Ropivacaine: an update of its use in regional anaesthesia.

UNLABELLED: Ropivacaine is a long-acting, enantiomerically pure (S-enantiomer) amide local anaesthetic with a high pKa and low lipid solubility which blocks nerve fibres involved in pain transmission (Adelta and C fibres) to a greater degree than those controlling motor function (Abeta fibres). The drug was less cardiotoxic than equal concentrations of racemic bupivacaine but more so than lidocaine (lignocaine) in vitro and had a significantly higher threshold for CNS toxicity than racemic bupivacaine in healthy volunteers (mean maximum tolerated unbound arterial plasma concentrations were 0.56 and 0.3 mg/L, respectively). Extensive clinical data have shown that epidural ropivacaine 0.2% is effective for the initiation and maintenance of labour analgesia, and provides pain relief after abdominal or orthopaedic surgery especially when given in conjunction with opioids (coadministration with opioids may also allow for lower concentrations of ropivacaine to be used). The drug had efficacy generally similar to that of the same dose of bupivacaine with regard to pain relief but caused less motor blockade at low concentrations. Lumbar epidural administration of 20 to 30ml ropivacaine 0.5% provided anaesthesia of a similar quality to that achieved with bupivacaine 0.5% in women undergoing caesarean section, but the duration of motor blockade was shorter with ropivacaine. For lumbar epidural anaesthesia for lower limb or genitourinary surgery, comparative data suggest that higher concentrations of ropivacaine (0.75 or 1.0%) may be needed to provide the same sensory and motor blockade as bupivacaine 0.5 and 0.75%. In patients about to undergo upper limb surgery, 30 to 40ml ropivacaine 0.5% produced brachial plexus anaesthesia broadly similar to that achieved with equivalent volumes of bupivacaine 0.5%, although the time to onset of sensory block tended to be faster and the duration of motor block shorter with ropivacaine. Ropivacaine had an adverse event profile similar to that of bupivacaine in clinical trials. Several cases of CNS toxicity have been reported after inadvertent intravascular administration of ropivacaine, but only 1 case of cardiovascular toxicity has been reported to date. The outcome of these inadvertent intravascular administrations was favourable. CONCLUSION: Ropivacaine is a well tolerated regional anaesthetic with an efficacy broadly similar to that of bupivacaine. However, it may be a preferred option because of its reduced CNS and cardiotoxic potential and its lower propensity for motor block.

Nateglinide.

Nateglinide is a novel D-phenylalanine derivative that inhibits ATP-sensitive K+ channels in pancreatic beta-cells in the presence of glucose and thereby stimulates the prandial release of insulin. Nateglinide reduces fasting and mealtime blood glucose levels in animals, healthy volunteers, and patients with type 2 (non-insulin-dependent) diabetes mellitus, and produces prompt prandial insulin responses with return to baseline insulin levels between meals. In randomised, double-blind 24-week studies in patients with type 2 diabetes, oral nateglinide 120 mg 3 times daily before meals improved glycaemic control significantly relative to placebo. Nateglinide 120 mg plus metformin 500 mg, both 3 times daily, conferred greater glycaemic improvement than either drug given alone, and nateglinide 60 or 120 mg 3 times daily plus metformin 1 g twice daily was superior to metformin plus placebo. Nateglinide 120 mg 3 times daily significantly reduced hyperglycaemia relative to placebo in a 16-week double-blind study in patients with type 2 diabetes mellitus. Combination therapy with troglitazone 600 mg daily produced significantly better glycaemic control than either drug given as monotherapy. Mild hypoglycaemia was the most frequently reported adverse event (1.3% of patients) after treatment with nateglinide 120 mg 3 times daily in a 16-week clinical study. No clinically significant abnormalities in laboratory results, ECGs, vital signs or physical examination findings have been noted in patients taking the drug.

Esomeprazole.

Esomeprazole, a new proton pump inhibitor, is the S-isomer of omeprazole and is the first such inhibitor to be developed as a single isomer. Esomeprazole provided better control of intragastric pH than omeprazole, lansoprazole and pantoprazole in trials conducted in patients with gastro-oesophageal reflux disease (GORD) or healthy volunteers (n = 20 to 115). In 2 large randomised, double-blind multicentre trials esomeprazole 20 and/or 40mg for 8 weeks produced higher healing rates of erosive oesophagitis and better symptom control than omeprazole 20 mg in patients with GORD. Esomeprazole 10, 20 or 40mg once daily for 6 months maintained healing versus placebo (p < 0.001) in patients with endoscopically confirmed healed erosive oesophagitis in 2 large randomised, double-blind multicentre trials. Similarly, symptom-driven on-demand use of esomeprazole effectively controlled symptoms of GORD (heartburn) for 6 months in 2 large placebo-controlled trials. Esomeprazole-based triple therapy for 7 days was as effective for eradication of Helicobacter pylori as longer omeprazole-based therapy in 2 randomised double-blind trials including about 450 patients each. Endoscopically confirmed ulcer healing 4 weeks after treatment initiation was reported in about 90% of patients with active duodenal ulcer in both treatment groups. Esomeprazole-based triple therapy for 10 days was more effective than esomeprazole plus clarithromycin for eradication of H. pylori in 233 patients.

The type IV phosphodiesterase specific inhibitor mesopram inhibits experimental autoimmune encephalomyelitis in rodents.

Experimental autoimmune encephalomyelitis (EAE) is an autoimmune disease with pathological features reminiscent of those seen in multiple sclerosis and thus serves as an animal model for this disease. Inhibition of type IV phosphodiesterase (PDE IV) in animals with this disease has been shown to result in amelioration of disease symptoms. Here we describe the immunomodulatory activity of the novel potent and selective PDE IV inhibitor mesopram. In vitro, mesopram selectively inhibits the activity of type 1 helper T (Th1) cells without affecting cytokine production or proliferation of type 2 helper T (Th2) cells. Administration of mesopram to rodents inhibits EAE in various models. Clinically, EAE is completely suppressed by mesopram in Lewis rats. This is accompanied by a reduction of inflammatory lesions in spinal cord and brain. RT-PCR analysis revealed a marked reduction in the expression of interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) in the brains of these animals. Furthermore, the ex vivo production of Th1 cytokines by activated spleen cells derived from mesopram-treated animals is significantly reduced compared to vehicle-treated controls. Amelioration of the clinical symptoms is also observed during chronic EAE in mesopram-treated SJL mice as well as in relapsing-remitting EAE in SWXJ mice using a therapeutic treatment regimen. These data demonstrate the anti-inflammatory activity of mesopram and provide a rationale for its clinical development.

Ganirelix.

Ganirelix is a synthetic third generation gonadotropin-releasing hormone (GnRH) antagonist that is administered via the subcutaneous route. The drug competitively blocks GnRH receptors in the anterior pituitary gland, preventing endogenous GnRH from inducing luteinising hormone (LH) and follicle stimulating hormone release. Ganirelix effectively inhibited LH surges during controlled ovarian stimulation in a large, multicentre clinical trial in women undergoing in vitro fertilisation. A vital pregnancy rate per embryo transfer of 40.3% was achieved at weeks 5 to 6 after treatment with the 0.25 mg/day dosage. Subcutaneous ganirelix has been generally well tolerated in clinical trials. The most common adverse events were local injection site events, asthenia, nausea, malaise, headache and fatigue.

Inhaled fluticasone propionate. A pharmacoeconomic review of its use in the management of asthma.

UNLABELLED: Contemporary asthma management guidelines list inhaled corticosteroids as the preferred controller medication for patients with persistent asthma. Despite the availability of explicit guidelines, there is evidence that these agents are underused and that guidelines are not always adhered to. Fluticasone propionate is one of several inhaled corticosteroids used for the treatment of asthma. Like other agents of its class, its efficacy is backed by extensive clinical data. More recently, the quality of life of recipients of fluticasone propionate and its relative cost effectiveness have been investigated. A series of comparative analyses show that inhaled fluticasone propionate is more cost effective than oral zafirlukast and triamcinolone acetonide and slightly more cost effective than flunisolide in adult patients with asthma. Analyses used cost per symptom-free day and/or cost per successfully treated patient as outcome measures and were generally conducted from the perspective of the third-party payer. When administered at a microgram dose of half or less than budesonide (as is therapeutically appropriate), the cost effectiveness of fluticasone propionate was similar to or better than that of budesonide. In children, fluticasone propionate was more cost effective per treatment success compared with inhaled sodium cromoglycate. Quality-of-life assessments in patients with mild to moderate disease show that inhaled fluticasone propionate achieved improvements which were deemed to be clinically meaningful in patients with mild to moderate asthma; these changes were significantly greater than those achieved with oral zafirlukast, inhaled triamcinolone acetonide or placebo. Greater improvements were evident with inhaled fluticasone propionate in patients with severe disease. CONCLUSIONS: In addition to the considerable body of clinical evidence supporting the use of inhaled fluticasone propionate in patients with asthma, accumulating short term cost-effectiveness data also suggest that this agent can be administered for a similar or lower cost per outcome than other inhaled corticosteroids or oral zafirlukast. Importantly, the clinical benefits offered by fluticasone propionate in patients with persistent asthma are accompanied by clinically significant improvements in quality of life.

Lopinavir.

Lopinavir is a protease inhibitor with high specificity for HIV-1 protease. Ritonavir strongly inhibits lopinavir metabolism; coadministration of lopinavir and ritonavir in healthy volunteers increased the area under the lopinavir plasma concentration-time curve >100-fold. Trough plasma concentration: antiviral 50% effective concentration ratio for lopinavir was >75 for wild-type HIV at the dose used in clinical trials, compared to values of < or = 4 for other commonly used protease inhibitors. Coformulated lopinavir and ritonavir (lopinavir/ ritonavir) 400/100mg twice daily for 48 weeks suppressed HIV replication in significantly more antiretroviral-naive patients than nelfinavir 750mg 3 times daily (all patients also received stavudine and lamivudine). Suppression of viral replication was observed in most protease inhibitor-experienced patients with lopinavir/ ritonavir (400/100, 400/200 or 533/133mg twice daily for 48 or 96 weeks) in combination with > or = 2 nucleoside reverse transcriptase inhibitors (NRTIs) and either efavirenz or nevirapine. 48 weeks of treatment with twice daily lopinavir/ ritonavir (230/57.5 or 300/75 mg/m2 for the first 12 weeks and then 300/75 mg/m2) in combination with 1 or2 NRTIs, with or without nevirapine, suppressed viral replication in the majority of antiretroviral-naive and -experienced paediatric patients (aged 6 months to 12 years). Diarrhoea, nausea and asthenia were the most frequently reported adverse effects in patients receiving lopinavir/ritonavir-based regimens. Elevated total cholesterol, triglyceride and hepatic enzyme levels were also reported.

Rizatriptan: a review of its efficacy in the management of migraine.

UNLABELLED: Rizatriptan is an orally active serotonin 5-HT1 receptor agonist selective for the 5-HT(1B/1D) subtypes. The efficacy of oral rizatriptan (5 or 10 mg) has been demonstrated in large (n = 309 to 1746) well designed comparative trials with placebo and oral sumatriptan. Two hours postdose, rizatriptan 5 or 10 mg was more effective than placebo at producing pain relief or a pain free status, relieving migraine-associated symptoms and normalising functional ability. In general, rizatriptan 10 mg appeared to be more effective than rizatriptan 5 mg. However, recurrence rates with rizatriptan 5 and 10 mg appeared to be similar to those with placebo. Patients were significantly more likely to achieve pain relief within 2 hours after receiving rizatriptan 5 mg than sumatriptan 25 mg and after rizatriptan 10 mg than sumatriptan 50 mg. This was also observed with rizatriptan 10 mg compared with sumatriptan 100 mg according to an age-adjusted and a prespecified per-protocol analysis. In general, rizatriptan was better than sumatriptan at relieving migraine-associated symptoms, particularly nausea, and in normalising functional ability depending on which doses were compared. The incidence of headache recurrence, time to onset of recurrence and the need for escape medication in nonresponders appeared to be similar between rizatriptan and sumatriptan. Over the 24 hours after the dose, rizatriptan 10 mg improved the quality of life of patients with migraine compared with placebo. Rizatriptan 10 mg also significantly improved work function compared with placebo and with sumatriptan 50 mg. Rizatriptan appears to be well tolerated with most adverse events being mild and transient. The most commonly experienced events included general digestive complaints, general neurological complaints, dizziness, somnolence, asthenia/fatigue and pain and pressure sensations. In clinical trials, the overall incidence of adverse events with rizatriptan 5 or 10 mg was similar to that with sumatriptan 25 or 50 mg but lower than that with sumatriptan 100 mg. Chest pain was reported by 1 to 3% of rizatriptan recipients and by 3 to 6% of patients receiving sumatriptan (25, 50 or 100 mg); clinically significant effects on ECG parameters, heart rate or blood pressure were not observed with rizatriptan. CONCLUSIONS: Rizatriptan produces pain relief and a pain free status, relieves associated symptoms of migraine, normalises functional ability and improves patient quality of life. Rizatriptan 10 mg appears to be more effective than rizatriptan 5 mg. In comparison with oral sumatriptan, rizatriptan may provide better relief from pain and nausea, with some evidence of a faster onset of action. Thus, rizatriptan 5 or 10 mg is likely to establish a place as an effective and well tolerated agent for the management of acute migraine.

Vinorelbine in advanced non-small cell lung cancer. A pharmacoeconomic review.

UNLABELLED: Vinorelbine is a semisynthetic vinca alkaloid that is effective against advanced non-small cell lung cancer (NSCLC). Myelosuppression is the primary dose-limiting toxicity; vinorelbine is otherwise relatively well tolerated. Two studies assessed the cost effectiveness of vinorelbine with or without cisplatin based primarily on data from a phase III comparison with vindesine plus cisplatin. Survival and cost data from this study were supplemented with those from other sources. One model simulated total management costs for the 4986 patients diagnosed with stage IV NSCLC in Canada in 1992. The other applied US cost data to the outcomes from the phase III trial. Using vinorelbine monotherapy or vinorelbine plus cisplatin produced a survival benefit and net cost savings compared with best supportive care according to the Canadian model (and preliminary data from a third analysis, conducted in the US). In the Canadian analysis, incremental cost effectiveness for inpatient or outpatient vinorelbine plus cisplatin ranged from 7450 Canadian dollars ($Can) to $Can30,770 (1993 values) per year of life saved (YLS) compared with outpatient cisplatin plus either etoposide or vinblastine. Cost-effectiveness ratios for vinorelbine plus cisplatin in the US analysis (1994 values) were $US18,000 (vs cisplatin plus etoposide) and $US15,500 (vs cisplatin plus vindesine) per YLS [all inpatient administration]. Detailed pharmacoeconomic comparisons with other current standard regimens (e.g. paclitaxel plus either cisplatin or carboplatin) are not available. Sensitivity analyses suggest that the cost effectiveness of vinorelbine-based therapy is robust to changes in assumptions regarding efficacy and the cost of managing toxicity. Limitations of the available pharmacoeconomic data include the retrospective nature of the analyses, inclusion of data from sources other than the main phase III trial (e.g. those for best supportive care and some chemotherapy regimens), and exclusion of some costs for hospitalisation and/or management of toxicity. CONCLUSIONS: Although some limitations apply, the available data suggest that vinorelbine alone or in combination with cisplatin is cost saving compared with best supportive care for NSCLC, and that vinorelbine plus cisplatin is cost effective compared with some other combination regimens. The pharmacoeconomic placing of vinorelbine in relation to a number of other currently recommended first-line treatments for NSCLC has yet to be resolved, and data from ongoing multicentre phase III trials are awaited with interest. In the meantime, vinorelbine-based chemotherapy appears to be a suitable choice for first-line treatment of advanced NSCLC from both clinical and pharmacoeconomic perspectives.

Lamivudine. A review of its therapeutic potential in chronic hepatitis B.

UNLABELLED: Lamivudine is a deoxycytidine analogue that is active against hepatitis B virus (HBV). In patients with chronic hepatitis B, lamivudine profoundly suppresses HBV replication. Clinically significant improvements in liver histology and biochemical parameters were obtained with lamivudine in double-blind, randomised, trials in hepatitis B e antigen (HBeAg)-positive patients with chronic hepatitis B and compensated liver disease. After 52 weeks of treatment, relative to placebo (< or = 25%), significantly more Chinese (56%) or Western patients (52%) treated with lamivudine 100 mg/day had reductions of > or = 2 or more points in Knodell necro-inflammatory scores. Moreover, significantly fewer lamivudine 100 mg/day than placebo recipients had progressive fibrosis in liver biopsies (< or = 5 vs > or = 15%) and fewer lamivudine- than placebo-treated patients progressed to cirrhosis (1.8 vs 7.1%). More lamivudine 100 mg/day than placebo recipients acquired antibodies to HBeAg after 52 weeks (16 vs 4% in Chinese patients and 17 vs 6% in Western patients). ALT levels normalised in significantly more lamivudine than placebo recipients enrolled in these trials. In HBeAg-negative, HBV DNA positive patients with compensated liver disease enrolled in a double-blind, randomised study, HBV DNA levels were suppressed to below the limit of detection (< 2.5 pg/ml) and ALT levels normalised in 63% and 6% of patients treated with lamivudine 100 mg/day or placebo for 24 weeks. Clinically significant improvements in liver histology were obtained in 60% of patients treated with lamivudine for 52 weeks in this study. Lamivudine 100 mg/day for 52 weeks produced similar or significantly greater improvements in liver histology and ALT levels than 24 weeks' treatment with lamivudine plus interferon-alpha. In liver transplant candidates with chronic hepatitis B and end-stage liver disease, lamivudine 100 mg/day alone, or in combination with hepatitis B immune globulin, generally suppressed HBV replication and appeared to protect the grafted liver from reinfection. Lamivudine 100 mg/day suppressed viral replication and improved liver histology in liver transplant recipients with recurrent or de novo chronic hepatitis B. Lamivudine 300 or 600 mg/day reduced HBV replication in HIV-positive patients. The incidence of adverse events in patients with chronic hepatitis B and compensated liver disease treated with lamivudine 100 mg/day or placebo for 52 to 68 weeks was similar. 3.1- to 10-fold increases in ALT over baseline occurred in 13% of patients during treatment with lamivudine 100 mg/day or placebo for 52 weeks. Post-treatment ALT elevations were more common in lamivudine than placebo recipients; however, these generally resolved spontaneously; < or = 1.5% of lamivudine- or placebo-treated patients experienced hepatic decompensation. CONCLUSION: Lamivudine inhibits HBV replication, reduces hepatic necro-inflammatory activity and the progression of fibrosis in patients with chronic hepatitis B, ongoing viral replication and compensated liver disease including HBeAg-negative patients. The drug also suppresses viral replication in liver transplant recipients and HIV-positive patients. Thus, lamivudine is potentially useful in a wide range of patients with chronic hepatitis B and ongoing viral replication.

Etanercept: a review of its use in rheumatoid arthritis.

UNLABELLED: Etanercept, a fusion protein consisting of the extracellular ligand-binding domain of the 75kD receptor for tumour necrosis factor-alpha and the constant portion of human IgG1, is administered by subcutaneous injection and is the first specific anti-cytokine therapy approved for rheumatoid arthritis. In patients with active rheumatoid arthritis [American College of Rheumatology (ACR) functional class I to III] who had failed to respond to previous treatment with > or = 1 disease-modifying antirheumatic drug (DMARD), etanercept, alone or in combination with methotrexate, produced improvements in all components included in the ACR core set of disease activity measures. A dose-response effect was apparent with etanercept 0.25 to 16 mg/m2 twice weekly in a randomised, double-blind study in 180 patients. The mean number of swollen or tender joints at the end of the 12-week study decreased by >50% in patients treated with etanercept 16 mg/m2 twice weekly and by <25% in patients treated with placebo. In a 24-week multicentre, randomised, double-blind study in 234 patients who were not allowed to use DMARDs, etanercept 10 or 25mg twice weekly had a rapid onset of effect. Significantly more patients treated with etanercept 25mg twice weekly than placebo experienced 20 (ACR 20), 50 (ACR 50) or 70% (ACR 70) improvement in ACR criteria after 3 and 6 months. Limited evidence suggests that the therapeutic effects of etanercept are maintained for up to 2 years. Etanercept 25mg twice weekly produced significant improvement in patients receiving oral or subcutaneous methotrexate 10 to 25 mg/week in a multicentre, randomised, double-blind, placebo-controlled study. A significantly greater proportion of patients treated with etanercept plus methotrexate (71%) than placebo plus methotrexate (27%) achieved the ACR 20 criteria after 6 months. Moreover, 39 and 15% of patients treated with etanercept plus methotrexate, but no placebo plus methotrexate recipients, had achieved the ACR 50 and ACR 70 criteria at this time. Etanercept 0.4 mg/kg twice weekly reduced disease activity in a preliminary, noncomparative study in 69 children aged > or =4 years with refractory juvenile rheumatoid arthritis. Although the overall frequency of infections was similar in patients treated with etanercept or placebo, upper respiratory tract infections were more common in patients treated with etanercept (29%) than placebo (16%). Injection site reactions occurred more frequently in etanercept- than placebo-treated patients, but did not bias the results of any study. CONCLUSIONS: When etanercept is administered alone or in combination with methotrexate in patients with refractory rheumatoid arthritis, significant reductions in disease activity occur within 2 weeks and are sustained for at least 6 months. Thus, etanercept appears to be particularly well suited for use in patients who fail to respond to treatment with DMARDs.

Inhaled fluticasone propionate: a review of its therapeutic efficacy at dosages < or = 500 microg/day in adults and adolescents with mild to moderate asthma.

UNLABELLED: Fluticasone propionate is a corticosteroid with comparatively high receptor affinity and topical activity. Inhaled fluticasone propionate < or =500 microg/day provided effective corticosteroid maintenance treatment in patients with mild to moderate asthma in randomised, controlled clinical studies of 4 to 24 weeks in duration. Dosages of 50 to 250 microg twice daily produced consistent improvement in spirometric measures of lung function, reduced the frequency of as-needed beta2-agonist bronchodilator use, asthma symptom scores and night-time wakenings, and prevented asthma exacerbations compared with placebo. Fluticasone propionate < or =250 microg twice daily provided significantly greater improvements in lung function than nedocromil 4 mg 4 times daily, theophylline (5 to 15 mg/L) or zafirlukast 20 mg twice daily. Health-related quality of life improved significantly with fluticasone propionate 88 microg twice daily, but not zafirlukast 20 mg twice daily or placebo. In comparative trials in which fluticasone propionate was given at half the dosage of beclomethasone dipropionate, budesonide or flunisolide, fluticasone propionate < or =250 microg twice daily produced equivalent or greater improvement in spirometric parameters and equivalent reductions in the use of as-needed beta2-agonists than beclomethasone dipropionate, budesonide or flunisolide. Fluticasone propionate 250 microg twice daily was generally more effective than triamcinolone acetonide 200 microg 4 times daily in two 24-week trials. The combination of inhaled fluticasone propionate < or =250 plus salmeterol < or =50 microg twice daily allowed for the use of lower dosages of the inhaled corticosteroid. The incidence of adverse events in patients receiving inhaled fluticasone propionate 50 to 250 microg twice daily was similar to that in beclomethasone dipropionate 168 to 500 microg twice daily and budesonide 100 to 600 microg twice daily recipients and greater than that in recipients of triamcinolone acetonide 200 microg 4 times daily in comparative trials. The incidence of oral candidiasis was < or =8% in patients treated with fluticasone propionate < or =250 microg twice daily or other agents. There was no evidence of clinically significant hypothalamo-pituitary-adrenal (HPA) axis suppression with fluticasone propionate < or =250 microg twice daily in comparative trials. CONCLUSIONS: Inhaled fluticasone propionate < or =500 microg/day is an effective antiinflammatory therapy for mild to moderate asthma in adolescents and adults. The drug is more effective than nedocromil, theophylline or zafirlukast and is at least as effective as other inhaled corticosteroids administered at twice the fluticasone propionate dosage. The addition of inhaled salmeterol allows the use of lower maintenance dosages of fluticasone propionate. The drug is well tolerated and there is no evidence of a clinically significant effect of this dosage on HPA axis function. Hence, fluticasone propionate < or =500 microg/day is a particularly suitable agent for patients with mild to moderate asthma.

Troglitazone: a review of its use in the management of type 2 diabetes mellitus.

UNLABELLED: Troglitazone is the first of a new group of oral antidiabetic drugs, the thiazolidinediones, and is indicated for the treatment of patients with type 2 (non-insulin-dependent) diabetes mellitus. Troglitazone acts by enhancing the effects of insulin at peripheral target sites and, unlike the sulphonylurea drugs, is not associated with hypoglycaemia when administered as monotherapy. Clinical trials with troglitazone (usually 200 to 600 mg/day) in patients with type 2 diabetes mellitus consistently showed marked improvement in glycaemic control, as well as reductions in fasting serum insulin, C-peptide and triglyceride levels. Comparative studies with either glibenclamide (glyburide) or metformin indicated similar glycaemic control with troglitazone or these agents. Serum insulin levels were lower with troglitazone than with glibenclamide. Clinical trials of up to approximately 2 years' duration showed that glycaemic control is maintained with troglitazone on a long term basis. In general, troglitazone is well tolerated by the majority of patients. However, discontinuation of troglitazone because of elevated liver enzyme levels occurs in approximately 2% of patients receiving the drug, and frequent monitoring of liver enzymes is required (e.g. at least 11 times during the first year of therapy). Among patients who started troglitazone therapy in 1998 (after the incorporation of a boxed warning and increased monitoring requirements in the product labelling), the estimated risk of liver-related death is approximately 1 in 100,000. CONCLUSIONS: Troglitazone improves the ability of target cells to respond to insulin. The drug has been shown to improve glycaemic control in patients with type 2 diabetes mellitus when used as monotherapy or in combination with other oral antidiabetic drugs or insulin, and its efficacy is similar to that of glibenclamide or metformin. Although troglitazone is generally well tolerated, close monitoring of liver enzyme function is required to minimise the rare occurrence of serious hepatic dysfunction. Drug acquisition and liver function monitoring costs, as well as potential adverse effects, are important factors that may ultimately determine the precise place of troglitazone in the management of type 2 diabetes mellitus. Nevertheless, as the first member of a new class of oral antidiabetic agents, the thiazolidinediones, troglitazone offers an effective treatment option in patients with type 2 diabetes mellitus through its action of improving insulin sensitivity.

Daclizumab: a review of its use in the prevention of acute rejection in renal transplant recipients.

UNLABELLED: The humanised monoclonal antibody daclizumab is an immunosuppressive agent that reduces acute rejection in renal transplant recipients. It is specific for the alpha subunit (Tac/CD25) of the interleukin-2 (IL-2) receptor on activated T cells and achieves immunosuppression by competitive antagonism of IL-2-induced T cell proliferation. Daclizumab has advantages over murine antibodies to the IL-2 receptor, including improved effector function, a low potential for immunogenicity and long elimination half-life. When added to standard cyclosporin-based immunosuppressive therapy with or without azathioprine, daclizumab (1 mg/kg prior to surgery and once every 2 weeks thereafter for a total of 5 doses) significantly reduced the 6-month rate of acute rejection compared with placebo in 2 phase III studies. The mean number of rejection episodes was significantly reduced and the time to first acute rejection significantly increased in daclizumab versus placebo recipients. Patient survival at 1 year after transplantation was significantly higher with daclizumab than placebo in 1 study and showed a trend in favour of the drug in the other study. The 1-year graft survival rate tended to be greater in daclizumab than in placebo recipients in both studies, In a phase II study, acute rejection rates in patients treated with both daclizumab and mycophenolate mofetil (plus standard cyclosporin-based immunosuppression) were lower than those achieved with mycophenolate mofetil alone. Preliminary results indicate that daclizumab is also a useful agent in paediatric renal transplant recipients. Further investigation of the efficacy and tolerability of the drug in this patient group is clearly warranted. Daclizumab does not increase the incidence of adverse events when added to standard cyclosporin-based therapy. The incidence of opportunistic infections, lymphoproliferative disorders and malignancies was not increased above that seen with placebo. CONCLUSIONS: Although the effects of daclizumab on long term graft and patient survival require further investigation, available data indicate that daclizumab is an important advance in renal transplant immunosuppression, reducing acute graft rejection without affecting the tolerability of standard cyclosporin-based immunosuppression.

Quinupristin/dalfopristin: a review of its use in the management of serious gram-positive infections.

UNLABELLED: Quinupristin/dalfopristin is the first parenteral streptogramin antibacterial agent, and is a 30:70 (w/w) ratio of 2 semisynthetic pristinamycin derivatives. The combination has inhibitory activity against a broad range of gram-positive bacteria including methicillin-resistant staphylococci, vancomycin-resistant Enterococcus faecium (VREF), drug-resistant Streptococcus pneumoniae, other streptococci, Clostridium perfringens and Peptostreptococcus spp. The combination also has good activity against selected gram-negative respiratory tract pathogens including Moraxella catarrhalis, Legioniella pneumophila and Mycoplasma pneumoniae. Quinupristin/dalfopristin has poor activity against E. faecalis. The combination is bactericidal against staphylococci and streptococci, although constitutive erythromycin resistance can affect its activity. As for many other agents, quinupristin/dalfopristin is generally bacteriostatic against E. faecium. In patients with methicillin-resistant S. aureus (MRSA) or VREF infections participating in prospective emergency-use trials, quinupristin/dalfopristin 7.5 mg/kg every 8 or 12 hours achieved clinical or bacteriological success in > or =64% of patients. Emergence of resistance to quinupristin/dalfopristin was uncommon (4% of patients) in those with VREF infections. Quinupristin/dalfopristin 7.5 mg/kg 8- or 12-hourly also achieved similar clinical success rates to comparator agents in patients with presumed gram-positive complicated skin and skin structure infections or nosocomial pneumonia (administered in combination with aztreoman) in 3 large multicentre randomised trials. Systemic adverse events associated with quinupristin/dalfopristin include gastrointestinal events (nausea, vomiting and diarrhoea), rash and pruritus. Myalgias and arthralgias also occur at an overall incidence of 1.3%, although higher rates (2.5 to 31%) have been reported in patients with multiple comorbidities. Venous events are common if the drug is administered via a peripheral line; however, several management options (e.g. use of central venous access, increased infusion volume) may help to minimise their occurrence. Hyperbilirubinaemia has been documented in 3.1% of quinupristin/dalfopristin recipients versus 1.3% of recipients of comparator agents. Quinupristin/dalfopristin inhibits cytochrome P450 3A4 and therefore has the potential to increase the plasma concentrations of substrates of this enzyme. CONCLUSIONS: Quinupristin/dalfopristin, the first parenteral streptogramin, offers a unique spectrum of activity against multidrug-resistant gram-positive bacteria. In serious gram-positive infections for which there are other treatment options available, the spectrum of activity and efficacy of quinupristin/ dalfopristin should be weighed against its tolerability and drug interaction profile. However, in VREF or unresponsive MRSA infections, where few proven treatment options exist, quinupristin/dalfopristin should be considered as a treatment of choice for these seriously ill patients.

Repaglinide.

Repaglinide is a novel insulin secretagogue being developed for the management of type 2 (non-insulin-dependent) diabetes mellitus. It stimulates release of insulin from the pancreatic beta-cell, but appears to bind to a different receptor site from sulphonylureas. Repaglinide lowers fasting and postprandial blood glucose levels in animals, healthy volunteers and patients with type 2 diabetes mellitus. Repaglinide is rapidly absorbed and eliminated, which may allow a relatively fast onset and offset of action. Excretion occurs almost entirely by non-renal mechanisms. In comparative clinical trials in patients with type 2 diabetes mellitus, repaglinide 0.5 to 4 mg twice or 3 times daily before meals provided similar glycaemic control to glibenclamide (glyburide) 2.5 to 15 mg/day. Addition of repaglinide to existing metformin therapy resulted in improved glycaemic control. In contrast with glibenclamide, use of repaglinide allowed patients to miss a meal without apparently increasing the risk of hypoglycaemia.

An orphan seven-transmembrane domain receptor expressed widely in the brain functions as a coreceptor for human immunodeficiency virus type 1 and simian immunodeficiency virus.

Both CD4 and an appropriate coreceptor are necessary for infection of cells by human immunodeficiency virus type 1 (HIV-1) and most strains of HIV-2. The chemokine receptors CCR5 and CXCR4 are the major HIV-1 coreceptors, although some virus strains can also utilize alternative coreceptors such as CCR3 to infect cells. In contrast, most if not all simian immunodeficiency virus (SIV) strains use CCR5 as a coreceptor, and many SIV strains can use CCR5 independently of CD4. In addition, several orphan seven-transmembrane receptors which can serve as HIV-1 and SIV coreceptors have been identified. Here we report that APJ, an orphan seven-transmembrane domain receptor with homology to the angiotensin receptor family, functions as a coreceptor for a number of HIV-1 and SIV strains. APJ was expressed widely in the human brain and in NT2N neurons. APJ transcripts were also detected by reverse transcription-PCR in the CD4-positive T-cell line C8166, but not in peripheral blood leukocytes, microglia, phytohemagglutinin (PHA)- or PHA/interleukin-2-stimulated peripheral blood mononuclear cells, monocytes, or monocyte-derived macrophages. The widespread distribution of APJ in the central nervous system coupled with its use as a coreceptor by some HIV-1 strains indicates that it may play a role in neuropathogenesis.

Montelukast.

Montelukast is a selective antagonist of the leukotriene D4 (LTD4) receptor. In patients with asthma, montelukast 5 to 250 mg/day attenuated LTD4-induced bronchoconstriction and, at a dosage of 10 mg, significantly reduced early and late airway response to allergen (dust mite extract) relative to placebo. In studies evaluating the effects of various dosages of montelukast on exercise-induced bronchoconstriction the optimal dose of the drug was found to be 10 mg. Montelukast 10 mg/day controlled asthma significantly more effectively than placebo in a 3-month randomised double-blind study. In a 9-month open extension of this trial, during which patients were randomised to treatment with montelukast 10 mg/day or beclomethasone (approximately 400 micrograms/day), daytime symptom score and beta-agonist use decreased to a similar extent in each group. In a further study, treatment with montelukast 10 mg/day permitted clinically significant tapering of corticosteroid dosage in patients with stable asthma. Montelukast (5 mg/day) has also demonstrated efficacy in childhood asthma. The tolerability profile of montelukast was similar to that of placebo in placebo-controlled clinical trials in adults and children; the most common adverse event was headache.

Ganciclovir. An update of its use in the prevention of cytomegalovirus infection and disease in transplant recipients.

UNLABELLED: Ganciclovir is a nucleoside analogue which is used to treat and prevent cytomegalovirus (CMV) infection. Most recent clinical studies of ganciclovir in transplant recipients have focused on preventive approaches. When ganciclovir was last reviewed in Drugs in 1994, substantial data on post-transplantation CMV prophylaxis with this drug were available only for patients undergoing allogeneic bone marrow transplantation (BMT). Two strategies had emerged: prophylaxis for all patients or early treatment started after detection of asymptomatic CMV infection. Subsequently, a large double-blind study has shown that ganciclovir prophylaxis is more effective than early treatment in preventing early CMV disease after allogeneic BMT and is not associated with an increased incidence of neutropenia. However, mortality for the 2 strategies was similar. The efficacy of prophylactic intravenous ganciclovir in liver transplant recipients [including high risk donor seropositive/recipient seronegative (D+/R-) or antilymphocyte-treated patients] is now well established. Prophylaxis with oral ganciclovir was effective both overall and in D+/R-patients in a large placebo controlled study, and prolonged intravenous ganciclovir was significantly more effective than high dose aciclovir (acyclovir) in seropositive liver recipients. Early treatment with ganciclovir has proved useful in this setting. More limited data indicate that CMV prophylaxis with intravenous ganciclovir may be useful after heart or lung transplantation but its value in D+/-patients remains unclear. Combined chemoimmunotherapy may be valuable in these high risk patients but controlled data are lacking. Targeted prophylaxis with intravenous ganciclovir is effective in renal transplant recipients receiving antilymphocyte therapy; the role of oral ganciclovir in this setting is less clear. The value of ganciclovir in D+/- renal transplant recipients and its efficacy compared with high dose aciclovir have not been determined. CONCLUSIONS: Ganciclovir is the only antiviral chemotherapy which reduces the risk of CMV infection or disease after most types of major transplantation. Unresolved issues include the best (and most cost-effective) use of ganciclovir and aciclovir after allogeneic BMT, the efficacy of oral ganciclovir compared with other anti-CMV regiments, the potential clinical effect of viral resistance during prolonged ganciclovir exposure and the value of ganciclovir in certain high risk transplant populations. In the meantime, ganciclovir has an important role in the prevention of CMV infection and disease after bone marrow and liver transplantation and is likely to gain wider clinical use in heart, lung and kidney transplant recipients.

Nelfinavir. A review of its therapeutic efficacy in HIV infection.

UNLABELLED: Nelfinavir is a selective inhibitor of HIV protease, the enzyme responsible for post-translational processing of HIV propeptides. In the presence of the drug, immature, noninfectious virus particles are produced. Nelfinavir in combination with nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors and/or other protease inhibitors profoundly suppresses viral replication. Plasma HIV RNA levels (viral loan) rapidly fall below the limit of detection (LOD; usually 400 or 500 copies/ml in the majority of patients. When used in combination with NRTIs, nelfinavir 1250mg twice daily produced similar results to 3-times-daily nelfinavir at a range of total daily dosages. In an ongoing study > 70% of adults receiving a nelfinavir based combination regimen had plasma HIV RNA levels below the LOD (< 400 copies/ml) after 84 weeks. In addition, 73% of paediatric patients receiving nelfinavir plus at least 1 new NRTI had viral loads below the LOD (< 400 copies/ml) after 34 weeks. Furthermore, CD4+ cell counts generally increased in conjunction with reductions in viral load. Combination therapy with nelfinavir and saquinavir results in higher saquinavir plasma concentrations, make twice-daily administration of saquinavir feasible and may delay the emergence of resistant viral strains. A unique mutation at codon 30 (D30N) of the protease gene confers resistance to nelfinavir, but HIV with D30N mutation remains fully susceptible to indinavir, ritonavir and saquinavir in vitro. Nonetheless, in clinical use, significant cross-resistance is seen with all currently available protease inhibitors. Diarrhoea is the most frequently reported adverse event in patients receiving nelfinavir-based combination therapy and has been reported in up to 32% of nelfinavir recipients in randomised trials. Diarrhoea is generally of mild to moderate severity and does not result in weight loss. Rash, nausea, headache and asthenia were each reported in < or = 5% of patients. Approximately 5% of patients enrolled in an expanded access programme in the US discontinued nelfinavir because of adverse events. Nelfinavir is metabolised by the cytochrome P450 system. Several clinically significant pharmacokinetic drug interactions between nelfinavir and other drugs (i.e. ketoconazole, rifabutin, rifabutin, rifampicin), including other protease inhibitors (i.e. indinavir, ritonavir, saquinavir) have been documented. As with other available protease inhibitors, hyperglycaemia, hyperlipidaemia and abnormal fat distribution have been reported, albeit infrequently, in association with nelfinavir. CONCLUSION: Nelfinavir-based combination regimens are well tolerated and produce profound and prolonged suppression of HIV replication in adult and paediatric patients. Hence, nelfinavir is suitable for inclusion in antiretroviral regimens for initial therapy for HIV infection and, alternatively, in regimens for patients unable to tolerate other protease inhibitors.