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Query: UMLS:C0030193 (pain)
 261,466 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

One hundred and sixty-four patients scheduled for elective termination of pregnancy under general anaesthesia were randomly assigned to receive one of three different supplements to propofol and oxygen in nitrous oxide anaesthesia: 0.1 mg fentanyl, 0.5 mg alfentanil or placebo. Postoperative pain and nausea, as well as complications during anaesthesia were studied. There were no differences in complications or complaints by surgeons during anaesthesia, and no patient in any group reacted unsatisfactorily to surgery. The patients in the placebo group consumed significantly more propofol during the procedure (P less than 0.001). No differences were seen in time until hospital discharge between the three groups. Complaints about postoperative pain were significantly less frequent among patients receiving fentanyl (P less than 0.01). The number of patients requesting postoperative analgetics, however, did not differ. There was no difference in the frequency of nausea or vomiting, but postoperative pain was found significantly to increase complaints of nausea (P less than 0.01) and also time until hospital discharge (P less than 0.01). In conclusion, opioid supplementation lowered the amount of propofol needed for anaesthesia. Alfentanil 0.5 mg did not improve the postoperative course. Fentanyl 0.1 mg decreased the frequency of postoperative pain without increasing the time to hospital discharge.
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PMID:Opioid supplementation to propofol anaesthesia for outpatient abortion: a comparison between alfentanil, fentanyl and placebo. 176 99

The pharmacokinetics, pharmacodynamics, and clinical uses of fentanyl, sufentanil, and alfentanil are reviewed. The fentanyl derivatives have reduced or eliminated many of the disadvantages of opioid anesthetics, such as incomplete amnesia and undesirable hemodynamic responses to surgery. Fentanyl is 50-100 times as potent as morphine and was the first of the three to be marketed. Sufentanil is even more potent than fentanyl. Alfentanil has the fastest onset of action, followed by sufentanil and then fentanyl. Alfentanil also has the shortest duration of action of the group. Most studies of these agents have been done to assess their role as anesthetics in cardiac surgery. All three provide cardiovascular stability when administered before noxious surgical stimuli, except when given as a single bolus during the induction of anesthesia. All seem to produce adequate anesthesia, particularly when used in combination with nitrous oxide. Because of its short duration of action, alfentanil is preferred for brief procedures or when rapid changes in the level of consciousness are desired. All three agents have also been used for analgesia; epidural administration provides adequate relief of pain. Fentanyl has been formulated as a transdermal patch that seems to provide the same degree of analgesia as a continuous i.v. infusion. Fentanyl has also been formulated as an investigational lozenge that has shown advantages as a preoperative sedative in children. As more is learned about these agents, their perioperative uses for anesthesia, analgesia, and sedation will continue to be refined.
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PMID:Clinical uses of fentanyl, sufentanil, and alfentanil. 183 93

Forty ASA I-III patients recovering from major abdominal or orthopedic operations were investigated in an open clinical study to evaluate analgesic efficacy and threshold plasma concentrations of alfentanil during the early postoperative period using patient-controlled analgesia (PCA) by means of the On-Demand Analgesia Computer. Alfentanil demand dose was 212 micrograms, continuous infusion rate 25 micrograms/hr, hourly maximum dose 1.5 mg/hr; the lockout time was set to 1 min. The duration of PCA was 18.1 +/- 5.2 hr (mean, SD) during which time 23.8 +/- 14.2 demands per patient were recorded, resulting in an average alfentanil consumption of 4.99 +/- 3.03 micrograms/kg/hr. Patient acceptance of PCA was high. Side effects were only of minor intensity and never gave rise to concern. Based on our own earlier PCA experience with other opiate analgesics, alfentanil proved to be about 1/15th as potent an analgesic as fentanyl and about 6-7 times more potent than morphine if both intensity and duration of effect were considered. Minimum effective alfentanil plasma concentration (MEC) varied greatly and could be best described by a lognormal distribution (range 0.6-99.2 ng/mL, median 14.9 ng/mL). Intraindividual MEC variability was consistently lower than intersubject variability (37.0% vs 65.2%).
J Pain Symptom Manage 1990 Aug
PMID:Postoperative patient-controlled analgesia with alfentanil: analgesic efficacy and minimum effective concentrations. 220 Aug 33

The effects of alfentanil on the midazolam dose-response curve for hypnosis was studied with response to the verbal command as an end point in 95 patients. The analgesic effect of alfentanil was studied by measuring the threshold for pain caused by pressure on the trapezius muscle with the use of a dolorimeter in 21 patients. The study was randomized, double-blind, and performed on the unpremedicated patients with ASA physical status I or II. Alfentanil was found to reduce the midazolam ED50 value for the induction of anesthesia in a dose-dependent fashion. The smallest dose of alfentanil (3 micrograms/kg) that caused a marked shift of the midazolam dose-response curve to the left along the dose axis (from the ED50 of 270 micrograms/kg to the ED50 of 142 micrograms/kg, P less than 0.0005) represents approximately 2% of the alfentanil ED50 for induction of unconsciousness (130 micrograms/kg). Alfentanil (10 micrograms/kg) caused only a tendency for increase in the pain threshold, whereas a dose of 15 micrograms/kg significantly increased the pain threshold by 37% (P less than 0.05). The results demonstrate that alfentanil potentiates the hypnotic effect of midazolam in very small doses. The high potency of alfentanil in this respect, as compared to its analgesic potency, suggests a very specific mechanism of alfentanil-midazolam hypnotic interaction, one that most likely is based on a functional relationship between the GABA receptor-benzodiazepine receptor system and the opioid receptor system in mediation of hypnosis.
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PMID:Alfentanil potentiates midazolam-induced unconsciousness in subanalgesic doses. 236 31

The influence of alfentanil on induction and recovery characteristics of propofol was examined in women presenting as day cases for minor gynaecological surgery. Alfentanil reduced the incidence of pain on injection and the induction and maintenance requirements of propofol. This was at the expense of more prolonged apnoea. Immediate recovery characteristics were similar in each group although changes in Critical Flicker Fusion Threshold as a measure of psychomotor impairment were more pronounced after alfentanil. Such differences were insignificant at three hours by which time Critical Flicker Fusion Threshold had returned to baseline and patients were ready for discharge home.
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PMID:Effects of alfentanil on induction and recovery from propofol anaesthesia in day surgery. 236 96

Morphinic drugs added to epidural local anesthetic during labour enhance analgesia and obstetrical conditions. Fentanyl, 1 microgram/kg-1, is safe for the newborn. Alfentanil is of faster and shorter duration and its pharmacokinetics suggests less accumulation than fentanyl. The aim of this study is to compare Alfentanil versus Fentanyl when added to an epidural continuous bupivacaine 0.125% infusion. Two groups of parturients are constituted: group A 10 micrograms/kg alfentanil, group F 1 microgram/kg fentanyl. Pain is assessed with a 0 to 10 points scale. There are no differences between the two groups for age, weight, parity, term, initial cervical dilatation and new born weight. Analgesia begins quickly in the two groups, and is more pronounced in the group A (than in the group F (p less than 0.005). Analgesia is maintained for the whole dilatation course. Pain scores increase during expulsion but are significantly lower than the initial scores. No difference is noted as regards analgesia supplementation. Obstetrical data: labour duration, oxytocin dosage, expulsion strength, instrumental extraction rate and uterin evacuation are similar in the 2 groups. No cesarean section is observed. Neonatal status, established according to Apgar scores and then Amiel Tison neurological scales (0 to 30) respectively at 30 to 120 minutes are in the same favorable ranges: Apgar score is in all cases more than 9. The neurological score is 24 (group A) and 22.9 (group F) at 30 minutes and increases significantly at 120 minutes in the 2 groups (27 in the two groups).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Addition of a morphinomimetic to the continuous perfusion of 0.125% bupivacaine for peridural obstetrical anesthesia. A comparative study of fentanyl and alfentanyl]. 256 2

A material of 36 patients to be submitted to direct laryngoscopy was subdivided at random in a double blind investigation to total intravenous anaesthesia with metohexitone or thiopentone. Alfentanil was employed as an analgesic and relaxation was obtained with vecuronium. The anaesthesia was maintained with continuous barbiturate infusion and supplementary alfentanil and vecuronium. The patients in the metohexitone group showed significantly faster recovery with an average of seven minutes as compared with 20 minutes in the thiopentone group and significantly more had Glasgow coma scores of over 12 after 30 minutes. After 60 and 90 minutes, no significant differences could be demonstrated between the groups. It is concluded that thiopentone is unsuitable for total intravenous anaesthesia for direct laryngoscopy whereas metohexitone was particularly suitable. Metohexitone is proposed as an alternative to the more recent and more expensive propofol. The frequency of pain on injection of metohexitone does not differ from that with propofol and this may be reduced by employing a vein in the cubital fossa instead of a vein on the dorsum of the hand.
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PMID:[Total intravenous anesthesia in direct laryngoscopy. A comparison of methohexital (Brietal) and thiopental]. 267 35

Amplitude changes of event-related sensory potentials (SEP's) present objective measurements for the evaluation of pain perception in man. Alfentanil, an opioid with dominant binding to the mu-receptor was given in graded doses (5-, 10- micrograms/kg) to volunteers. Nalbuphine, an opioid with reported kappa-agonist activity, was given in graded doses (100-, 500-, 1000- micrograms/kg) to another group i.v. Both groups were also exposed to progressively increased electrical stimulations (mA) in order to determine tolerance threshold before and after drug administration. In the alfentanil group (n = 5) there was a dose- related decrease of the amplitude of the early N20-peak. The late N100-peak was not, however, affected. This correlated closely (r = 0.87) with a naloxone-reversible increase of tolerance to electrical current. In the nalbuphine group (n = 15), there was a dose-related, naloxone non-reversible reduction of amplitude of the late N100-peak which showed a good correlation (r = 0.9) with an increase in current threshold. As the early evoked potentials are primarily generated in the pontine-thalamic region, it is suggested that the mode of action of alfentanil resembles that of a blockade of sensory impulses. The latter takes place before impulses are transmitted to more rostrally located CNS structures which are responsible for pain identification. The late evoked potential affected by nalbuphine indicates an activity on thalamo-cortical projection sites which are involved in subjects' cognitive activities. Kappa-ligands, therefore, seem to exert a different mode of action than mu-opioids, which results in a modulation of the negative emotional response associated with pain, rather than an attenuation of pain impulses.
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PMID:Opioids with different affinity for subreceptors induce different effects on early and late sensory evoked potentials (SEP) in man. 282 1

Opioids remain the drugs of choice for the treatment of severe pain. In recent years several new potent opioids have become available for clinical use. These newer drugs are generally safer than the older morphine-like compounds and their differing pharmacological and pharmacokinetic properties allow the physician to choose an appropriate drug according to the clinical situation and need of an individual patient. These drugs are classified according to their activity at the opioid receptors. The opioid agonists produce their pharmacological effect by an almost exclusive action at mu-receptors. The agonist-antagonist group are kappa-receptor agonists and either competitive antagonists at the mu-receptor or weak mu-agonists. The use of the potent opioid agonists, because of their potential for causing respiratory depression, is restricted to hospitals. Fentanyl, the oldest drug of this class, is extensively used as a supplement to general anaesthesia, or in high doses as a 'complete' anaesthetic for patients undergoing cardiac surgery. Alfentanil and sufentanil are newer fentanyl derivatives. Alfentanil is unique in having a very short elimination half-life. This is a particular advantage during short operations and for day-case surgery. For longer operations alfentanil can be given as a continuous infusion to supplement nitrous oxide anaesthesia. Sufentanil is about 10 times more potent than fentanyl and is more rapidly eliminated. Initial reports suggest that it may be more effective than fentanyl as an anaesthetic supplement and that recovery may be more rapid. Both sufentanil and alfentanil are also used in cardiac anaesthesia. The newer agonist-antagonist opioids, butorphanol, nalbuphine and buprenorphine, have largely replaced pentazocine in clinical practice. Unlike pentazocine, they cause a low incidence of dysphoric side effects. Like the pure agonists, they cause respiratory depression; however, in contrast to the pure agonists this is not dose related, reaching a 'ceiling' as dose increases. The risk of dependence is also less, so that these drugs are safer for the treatment of chronic pain. Additionally, it is particularly worth noting that buprenorphine and nalbuphine cause minimal cardiovascular changes, and are safe and effective drugs for treatment of pain associated with myocardial infarction. Buprenorphine, which is effective parenterally, orally and sublingually, has a prolonged duration of action (up to 12 hours after a single dose).
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PMID:Which potent opioid? Important criteria for selection. 295 11

Alfentanil, a rapidly acting opioid, was given in subanesthetic doses to 10 subjects in a laboratory setting. Analgesia was assessed from the subjects' responses to painful dental stimulation. A subjective pain report (PR) and brain evoked potential (EP) amplitude were obtained repeatedly before and after injection on each of 4 testing days, on which the following intravenous doses were administered: 0 (saline solution), 5, 10, and 15 micrograms/kg. Significant dose effects were observed for EP amplitude during but not beyond the distributional t1/2 of the drug, but significant effects on the PR extended beyond this time point. Mean volume of distribution, total body clearance, and distribution t1/2 did not differ significantly across the doses of alfentanil. Strong correlations between each effect measure and plasma drug concentration were observed at all doses and were significant at P less than 0.01. The EP scores tracked the distribution of alfentanil very closely, but the correlation between EP amplitude and plasma alfentanil concentration was lower during the elimination phase. In contrast, the PR effects closely tracked the elimination of alfentanil but not its distribution. These findings suggest that EP amplitude and the PR represent two different central effects in opioid analgesia.
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PMID:Dose effects of alfentanil in human analgesia. 308 70


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