Measured Context-Sensitive Half-Times of Remifentanil and Alfentanil

Kapila, Atul; Glass, Psa; Jacobs, Joachim; Muir, Keith T.; Hermann, David; Shiraishi, Masayuki; Howell, Scott; Smith, R. L.

doi:10.1097/00132586-199610000-00053

Cited by 46 publications

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“…EEG measurements have yielded a context-sensitive half-life of 3-5 min (estimated at 3.7 min from the population model, for volunteers in this study) (Minto et al, 1997b), in agreement with our fMRI estimate from the insular cortex t 1/2W ¼ 3.07 min (1.09, 5.05 min: 95% confidence intervals), and from reported pain intensity t 1/2W ¼ 2.80 min (1.12, 4.48 min: 95% confidence intervals). Half-life measurements based on concentration data give 3.270.9 min (Kapila et al, 1995) and based on a pharmacodynamic measure of ventilation give 5.471.8 min (Kapila et al, 1995).…”

Section: Discussionmentioning

confidence: 99%

Using fMRI to Quantify the Time Dependence of Remifentanil Analgesia in the Human Brain

Wise

Williams

Tracey

2003

Neuropsychopharmacol

108

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To understand and exploit centrally acting drugs requires reliable measures of their time course of action in the human brain. Functional magnetic resonance imaging (fMRI) is able to measure noninvasively, drug-induced changes in task-related brain activity. Here, we have characterized, in a specific region of the brain, the time of onset of action and the half-life of action of a clinically relevant dose of a potent opioid analgesic agent, remifentanil. These times were established from the temporal variation of the amplitude of the blood oxygen level-dependent response in the insular cortex contralateral to a painfully hot thermal stimulus, in volunteers receiving a remifentanil infusion. The insular cortex has repeatedly been reported as activated by noxious thermal stimulation. The times of onset and offset of drug action were each characterized by a half-life for changes in fMRI signal from within the insula. These characteristic times agreed with the observed drug-induced analgesia and previous pharmacokinetic-pharmacodynamic measurements for remifentanil. We have successfully measured, for the first time using fMRI, temporal pharmacological parameters for a CNS-active drug based on its effect on task-related activity in a specific brain region. Comparison of the time course of regional brain activity with pain perception could reveal those regions engaged in drug-induced analgesia.

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Section: Discussionmentioning

confidence: 99%

Using fMRI to Quantify the Time Dependence of Remifentanil Analgesia in the Human Brain

Wise

Williams

Tracey

2003

Neuropsychopharmacol

108

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“…6,7 Fentanyl is also a short-acting synthetic opioid with a rapid onset of action (blood-effect site equilibration 6.4 min), but it exhibits cumulative effect with repeated or prolonged administration due to reuptake from inactive tissue sites, which leads to an increase in its context-sensitive halftime. 5,8 The elimination half-life in neonates varies from 75 to 440 min. 9 A randomized controlled trial by Douma et al has compared IVPCA with remifentanil, fentanyl, and meperidine for labour analgesia.…”

Section: Résumémentioning

confidence: 99%

Remifentanil versus fentanyl for intravenous patient-controlled labour analgesia: an observational study

Marwah

Hassan

Carvalho

et al. 2011

Can J Anesth/J Can Anesth

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Purpose We undertook a retrospective study to compare the analgesic efficacy and effects on neonatal outcome of administering either remifentanil or fentanyl intravenous patient-controlled analgesia (IVPCA) during labour. Methods A five-year retrospective cohort study was undertaken of women with more than 24 weeks of gestation who had received either IVPCA remifentanil or fentanyl for labour analgesia at Mount Sinai Hospital. The sampling timeframe was from November 2005 to March 2010. The standard IVPCA regimen for the remifentanil group consisted of a PCA bolus 0.25 lgÁkg -1 with a lockout interval of two minutes, a four-hour limit of 3 mg, and a background infusion of 0.025-0.05 lgÁkg -1 Ámin -1 , whereas the standard IVPCA regimen for the fentanyl group consisted of a PCA bolus 25-50 lg with a lockout interval of three to six minutes and a four-hour limit of 1-1.5 mg. The following data were compared: maternal hourly pain scores (verbal pain score scale 0-10), sedation scores (scale 0-3), adverse effects, and neonatal outcomes. Mixed linear modelling was used to analyze longitudinal data on pain scores over time. The exact Wilcoxon test and the Fisher's exact test were used for other comparisons.Results Ninety-eight women were studied. There was no significant difference in the model-adjusted pain scores between the two groups (P = 0.86). There was a moderate decrease in pain scores in both groups compared with the baseline values. There was no difference in maternal side effects between the two groups, although transient oxygen desaturation was observed more frequently in the remifentanil group than in the fentanyl group (13% vs 2%, respectively; odds ratio, 7.32; 95% confidence interval [CI], 0.85 to 63.3). A larger number of neonates in the fentanyl group required resuscitation compared with neonates in the remifentanil group (59% vs 25%, respectively; odds ratio, 4.33; 95% CI, 1.75 to 10.76); adjusted (44% vs 8%, respectively; odds ratio, 8.56; 95% CI, 2.17 to 33

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“…5 However, compared with remifentanil, the context-sensitive half-times of alfentanil do not always allow prolonged infusion or repeated administration of this opioid due to the potential for alfentanil drug cumulation over time. 6,16 Remifentanil is an ultra-short-acting opioid with a context-sensitive half-time that is independent of the duration of drug administration. 6 Therefore, remifentanil has a pharmacokinetic profile wellsuited for rapid recovery, even for more prolonged outpatient procedures requiring moderate or high levels of intraoperative analgesia.…”

Section: Discussionmentioning

confidence: 99%

“…6,16 Remifentanil is an ultra-short-acting opioid with a context-sensitive half-time that is independent of the duration of drug administration. 6 Therefore, remifentanil has a pharmacokinetic profile wellsuited for rapid recovery, even for more prolonged outpatient procedures requiring moderate or high levels of intraoperative analgesia. Its addition to propofol, remifentanil significantly improved LMA insertion conditions during induction of anesthesia.…”

Section: Discussionmentioning

confidence: 99%

“…Due to its pharmacokinetic properties, the use of remifentanil is of particular interest whenever maintenance of sufficient analgesia level is required during the procedure. 6 Its combination with propofol significantly improved the ease of insertion of the LMA in comparison with propofol alone. 7,8 The optimum effect-site concentration (EC) of remifentanil for LMA insertion during target-controlled infusion of propofol was recently determined through use of a modified Dixon's up-and-down method followed by a probit analysis for the EC 95 estimation.…”

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confidence: 99%

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Dose optimale de rémifentanil pour l’insertion d’un masque laryngé lors de la co-administration d’une dose standard unique de propofol

Bouvet

Da-Col

Rimmelé

et al. 2010

Can J Anesth/J Can Anesth

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Purpose This dose-response study aimed to determine the optimal dose of remifentanil combined with propofol 2.5 mgÁkg -1 iv in order to achieve excellent conditions for laryngeal mask airway (LMA TM ) insertion in 95% of adult female patients. Methods Sixty-eight adult premedicated female patients, American Society of Anesthesiologists (ASA) physical status I and II requiring anesthesia for ambulatory surgery, were randomly allocated to one of four remifentanil dose groups (0.25, 0.5, 1, or 2 lgÁkg -1 ). Induction of anesthesia was achieved with one of the four blinded doses of remifentanil infused over 60 sec and simultaneously co-administered with propofol 2.5 mgÁkg -1 iv infused over 45 sec. Insertion of the LMA was attempted 150 sec after the beginning of the induction sequence. Insertion conditions were assessed using a six-category score according to resistance to mouth opening and insertion, swallowing, coughing and gagging, movement, and laryngospasm. A probit analysis was performed to calculate the effective dose for insertion of the LMA in 95% of patients (efficient dose [ED] 95 ). The changes in heart rate (HR) and mean arterial blood pressure (MAP) in response to LMA insertion were recorded and compared as secondary outcome variables. Results The ED 95 of remifentanil was 1.32 (95% confidence interval [CI] 0.99-2.46) lgÁkg -1 . Changes in heart rate and mean arterial pressure were modest and similar over time across groups, with maximum decreases in heart rate and mean arterial pressure \ 30% each during induction of anesthesia. Conclusions The required dose of remifentanil is 1.32 (95% CI 0.99-2.46) lgÁkg -1 to achieve excellent LMA insertion conditions in 95% of patients when co-administered with propofol 2.5 mgÁkg -1 in healthy premedicated female patients undergoing elective ambulatory surgery. RésuméObjectif L'objectif de cette e´tude de dose-re´ponse e´tait de de´terminer la dose optimale de re´mifentanil lors de l'administration conjointe de propofol 2,5 mgÁkg -1 iv afin d'obtenir des conditions excellentes pour l'insertion d'un masque larynge´(LMAÒ) chez 95 % de patientes adultes. Méthode Soixante-huit patientes adultes ASA I et II pre´me´dique´es et ne´cessitant une anesthe´sie pour une chirurgie ambulatoire ont e´te´randomise´es en quatre groupes selon la dose de re´mifentanil (0,25, 0,5, 1 ou 2 lgÁkg -1 ). L'induction de l'anesthe´sie a e´te´re´alise´e avec l'une des quatre doses de re´mifentanil en aveugle perfuse´e sur 60 secondes, administre´e simultane´ment a`du propofol 2,5 mgÁkg -1 iv perfuse´sur 45 secondes. L'insertion du Support was provided solely by institutional sources.

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Measured Context-Sensitive Half-Times of Remifentanil and Alfentanil

Cited by 46 publications

References 0 publications

Using fMRI to Quantify the Time Dependence of Remifentanil Analgesia in the Human Brain

Using fMRI to Quantify the Time Dependence of Remifentanil Analgesia in the Human Brain

Remifentanil versus fentanyl for intravenous patient-controlled labour analgesia: an observational study

Dose optimale de rémifentanil pour l’insertion d’un masque laryngé lors de la co-administration d’une dose standard unique de propofol

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