In Vitro Plasma Protein Binding of Neuromuscular Blocking Agents in Different Subpopulations of Patients

• Published in: Anesthesia and analgesia Vol. 81; no. 5; pp. 1019 - 1025
• Main Authors: Cameron, Maryse, Donati, Francois, Varin, France
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD International Anesthesia Research Society 01.11.1995; Lippincott
• Subjects: Adult; Age Factors; Aged; Anesthetics. Neuromuscular blocking agents; Atracurium - blood; Biological and medical sciences; Blood Proteins - metabolism; Body Weight; Cholesterol - blood; Female; Humans; Hyperlipidemias - blood; Isoquinolines - blood; Male; Medical sciences; Middle Aged; Mivacurium; Neuromuscular Nondepolarizing Agents - blood; Neuropharmacology; Pharmacology. Drug treatments; Protein Binding; Triglycerides - blood; Vecuronium Bromide - blood; Human; Obesity; Nutrition disorder; Metabolic diseases; Lipids; In vitro; Blood plasma; Proteins; Biological fixation; Non depolarisant myorelaxant; Interindividual comparison; Hyperlipemia; Pharmacokinetics; Age; Nutritional status
• ISSN: 0003-2999; 1526-7598
• DOI: 10.1097/00000539-199511000-00022

In vitro protein binding of several neuromuscular blocking agents (NMBAs) was measured by ultrafiltration in plasma from patients susceptible to demonstrate changes in their protein constituents.First, the relationship between the free fraction of atracurium and plasma lipoproteins levels in young volunteers (22-32 yr old, n = 6) and hyperlipidemic patients (44-68 yr old, n = 13) was studied, and second, the free fraction of atracurium, mivacurium, doxacurium, and vecuronium was determined in plasma of healthy young (27-47 yr old, n = 10), elderly (72-89 yr old, n = 11) and obese (21-57 yr old, n = 9, 200%-360% ideal body weight) patients scheduled for elective surgery. In hyperlipidemic patients, atracurium free fraction was significantly less than in young volunteers (40% +/- 5% vs 50% +/- 5%, mean +/- SD), and decreased as total cholesterol, low-density lipoprotein cholesterol and triglycerides increased (P < 0.05). In young individuals, NMBA free fraction was 25% +/- 5% for vecuronium, 58% +/- 8% for doxacurium, 52% +/- 6% for atracurium, and 72% +/- 3%, 70% +/- 3%, 70% +/- 4% for mivacurium trans-trans, cis-trans, and cis-cis isomers, respectively. Higher triglyceride concentrations in obese patients and lower high-density-lipoprotein cholesterol concentrations in both obese and elderly patients were observed when compared with young subjects. However, there was no significant difference in protein binding of NMBAs among these three groups. We conclude that, in otherwise healthy patients, age and weight are not likely to alter the free fraction of NMBAs.(Anesth Analg 1995;81:1019-25)