Break-join recombination in phage lambda.

In phage lambda, when DNA replication is blocked, recombination mediated by the Red pathway occurs only near the double-chain break site, cos, that defines the termini of the virion chromosome. The recombinants initiated by cos contain newly synthesized DNA near cos, in amount corresponding to a few percent of the length of lambda. A restriction enzyme cut delivered to one parent far from cos results in elevated recombination near the restriction site. Recombinants induced by this cut have a similarly small amount of DNA synthesis in these replication-blocked crosses. When restriction cuts are introduced in the presence of normal amounts of all of the DNA replication enzymes, many of the resulting recombinants still enjoy, at most, a small amount of DNA synthesis associated with the exchange event. Thus, these experiments fail to support the previously considered possibility that Red-mediated recombination in lambda proceeds largely through a break-copy pathway.

Phosphodiesterase type IV inhibitors in the treatment of multiple sclerosis.

Multiple sclerosis is an autoimmune disease with inflammatory lesions localized to the white matter of the central nervous system. Early on, the disease is characterized by episodes of exacerbations and remissions. During exacerbations there is an acute inflammatory infiltrate characterized by the presence of mononuclear cells, monocytes, and T lymphocytes. These cells produce proinflammatory cytokines that have been implicated in the amplification of the inflammatory response as well as in the damage of oligodendrocytes. The inflammation ultimately results in loss of myelin and oligodendrocyte cell death (demyelination). Thus therapies aimed at preventing the inflammatory response may have a beneficial effect on the course of the disease. One such therapy is treatment with inhibitors of phosphodiesterase type IV. These drugs have proven to be extremely effective in the prevention and treatment of experimental allergic encephalomyelitis, the animal model for multiple sclerosis. These experiments, as well as other data discussed here, provide a rationale for the treatment of multiple sclerosis with inhibitors of phosphodiesterase type IV.

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.

Current options in the treatment of non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) is a leading cause of cancer death in industrialised countries, with an overall 5-year survival rate of less than 10%. Good patient performance status is associated with a significantly improved prognosis, whereas the presence of metastases, particularly to the bone or liver, is associated with a poor outcome. Disease staging has largely been standardised using the tumour, node, metastasis (TNM) system, and also provides significant prognostic information. More recently, several biomarkers have been identified in patients with NSCLC, although their prognostic relevance remains to be established. Surgery, when feasible, is the treatment of choice in patients with NSCLC. However, most patients present with locally advanced disease that is not completely resectable. The use of combination chemotherapy regimens has generally been restricted to patients with metastatic, recurrent or unresectable disease, and several relatively active drugs that are generally used in combination have been identified. Combination chemotherapy either alone, or with surgery and/or radiotherapy, has produced some improvements in response rates and, in the neoadjuvant setting, has allowed complete resection in an increased number of patients with otherwise marginally resectable disease. There is also evidence that this approach may increase both disease-free interval and survival time. Thus, the most active chemotherapy regimens (generally those including cisplatin and a vinca alkaloid) appear to provide some benefit in patients with advanced non-small cell lung cancer, but the identification of more active combinations remains a priority.

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.

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.

Theophylline. A review of its potential steroid sparing effects in asthma.

UNLABELLED: Theophylline is generally considered to be a bronchodilatory drug. However, recent pharmacodynamic studies indicate that it has anti-inflammatory effects. It reduced eosinophil survival rates in vitro, and reduced eosinophil accumulation in bronchial tissue in patients with atopic asthma. Theophylline has also been shown to reduce T cell proliferation and accumulation. These changes were mirrored by improved pulmonary function in patients with asthma in studies that evaluated this parameter. Three randomised double-blind studies have evaluated the potential role of theophylline as an anti-inflammatory treatment in patients with asthma not controlled by low doses of inhaled corticosteroids. Patients were randomised to receive low dose theophylline (400 to 750 mg daily) plus low dose inhaled corticosteroids, or an increased dose of inhaled corticosteroids. Clinical pulmonary function improved to the same or a greater extent in patients who received low dose inhaled corticosteroids plus theophylline than in those treated with high dose inhaled corticosteroids plus placebo. Where reported, the dosages of theophylline used in these studies resulted in serum theophylline concentrations of approximately 9 to 10 mg/L. Approximate monthly costs were provided in one study: these were $60 (year and currency not specified) for theophylline plus budesonide 800 micrograms/day, compared with $100 for budesonide 1600 micrograms/day, and $155 for a regimen of budesonide 800 micrograms/day and salmeterol 100 micrograms/day. CONCLUSIONS: Low dose theophylline has been shown to reduce requirements for inhaled corticosteroid therapy in patients with asthma and may reduce overall treatment costs.

Roxithromycin. An update of its antimicrobial activity, pharmacokinetic properties and therapeutic use.

Roxithromycin is a derivative of the macrolide antibacterial erythromycin with in vitro antibacterial activity resembling that of the parent compound. The drug has activity against some Staphylococcus spp., many Streptococcus spp., Moraxella (Branhamella) catarrhalis, Mycoplasma pneumoniae, Legionella pneumophila and Chlamydia trachomatis as well as many less common organisms. Measured using recently proposed guidelines, roxithromycin has in vitro activity against Haemophilus influenzae. In comparison with that of its parent compound, the pharmacokinetic profile of roxithromycin is characterised by high plasma, tissue and body fluid concentrations and a long half-life permitting an extended dosage interval. Roxithromycin has proven clinical efficacy in upper and lower respiratory infections, skin and soft tissue infections, urogenital infections and orodental infections, and appears to be as effective as more established treatments including erythromycin, amoxicillin/clavulanic acid and cefaclor. The drug has also shown promise in a variety of more specialised indications including opportunistic infections in human immunodeficiency virus (HIV)-positive patients and as part of a Helicobacter pylori eradication regimen. Roxithromycin is very well tolerated with an overall incidence of adverse events of approximately 4%. Thus, roxithromycin is an attractive therapeutic alternative in its established indications, especially when the option of once-daily administration is considered.

Ganciclovir. An update of its therapeutic use in cytomegalovirus infection.

The antiviral nucleoside analogue ganciclovir has demonstrated in vitro activity against human cytomegalovirus and effectively treats infection caused by this organism in various immunocompromised patient groups. The drug prolongs time to progression in patients with acquired immune deficiency syndrome (AIDS)-related cytomegalovirus retinitis although life-long maintenance therapy is required. Direct comparisons between ganciclovir and foscarnet in this indication are few; nevertheless, the 2 drugs appear to have equal therapeutic efficacy in treating cytomegalovirus retinitis although results from 1 study in this indication suggest that foscarnet has an advantage in terms of patient survival. AIDS-related gastrointestinal and, to a lesser extent, pulmonary cytomegalovirus infection also respond to treatment with ganciclovir; maintenance therapy does not appear to be required in these latter 2 indications. Ganciclovir is also useful against cytomegalovirus infection in organ transplant recipients. The drug is most effective when given prophylactically or as early treatment for asymptomatic infection in bone marrow transplant recipients; treatment of established infection is less effective in this patient group. However, established infection in solid organ transplant recipients appears to respond to treatment with ganciclovir. The most common adverse event during ganciclovir therapy is haematological toxicity but this appears to be readily reversible on discontinuation of the drug. In addition, coadministration of granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage CSF (GM-CSF) has been shown to prevent ganciclovir-associated neutropenia. Thus, ganciclovir is a valuable treatment for cytomegalovirus infection in patients with AIDS and in organ transplant recipients. Further studies comparing ganciclovir and foscarnet-ideally incorporating the use of G-CSF or GM-CSF to prevent ganciclovir-associated neutropenia and assessing survival as 1 endpoint--should further clarify the relative role of ganciclovir as treatment or prophylaxis for cytomegalovirus infection.

Saquinavir. A review of its pharmacology and clinical potential in the management of HIV infection.

Saquinavir is a peptide derivative which inhibits the HIV protease enzyme, preventing post-translational processing of viral polyproteins. It was the first agent of its class to become available for the treatment of HIV infection. Well controlled studies have assessed the effects of saquinavir, when used alone or in combination with reverse transcriptase inhibitors, in patients with advanced HIV infection. Analysis of CD4+ cell counts and measures of viral load in the ACTG 229 study suggest that triple therapy with saquinavir, zidovudine and zalcitabine is more effective than double therapy with saquinavir plus zidovudine or zidovudine plus zalcitabine in patients who have previously received long term treatment with zidovudine. Similar assessments from a small study in previously untreated patients suggest that double therapy with saquinavir plus zidovudine is more effective than monotherapy with either agent. Combination therapy with saquinavir and zalcitabine significantly reduced the time to the first AIDS-defining event or death, and the time to death, compared with zalcitabine alone, according to data from a large, long term study (NV 14256) in patients with advanced HIV infection who had previously received zidovudine. Saquinavir is generally well tolerated, either as monotherapy or in combination with reverse transcriptase inhibitors; no change in tolerability profile was reported when saquinavir was added to treatment with nucleoside analogues. In vitro and clinical studies have documented the emergence of saquinavir-resistant HIV strains. Although the possible impact of resistance on the clinical efficacy of saquinavir has yet to be fully characterised, genotypic and phenotypic resistance appear to develop slowly during treatment with saquinavir, and the drug does not appear to have a significant effect on the incidence of mutations associated with cross-resistance to other protease inhibitors. Thus, laboratory and clinical results suggest that saquinavir in combination with reverse transcriptase inhibitors is effective in the treatment of advanced HIV infection. Initial data on the effects of saquinavir on disease progression and mortality are promising, and the apparent absence of mutations conferring cross-resistance to other protease inhibitors is a potentially valuable clinical feature. Additional data on disease progression, mortality and viral resistance, together with information on relative efficacy (in comparison with other protease inhibitors), will need to be assessed before the clinical value of saquinavir can be fully determined. Nevertheless, saquinavir represents a valuable new pharmacological option for the treatment of HIV infection and is likely to be a useful component of combined therapy with reverse transcriptase inhibitors and/or other protease inhibitors.

Moxonidine. A review of its pharmacology, and therapeutic use in essential hypertension.

Interest in centrally acting antihypertensive agents has recently been renewed with the development of drugs that are associated with fewer central adverse effects (e.g. sedation, dry mouth) than the older drugs in this class. Moxonidine reduces sympathetic outflow and hence lowers blood pressure through stimulation of central imidazoline receptors. Blood pressure is decreased by 10 to 20% during moxonidine treatment, with about 70% of patients with mild to moderate hypertension achieving a diastolic pressure of < 90mm Hg. The relatively few published comparative studies demonstrate that moxonidine has efficacy comparable with that of clonidine, prazosin, atenolol, nifedipine, captopril and hydrochlorothiazide. It is at least as well tolerated as these agents in trials and, importantly, appears to cause less sedation and dry mouth than clonidine. Compliance may be aided by the once- or twice-daily administration schedule with moxonidine, and dosage adjustment is only necessary in patients with moderate renal impairment. While its published clinical data base needs further expanding, moxonidine thus appears to be a more attractive option than oral clonidine, and may be considered along with the other classes of drug used to treat patients with mild to moderate hypertension.

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.

Rabeprazole.

Rabeprazole is a proton pump inhibitor with antisecretory properties. In vitro animal experiments have indicated that the inhibition of the proton pump by rabeprazole is partially reversible. Rabeprazole has 2- to 10-fold greater antisecretory activity than omeprazole in vitro. However, it dissociates more readily from H+,K(+)-ATPase than omeprazole, resulting in a shorter duration of action. In comparative clinical trials rabeprazole was significantly more effective than placebo, famotidine or ranitidine and as effective as omeprazole in the treatment of patients with erosive or ulcerative gastro-oesophageal reflux disease or gastric or duodenal ulcers. Healing rates with rabeprazole were independent of Helicobacter pylori status. Rabeprazole in combination with either clarithromycin and metronidazole or clarithromycin and amoxicillin or amoxicillin and metronidazole or clarithromycin for 7 days produced eradication of H. pylori in 100, 95, 90 and 63% of patients. The tolerability profile of rabeprazole 20mg once daily was similar to that of famotidine 20mg twice daily, ranitidine 150mg 4 times daily or omeprazole 20mg once daily in comparative trials. The adverse events reported with once daily administration of rabeprazole 20mg include malaise, nausea, diarrhoea, headache, dizziness and skin eruptions in 0.7 to 2.2% of patients.

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.

Ropivacaine. A review of its pharmacology and therapeutic use in regional anaesthesia.

The enantiomerically pure (S-enantiomer) amide local anaesthetic drug ropivacaine blocked nerve fibres responsible for transmission of pain (A delta and C fibres) more completely than those that control motor function (A beta fibres) in in vitro studies. The drug shares the biphasic vascular effects common to the amide local anaesthetic drug class. In vitro studies indicate that ropivacaine is less cardiotoxic than equimolar concentrations of bupivacaine. Apart from one trial in women undergoing hysterectomy, clinical studies that compared the efficacy of different doses of epidurally administered ropivacaine in patients undergoing various surgical procedures did not reveal any consistent dose-related differences with respect to sensory blockade. However, motor blockade did become more intense as the dose of ropivacaine increased. Overall, direct comparisons show that epidural ropivacaine is less potent than epidural bupivacaine when the 2 drugs are administered at the same concentration. However, this difference is less marked in terms of sensory blockade than motor blockade. The greater degree of separation between motor and sensory blockade seen with ropivacaine relative to bupivacaine is more apparent at the lower end of the dosage scale. Nevertheless, higher doses of ropivacaine than bupivacaine are generally required to elicit equivalent anaesthetic effects. Ropivacaine has been shown to induce successful brachial plexus anaesthesia when given at a concentration of 5 mg/ml, but not 2.5 mg/ml, and was as effective as bupivacaine in comparative studies in this indication. Limited data indicate that continuous epidural infusion of ropivacaine postoperatively reduces postsurgical pain in a dose-related manner. Morphine consumption was also reduced. Higher doses of ropivacaine were significantly more effective than placebo. Similarly, ropivacaine controlled postsurgical pain when infiltrated directly into surgical wound sites (i.e. would infiltration) and was as effective as bupivacaine, and more effective than placebo, in this regard. Adverse events associated with epidurally administered ropivacaine include hypotension, nausea, bradycardia, transient paraesthesia, back pain, urinary retention and fever. The drug appears to have an adverse event profile similar to that of bupivacaine. In animal studies, overdoses of ropivacaine were better tolerated than overdoses of bupivacaine but not lidocaine (lignocaine). Human volunteers tolerated a higher intravenous dosage of ropivacaine than bupivacaine before developing initial signs of toxicity. Thus, ropivacaine, according to animal data, is less cardiotoxic than bupivacaine. Based on available clinical data, ropivacaine appears to be as effective and well tolerated as bupivacaine when equianalgesic doses are compared. The greater degree of separation between motor and sensory blockade seen withropivacaine relative to bupivacaine at lower concentrations (approximately 5 mg/ml) will be advantageous in certain applications.

Dexfenfluramine. An updated review of its therapeutic use in the management of obesity.

Dexfenfluramine increases serotonergic activity by stimulating serotonin (5-hydroxytryptamine; 5-HT) release into brain synapses, inhibiting its reuptake into presynaptic neurons and by directly stimulating postsynaptic serotonin receptors. On the basis of the serotonin hypothesis of appetite control, these actions would be expected to reduce appetite and, consequently, bodyweight. Studies conducted in animals and in overweight patients with and without associated disorders have confirmed the weight-reducing efficacy and good tolerability of dexfenfluramine. In 3-month clinical studies in obese patients, weight reductions with dexfenfluramine 15mg twice daily combined with dietary support were significantly higher than those achieved with placebo and similar to those with ephedrine/caffeine 20/20mg 3 times daily, sibutramine 10mg once daily and fluoxetine 60 mg/day. Furthermore, dexfenfluramine recipients with non-insulin-dependent diabetes mellitus, hyperlipidaemia or hypertension consistently show improvements in glycaemic control, blood lipid profiles and blood pressure. 12-month trial results indicate that most weight loss occurs in the initial 6 months and appears to be maintained for a further 6 months. Weight regain after withdrawal of treatment in 12-month studies demonstrates that dexfenfluramine is effective in maintaining a stable bodyweight at a lower level than placebo and in limiting food intake over this time period. Commonly reported adverse events with dexfenfluramine include diarrhoea, tiredness, dry mouth and somnolence; these symptoms are generally mild and transient. Approximately 7 and 10% of dexfenfluramine recipients in short and long term studies withdrew because of adverse events. Dexfenfluramine was better tolerated than ephedrine/caffeine and fluoxetine in short term studies. Obesity is a chronic condition that is accompanied by a number of metabolic complications. It is a significant health problem in developed countries, and as a major risk factor for many chronic diseases, including diabetes and cardiovascular disease, the economic burden of this condition is considerable. As with other chronic conditions, there is a role for pharmacological intervention in patients with severe obesity. However, drugs should be considered as only one component of a weight-control programme, since additional lifestyle modification is required to maintain weight loss. The promising data on the long term efficacy and tolerability of dexfenfluramine as well as its favourable effects on risk factors associated with obesity requires confirmation in long term studies. In the meantime, dexfenfluramine should be considered a valuable adjunct to a reduced-calorie diet in the management of severe obesity, particularly in patients with associated disorders and those unsuccessful with conventional weight loss measures. Available data support the use of the drug for up to 1 year to maintain weight loss and thus dexfenfluramine should be considered for long term administration.

Triamcinolone acetonide. A review of its pharmacological properties and therapeutic efficacy in the management of allergic rhinitis.

Triamcinolone acetonide is a synthetic glucocorticoid which has been formulated as both an aerosol and an aqueous metered-dose pump spray for nasal inhalation in the treatment of allergic rhinitis. Nasally administered triamcinolone acetonide is not significantly absorbed into the systemic circulation and does not suppress hypothalamic-pituitary-adrenal (HPA) axis function at therapeutic dosages. Clinical trials with either formulation have shown that once-daily triamcinolone acetonide 110 to 220 micrograms reduces symptoms of allergic rhinitis within the first day of administration. Once symptoms are under control, the dosage of aqueous triamcinolone acetonide may be reduced from 220 to 110 micrograms/day without loss of effect. Both aqueous and aerosol formulations of triamcinolone acetonide are significantly more effective in relieving symptoms and reducing nasal eosinophil influx than placebo. Once-daily intranasal triamcinolone acetonide 220 micrograms/day produced similar reductions from baseline in nasal symptoms of allergic rhinitis, when measured both subjectively (visual analogue scales) and objectively (anterior rhinomanometry), to those seen with beclomethasone 84 to 168 micrograms twice daily, fluticasone 200 micrograms once daily or flunisolide 100 micrograms twice daily for 3 to 12 weeks. Furthermore, triamcinolone acetonide aerosol 220 micrograms/day was significantly more effective at reducing the nasal symptoms of allergic rhinitis than the oral antihistamines loratadine and astemizole (both 10mg daily) and was equally as effective in reducing the associated ocular symptoms. The use of intranasal triamcinolone acetonide and oral loratadine in combination did not confer any additional advantage over triamcinolone acetonide alone. Triamcinolone acetonide [110 to either 220 micrograms/day (aqueous) or 440 micrograms/day (aerosol)] was well tolerated in clinical trials; headache and epistaxis were the only adverse events considered possibly or probably related to aerosol therapy in a 1-year study (110 to 440 micrograms/day). Therefore, in accordance with the recommendations from the International Rhinitis Management Working Group regarding the use of nasal glucocorticoids, triamcinolone acetonide may be considered a first-line therapy option in adults with moderately severe seasonal allergic rhinitis with predominantly nasal symptoms and also in children and adult patients with perennial allergic rhinitis.

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.