Three Newly Approved Analgesics: An Update

Since 2008, three new analgesic entities, tapentadol immediate release (Nucynta) diclofenac potassium soft gelatin capsules (Zipsor), and bupivacaine liposome injectable suspension (EXPAREL) were granted US Food and Drug Administration (FDA) approval to treat acute pain. Tapentadol immediate-release is a both a mu-opioid agonist and a norepinephrine reuptake inhibitor, and is indicated for the treatment of moderate to severe pain. Diclofenac potassium soft gelatin capsules are a novel formulation of diclofenac potassium, which is a nonsteroidal anti-inflammatory drug (NSAID), and its putative mechanism of action is through inhibition of cyclooxygenase enzymes. This novel formulation of diclofenac allows for improved absorption at lower doses. Liposomal bupivacaine is a new formulation of bupivacaine intended for single-dose infiltration at the surgical site for postoperative analgesia. Bupivacaine is slowly released from this liposomal vehicle and can provide prolonged analgesia at the surgical site. By utilizing NSAIDs and local anesthetics to decrease the transmission of afferent pain signals, less opioid analgesics are needed to achieve analgesia. Since drug-related adverse events are frequently dose related, lower doses from different drug classes may be employed to reduce the incidence of adverse effects, while producing synergistic analgesia as part of a multimodal analgesic approach to acute pain.Key Words: Liposomal bupivacaine, Tapentadol, Diclofenac potassium soft gelatin capsules, AnalgesicsPain, as defined by the International Association for the Study of Pain, is “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.”¹ Although there is a subjective and perhaps emotional component to pain, acute pain is usually proportional to the degree of tissue damage.²Pain may serve a protective mechanism to the individual by signaling tissue injury or organ dysfunction that may otherwise result in illness if left unnoticed and untreated. However, pain that is secondary to a surgical intervention is undesirable. Postoperative pain can result in increased sympathetic nervous system activity, guarded breathing, increased likelihood of thrombi formation, and delayed recovery.³ The benefits of adequate postoperative analgesia include improved respiratory, cardiovascular, and gastrointestinal function, improved arterial graft survival, and decreased incidence of thrombotic or septic complications. Not only does adequate postoperative analgesia result in earlier return to function, more rapid patient mobilization, improved healing, reduced health care costs, and improved patient satisfaction, but it may play a role in preventing the progression of chronic pain.^4–6Opioids have traditionally been the most common analgesic for treating moderate to severe postoperative pain.² However, their utility is hampered by undesirable side effects, which are sometimes intolerable to the patient. These side effects include central nervous depression, respiratory depression, pruritus, nausea, vomiting, ileus, tolerance, and opioid-induced hyperalgesia.^4–6 By treating pain with several modalities, including local anesthetics and nonsteroidal anti-inflammatory drugs (NSAIDs,) lower doses of opioids are needed to achieve analgesia while reducing or eliminating opioid-mediated adverse effects.^4,5The multimodal approach to analgesia intervenes pharmacologically at many different inputs along the pain pathway. The synergistic analgesia achieved by affecting pain transmission at multiple points also results in lower doses of each drug administered. Adverse drug reactions or drug toxicities are dose-dependent, so there are fewer side effects from each drug class. This article presents and reviews 3 new analgesic agents that may be useful in treating postoperative dental and maxillofacial pain: tapentadol immediate release (Nucynta) diclofenac potassium soft gelatin capsules (Zipsor) and bupivacaine liposome injectable suspension (EXPAREL).     

Stroke management: updated recommendations for treatment along the care continuum

The Australian Clinical Guidelines for Stroke Management 2010 represents an update of the Clinical Guidelines for Stroke Rehabilitation and Recovery (2005) and the Clinical Guidelines for Acute Stroke Management (2007). For the first time, they cover the whole spectrum of stroke, from public awareness and prehospital response to stroke unit and stroke management strategies, acute treatment, secondary prevention, rehabilitation and community care. The guidelines also include recommendations on transient ischaemic attack. The most significant changes to previous guideline recommendations include the extension of the stroke thrombolysis window from 3 to 4.5 h and the change from positive to negative recommendations for the use of thigh-length antithrombotic stockings for deep venous thrombosis prevention and the routine use of prolonged positioning for contracture management.     

The Caenorhabditis elegans mucolipin-like gene cup-5 is essential for viability and regulates lysosomes in multiple cell types

The misregulation of programmed cell death, or apoptosis, contributes to the pathogenesis of many diseases. We used Nomarski microscopy to screen for mutants containing refractile cell corpses in a C. elegans strain in which all programmed cell death is blocked and such corpses are absent. We isolated a mutant strain that accumulates refractile bodies resembling irregular cell corpses. We rescued this mutant phenotype with the C. elegans mucolipidosis type IV (ML-IV) homolog, the recently identified cup-5 (coelomocyte-uptake defective) gene. ML-IV is a human autosomal recessive lysosomal storage disease characterized by psychomotor retardation and ophthalmological abnormalities. Our null mutations in cup-5 cause maternal-effect lethality. In addition, cup-5 mutants contain excess lysosomes in many and possibly all cell types and contain lamellar structures similar to those observed in ML-IV cell lines. The human ML-IV gene is capable of rescuing both the maternal-effect lethality and the lysosome-accumulation abnormality of cup-5 mutants. cup-5 mutants seem to contain excess apoptotic cells as detected by staining with terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling. We suggest that the increased apoptosis seen in cup-5 mutants is a secondary consequence of the lysosomal defect, and that abnormalities in apoptosis may be associated with human lysosomal storage disorders.     

Influence of cardiac fiber orientation on wavefront voltage, conduction velocity, and tissue resistivity in the dog.

When the canine epicardium is stimulated, the spread of epicardial excitation is 2.4 times faster parallel to the long axes of the cardiac fibers than perpendicular to them. Likewise, gross tissue resistivity is lower parallel to fibers by a factor of 3.2, and the voltage across the depolarization wave is approximately three times as great in the longitudinal direction. Equations are presented which relate these variables. Theoretical considerations confirm the experimental finding that the potentials around a wave of depolarization cannot be accounted for by the conventional hypothesis that the wavefront is a uniform double-layer current source.     

Health care costs and costs associated with changes in work productivity among persons with systemic lupus erythematosus

Objective

To estimate health care costs and costs associated with changes in work productivity among persons with systemic lupus erythematosus (SLE) in the US.

Methods

Data were derived from the University of California, San Francisco Lupus Outcomes Study. Participants provided information on their health care resource use and employment. Cost estimates were derived for both direct health care costs and costs related to changes in work productivity. Direct health care costs included costs for hospitalizations, emergency department services, physician visits, outpatient surgical procedures, dialysis, and medications. Productivity costs were estimated by measuring changes in hours of work productivity since diagnosis of SLE; these estimates were also compared with normal US population data.

Results

For the total population of participants, the mean annual direct cost was $12,643 (2004 US dollars). The mean annual productivity cost for subjects of employment age (≥18 and <65 years) was $8,659. The mean annual total cost (direct and productivity) for subjects of employment age was $20,924. Regression results showed that greater disease activity, longer disease duration, and worse physical and mental health were significant predictors of higher direct costs; older age predicted lower direct costs. Older age, greater disease activity, and worse physical and mental health status were significant predictors of higher costs due to changes in work productivity.

Conclusion

Both direct health care costs and costs associated with changes in work productivity are substantial and both represent important contributors to the total costs associated with SLE.