Search PubMed⌕ Search

Biomedical subjects

C M Spencer

Publications and source records attributed to C M Spencer.

At least 19 recordsLinked to original sources

Miglitol: a review of its therapeutic potential in type 2 diabetes mellitus.

UNLABELLED: Miglitol, the first pseudomonosaccharide alpha-glucosidase inhibitor, smooths postprandial peak plasma glucose levels and thus improves glycaemic control, which is reflected in a reduced glycosylated haemoglobin (HbA1c) level. This oral antihyperglycaemic agent is indicated for the treatment of patients with type 2 diabetes mellitus. Miglitol is generally well tolerated and, unlike the sulphonylurea agents, is not associated with bodyweight gain or hypoglycaemia when administered as monotherapy. The drug is systemically absorbed but is not metabolised and is rapidly excreted via the kidneys. Clinical trials with miglitol (usually 50 or 100 mg 3 times daily) in patients with type 2 diabetes mellitus consistently demonstrated a significant improvement in glycaemic control for periods of 6 to 12 months. There were also marked reductions in postprandial serum insulin levels, although miglitol generally had no effect on fasting insulin levels. In comparative studies miglitol had similar efficacy to acarbose, but at lower therapeutic doses (50 and 100 mg 3 times daily, respectively). In addition, although sulphonylurea agents provided superior reductions in HbA1c levels, miglitol provided similar or superior reductions in fasting and postprandial plasma glucose levels. In combination with other oral antidiabetic agents or insulin, miglitol improved glycaemic control in patients in whom metabolic control was suboptimal despite dietary and pharmacological intervention. Most adverse events associated with miglitol treatment involve disturbances of the gastrointestinal tract (most common effects are flatulence, abdominal pain and diarrhoea). These symptoms are usually dose dependent, mild to moderate in severity, occur at the onset of treatment, decline with time and resolve promptly on discontinuation of the drug or with dosage adjustment. As monotherapy, miglitol is not associated with hypoglycaemia, but concomitant use with other oral antidiabetic agents may necessitate dosage adjustment of the other agents. Miglitol had no significant effects on renal, cardiovascular, respiratory or haematological parameters in long term studies. No dosage adjustments are required in elderly patients, in those with hepatic impairment or in those with mild to moderate renal insufficiency. CONCLUSIONS: In long term, well designed trials miglitol reduces fasting and postprandial plasma glucose levels, thus improving glycaemic control, which is reflected in a reduced HbA1c level in patients with type 2 diabetes mellitus. Most adverse events associated with miglitol involve disturbances of the gastrointestinal tract. This agent is a useful first-line therapy in patients with type 2 diabetes mellitus insufficiently controlled by diet alone and as second-line or as adjuvant therapy in those insufficiently controlled with diet and sulphonylurea agents. Miglitol may prove particularly beneficial in elderly patients and those with hepatic impairment or mild to moderate renal impairment, in whom other oral antidiabetic agents are contraindicated or need to be used with caution.

1-Deoxynojirimycin↗

Ebastine: an update of its use in allergic disorders.

UNLABELLED: Ebastine is a second-generation antihistamine which undergoes transformation to its active metabolite, carebastine. Its antihistaminic and antiallergic effects have been demonstrated in in vitro and in vivo studies, in addition to data obtained from clinical trials. Patients with allergic rhinitis or chronic idiopathic urticaria experienced significant improvement in their symptoms with ebastine 10 or 20 mg once daily. Some studies in patients with seasonal allergic rhinitis (SAR) have indicated trends towards greater efficacy with the 20 mg than the 10 mg dose, although only 1 study has shown statistically significant benefits. In comparative trials in patients with SAR, ebastine 10 mg was as effective as most other second-generation antihistamines, including astemizole, azelastine, cetirizine, loratadine and terfenadine. Ebastine 20 mg/day was significantly superior to loratadine 10 mg/day in patients with SAR according to effects on secondary efficacy variables in comparative studies; 1 study found significantly greater changes from baseline in mean total symptom score with ebastine 20 mg (-43 vs -36% with loratadine, p = 0.045). In patients with perennial allergic rhinitis, ebastine 10 or 20 mg daily was significantly more effective than loratadine in reducing total symptom scores from baseline 1 comparative study. There have been no reports of serious adverse cardiac effects during ebastine therapy. Increases in corrected QT interval have been observed during clinical trials; however, these have not been considered clinically significant and were generally of similar magnitude to those seen with loratadine. The normal diurnal variation in QTc interval and the problems associated in correcting for changes in heart rate also complicate assessment of this issue. The incidence of adverse events during ebastine treatment is not significantly greater than that observed with placebo or other second-generation antihistamines. CONCLUSIONS: Ebastine 10 mg daily is a well tolerated and effective treatment for allergic rhinitis and chronic idiopathic urticaria. At this dosage, it is as effective as the other second-generation antihistamines against which it has been compared. Ebastine 20 mg has similar tolerability to the 10 mg dose, and trends towards greater efficacy with the higher dose have been shown in some studies. Ebastine does not appear to be associated with any significant cardiac adverse events. Ebastine is a useful treatment option for patients with allergic rhinitis or chronic idiopathic urticaria.

Animals↗

Bupropion: a review of its use in the management of smoking cessation.

UNLABELLED: Sustained release bupropion (amfebutamone) is a non-nicotine agent that is indicated as an aid to smoking cessation. In 2 large well designed clinical trials, sustained release bupropion 300 mg/day (the recommended dose) for 7 or 9 weeks was associated with considerably and significantly higher smoking abstinence rates (continuous abstinence and 7-day point prevalence rates) than placebo during treatment and at follow-up at 6 and 12 months. Point prevalence rates at 12 months in 2 studies were 23.1 and 30.3% with bupropion, whereas values for placebo were 12.4 and 15.6%. Continuous abstinence rates at 12 months, available from 1 trial, were 18.4% with bupropion and 5.6% with placebo. Furthermore, bupropion was associated with significantly higher quitting rates than nicotine patch in a comparative study. Combination therapy with bupropion and nicotine patch provided slightly higher abstinence rates than bupropion alone, although differences were not statistically significant. The combination was superior to nicotine patch alone. Data from a preliminary report of long term bupropion treatment (52 weeks) showed that the drug was associated with significantly higher continuous abstinence rates than placebo only to 6 months. However, point prevalence abstinence rates were significantly higher with bupropion than placebo to 18 months. Bupropion 300 mg/day recipients reported nicotine withdrawal symptoms during treatment; however, the symptoms were significantly less severe with bupropion than placebo. Patients receiving bupropion 300 mg/day or bupropion in combination with nicotine patch for smoking cessation generally gained less bodyweight than placebo recipients. The benefits of bupropion for preventing weight gain persisted after the completion of long term, but not short term therapy. Bupropion was well tolerated in clinical trials, and the only adverse events that were significantly more common with bupropion than placebo were insomnia and dry mouth. Data published so far suggest that sustained release bupropion has a low potential for inducing seizures (seizure rate approximately 0.1% in patients with depression). CONCLUSIONS: Bupropion is an effective and well tolerated smoking cessation intervention. Further studies with long term follow-up will be useful in determining whether abstinence rates are maintained with bupropion. In addition, clarification of its efficacy in comparison with other therapies used for smoking cessation would help to establish its clinical value. The reduced potential for weight gain with bupropion and the ability to use bupropion in combination with nicotine replacement therapy make the drug a useful treatment option for smoking cessation.

Antidepressive Agents, Second-Generation↗

Cytoplasmic proteins interact with a translational control element in the protein-coding region of proopiomelanocortin mRNA.

Previous studies have indicated that proopiomelanocortin (POMC) is translationally regulated. We proposed that the regulatory mechanism involves an interaction between trans-acting protein factors and a cis-acting stem-loop structure in the coding region of POMC mRNA. Functional interactions were tested by examining the translation of mouse POMC mRNA in a rabbit reticulocyte system. Specific binding was demonstrated with ultraviolet-crosslinking and RNA gel mobility shift assays. The evidence presented supports our hypothesis that the translational regulation of POMC gene expression involves recognition of the stem-loop by RNA-binding proteins. Furthermore, POMC stem-loop RNA-binding proteins specifically recognized a predicted stem-loop found in the coding region of corticotropin-releasing hormone, suggesting a novel mechanism of gene regulation that may extend to other neuropeptides as well.

Animals↗

Insulin aspart.

Insulin aspart is a recombinant analogue of human insulin. Following subcutaneous insulin injection (0.15 to 0.2 U/kg), significantly higher serum insulin concentrations are achieved in a shorter time with insulin aspart than with human insulin. The subsequent decline in serum insulin concentrations is also more rapid with insulin aspart. In healthy individuals undergoing euglycaemic glucose clamp testing, glucose infusion rates were higher and reached maximum concentrations significantly earlier after insulin aspart than after human insulin. Interindividual variability in pharmacodynamic and pharmacokinetic parameters with insulin aspart was generally less than that with human insulin, whereas the intraindividual variability in these parameters was similar after each insulin. In patients with type 1 diabetes postprandial glucose excursions were less pronounced with insulin aspart than human insulin. Daytime glucose control was better and minimum glucose levels during the night were not as low with insulin aspart as with human insulin. In diabetic patients treated with insulin aspart there was generally a lower frequency of hypoglycaemic events than in patients treated with human insulin.

Clinical Trials as Topic↗

Salmeterol/fluticasone propionate combination.

Current evidence suggests that addition of the long-acting beta2-agonist salmeterol to an inhaled corticosteroid in patients with persistent asthma symptoms provides greater clinical benefit than doubling the dosage of the inhaled corticosteroid. Fixed combination salmeterol/fluticasone propionate in 3 different fluticasone propionate dosage strengths administered via the Diskus powder inhaler does not result in any untoward interaction that affects the pharmacodynamic or pharmacokinetic profiles of the individual drugs, or their adverse effect profiles - including the influence of the corticosteroid on plasma cortisol levels. Administration of fixed combination salmeterol/ fluticasone propionate to both adults and children with persistent asthma provides greater improvements in lung function than either agent alone, and at least equal effectiveness to the same dosages of the 2 agents given by separate powder inhalers. Preliminary reports indicate that combination therapy has also demonstrated superior efficacy to budesonide (fluticasone propionate dosages were 25% those of budesonide). The most commonly encountered adverse effects in clinical trials with combined salmeterol/fluticasone propionate therapy have been oropharyngeal candidiasis. hoarseness/dysphonia, throat irritation, headache, tachycardia/palpitations, tremor and dizziness (all in < or =5% of patients).

Administration, Inhalation↗

Entacapone. A review of its use in Parkinson's disease.

UNLABELLED: Entacapone is a potent and specific peripheral catechol-O-methyltransferase (COMT) inhibitor. It has been shown to improve the clinical benefits of levodopa plus an aromatic L-amino acid decarboxylase inhibitor (AADC) when given to patients with Parkinson's disease and end-of-dose deterioration in the response to levodopa (the 'wearing off' phenomenon). The efficacy of entacapone is currently being assessed in patients with stable Parkinson's disease. In 2 well conducted trials of 6 months' duration and smaller short term studies, treatment with entacapone (200 mg with each dose of levodopa/AADC inhibitor) was associated with significant increases in daily 'on' time and decreases in 'off' time. Changes in Unified Parkinson's Disease Rating Scale (UPDRS) scores concurred with changes in 'on' and 'off' times: entacapone improved total, activities of daily living and motor function scores, but it had no effect on mentation scores. Entacapone also provided benefits when given with controlled release levodopa/ AADC inhibitor or with standard levodopa/AADC inhibitor and selegiline in small trials. Dopaminergic events, including dyskinesia and nausea, are among the most common events with entacapone, and are related to the drug's ability to potentiate the effects of levodopa. Diarrhoea, abdominal pain, constipation and urine discolouration are the most common nondopaminergic events, although the latter event is the only one to occur consistently more frequently with entacapone than with placebo. However, adverse events of any type infrequently led to study discontinuation. CONCLUSIONS: The efficacy and tolerability of entacapone administered with levodopa/AADC inhibitor have not yet been compared with those of other strategies for the treatment of Parkinson's disease. However, once the decision to initiate levodopa therapy has been made, studies generally support the use of entacapone as an adjunct to levodopa in patients with Parkinson's disease and the 'wearing off' phenomenon.

Animals↗

Zolmitriptan: a review of its use in migraine.

UNLABELLED: Zolmitriptan is a selective serotonin 5-HT1B/1D receptor agonist ('triptan'). Its efficacy and tolerability have been assessed in a number of randomised, placebo-controlled, double-blind trials in large numbers of adults with moderate to severe migraine attacks. Oral zolmitriptan 2.5 and 5mg has a rapid onset of action (significant headache relief is observed at 45 minutes) and efficacy is sustained in most patients who respond at 2 hours. The drug is significantly more effective than placebo as measured by a number of parameters including 2-hour headache response rates and pain-free response rates. Other symptoms of migraine, including nausea, photophobia and phonophobia are also alleviated with zolmitriptan. Zolmitriptan is effective in the treatment of migraine associated with menses and migraine with aura. There is some evidence to support the use of zolmitriptan in patients with migraine who have had a poor response to previous therapy. The efficacy of zolmitriptan appears to be maintained, with no tachyphylaxis, following repeated administration for multiple attacks of migraine over a prolonged period of time, with high headache response rates reported over all attacks. In comparison with placebo, the incidence of persistent migraine headache is reduced by zolmitriptan and recurrent migraine headache occurs less frequently with the active treatment. Zolmitriptan has also demonstrated efficacy in the treatment of persistent and/or recurrent migraine headache. For relief of migraine headache, zolmitriptan 5mg had similar efficacy to sumatriptan 100mg for a single attack, but generally was more effective than sumatriptan 25 and 50mg for multiple attacks, in single trials. The incidence of recurrent headache with zolmitriptan was similar to that with sumatriptan. Zolmitriptan is generally well tolerated with most adverse events being mild to moderate, transient and resolving without intervention or the need for treatment withdrawal. The most common adverse events with zolmitriptan therapy are asthenia, heaviness other than that of the chest or neck, dry mouth, nausea, dizziness, somnolence, paraesthesia, warm sensation, tightness, vasodilation and chest pain. CONCLUSION: Zolmitriptan is effective across a wide range of migraine subtypes, maintains efficacy when used in the long term and is generally well tolerated. Further clinical experience is necessary to define the position of zolmitriptan among other currently or soon to be available selective 5-HT1B/1D receptor agonists. However, on the basis of available data, zolmitriptan should emerge as a useful treatment option in the management of patients with moderate to severe migraine.

Age Factors↗

Topotecan: a review of its efficacy in small cell lung cancer.

UNLABELLED: Topotecan, a water soluble semisynthetic derivative of camptothecin, has demonstrated antineoplastic activity in a wide range of cell culture and xenograft systems and is currently approved for second-line therapy in ovarian and small cell lung cancer (SCLC). The drug inhibits replication of rapidly dividing cells by disrupting the normal function of the nuclear enzyme topoisomerase I. The efficacy of topotecan is related to exposure time and the recommended regimen is 1.5 mg/m2 as a 30-minute intravenous infusion, daily for 5 days, repeated every 21 days. In phase II trials of topotecan in SCLC (usually with the 1.5mg/m2, 5 day regimen) the overall response rate in refractory patients (those who had relapsed < or =90 days after first-line therapy) was low at 2 to 11%, whereas in sensitive patients (those relapsing > or =90 days after first-line therapy) the overall response rate was 14 to 37%. Topotecan was compared with combined cyclophosphamide/doxorubicin(adriamycin)/vincristine (CAV) therapy in patients with relapsed, sensitive (relapsed > or =60 days after first-line therapy) SCLC. The response rates were 24.3% and 18.3% and, respectively, for the topotecan- and CAV-treated groups, and no significant differences were detected when primary efficacy endpoints (response rates and duration) were compared. However, the results of a symptom-specific questionnaire for SCLC did suggest that topotecan offered superior control of some symptoms. SCLC is usually treated with combinations of cytotoxic drugs, and topotecan is showing promise when partnered with paclitaxel and platinum compounds. The efficacy of an oral formulation of topotecan is also being investigated; preliminary results are encouraging and suggest similar efficacy to intravenous formulations, but with less frequent neutropenia. The tolerability and compliance advantages of oral topotecan may make this the route of choice in the future. Noncumulative anaemia, neutropenia and thrombocytopenia are the dose-limiting adverse effects associated with topotecan. CAV and topotecan therapy had similar suppressive effects on neutrophils in patients with SCLC, but the incidences of grade 3 or 4 anaemia and grade 4 thrombocytopenia were significantly higher in topotecan-treated patients. Non-haematological adverse events in SCLC patients treated with topotecan or CAV were similar and most were grade 1 or 2. Gastrointestinal disturbances were common in both groups, as were alopecia and fatigue. CONCLUSIONS: In a large randomised comparative study, topotecan was as effective as CAV in treating relapsed SCLC. The response rate was modest and further comparative and drug-combination studies are required to accurately position topotecan within the schedule of available drugs used to treat SCLC, particularly in relation to first-line therapy. However, recurrent SCLC is extremely intractable to therapy and topotecan is a valuable extension to the limited range of treatment options for SCLC.

Animals↗

Paclitaxel. An update of its use in the treatment of metastatic breast cancer and ovarian and other gynaecological cancers.

UNLABELLED: The antitumour agent paclitaxel has proved to be effective for the treatment of patients with metastatic breast or ovarian cancer, and limited data also indicate its clinical potential in patients with cervical or endometrial cancer. The regimen of paclitaxel administration has varied in clinical trials, the most common including a dosage of between 135 and 250 mg/m2 administered over an infusion period of 3 or 24 hours once every 3 weeks. Promising results have been achieved in phase I/II trials of a weekly regimen of paclitaxel (60 to 175 mg/m2). The objective response rate in patients with metastatic breast cancer (either pretreated or chemotherapy-naive) is generally between 20 and 35% with paclitaxel monotherapy, which compares well with that of other current treatment options including the anthracycline doxorubicin. Combination therapy with paclitaxel plus doxorubicin appears superior to treatment with either agent alone in terms of objective response rate and median duration of response. However, whether combination therapy also provides a survival advantage remains unclear; recent results of a phase III study indicate that it does not. Paclitaxel is also a useful second-line option in some patients with anthracycline-resistant disease. Combination therapy with paclitaxel and cisplatin has proved highly effective as first-line therapy for patients with advanced ovarian cancer, showing superior efficacy to cyclophosphamide/cisplatin in terms of progression-free survival time and median duration of survival. Combination therapy with paclitaxel and carboplatin has also shown promising results. Paclitaxel monotherapy is a useful second-line option for patients with platinum-refractory metastatic ovarian cancer (objective response rates have ranged from 15 to 48%). The major dose-limiting adverse events associated with paclitaxel include myelotoxicity and peripheral neuropathy. Paclitaxel has acceptable tolerability in most patients, although adverse events are common. CONCLUSION: Paclitaxel generally appears to be as effective as other antineoplastic agents used in the treatment of metastatic breast cancer, including doxorubicin. Importantly, it is a useful second-line option for some patients with anthracycline-resistant disease. Combination therapy with both paclitaxel and doxorubicin is a highly effective first-line option for metastatic breast cancer; however, recent results indicate no survival advantage versus monotherapy. Paclitaxel is a valuable agent for second-line treatment of patients with platinum-refractory metastatic ovarian cancer and, when combined with cisplatin or carboplatin, is recommended as first-line therapy for this disease.

Animals↗

Bicalutamide in advanced prostate cancer. A review.

UNLABELLED: Bicalutamide is a nonsteroidal antiandrogen with a long elimination half-life (t1/2) that permits once-daily administration. When combined with a gonadorelin (gonadotrophin releasing hormone; GnRH) agonist in maximum androgen blockade (MAB) regimens, bicalutamide 50 mg once daily is at least as effective as flutamide 250 mg 3 times daily, as shown in a large randomised trial. Rate of treatment failure, the primary end-point, was significantly lower at 49 weeks with bicalutamide in this study, mainly because of a lower rate of withdrawal due to adverse events. Final results at a median follow-up of 160 weeks revealed longer median times to progression and death with bicalutamide than flutamide, but between-group differences were not significant overall. Although early trials demonstrated clinical benefits with bicalutamide 50 mg/day as monotherapy, the drug in this dosage is less effective than castration. Increasing the dosage to 150 mg/day has improved its efficacy in patients with non-metastatic disease: combined data from 2 trials demonstrate similar survival with bicalutamide in this dosage compared with castration. Accumulating evidence from these and other studies indicates that sexual interest appears to be better preserved with bicalutamide than with castration. The tolerability profile of bicalutamide is characteristic of antiandrogens, with breast pain and gynaecomastia occurring most often. Bicalutamide has not been causally associated with problems such as interstitial pneumonitis and difficulty with light/dark adaptation seen with nilutamide, and in a 50 mg/day dosage causes a lower incidence of diarrhoea than flutamide 750 mg/day. Changes in hepatic function are generally transient and resolve or improve during therapy or after bicalutamide treatment is withdrawn. CONCLUSIONS: Bicalutamide, with its once-daily regimen and good tolerability, is an attractive option when combined with a GnRH agonist in patients with advanced prostate cancer who are suitable to receive MAB regimens. The role of bicalutamide as monotherapy in the management of this common malignancy is currently being assessed.

Androgen Antagonists↗

Rivastigmine. A review of its use in Alzheimer's disease.

UNLABELLED: Rivastigmine (SDZ ENA 713) is a carbamylating, long-acting reversible and noncompetitive carbamate acetylcholinesterase inhibitor that is indicated as an oral treatment for patients with mild to moderately severe Alzheimer's disease. The drug has been evaluated for this use in 3 well designed, adequately powered, phase II/III, 26-week clinical trials that included a total of 1479 rivastigmine and 647 placebo recipients. Most of these patients had concomitant disorders that were being treated with numerous other drugs. Individual and pooled results of these trials indicate that rivastigmine 6 to 12 mg/day usually produces cognitive, global and functional changes that indicate significantly less deterioration than was observed with placebo in patients with mild to moderately severe Alzheimer's disease. Individual results of the 2 pivotal trials and pooled analysis also show that, compared with placebo recipients, significantly more rivastigmine 6 to 12 mg/day recipients respond to therapy. Indeed, after 26 weeks of therapy in the 2 pivotal trials, significantly more rivastigmine 6 to 12 mg/day than placebo recipients achieved clinically meaningful improvements as defined by 3 separate response criteria. The lower dosage range of 1 to 4 mg/day was not as effective as 6 to 12 mg/day, as measured using these criteria and other efficacy parameters. Rivastigmine causes adverse events that are generally those expected from an acetylcholinesterase inhibitor. They are usually mild to moderate, of short duration and responsive to dosage reduction. Unpublished data from 3989 patients indicate that rivastigmine and placebo were associated with similar incidences of serious adverse events and changes in laboratory parameters, ECG and cardiorespiratory vital signs. The most common events were gastrointestinal, central and peripheral nervous system and whole body adverse events. However, compared with placebo, rivastigmine more commonly caused adverse events resulting in treatment withdrawal. These events were most frequently gastrointestinal and were more common in women. CONCLUSION: Rivastigmine is a useful option for the treatment of patients with mild to moderately severe Alzheimer's disease. Although only short term (6- month) comparisons with placebo are available, given the lack of established treatment options it should be considered for first-line use in this population.

Alzheimer Disease↗

Butenafine.

Butenafine is a new antifungal agent with primary fungicidal activity against dermatophytes such as Trichophyton mentagrophytes, Microsporum canis and Trichophyton rubrum which cause tinea infections. 14C-labelled butenafine (approximately 30 micrograms/g tissue) was found within guinea-pig dorsal skin 24 hours after topical application. Most of the drug was distributed into the epidermis including the horny layer. Small amounts were found in the dermis, probably transported via sebaceous glands and hair follicles. In vitro, the minimum concentration that completely inhibited growth of dermatophytes (MIC) and the minimum fungicidal concentrations (MFC) for butenafine against T. mentagrophytes and M. canis were similar (0.012 to 0.05 mg/L) and were 4 to 130 times lower than those for naftifine, tolnaftate, clotrimazole and bifonazole. It also has greater activity against T. rubrum, M. gypseum and Epidermophyton floccosum when compared with naftifine, tolnaftate and clotrimazole; comparisons with bifonazole against these strains were not available. Assessment after 1 week's treatment in patients with tinea pedis revealed that mycological cure rates were greater in those who received twice-daily butenafine for 1 week or once-daily butenafine for 4 weeks than in placebo recipients. Mycological and overall cure rates were either further increased or maintained up to 5 weeks after treatment cessation compared with end-of-treatment values. In patients with tinea cruris or tinea corporis who received once-daily butenafine 1% for 2 weeks, the mycological and overall cure rates continued to increase for up to 4 weeks after treatment cessation.

Animals↗

Balsalazide.

Balsalazide is a prodrug of mesalazine which has an inert carrier molecule instead of the sulfapyridine moiety of sulfasalazine. Balsalazide 6.75 g/day was more effective than mesalazine 2.4 g/day in at least 1 trial and as effective as sulfasalazine 3 g/day for inducing remission in patients with acute ulcerative colitis in 8- and 12-week trials. Moreover, complete symptom relief occurred more promptly with balsalizide 6.75 g/day than with mesalazine 2.4g/day. In long term studies, balsalazide 2 g/day was as effective as sulfasalazine 2 g/day and balsalazide 6 g/day was as effective as mesalazine 1.5 g/day, in maintaining remission in patients with ulcerative colitis. The tolerability profile of balsalazide is significantly better than that of sulfasalazine; 70% of sulfasalazine-intolerant patients were able to tolerate balsalazide.

Aminosalicylic Acids↗

Enoxaparin. A review of its clinical potential in the management of coronary artery disease.

UNLABELLED: Enoxaparin (enoxaparin sodium) is a low molecular weight heparin (LMWH) that is widely used in the prevention of deep venous thrombosis and pulmonary embolism in patients undergoing orthopaedic or general surgery. Its efficacy in these indications has led to study of its use in patients with coronary artery disease, particularly those with unstable angina, who have a high risk of myocardial infarction and death. A double-blind multicentre study [ESSENCE (Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q Wave Coronary Events)] showed that subcutaneous enoxaparin was more effective than intravenous unfractionated heparin (UFH) in reducing the incidence of the composite end-point of death, myocardial infarction or recurrent angina after 14 days in 3171 patients with recent-onset resting angina (i.e. unstable angina). There were no statistically significant between-group differences for the secondary end-point of death or myocardial infarction. Preliminary reports of long term follow-up data indicate that the clinical benefit of enoxaparin over UFH is maintained after 1 year. The only significant difference in tolerability between enoxaparin and UFH in ESSENCE was for minor haemorrhage (mostly injection-site ecchymosis), which was more common with the LMWH. Prospective pharmacoeconomic substudies of the ESSENCE trial suggest that total medical costs (including those for subsequent revascularisation procedures) for enoxaparin treatment are lower than those for UFH. The ESSENCE study is the first double-blind trial to show that a LMWH is more effective than UFH in patients with unstable angina. The superiority of enoxaparin was attributable mainly to its effects on recurrent angina. The level of anticoagulation achieved in the UFH group raises a number of issues which might have affected the apparent relative efficacy of enoxaparin and UFH. Preliminary data suggest that enoxaparin is at least as effective as UFH in reducing the incidence of subsequent cardiac events in patients receiving thrombolysis for acute myocardial infarction, and a randomised comparison with no additional treatment (other than aspirin) has demonstrated its efficacy in this indication. Enoxaparin has been ineffective in preventing restenosis after angioplasty CONCLUSIONS: The ESSENCE study has shown that enoxaparin is more effective than UFH in patients with unstable angina. Although clarification of some methodological issues would be beneficial, the available efficacy data, together with the practical advantages of LMWHs in general, suggest that enoxaparin is an effective and convenient means of treating unstable angina and should provide cost savings compared with UFH.

Angina, Unstable↗

Levobupivacaine.

Levobupivacaine is an enantiomer of the long-acting local anaesthetic bupivacaine, which, although currently the most widely used agent in surgery and obstetrics, is associated with potentially fatal cardiotoxicity. Levobupivacaine 75 to 122 mg was less arrhythmogenic than the same dose range of bupivacaine in healthy volunteers. Its effects on the corrected QT interval were significantly weaker than those of bupivacaine, and it tended to have a weaker effect on QRS duration. The CNS depressant effect of intravenous levobupivacaine 40 mg was less than that of bupivacaine 40 mg in healthy volunteers, both in terms of the magnitude of the effect and the regions of the cortex affected. Clinical studies have demonstrated that epidural levobupivacaine produces a sensory and motor block clinically similar to that of bupivacaine in patients requiring anaesthesia during surgery. However, the duration of sensory block was significantly longer with levobupivacaine 0.75% than with levobupivacaine 0.5% or bupivacaine 0.5% or 0.75% in one study. Levobupivacaine 0.25% was as effective as bupivacaine 0.25% in women requiring epidural anaesthesia during labour with respect to time to onset of pain relief, overall quality of analgesia, extent of sensory blockade and number of patients reporting motor block. Levobupivacaine is as well tolerated as bupivacaine. In a clinical study involving 88 patients who received either drug, intraoperative hypotension was the most commonly reported adverse event with levobupivacaine and no serious arrhythmias occurred.

Anesthetics, Local↗

Dexrazoxane. A review of its use as a cardioprotective agent in patients receiving anthracycline-based chemotherapy.

UNLABELLED: Dexrazoxane has been used successfully to reduce cardiac toxicity in patients receiving anthracycline-based chemotherapy for cancer (predominantly women with advanced breast cancer). The drug is thought to reduce the cardiotoxic effects of anthracyclines by binding to free and bound iron, thereby reducing the formation of anthracycline-iron complexes and the subsequent generation of reactive oxygen species which are toxic to surrounding cardiac tissue. Clinical trials in women with advanced breast cancer have found that patients given dexrazoxane (about 30 minutes prior to anthracycline therapy; dexrazoxane to doxorubicin dosage ratio 20:1 or 10:1) have a significantly lower overall incidence of cardiac events than placebo recipients (14 or 15% vs 31%) when the drug is initiated at the same time as doxorubicin. Cardiac events included congestive heart failure (CHF), a significant reduction in left ventricular ejection fraction and/or a > or = 2-point increase in the Billingham biopsy score. These results are supported by the findings of studies which used control groups (patients who received only chemotherapy) for comparison. The drug appears to offer cardiac protection irrespective of pre-existing cardiac risk factors. In addition, cardiac protection has been shown in patients given the drug after receiving a cumulative doxorubicin dose > or = 300 mg/m2. It remains to be confirmed that dexrazoxane does not affect the antitumour activity of doxorubicin: although most studies found that clinical end-points (including tumour response rates, time to disease progression and survival duration) did not differ significantly between treatment groups, the largest study did show a significant reduction in response rates in dexrazoxane versus placebo recipients. Dexrazoxane permits the administration of doxorubicin beyond standard cumulative doses; however, it is unclear whether this will translate into prolonged survival. Preliminary results (from small nonblind studies) indicate that dexrazoxane reduces cardiac toxicity in children and adolescents receiving anthracycline-based therapy for a range of malignancies. The long term benefits with regard to prevention of late-onset cardiac toxicity remain unclear. With the exception of severe leucopenia [Eastern Cooperative Oncology Group (ECOG) grade 3/4 toxicity], the incidence of haematological and nonhaematological adverse events appears similar in patients given dexrazoxane to that in placebo recipients undergoing anthracycline-based chemotherapy. Although preliminary pharmacoeconomic analyses have shown dexrazoxane to be a cost-effective agent in women with advanced breast cancer, they require confirmation. CONCLUSIONS: Dexrazoxane is a valuable drug for protecting against cardiac toxicity in patients receiving anthracycline-based chemotherapy. Whether it offers protection against late-onset cardiac toxicity in patients who received anthracycline-based chemotherapy in childhood or adolescence remains to be determined. Further clinical experience is required to confirm that it does not adversely affect clinical outcome, that it is a cost-effective option, and to determine the optimal treatment regimen.

Animals↗