The interaction between succinylcholine (SCC) and non-depolarizers, atracurium or vecuronium was investigated in 36 cats of either sex using the sciatic nerve-anterior tibialis muscle preparation. Additionally, the relation of SCC to pseudocholinesterase activity was examined. The duration of action of vecuronium (6.5 +/- 1.3 to 7.3 +/- 2.2 minutes) in cats pretreated with SCC was greater than those (2.0 +/- 0.6 minutes) in non-pretreated cats. However, SCC had no influence on the duration of atracurium. The serum pseudocholinesterase activity was decreased after the injection of atracurium or neostigmine in contrast to vecuronium. The authors conclude that the prior administration of SCC prolongs the duration of vecuronium but not that of atracurium, and pseudocholinesterase activity is not related to the prolonging effect of SCC.
Animal ; Atracurium/*pharmacology ; Cats ; Female ; Male ; Succinylcholine/*pharmacology ; Vecuronium Bromide/*pharmacology

OBJECTIVETo study the pharmacodynamics of vecuronium,atracurium, mivacurium and rocuronium in patients with end-stage renal failure.

METHODSForty-six patients with end-stage renal failure scheduled for renal transplantation and 53 patients with normal renal function were given either vecuronium, atracurium, mivacurium or rocuronium. The neuromuscular effects were monitored by the evoked response of the adductor pollicis to train-of-four stimulation of the ulnar nerve.

RESULTSOnset of vecuronium, atracurium and mivacurium occurred faster or tended to be faster in patients with end-stage renal failure, but there was no significant difference in onset by rocuronium between the control patients and renal failure patients. Furthermore, the no-response period, duration of action and recovery of atracurium did not differ between the two groups. There was no significant difference in duration of action or recovery of mivacurium between the two groups, whereas its no-response period was significantly prolonged in the patients with end-stage renal failure. There was no difference in no-response period or duration of action after the initial dose of vecuronium or rocuronium between the two groups. However, no-response period and duration of effect by vecuronium and rocuronium were prolonged with increasing incremental doses in patients with end-stage renal failure.

CONCLUSIONSAll four muscle relaxants could be safely used in patients with end-stage renal failure. Onset of the relaxants were, in some cases, accelerated and no-response period of mivacurium was prolonged in patients with end-stage renal failure undergoing dialysis therapy. End-stage renal failure prolonged the no-response period and duration of action of vecuronium and rocuronium after repeated incremental doses, but did not alter those attributed to atracurium.

Adult ; Androstanols ; pharmacology ; Anesthesia, General ; Atracurium ; pharmacology ; Female ; Humans ; Isoquinolines ; pharmacology ; Kidney Transplantation ; Male ; Middle Aged ; Neuromuscular Blocking Agents ; pharmacology ; Succinylcholine ; pharmacology ; Time Factors ; Vecuronium Bromide ; pharmacology

OBJECTIVETo determine the effect of neostigmine on antagonizing atracurium-induced neuromuscular blockage with sulfate magnesium pretreatment.

METHODSForty patients who undertook elective gynecologic laparoscopic examinations and treatments under general anesthesia were randomized into four groups (group A, B, C, and D, group A paired with group C, and group B paired with group D). Before induction of general anesthesia, patients in group A and group C received MgSO4 30 mg/kg in saline intravenously within 5 min, while patients in group B and group D received the same volume of saline. Anesthesia was induced with fentanyl and propofol; subsequently tracheal intubation was performed with 0.5 mg/kg atracurium after stabilization of the electromyography recording, and neostigmine (0.02 mg/kg) and atropine (0.01 mg/kg) were infused in group C and group D when neuromuscular recovery (T1/T(C)) reached 10%. T1/T(C) changes after neostigmine infusion as well as haemodynamic changes and other responses during induction and neostigmine and atropine infusion were recorded.

RESULTSThe neuromuscular recovery speed had no significant difference between group A and group B after the neuromuscular recovery reached 10%, but it was lower in group C than in group D (P < 0.05). Significant difference existed between group AC and group BD (P < 0.05). No haemodynamic changes and other responses were found during induction and neostigmine and atropine infusion.

CONCLUSIONNeostigmine-induced neuromuscular recovery can be attenuated in patients pretreated with magnesium sulfate.

Adolescent ; Adult ; Anesthesia, General ; Atracurium ; antagonists & inhibitors ; Cholinesterase Inhibitors ; pharmacology ; Female ; Humans ; Laparoscopy ; Magnesium Sulfate ; pharmacology ; Middle Aged ; Neostigmine ; pharmacology ; Neuromuscular Blockade ; Neuromuscular Nondepolarizing Agents ; antagonists & inhibitors

OBJECTIVETo determine the effects of atracurium pretreatment with magnesium on speed of onset, duration, and recovery of neuromuscular block.

METHODSThirty patients who were undergoing elective gynecologic laparoscopic examination and treatments under general anesthesia were randomized into magnesium group (n = 15) and control group (n = 15). Before induction of general anesthesia, patients in magnesium group intravenously received MgSO4 30 mg/kg in saline within 5 minutes, and patients in control group received the same volume of saline without MgSO4. In both groups, the train-of-four (TOF) responses to stimuli of the ulnar nerve were measured at intervals of 12 seconds. Anesthesia was induced with Fentanyl and Propofol through target controlled infusion (TCI), and tracheal intubation was performed with 0.5 mg/kg atracurium after stabilization of the electromyography recording. The onset time of muscle relaxation, clinical duration of action, recovery index, and recovery time were recorded. To determine serum magnesium and calcium levels, blood samples were collected before MgSO4/saline infusion and at the end of operation. Haemodynamic changes and other responses during induction were also recorded.

RESULTSThe onset time from the end of injection to maximum neuromuscular blockade was significantly shorter in magnesium group than in control group (P < 0.01). Duration of relaxant action, recovery index, and recovery time in magnesium group were significantly prolonged than in control group (P < 0.01). Serum magnesium level significantly decreased after management (P < 0.01), and there was also a decrease trend in magnesium group. No change of serum calcium levels in both groups was observed. No adverse event was reported.

CONCLUSIONPrior administration of magnesium sulphate can increase the onset speed of atracurium and prolong the duration of atracurium-induced neuromuscular blockade.

Adolescent ; Adult ; Anesthesia Recovery Period ; Anesthesia, General ; Atracurium ; pharmacology ; Drug Synergism ; Female ; Humans ; Magnesium Sulfate ; pharmacology ; Middle Aged ; Neuromuscular Blockade ; Neuromuscular Junction ; drug effects ; Neuromuscular Nondepolarizing Agents ; pharmacology ; Time Factors ; Young Adult

OBJECTIVETo evaluate the impact of gender differences on the dose-effect relationship of cisatracurium.

METHODSEighty ASA class I or II patients (40 male and 40 female patients) undergoing elective abdominal surgeries received a single-dose intravenous injection of midazolam and fentanyl. The male and female patients were subdivided into 4 equal groups to receive a intravenous bolus of 20, 30, 40, or 50 µg/kg of cisatracurium. The neuromuscular block was measured using a neuromuscular transmission monitor, and the responses were defined in terms of the percentages of maximum suppression in T1 of TOF of the adductor pollicis muscle. According to log-probit transformation of the data of the dose and response, the dose-response curve of cisatracurium was established through linear regression. The onset time of vecuronium was also observed.

RESULTSThe ED95 value of cisatracurium in male patients was 67.4±4.4 µg/kg, significantly higher than that in female patients (48.7±1.0 µg/kg, P<0.05). No significant variation in the onset time was found in the 4 dose groups of either male or female patients (P>0.05).

CONCLUSIONFemale patients are more sensitive to cisatracurium than male patients.

Abdomen ; surgery ; Adolescent ; Adult ; Anesthesia, General ; Atracurium ; administration & dosage ; analogs & derivatives ; pharmacology ; Dose-Response Relationship, Drug ; Elective Surgical Procedures ; Female ; Humans ; Male ; Neuromuscular Blockade ; methods ; Neuromuscular Blocking Agents ; administration & dosage ; pharmacology ; Pharmacological Phenomena ; physiology ; Sex Factors ; Young Adult

OBJECTIVETo compare the effects of sevoflurane and propofol-remifentanil anesthesia on neuromuscular blockade produced by continuous cisatracurium infusion.

METHODSForty ASA I or II patients undergoing selective surgery were randomly divided into sevoflurane and propofol-remifentanil anesthesia groups (n=20). Neuromuscular blockade was monitored using train-of-four (TOF) stimulation by recording the contraction force of the adductor pollicis muscle with a muscle relaxation monitor. A bolus dose of cisatracurium of 0.15 mg/kg was administered to facilitate endotracheal intubation, followed by continuous infusion adjusted manually to maintain the first twitch (T1) < or = 5% of the control level. The following variables were recorded including the infusion rate, total amount of cisatracurium, spontaneous recovery index (RI), and the time interval from termination of infusion cisatracurium to recovery of TOF ratio (TOFR) to 0.9.

RESULTSWith the maintenance of a 95%-99% neuromuscular blockade, the infusion rate was significantly lower in sevoflurane group than in propofol-remifentanil group (P<0.05), and stabilized in both groups after 120 min. No significant differences were found in RI or the time to TOFR of 0.9 between the two groups (P>0.05).

CONCLUSIONDuring the maintenance of stable neuromuscular blockade by continuous cisatracurium infusion, both sevoflurane and propofol-remifentanil anesthesia can time-dependently enhance the effect of cisatracurium without producing significant differences in the recovery properties.

Adolescent ; Adult ; Aged ; Anesthetics, General ; administration & dosage ; pharmacology ; Anesthetics, Intravenous ; Atracurium ; administration & dosage ; analogs & derivatives ; pharmacology ; Drug Synergism ; Elective Surgical Procedures ; Female ; Humans ; Infusions, Intravenous ; Male ; Methyl Ethers ; administration & dosage ; pharmacology ; Middle Aged ; Neuromuscular Blocking Agents ; administration & dosage ; pharmacology ; Piperidines ; administration & dosage ; pharmacology ; Propofol ; administration & dosage ; pharmacology ; Young Adult