Chronic Pain Syndromes: Chronic Neuropathic Pain.

Neuropathic pain affects 7% to 10% of the population and has major effects on quality of life. It is defined as pain caused by a lesion or disease of the somatosensory nervous system and may be central or peripheral. Diagnostic testing may yield inconclusive or inconsistent results, so physicians often rely on clinical judgment based on the history and physical examination findings. Questionnaires and scoring systems can aid in diagnosis. Neuropathic pain is differentiated from other types of chronic pain by abnormal sensory symptoms, such as shooting pain, burning pain, or numbness. It is difficult to manage and can be accompanied by mood and sleep disturbances. Referral for psychotherapy may be useful for these patients. Nonpharmacotherapy options include mindfulness training, transcutaneous electrical nerve stimulation, and massage. Acupuncture also may be effective, but the data are mixed. Topical drugs (eg, lidocaine, capsaicin), gabapentinoids, tricyclic antidepressants, and serotonin-norepinephrine reuptake inhibitors are considered first-line drugs. Tramadol is considered a second-line drug, but may considered first-line for certain patients. For persistent pain, physicians can consider referring patients to a pain specialist for nerve blocks or other procedural interventions. Opioids may be considered for refractory pain, but their additional benefit has been shown to be modest compared with those of other treatments.

Chronic Asthma Treatment: Common Questions and Answers.

Asthma affects more than 25 million people in the United States, and 62% of adults with asthma do not have adequately controlled symptoms. Asthma severity and level of control should be assessed at diagnosis and evaluated at subsequent visits using validated tools such as the Asthma Control Test or the asthma APGAR (activities, persistent, triggers, asthma medications, response to therapy) tools. Short-acting beta2 agonists are preferred asthma reliever medications. Controller medications consist of inhaled corticosteroids, long-acting beta2 agonists, long-acting muscarinic antagonists, and leukotriene receptor antagonists. Treatment typically begins with inhaled corticosteroids, and additional medications or dosage increases should be added in a stepwise fashion according to guideline-directed therapy recommendations from the National Asthma Education and Prevention Program or the Global Initiative for Asthma when symptoms are inadequately controlled. Single maintenance and reliever therapy combines an inhaled corticosteroid and long-acting beta2 agonist for controller and reliever treatments. This therapy is preferred for adults and adolescents because of its effectiveness in reducing severe exacerbations. Subcutaneous immunotherapy may be considered for those five years and older with mild to moderate allergic asthma; however, sublingual immunotherapy is not recommended. Patients with severe uncontrolled asthma despite appropriate treatment should be reassessed and considered for specialty referral. Biologic agents may be considered for patients with severe allergic and eosinophilic asthma.

Depression: Screening and Diagnosis.

Depression affects an estimated 8% of persons in the United States and accounts for more than $210 billion in health care costs annually. The U.S. Preventive Services Task Force (USPSTF) and American Academy of Family Physicians recommend screening for depression in the general adult population. Additionally, the USPSTF recommends screening children and adolescents 12 to 18 years of age for major depressive disorder. All screening should be implemented with adequate systems in place to ensure accurate diagnosis, effective treatment, and appropriate follow-up. The two-item and nine-item Patient Health Questionnaires (PHQs) are commonly used validated screening tools. The PHQ-2 has sensitivity comparable with the PHQ-9 in most populations; however, the specificity of the PHQ-9 ranges from 91% to 94%, compared with 78% to 92% for the PHQ-2. If the PHQ-2 is positive for depression, the PHQ-9 or a clinical interview should be administered. Screening all postpartum women for depression is recommended by the USPSTF, American Academy of Family Physicians, American Academy of Pediatrics, and American College of Obstetricians and Gynecologists. Women should be screened for depression at least once during the perinatal period using the PHQ-2, PHQ-9, or Edinburgh Postnatal Depression Scale. In older adults, the Geriatric Depression Scale is also an appropriate screening tool for depression. If screening is positive for possible depression, the diagnosis should be confirmed using Diagnostic and Statistical Manual of Mental Disorders, 5th ed., criteria.

Recognition and treatment of freezing and nonfreezing cold injuries.

This article reviews recent medical literature to provide an overview of the recognition and treatment of the two broad categories of cold injuries, freezing and nonfreezing. Frostbite, a freezing cold injury, is treated traditionally with rapid rewarming followed by tissue care and surgical debridement of necrotic tissue. Recently, newer therapies aimed at prevention of tissue necrosis have shown improved outcomes compared with more traditional therapies. These newer treatment regimens for frostbite include the use of various drugs such as ibuprofen, aspirin, warfarin, tissue plasminogen activator, and prostacyclin. The use of Tc bone scans, magnetic resonance imaging arthrogram, or angiography may have prognostic value for early determination of the extent of tissue loss. The more common nonfreezing cold injuries, though less severe than frostbite, may lead to short- and long-term complications requiring treatment and are discussed also.

In vivo characterization of MMP-2200, a mixed δ/µ opioid agonist, in mice.

We have previously reported the chemistry and antinociceptive properties of a series of glycosylated enkephalin analogs (glycopeptides) exhibiting approximately equal affinity and efficacy at δ opioid receptors (DORs) and µ opioid receptors (MORs). More detailed pharmacology of the lead glycopeptide MMP-2200 [H2N-Tyr-D-Thr-Gly-Phe-Leu-Ser-(O-ß-D-lactose)-CONH2] is presented. MMP-2200 produced dose-related antinociception in the 55°C tail-flick assay after various routes of administration. The antinociceptive effects of MMP-2200 were blocked by pretreatment with the general opioid antagonist naloxone and partially blocked by the MOR-selective antagonist ß-funaltrexamine and the DOR-selective antagonist naltrindole. The κ opioid receptor antagonist nor-binaltorphimine and the peripherally active opioid antagonist naloxone-methiodide were ineffective in blocking the antinociceptive effects of MMP-2200. At equi-antinociceptive doses, MMP-2200 produced significantly less stimulation of locomotor activity compared with morphine. Repeated administration of equivalent doses of morphine and MMP-2200 (twice daily for 3 days) produced antinociceptive tolerance (~13- and 5-fold rightward shifts, respectively). In acute and chronic physical dependence assays, naloxone precipitated a more severe withdrawal in mice receiving morphine compared with equivalent doses of the glycopeptide. Both morphine and MMP-2200 inhibited respiration and gastrointestinal transit. In summary, MMP-2200 acts as a mixed DOR/MOR agonist in vivo, which may in part account for its high antinociceptive potency after systemic administration, as well as its decreased propensity to produce locomotor stimulation, tolerance, and physical dependence in mice, compared with the MOR-selective agonist morphine. For other measures (e.g., gastrointestinal transit and respiration), the significant MOR component may not allow differentiation from morphine.

6beta-naltrexol preferentially antagonizes opioid effects on gastrointestinal transit compared to antinociception in mice.

AIMS: The current studies were designed to compare the in vivo potencies of the opioid antagonists 6beta-naltrexol and naltrexone in blocking the effects of the opioid agonist hydrocodone following intravenous (i.v.) or oral (p.o.) administration. MAIN METHODS: Adult male CD-1 mice were used for all experiments. The 55 degrees C tail-flick assay was used to assess the CNS antinociceptive activity of hydrocodone, and a charcoal meal gastrointestinal transit assay was used to assess the peripheral effects of hydrocodone. Graded antagonist dose-response curves for i.v. and p.o. 6beta-naltrexol and naltrexone were generated to determine ID(50) antagonist potency estimates against fixed doses of hydrocodone. KEY FINDINGS: Both antagonists produced dose-related blockade of hydrocodone-induced antinociception and inhibition of gastrointestinal transit. Naltrexone was between 5- and 13-fold more potent than 6beta-naltrexol in blocking a CNS effect of hydrocodone, whereas the drugs were nearly equipotent in blocking inhibition of gastrointestinal transit. Co-administration studies indicated an approximate 10-fold greater potency of 6beta-naltrexol for antagonism of hydrocodone-induced inhibition of gastrointestinal transit versus antinociception, whereas naltrexone blocked both effects with near equal potency. 6beta-naltrexol produced a longer duration of antagonist blockade and had a slower time to peak effect compared to naltrexone. SIGNIFICANCE: The pharmacology of 6beta-naltrexol differentiates it from currently available opioid antagonists. This includes an intermediate selectivity for peripheral versus central opioid receptors, a long duration of action, and neutral antagonist qualities in opioid exposed systems. These properties render it a drug candidate for a co-formulation product with opioid analgesics to reduce peripheral opioid side effects and limit abuse potential.

Opioid ligands with mixed properties from substituted enantiomeric N-phenethyl-5-phenylmorphans. Synthesis of a micro-agonist delta-antagonist and delta-inverse agonists.

Enantiomeric N-phenethyl-m-hydroxyphenylmorphans with various substituents in the ortho, meta or para positions of the aromatic ring in the phenethylamine side-chain (chloro, hydroxy, methoxy, nitro, methyl), as well as a pyridylethyl and a indolylethyl moiety on the nitrogen atom, were synthesized and their binding affinity to the mu-, delta-, and kappa-opioid receptors was examined. The higher affinity ligands were further examined in the [(35)S]GTPgammaS assay to study their function and efficacy. 3-((1R,5S)-(-)-2-(4-Nitrophenethyl)-2-aza-bicyclo[3.3.1]nonan-5-yl)phenol ((-)-) was found to be a mu-agonist and delta-antagonist in that functional assay and was about 50 fold more potent than morphine in vivo. 3-((1R,5S)-(-)-2-(4-Chlorophenethyl)-2-aza-bicyclo[3.3.1]nonan-5-yl)phenol ((-)-) and several other ligands displayed inverse agonist activity at the delta-opioid receptor. The absolute configuration of all of the reported compounds was established by chemical conversion of (-)- to 1R,5S-(-)-.HBr.