Lowell Reynolds

Efficacy and Safety of Single and Repeated Administration of 1 Gram Intravenous Acetaminophen Injection (Paracetamol) for Pain Management after Major Orthopedic Surgery

Background: Intravenous acetaminophen injection (paracetamol) is marketed in Europe for the management of acute pain. A repeated-dose, randomized, double-blind, placebo-controlled, three-parallel group study was performed to evaluate the analgesic efficacy and safety of intravenous acetaminophen as compared with its prodrug (propacetamol) and placebo. Propacetamol has been available in many European countries for more than 20 yr. Methods: After orthopedic surgery, patients reporting moderate to severe pain received either 1 g intravenous acetaminophen, 2 g propacetamol, or placebo at 6-h intervals over 24 h. Patients were allowed “rescue” intravenous patient-controlled analgesia morphine. Pain intensity, pain relief, and morphine use were measured at selected intervals. Safety was monitored through adverse event reporting, clinical examination, and laboratory testing. Results: One hundred fifty-one patients (intravenous acetaminophen: 49; propacetamol: 50; placebo: 52) received at least one dose of study medication. The intravenous acetaminophen and propacetamol groups differed significantly from the placebo group regarding pain relief from 15 min to 6 h (P < 0.05) and median time to morphine rescue (intravenous acetaminophen: 3 h; propacetamol: 2.6 h; placebo: 0.8 h). Intravenous acetaminophen and propacetamol significantly reduced morphine consumption over the 24-h period: The total morphine doses received over 24 h were 38.3 ± 35.1 mg for intravenous acetaminophen, 40.8 ± 30.2 mg for propacetamol, and 57. 4 ± 52.3 mg for placebo, corresponding to decreases of −33% (19 mg) and −29% (17 mg) for intravenous acetaminophen and propacetamol, respectively. Drug-related adverse events were reported in 8.2%, 50% (most of them local), and 17.3% of patients treated with intravenous acetaminophen, propacetamol, and placebo, respectively. Conclusion: Intravenous acetaminophen, 1 g, administered over a 24-h period in patients with moderate to severe pain after orthopedic surgery provided rapid and effective analgesia and was well tolerated.

An iontophoretic fentanyl patient-activated analgesic delivery system for postoperative pain: a double-blind, placebo-controlled trial.

An iontophoretic fentanyl HCl patient-activated transdermal system (fentanyl HCl PATS) is under development for the treatment of acute postoperative pain. The fentanyl HCl PATS is a needle-free, credit card-sized, preprogrammed system that is applied to the patients upper outer arm or chest. The fentanyl HCl PATS was demonstrated to be superior to placebo in a previous trial; however, the randomization scheme used and the lack of control of entry pain level may have contributed to the lack of robust findings. We compared the fentanyl HCl PATS with placebo for acute postoperative pain management in a larger trial that addressed the limitations of the previous study. Adult patients admitted to the postanesthesia care unit after major surgery were titrated to comfort with opioids and randomized 1:1 to receive the fentanyl HCl PATS 40 &mgr;g or placebo for 24 hours. Supplemental IV fentanyl was available to patients upon request in both treatment groups for the first 3 hours after enrollment. The primary efficacy end-point was the percentage of patients who discontinued participation in the study because of inadequate analgesia. Pain intensity scores, patient global assessments (PGA), and investigator global assessments (IGA) were collected. Four-hundred-eighty-four patients (PATS, n = 244; placebo, n = 240) were enrolled. Fewer patients receiving the fentanyl HCl PATS discontinued because of inadequate analgesia compared with placebo (28.7% versus 60.0%; P < 0.0001). Mean last pain intensity scores were 3.5 and 5.4 for the fentanyl HCl PATS and placebo groups, respectively. Patients (73.4%, PGA) and investigators (72.1%, IGA) considered the fentanyl HCl PATS a good or excellent method of pain control. Treatment-related adverse events were similar between groups. This study demonstrated the superiority of the iontophoretic fentanyl HCl PATS over placebo for acute postoperative pain management.

Focal cerebral ischemia during anesthesia with etomidate, isoflurane, or thiopental : a comparison of the extent of cerebral injury

An investigation was performed to compare the cerebral protective properties of etomidate, isoflurane, and thiopental. In separate groups of spontaneously hypertensive rats, etomidate, isoflurane, or thiopental was administered to achieve and maintain burst-suppression of the electroencephalogram (3-5 bursts/min) for the duration of the experiment. A fourth group received 1.2 minimal alveolar concentration halothane. All groups underwent 3 hours of middle cerebral artery occlusion and then 2 hours of reperfusion. Thereafter, the animals were killed and the volume of injured brain was determined by staining with 2,3,5-triphenyltetrazolium. Physiological parameters did not differ among the four groups during the investigation, with the exception that hemolysis occurred in the etomidate group (free hemoglobin levels, approximately 0.4 g.dl-1). The volume of injured brain in the thiopental group (56 +/- 10 mm3) was significantly smaller than that in the halothane control group (99 +/- 13 mm3). The volumes of injured brain in the etomidate and isoflurane groups (145 +/- 11 mm3 and 139 +/- 14 mm3, respectively) were significantly larger than those in the control and thiopental groups. We speculate that the apparently detrimental effect of etomidate may be the result of the binding of nitric oxide of cerebral endothelial origin by the iron component of free hemoglobin. Intracranial pressure was not recorded, and in the isoflurane group, there may have been adverse effects on cerebral perfusion pressure associated with vasodilation caused by high concentrations of isoflurane. The results are consistent with a protective effect by barbiturates.

Focal cerebral ischemia in rats. Effect of hypervolemic hemodilution with diaspirin cross-linked hemoglobin versus albumin on brain injury and edema.

Background:Hemodilution has had limited success as a treatment of cerebral ischemia. When using a non-oxygen-binding fluid, the therapeutic efficacy of hemodilution-induced Increases in blood flow are offset by concomitant decreases in oxygen content. Methods:The effect of hemodilution, with diaspirin cross-linked hemoglobin (DCLHb), on brain injury and edema was assessed during middle cerebral artery occlusion (180 min) and reperfusion (120 min) in rats (blood volume increased by “30% and n = 10 for each group): (1) 44/B: 8.0 ml of donor blood was given; (2) 30/albumln: hematocrit was decreased to 30% with 10% albumin; (3) 30/DCLHb: hematocrit was decreased to 30% with 10% DCLHb; or (4) 9/DCLHb: hematocrit was decreased to 9% with DCLHb. infarct size was analyzed with 2,3,5-triphenyltetrazollum chloride, and edema by microgravimetry. Results:Brain injury (percent of the hemispheric area ipsi-lateral to ischemia, mean ± SD) was greater in the 44/B group (44 ± 4) versus the 30/albumin group (37 ± 3). in addition, brain injury was greater in the 44/B and 30/albumin groups versus the 30/DCLHb group (27 ± 4); which was in turn greater than the 9/DLCHb group (18 ± 3). Specific gravity was greater (less brain water) in all hemodiluted groups versus the 44/B group. Conclusions:These results support a hypothesis that hemodilution decreases focal cerebral ischemic injury, and when an oxygen-binding fluid is used, there is a dose-dependent effect of hemodilution on ischemia. in addition, these results suggest that hemodilution, as achieved with DCLHb, was more effective in reducing ischemic brain damage than was the same degree of hemodilution as achieved with albumin.

The COX-2 Specific Inhibitor, Valdecoxib, Is An Effective, Opioid-Sparing Analgesic in Patients Undergoing Total Knee Arthroplasty

This multicenter, randomized, double-blind, placebo-controlled study evaluated the analgesic efficacy and opioid-sparing effects of valdecoxib, a potent COX-2 specific inhibitor, in patients undergoing knee replacement. Patients received morphine by patient-controlled analgesia (PCA), and valdecoxib 40 mg or 80 mg daily, or placebo, for up to two days. Efficacy was assessed by the cumulative amount of morphine administered over 48 hours, pain intensity and patients evaluation of medication. Morphine consumption over 48 hours by patients receiving valdecoxib 40 mg or 80 mg daily plus morphine was 83.7% and 75.8% (P < 0.05) of the total amount consumed by patients receiving morphine alone. Patients receiving valdecoxib 40 mg and 80 mg daily experienced significantly lower maximum pain intensity on Day 2 (P < 0.05), and rated their study medication significantly higher than patients receiving morphine alone. Valdecoxib plus morphine was well tolerated. Thus, valdecoxib in combination with morphine provides multi-modal analgesia that reduces pain and opioid use and increases patient satisfaction following knee replacement surgery.

Intravenous acetaminophen for pain after major orthopedic surgery: an expanded analysis.

Background and Methods:  From the time that Sinatra et al. (Anesthesiology. 2005;102:822) was published to FDA apaproval of intravenous (IV) acetaminophen, an expanded analysis of the original raw study data became necessary for the regulatory submission. The following analyses were conducted: (1) sum of pain intensity differences over 24 hours (SPID24) using currently accepted imputation methods to account for both missing data and the effects of rescue; (2) efficacy results after the first 6 hours; (3) effects of gender, race/ethnicity, age, weight, surgical site, ASA Class, and serotonin antagonists; and (4) a stepwise regression analysis of why adverse events of nausea and vomiting were numerically (although not statistically) higher in the IV acetaminophen group compared with placebo.

Efficacy and safety of fentanyl sublingual spray for the treatment of breakthrough cancer pain: a randomized, double-blind, placebo-controlled study

Abstract Background and objectives: A number of transmucosal fentanyl formulations have been developed for the management of breakthrough cancer pain (BTCP). Sublingual delivery of fentanyl, formulated as fentanyl sublingual spray, offers the potential for more rapid and greater absorption of fentanyl and associated onset of analgesic effect compared with other formulations. The objective of this study was to assess the efficacy and safety of fentanyl sublingual spray for the treatment of BTCP. Research design and methods: This was a randomized, double-blind, placebo-controlled phase III trial conducted in opioid-tolerant patients with BTCP. An open-label titration period was followed by a double-blind treatment period during which patients received fentanyl sublingual spray (100–1600 mcg) or placebo. Clinical trial registration: Trial registration: ClinicalTrials.gov identifier: NCT00538850. Main outcome measures: The primary efficacy measure was summed pain intensity difference at 30 minutes (SPID30). Secondary efficacy measures included total pain relief at 30 minutes (TOTPAR30) and patient global evaluation of study medication at 30 minutes. Efficacy measures were also assessed at various time points from 5–60 minutes postdose. Adverse events were monitored throughout the study. Results: A total of 130 patients were treated during the titration period, of whom 98 (75.4%) entered the double-blind period. Relative to placebo, fentanyl sublingual spray significantly improved mean SPID scores from 5 minutes (p = 0.0219) through 60 minutes (p < 0.0001), including the primary endpoint at 30 minutes (p < 0.0001). Fentanyl sublingual spray produced significantly greater pain relief (expressed in terms of TOTPAR) from 5 through 60 minutes (p < 0.0001), and significantly greater global evaluation of treatment effectiveness (p < 0.0001), compared with placebo. During double-blind treatment, the most frequently reported adverse events were nausea (7.1%), hyperhidrosis (5.1%), and peripheral edema (5.1%). Serious adverse events occurred in seven patients (5.4%) during titration and six (6.1%) during double-blind treatment; none were considered related to treatment. Conclusions: These findings indicate that treatment with fentanyl sublingual spray results in effective relief of BTCP, with a rapid onset of action, and is well tolerated.

relative analgesic potency of fentanyl and sufentanil during intermediate-term infusions in patients after long-term opioid treatment for chronic pain

&NA; Sufentanil, a potent mu‐opioid agonist, historically has not been been given systemically to treat chronic pain. An implantable, fixed‐rate osmotic pump that delivers sufentanil subcutaneously is being developed for this purpose. In that transdermal fentanyl may be a useful intermediary to estimate the appropriate sufentanil dose before implant, accurate information is needed about the relative analgesic potency of sufentanil and fentanyl during continuous infusion. To determine this relative potency, we administered these drugs to opioid‐treated chronic pain patients using a target‐controlled infusion (TCI). Sixty‐three patients with stable chronic pain and daily oral opioid requirements equivalent to 100–1000 mg of morphine received TCI of fentanyl and sufentanil, each for a minimum of 16 h. Drug administration was double‐blind and the order of administration was randomly assigned. Target concentration was changed until the patient reported that analgesia was adequate (defined as a pain level equal to or better than baseline). Seven patients did not complete the infusion and protocol violations invalidated data for 15 patients. For the remaining 41 patients, target concentrations associated with adequate analgesia were achieved for both sufentanil and fentanyl. The median value for the equianalgesic concentration ratio (steady‐state fentanyl infusion to steady‐state sufentanil infusion) was 7.5; mean potency ratio was 7.44 (95% confidence interval 6.8–8.2). During titrated, intermediate‐term infusions in patients previously treated with opioids for chronic pain, sufentanil is approximately 7.5 times as potent as fentanyl.

Experimental Subarachnoid Hemorrhage in Rats Effect of Intravenous α-α Diaspirin Crosslinked Hemoglobin on Hypoperfusion and Neuronal Death

Background: Hemodilution with diaspirin crosslinked hemoglobin (DCLHb) ameliorates occlusive cerebral ischemia. However, subarachnoid hemoglobin has been implicated as a cause of cerebral hypoperfusion. The effect of intravenous DCLHb on cerebral perfusion and neuronal death after experimental subarachnoid hemorrhage was evaluated. Methods: Rats (n = 48) were anesthetized with isoflurane and subarachnoid hemorrhage was induced by injecting 0.3 ml of autologous blood into the cistema magna. Each animal received one of the following regimens: Control, no hematocrit manipulation; DCLHb, hematocrit concentration decreased to 30% with DCLHb; or Alb, hematocrit concentration decreased to 30% with human serum albumin. The experiments had two parts, A and B. In part A, after 20 min, cerebral blood flow (CBF) was assessed with14 C‐iodoantipyrine autoradiography. In part B, after 96 h, in separate animals, the number of dead neurons was determined in predetermined coronal sections by hematoxylin and eosin staining. Results: Cerebral blood flow was greater for the DCLHb group than for the control group; and CBF was greater for the Alb group than the other two groups (P < 0.05). In one section, CBF was 45.5 +/‐ 10.9 ml [center dot] 100 g sup ‐1 [center dot] min sup ‐1 (mean +/‐ SD) for the control group, 95.3 +/‐ 16.6 ml [center dot] 100 g sup ‐1 [center dot] min sup ‐1 for the DCLHb group, and 138.1 +/‐ 18.7 ml [center dot] 100 g sup ‐1 [center dot] min sup ‐1 for the Alb group. The number of dead neurons was less in the Alb group (611 +/‐ 84) than in the control group (1,097 +/‐ 211), and was less in the DCLHb group (305 +/‐ 38) than in the other two groups (P < 0.05). Conclusions: These data support a hypothesis that hemodilution decreases hypoperfusion and neuronal death after subarachnoid hemorrhage. The data do not support the notion that intravascular molecular hemoglobin has an adverse effect on brain injury after subarachnoid hemorrhage.

Subarachnoid hemorrhage in rats: effect of singular or sustained hemodilution with alpha-alpha diaspirin crosslinked hemoglobin on cerebral hypoperfusion.

OBJECTIVE To evaluate the effect of singular or sustained hemodilution, with alpha-alpha diaspirin crosslinked hemoglobin (DCLHb), on the area of hypoperfusion after subarachnoid hemorrhage. DESIGN Prospective animal study. SETTING Animal research laboratory. SUBJECTS Isoflurane anesthetized, mechanically ventilated rats. INTERVENTIONS Subarachnoid hemorrhage was induced by injecting 0.3 mL of blood into the cisterna magna. The animals were randomly assigned to one of the following groups (n = 16 in each hemodilution group; eight animals received a single treatment of hemodilution after subarachnoid hemorrhage; and, for eight animals, treatment was sustained for 48 hrs): control group (n = 8), no hematocrit (45%) manipulation; DCLHb group (n = 16), hematocrit decreased to 30% with DCLHb; or Alb group (n = 16), hematocrit decreased to 30% with human serum albumin. After 48 hrs, the area of hypoperfusion (cerebral blood flow < 40 ml/100g/min) was determined with 14C-iodoantipyrine in five coronal brain sections. MEASUREMENTS AND MAIN RESULTS For both singular and sustained treatment, the area of hypoperfusion was less in both hemodilution groups than in the control group (p<.05). For four of the five coronal brain sections, no differences were found between the DCLHb and Alb groups within a given hemodilution protocol. In addition, in four of the five coronal brain sections for the DCLHb hemodilution groups and in all five sections for the albumin hemodilution groups, the area of hypoperfusion was less for rats that received sustained hemodilution compared with their respective groups in the singular treatment protocol (p<.05). CONCLUSIONS These data support the hypothesis that hemodilution with molecular hemoglobin decreases hypoperfusion after subarachnoid hemorrhage and that sustained hemodilution is more effective than singular treatment. The data do not support the notion that intravascular DCLHb has an adverse effect on cerebral ischemia after subarachnoid hemorrhage.