Efficacy of tramadol vs meperidine in vasoocclusive sickle cell crisis

Pain Control for Sickle Cell Crisis, a Novel Approach? A Retrospective Study

Background and Objectives: Pain management poses a significant challenge for patients experiencing vaso-occlusive crisis (VOC) in sickle cell disease (SCD). While opioid therapy is highly effective, its efficacy can be impeded by undesirable side effects. Local regional anesthesia (LRA), involving the deposition of a perineural anesthetic, provides a nociceptive blockade, local vasodilation and reduces the inflammatory response. However, the effectiveness of this therapeutic approach for VOC in SCD patients has been rarely reported up to now. The objective of this study was to assess the effectiveness of a single-shot local regional anesthesia (LRA) in reducing pain and consequently enhancing the management of severe vaso-occlusive crisis (VOC) in adults with sickle cell disease (SCD) unresponsive to conventional analgesic therapy. Materials and Methods: We first collected consecutive episodes of VOC in critical care (ICU and emergency room) for six months in 2022 in a French University hospital with a large population of sickle cell patients in the West Indies population. We also performed a systematic review of the use of LRA in SCD. The primary outcome was defined using a numeric pain score (NPS) and/or percentage of change in opioid use. Results: We enrolled nine SCD adults (28 years old, 4 females) for ten episodes of VOC in whom LRA was used for pain management. Opioid reduction within the first 24 h post block was -75% (50 to 96%). Similarly, the NPS decreased from 9/10 pre-block to 0-1/10 post-block. Five studies, including one case series with three patients and four case reports, employed peripheral nerve blocks for regional anesthesia. In general, local regional anesthesia (LRA) exhibited a reduction in pain and symptoms, along with a decrease in opioid consumption post-procedure. Conclusions: LRA improves pain scores, reduces opioid consumption in SCD patients with refractory pain, and may mitigate opioid-related side effects while facilitating the transition to oral analgesics. Furthermore, LRA is a safe and effective procedure.

Ketamine administration for acute painful sickle cell crisis: A randomized controlled trial

OBJECTIVE

The objective was to evaluate the efficacy and safety of single-dose ketamine infusion in adults with sickle cell disease (SCD) who presented with acute sickle vasoocclusive crisis (VOC).

METHODS

This study was a parallel-group, prospective, randomized, double-blind, pragmatic trial. Participants were randomized to receive a single dose of either ketamine or morphine, infused over 30 min. Primary outcome was mean difference in the numerical pain rating scale (NPRS) score over 2 h. NPRS was recorded every 30 min for a maximum of 180 min and secondary outcomes were cumulative dose of opioids, emergency department (ED) length of stay, hospital admission, change in vital signs, and drug-related side effects. Authors performed the analysis using intention-to-treat principle.

RESULT

A total of 278 adults with SCD and who presented with acute sickle VOC participated in this trial. A total of 138 were allocated to the ketamine group. Mean (±standard deviation [SD]) NPRS scores over 2 h were 5.7 (±2.13) and 5.6 (±1.90) in the ketamine and morphine groups. The ketamine group received significantly lower cumulative doses of morphine during their ED stay (mean ± SD = 4.5 ± 4.6 mg) than of the morphine group (mean ± SD = 8.5 ± 7.55 mg). Both groups had similar rates of hospital admission: 6.3% in the ketamine group had drug-related side effects compared to 2.2% in the morphine group.

CONCLUSION

Early use of ketamine in adults with VOC resulted in a meaningful reduction in pain scores over a 2-h period and reduced the cumulative morphine dose in the ED with no significant drug-related side effects in the ketamine-treated group.

Mechanisms of pain in sickle cell disease

Objectives

The hallmark of sickle cell disease (SCD) is acute and chronic pain, and the pain dominates the clinical characteristics of SCD patients. Although pharmacological treatments of SCD targeting the disease mechanisms have been improved, many SCD patients suffer from pain. To overcome the pain of the disease, there have been renewed requirements to understand the novel molecular mechanisms of the pain in SCD.

Methods

We concisely summarized the molecular mechanisms of SCD-related acute and chronic pain, focusing on potential drug targets to treat pain.

Results

Acute pain of SCD is caused by vaso-occulusive crisis (VOC), impaired oxygen supply or infarction-reperfusion tissue injuries. In VOC, inflammatory cytokines include tryptase activate nociceptors and transient receptor potential vanilloid type 1. In tissue injury, the secondary inflammatory response is triggered and causes further tissue injuries. Tissue injury generates cytokines and pain mediators including bradykinin, and they activate nociceptive afferent nerves and trigger pain. The main causes of chronic pain are from extended hyperalgesia after a VOC and central sensitization. Neuropathic pain could be due to central or peripheral nerve injury, and protein kinase C might be associated with the pain. In central sensitization, neuroplasticity in the brain and the activation of glial cells may be related with the pain.

Discussion

In this review, we summarized the molecular mechanisms of SCD-related acute and chronic pain. The novel treatments targeting the disease mechanisms would interrupt complications of SCD and reduce the pain of the SCD patients.

Pharmacological interventions for painful sickle cell vaso-occlusive crises in adults

BACKGROUND

Sickle cell disease (SCD) is a group of inherited disorders of haemoglobin (Hb) structure in a person who has inherited two mutant globin genes (one from each parent), at least one of which is always the sickle mutation. It is estimated that between 5% and 7% of the world's population are carriers of the mutant Hb gene, and SCD is the most commonly inherited blood disorder. SCD is characterized by distorted sickle-shaped red blood cells. Manifestations of the disease are attributed to either haemolysis (premature red cell destruction) or vaso-occlusion (obstruction of blood flow, the most common manifestation). Shortened lifespans are attributable to serious comorbidities associated with the disease, including renal failure, acute cholecystitis, pulmonary hypertension, aplastic crisis, pulmonary embolus, stroke, acute chest syndrome, and sepsis. Vaso-occlusion can lead to an acute, painful crisis (sickle cell crisis, vaso-occlusive crisis (VOC) or vaso-occlusive episode). Pain is most often reported in the joints, extremities, back or chest, but it can occur anywhere and can last for several days or weeks. The bone and muscle pain experienced during a sickle cell crisis is both acute and recurrent. Key pharmacological treatments for VOC include opioid analgesics, non-opioid analgesics, and combinations of drugs. Non-pharmacological approaches, such as relaxation, hypnosis, heat, ice and acupuncture, have been used in conjunction to rehydrating the patient and reduce the sickling process.

OBJECTIVES

To assess the analgesic efficacy and adverse events of pharmacological interventions to treat acute painful sickle cell vaso-occlusive crises in adults, in any setting.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online, MEDLINE via Ovid, Embase via Ovid and LILACS, from inception to September 2019. We also searched the reference lists of retrieved studies and reviews, and searched online clinical trial registries.

SELECTION CRITERIA

Randomized, controlled, double-blind trials of pharmacological interventions, of any dose and by any route, compared to placebo or any active comparator, for the treatment (not prevention) of painful sickle cell VOC in adults.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed studies for eligibility. We planned to use dichotomous data to calculate risk ratio (RR) and number needed to treat for one additional event, using standard methods. Our primary outcomes were participant-reported pain relief of 50%, or 30%, or greater; Patient Global Impression of Change (PGIC) very much improved, or much or very much improved. Our secondary outcomes included adverse events, serious adverse events, and withdrawals due to adverse events. We assessed GRADE and created three 'Summary of findings' tables.

MAIN RESULTS

We included nine studies with data for 638 VOC events and 594 participants aged 17 to 42 years with SCD presenting to a hospital emergency department in a painful VOC. Three studies investigated a non-steroidal anti-inflammatory drug (NSAID) compared to placebo. One study compared an opioid with a placebo, two studies compared an opioid with an active comparator, two studies compared an anticoagulant with a placebo, and one study compared a combination of three drugs with a combination of four drugs. Risk of bias across the nine studies varied. Studies were primarily at an unclear risk of selection, performance, and detection bias. Studies were primarily at a high risk of bias for size with fewer than 50 participants per treatment arm; two studies had 50 to 199 participants per treatment arm (unclear risk). Non-steroidal anti-inflammatory drugs (NSAID) compared with placebo No data were reported regarding participant-reported pain relief of 50% or 30% or greater. The efficacy was uncertain regarding PGIC very much improved, and PGIC much or very much improved (no difference; 1 study, 21 participants; very low-quality evidence). Very low-quality, uncertain results suggested similar rates of adverse events across both the NSAIDs group (16/45 adverse events, 1/56 serious adverse events, and 1/56 withdrawal due to adverse events) and the placebo group (19/45 adverse events, 2/56 serious adverse events, and 1/56 withdrawal due to adverse events). Opioids compared with placebo No data were reported regarding participant-reported pain relief of 50% or 30%, PGIC, or adverse events (any adverse event, serious adverse events, and withdrawals due to adverse events). Opioids compared with active comparator No data were reported regarding participant-reported pain relief of 50% or 30% or greater. The results were uncertain regarding PGIC very much improved (33% of the opioids group versus 19% of the placebo group). No data were reported regarding PGIC much or very much improved. Very low-quality, uncertain results suggested similar rates of adverse events across both the opioids group (9/66 adverse events, and 0/66 serious adverse events) and the placebo group (7/64 adverse events, 0/66 serious adverse events). No data were reported regarding withdrawal due to adverse events. Quality of the evidence We downgraded the quality of the evidence by three levels to very low-quality because there are too few data to have confidence in results (e.g. too few participants per treatment arm). Where no data were reported for an outcome, we had no evidence to support or refute (quality of the evidence is unknown).

AUTHORS' CONCLUSIONS

This review identified only nine studies, with insufficient data for all pharmacological interventions for analysis. The available evidence is very uncertain regarding the efficacy or harm from pharmacological interventions used to treat pain related to sickle cell VOC in adults. This area could benefit most from more high quality, certain evidence, as well as the establishment of suitable registries which record interventions and outcomes for this group of people.

Study protocol for a randomized, blinded, controlled trial of ketamine for acute painful crisis of sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is an inherited hematological disorder where the shape of red blood cells is altered, resulting in the destruction of red blood cells, anemia, and other complications. SCD is prevalent in the southern and eastern provinces of the Arabian peninsula. The most common complications for individuals with SCD are acute painful episodes that require several doses of intravenous opioids, making pain control for these individuals challenging. Instead of opioids, some studies have suggested that ketamine might be used for pain control in acute pain episodes of individuals with SCD. This study aims to evaluate whether the addition of ketamine to morphine can achieve better pain control, decreasing the number of repeated doses of opiates. We hypothesize that early administration of ketamine would lead to a more rapid improvement in pain score and lower opioid requirements.

METHODS AND ANALYSIS

This study will be a prospective, randomized, concealed, blinded, pragmatic parallel group, controlled trial enrolling adult patients with SCD and acute vaso-occlusive crisis pain. All patients will receive standard analgesic therapy during evaluation. Patients randomized to the treatment arm will receive low-dose ketamine (0.3 mg/kg in 0.9% sodium chloride, 100 ml bag) in addition to standard intravenous hydration, while those in the control group will receive a standard dose of morphine (0.1 mg/kg in 0.9% sodium chloride, 100 ml bag) in addition to the standard intravenous hydration. All healthcare providers will be blinded to the treatment arm. Data will be analyzed according to the intention-to-treat principle. The primary outcome is improvement in pain severity using the Numerical Pain Rating Score.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT03431285 . Registered on 13 February 2018.

Drepa-Opia: A Pilot Study to Determine the Predictive Factors of Morphine Use and Consumption in Hospitalized Adult Patients with Sickle Cell Disease

The aim of this study was to evaluate the clinical, biological and genetic factors that could be associated with the use and dose of morphine during hospitalization for vaso-occlussive crisis (VOC) in adults with sickle cell disease. Ninety-nine hospitalizations for acute VOC (58 sickle cell disease patients aged 18 to 60 years, one to six hospitalizations each) were recorded; we investigated the associations between qualitative and quantitative opioid requirements and several biological, clinical, epidemiological and genetic parameters. Visual analog pain scale (VAS) was the only independent predictor of the qualitative need for morphine (mean value of 8.5 vs. 6.1 for the 77 hospitalizations that required morphine). A higher total administered morphine dose, which relates mainly to the overall crisis severity, was associated with a lower hemoglobin (Hb) level at entry. The mean daily morphine dose, which is more influenced by the individual sensitivity to morphine, was not influenced by the studied genetic parameters [sickle cell disease type, α-thalassemia (α-thal) status, UGT2B7 and ABCB1 genotypes] but a very slight negative association was found with the total bilirubin (BIL) level at entry. Our study demonstrated that physicians are often reluctant to prescribe morphine in sickle cell disease as a VAS of 6 corresponds to the usual threshold of administration in other instances. Total Hb at entry was also associated for the first time with higher total morphine consumption and could be used in a predictive VOC severity score. These results have to be confirmed and completed on larger cohorts.

Drugs for preventing red blood cell dehydration in people with sickle cell disease

BACKGROUND

Sickle cell disease is an inherited disorder of hemoglobin, resulting in abnormal red blood cells. These are rigid and may block blood vessels leading to acute painful crises and other complications. Recent research has focused on therapies to rehydrate the sickled cells by reducing the loss of water and ions from them. Little is known about the effectiveness and safety of such drugs. This is an updated version of a previously published review.

OBJECTIVES

To assess the relative risks and benefits of drugs to rehydrate sickled red blood cells.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register. We also searched online trials registries for any ongoing trials (01 July 2018).Last search of the Group's Haemoglobinopathies Trials Register: 08 October 2018.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials of drugs to rehydrate sickled red blood cells compared to placebo or an alternative treatment.

DATA COLLECTION AND ANALYSIS

Both authors independently selected studies for inclusion, assessed study quality and extracted data.

MAIN RESULTS

Of the 51 studies identified, three met the inclusion criteria, including 524 people with sickle cell disease aged between 12 and 65 years of age. One study tested the effectiveness of zinc sulphate as compared to placebo and the remaining two assessed senicapoc versus placebo. No deaths were seen in any of the studies (low-quality evidence). The zinc sulphate study showed a significant reduction in painful crises (in a total of 145 participants) over one and a half years, mean difference -2.83 (95% confidence interval -3.51 to -2.15) (moderate-quality evidence). However, analysis was restricted due to limited statistical data. Changes to red blood cell parameters and blood counts were inconsistent (very low-quality evidence). No serious adverse events were noted in the study. The Phase II dose-finding study of senicapoc (a Gardos channel blocker) compared to placebo showed that the high dose senicapoc showed significant improvement in change in hemoglobin level, the number and proportion of dense red blood cells, red blood cell count and indices and hematocrit value (very low-quality evidence). The results with low-dose senicapoc were similar to the high-dose senicapoc group but of lesser magnitude. There was no difference in the frequency of painful crises between the three groups (low-quality evidence). A subsequent Phase III study of senicapoc was terminated early since there was no difference observed between the treatment and control groups in the primary end point of painful crises.

AUTHORS' CONCLUSIONS

While the results of zinc for reducing sickle-related crises are encouraging, larger and longer-term multicenter studies are needed to evaluate the effectiveness of this therapy for people with sickle cell disease.While the Phase II and the prematurely terminated phase III studies of senicapoc showed that the drug improved red blood cell survival (depending on dose), this did not lead to fewer painful crises.Given this is no longer an active area of research, this review will no longer be regularly updated.

A randomized controlled trial comparing two vaso-occlusive episode (VOE) protocols in sickle cell disease (SCD)

Limited evidence guides opioid dosing strategies for acute Sickle Cell (SCD) pain. We compared two National Heart, Lung and Blood (NHBLI) recommended opioid dosing strategies (weight-based vs. patient-specific) for ED treatment of acute vaso-occlusive episodes (VOE). A prospective randomized controlled trial (RCT) was conducted in two ED's. Adults ≥ 21 years of age with SCD disease were eligible. Among the 155 eligible patients, 106 consented and 52 had eligible visits. Patients were pre-enrolled in the outpatient setting and randomized to one of two opioid dosing strategies for a future ED visit. ED providers accessed protocols through the electronic medical record. Change in pain score (0-100 mm VAS) from arrival to ED disposition, as well as side effects were assessed. 52 patients (median age was 27 years, 42% were female, and 89% black) had one or more ED visits for a VOE (total of 126 ED study visits, up to 5 visits/patient were included). Participants randomized to the patient-specific protocol experienced a mean reduction in pain score that was 16.6 points greater than patients randomized to the weight-based group (mean difference 95% CI = 11.3 to 21.9, P = 0.03). Naloxone was not required for either protocol and nausea and/or vomiting was observed less often in the patient-specific protocol (25.8% vs 59.4%, P = 0.0001). The hospital admission rate for VOE was lower for patients in the patient-specific protocol (40.3% vs 57.8% P = 0.05). NHLBI guideline-based analgesia with patient-specific opioid dosing resulted in greater improvements in the pain experience compared to a weight-based strategy, without increased side effects.

Acute Chest Syndrome in Children with Sickle Cell Disease

Acute chest syndrome (ACS) is a frequent cause of acute lung disease in children with sickle cell disease (SCD). Patients may present with ACS or may develop this complication during the course of a hospitalization for acute vaso-occlusive crises (VOC). ACS is associated with prolonged hospitalization, increased risk of respiratory failure, and the potential for developing chronic lung disease. ACS in SCD is defined as the presence of fever and/or new respiratory symptoms accompanied by the presence of a new pulmonary infiltrate on chest X-ray. The spectrum of clinical manifestations can range from mild respiratory illness to acute respiratory distress syndrome. The presence of severe hypoxemia is a useful predictor of severity and outcome. The etiology of ACS is often multifactorial. One of the proposed mechanisms involves increased adhesion of sickle red cells to pulmonary microvasculature in the presence of hypoxia. Other commonly associated etiologies include infection, pulmonary fat embolism, and infarction. Infection is a common cause in children, whereas adults usually present with pain crises. Several risk factors have been identified in children to be associated with increased incidence of ACS. These include younger age, severe SCD genotypes (SS or Sβ⁰ thalassemia), lower fetal hemoglobin concentrations, higher steady-state hemoglobin levels, higher steady-state white blood cell counts, history of asthma, and tobacco smoke exposure. Opiate overdose and resulting hypoventilation can also trigger ACS. Prompt diagnosis and management with intravenous fluids, analgesics, aggressive incentive spirometry, supplemental oxygen or respiratory support, antibiotics, and transfusion therapy, are key to the prevention of clinical deterioration. Bronchodilators should be considered if there is history of asthma or in the presence of acute bronchospasm. Treatment with hydroxyurea should be considered for prevention of recurrent episodes. This review evaluates the etiology, pathophysiology, risk factors, clinical presentation of ACS, and preventive and treatment strategies for effective management of ACS.

The Use of Cannabis by Patients with Sickle Cell Disease Increased the Frequency of Hospitalization due to Vaso-Occlusive Crises

Introduction: The objective of this study was to determine if patients with sickle cell disease using cannabis had decreased frequency of acute vaso-occlusive crises (VOCs) that required hospitalization.

Method: This was a retrospective study in which 270 urine drug screen tests were done on 72 patients: 40 males and 32 females.

Results: Cannabinoids were found in 144 urine tests from 37 patients and were negative in 126 tests from 35 patients. Males who used cannabis were significantly younger (p<0.001) than males who did not. Patients who tested positive used benzodiazepines, cocaine, and phencyclidine significantly more often than patients who tested negative. There was no significant difference in the amounts of opioids consumed by users and nonusers of cannabis. The cannabis cohort was seen in the clinic significantly (p<0.05) less often than controls, but hospital admissions were significantly greater in the cannabis group than controls (p<0.05).

Conclusion: These data show an unexpected negative effect of cannabis on the frequency of VOCs. This may be due to the effect of cannabis on the brain and/or the severity of the disease in the cannabis users. More controlled studies are needed to clarify these findings.

Drugs for preventing red blood cell dehydration in people with sickle cell disease

BACKGROUND

Sickle cell disease is an inherited disorder of hemoglobin, resulting in abnormal red blood cells. These are rigid and may block blood vessels leading to acute painful crises and other complications. Recent research has focused on therapies to rehydrate the sickled cells by reducing the loss of water and ions from them. Little is known about the effectiveness and safety of such drugs. This is an updated version of a previously published review.

OBJECTIVES

To assess the relative risks and benefits of drugs to rehydrate sickled red blood cells.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register.Last search of the Group's Trials Register: 28 November 2015.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials of drugs to rehydrate sickled red blood cells compared to placebo or an alternative treatment.

DATA COLLECTION AND ANALYSIS

Both authors independently selected studies for inclusion, assessed study quality and extracted data.

MAIN RESULTS

Of the 51 studies identified, three met the inclusion criteria. The first study tested the effectiveness of zinc sulphate to prevent sickle cell-related crises in a total of 145 participants and showed a significant reduction in painful crises over one and a half years, mean difference -2.83 (95% confidence interval -3.51 to -2.15). However, analysis was restricted due to limited statistical data. Changes to red cell parameters and blood counts were inconsistent. No serious adverse events were noted in the study.The second study was a Phase II dose-finding study of senicapoc (a Gardos channel blocker) compared to placebo. Compared to the placebo group the high dose senicapoc showed significant improvement in change in hemoglobin level, number and proportion of dense red blood cells, red blood cell count and indices and hematocrit. The results with low-dose senicapoc were similar to the high-dose senicapoc group but of lesser magnitude. There was no difference in the frequency of painful crises between the three groups. A subsequent Phase III study of senicapoc was terminated early since there was no difference observed between the treatment and control groups in the primary end point of painful crises.

AUTHORS' CONCLUSIONS

While the results of zinc for reducing sickle-related crises are encouraging, larger and longer-term multicenter studies are needed to evaluate the effectiveness of this therapy for people with sickle cell disease.While the Phase II and the prematurely terminated phase III studies of senicapoc showed that the drug improved red cell survival (depending on dose), this did not lead to fewer painful crises.We will continue to run searches to identify any potentially relevant trials; however, we do not plan to update other sections of the review until new trials are published.

Factors impacting variability of the urinary normeperidine-to-meperidine metabolic ratio in patients with chronic pain

Meperidine (Demerol(®)) is a mu- and kappa-opiate receptor agonist used for moderate to severe pain. Overdose can result in respiratory depression, hypotension and coma, while accumulation of its toxic metabolite, normeperidine, can cause delirium and seizures. Little data exist examining the inter- and intrasubject variability of the normeperidine-to-meperidine metabolic ratio (MR) in urine. This retrospective data analysis examined meperidine and normeperidine urine concentrations collected from chronic pain patients. In 98 subjects with multiple visits, the geometric mean urinary MR = 6.1 (coefficient of variation, %CV = 68%). From single specimens obtained from 799 subjects, the geometric mean urinary MR = 6.2 (%CV = 212%). The urinary MR increased in young subjects compared with elderly (P = 0.004) and middle-aged subjects (P = 0.01). A 27% difference was found between the male and female urinary MR (male geometric mean MR = 5.1, female geometric mean MR = 7.0, P = 0.02). Intersubject variability in meperidine metabolism was 3-fold greater than intrasubject variability. A significant difference in the urinary MR was found between males and females. The substantial variability in meperidine metabolism and the serious side effects of its metabolite normeperidine require greater vigilance in patient medication monitoring.

Randomized clinical trial of efficacy and safety of a single 2-mg intravenous dose of hydromorphone versus usual care in the management of acute pain

OBJECTIVES

The objective was to test the efficacy and safety of 2 mg of intravenous (IV) hydromorphone (Dilaudid) against "usual care" in emergency department (ED) patients with acute severe pain.

METHODS

This was a randomized clinical trial. Patients allocated to 2 mg of IV hydromorphone received their medication in a single dose. Those randomized to usual care received any IV opioid, with type, dose, and frequency chosen by the ED attending. All patients received 2 L/min. nasal cannula oxygen. The primary outcome was the difference in the proportion of patients who achieved clinically satisfactory analgesia by 30 minutes. This was defined as the patient declining additional analgesia when asked the question, "Do you want more pain medicine?" A 10% absolute difference was chosen a priori as the minimum difference considered clinically significant.

RESULTS

Of 175 subjects randomized to each group, 164 in the 2 mg hydromorphone group and 161 in the usual care group had sufficient data for analysis. Additional pain medication was declined by 77.4% of patients in the 2 mg hydromorphone group at 30 minutes, compared to 65.8% in the usual care group. This difference of 11.6% was statistically and clinically significant (95% confidence interval [CI] = 1.8% to 21.1%). Safety profiles were similar and no patient required naloxone. There was more pruritus in the hydromorphone group (18.3% vs. 8.7%; difference = 9.6%, 95% CI = 2.6% to 16.6%).

CONCLUSIONS

Using a simple dichotomous patient-centered endpoint in which a difference of 10% in proportion obtaining adequate analgesia was considered clinically significant, 2 mg of hydromorphone in a single IV dose is clinically and statistically more efficacious when compared to usual care for acute pain management in the ED.

Drugs for preventing red blood cell dehydration in people with sickle cell disease

BACKGROUND

Sickle cell disease is an inherited disorder of hemoglobin, resulting in abnormal red blood cells. These are rigid and may block blood vessels leading to acute painful crises and other complications. Recent research has focused on therapies to rehydrate the sickled cells by reducing the loss of water and ions from them. Little is known about the effectiveness and safety of such drugs.

OBJECTIVES

To assess the relative risks and benefits of drugs to rehydrate sickled red blood cells.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register.Last search of the Group's Trials Register: 25 October 2011.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials of drugs to rehydrate sickled red blood cells compared to placebo or an alternative treatment.

DATA COLLECTION AND ANALYSIS

Both authors independently selected studies for inclusion, assessed study quality and extracted data.

MAIN RESULTS

Of the 51 studies identified, three met the inclusion criteria. The first study tested the effectiveness of zinc sulphate to prevent sickle cell-related crises in a total of 145 participants and showed a significant reduction in painful crises over one and a half years, mean difference -2.83 (95% confidence interval -3.51 to -2.15). However, analysis was restricted due to limited statistical data. Changes to red cell parameters and blood counts were inconsistent. No serious adverse events were noted in the study.The second study was a Phase II dose-finding study of senicapoc (a Gardos channel blocker) compared to placebo. Compared to the placebo group the high dose senicapoc showed significant improvement in change in hemoglobin level, number and proportion of dense red blood cells, red blood cell count and indices and hematocrit. The results with low-dose senicapoc were similar to the high-dose senicapoc group but of lesser magnitude. There was no difference in the frequency of painful crises between the three groups. A subsequent Phase III study of senicapoc was terminated early since there was no difference observed between the treatment and control groups in the primary end point of painful crises.

AUTHORS' CONCLUSIONS

While the results of zinc for reducing sickle-related crises are encouraging, larger and longer-term multicenter studies are needed to evaluate the effectiveness of this therapy for people with sickle cell disease.While the Phase II and the prematurely terminated phase III studies of senicapoc showed that the drug improved red cell survival (depending on dose), this did not lead to fewer painful crises.

Intravenous Opioids for Severe Acute Pain in the Emergency Department

Objective:

To review clinical trials of intravenous opioids for severe acute pain in the emergency department (ED) and to provide an approach for optimization of therapy.

Data Sources:

Articles were identified through a search of Ovid/MEDLINE (1948-August 2010), PubMed (1950-August 2010), Cochrane Central Register of Controlled Trials (1991-August 2010), and Google Scholar (1900-August 2010). The search terms used were pain, opioid, and emergency department.

Study Selection and Data Extraction:

The search was limited by age group to adults and by publication type to comparative studies. Studies comparing routes of administration other than intravenous or using non-opioid comparators were not included. Bibliographies of all retrieved articles were reviewed to obtain additional articles. The focus of the search was to identify original research that compared intravenous opioids used for treatment of severe acute pain for adults in the ED.

Data Synthesis:

At equipotent doses, randomized controlled trials have not shown clinically significant differences in analgesic response or adverse effects between opioids studied. Single opioid doses less than 0.1 mg/kg of intravenous morphine, 0.015 mg/kg of intravenous hydromorphone, or 1 μg/kg of intravenous fentanyl are likely to be inadequate for severe, acute pain and the need for additional doses should be anticipated. In none of the randomized controlled trials did patients develop respiratory depression requiring the use of naloxone. Future trials could investigate the safety and efficacy of higher doses of opioids. Implementation of nurse-initiated and patient-driven pain management protocols for opioids in the ED has shown improvements in timely provision of appropriate analgesics and has resulted in better pain reduction.

Conclusions:

Currently, intravenous administration of opioids for severe acute pain in the ED appears to be inadequate. Opioid doses in the ED should be high enough to provide adequate analgesia without additional risk to the patient. EDs could implement institution-specific protocols to standardize the management of pain.