.kg-1, respectively (mean +/- s.e. mean). Requirements of atracurium and vecuronium to maintain an 85-95% neuromuscular blockade were 301 and 83 micrograms kg-1 h-1, respectively. An additional 15 patients received a combination of atracurium and vecuronium (cAV) in an equipotent dose ratio. An ED95 of a cAV was 94 +/- 7 micrograms.kg-1 of atracurium together with 21 +/- 2 micrograms.kg-1 of vecuronium, or 72 +/- 6% of one ED95 dose of a parent agent. Potentiation was significant (P = 0.0001). A maintenance requirement of a cAV was 120 micrograms kg-1 h-1 of atracurium together with 27 micrograms kg-1 h-1 of vecuronium. Thus, a significant potentiation was maintained also during the course of anaesthesia. A cAV had an effect like one intermediate-acting agent. If a cAV is used instead of using atracurium or vecuronium alone, the maximal reduction of drug consumption would be approximately 30%.