Oral hypoglycemic agent update

Vaccination Strategies Against Mycobacterium tuberculosis: BCG and Beyond

Tuberculosis (TB) is a highly contagious disease caused by Mycobacterium tuberculosis (Mtb) and is the major cause of morbidity and mortality across the globe. The clinical outcome of TB infection and susceptibility varies among individuals and even among different populations, contributed by host genetic factors such as polymorphism in the human leukocyte antigen (HLA) alleles as well as in cytokine genes, nutritional differences between populations, immunometabolism, and other environmental factors. Till now, BCG is the only vaccine available to prevent TB but the protection rendered by BCG against pulmonary TB is not uniform. To deliver a vaccine which can give consistent protection against TB is a great challenge with rising burden of drug-resistant TB. Thus, expectations are quite high with new generation vaccines that will improve the efficiency of BCG without showing any discordance for all forms of TB, effective for individual of all ages in all parts of the world. In order to enhance or improve the efficacy of BCG, different strategies are being implemented by considering the immunogenicity of various Mtb virulence factors as well as of the recombinant strains, co-administration with adjuvants and use of appropriate vehicle for delivery. This chapter discusses several such pre-clinical attempts to boost BCG with subunit vaccines tested in murine models and also highlights various recombinant TB vaccines undergoing clinical trials. Promising candidates include new generation of live recombinant BCG (rBCG) vaccines, VPM1002, which are deleted in one or two virulence genes. They encode for the mycobacteria-infected macrophage-inhibitor proteins of host macrophage apoptosis and autophagy, key events in killing and eradication of Mtb. These vaccines are rBCG- ΔureC::hly HM^R, and rBCG-ΔureC::hly ΔnuoG. The former vaccine has passed phase IIb in clinical trials involving South African infants and adults. Thus, with an aim of elimination of TB by 2050, all these cumulative efforts to develop a better TB vaccine possibly is new hope for positive outcomes.

QSAR analysis of hypoglycemic agents using the topological indices

The molecular topology model and discriminant analysis have been applied to the prediction of some pharmacological properties of hypoglycemic drugs using multiple regression equations with their statistical parameters. Regression analysis showed that the molecular topology model predicts these properties. The corresponding stability (cross-validation) studies performed on the selected prediction models confirmed the goodness of the fits. The method used for hypoglycemic activity selection was a linear discriminant analysis (LDA). We make use of the pharmacological distribution diagrams (PDDs) as a visualizing technique for the identification and selection of new hypoglycemic agents, and we tested on rats the predictive ability of the model.

Problems and pitfalls of sulphonylurea therapy in older patients

The prevalence of non-insulin-dependent diabetes mellitus (type II) increases with age, so that approximately half of all known patients in English-speaking countries are over 65 years of age. There is no reason to believe that the criteria for blood glucose control should be any less stringent for elderly patients unless they have a limited life expectancy. Sulphonylurea drugs remain an effective means of achieving blood glucose control after failure of dietary therapy alone in older patients. However, changes in normal metabolism of drugs with age and the development of other pathologies in elderly patients make it important that these drugs are prescribed with care. Severe symptomatic hypoglycaemia is the most serious adverse effect of sulphonylurea drugs and this becomes progressively more likely with increasing age, depending primarily on the substantial reduction of renal function with normal aging. Other adverse effects are much less commonly of clinical importance. To minimise the risk of hypoglycaemia, it is important that patients receive closely supervised dietary management with education about their disease for at least 3 months before sulphonylurea drugs are prescribed. In elderly patients a short-acting agent with no active metabolites should be used. As patients become older, those receiving long-acting agents can be changed to short-acting agents before problems arise. If blood glucose control appears satisfactory on treatment, then symptoms of hypoglycaemia should be sought. If control is poor, then the criteria for introduction of insulin, with appropriate education, do not differ from those in younger patients.

Hypoglycemic Adverse Reactions to Insulin and Sulfonylureas

The physiology and pathophysiology of hypoglycemia secondary to insulin and oral hypoglycemics are reviewed. Literature and clinical experiences, as well as litigated experiences, are discussed, and pharmacists are cautioned to exercise extreme caution when working with these agents, lest permanent brain damage or death result from their inappropriate use and monitoring.

Oral hypoglycemic agents

The sulfonylureas remain the most important oral agents, although their chronic hypoglycemic actions are still unexplained and the evidence on their relative efficacy is inconclusive. Data on relative safety suggest that chlorpropamide is the most toxic sulfonylurea but glyburide causes dangerous hypoglycemia as often as chlorpropamide. For many patients, good blood glucose control will be achieved by taking tolbutamide or another sulfonylurea 30 minutes before breakfast and the main evening meal. The biguanide metformin, which is as safe as glyburide, is of use in treating overweight diabetic patients who do not have cardiovascular, hepatic, or renal dysfunction.

Secondary prevention after myocardial infarction: subgroup analysis of patients at risk in the Norwegian Timolol Multicenter Study

Timolol treatment after myocardial infarction is generally related to a significant reduction in both mortality and reinfarction compared with placebo. Retrospective analyses of the timolol study are performed on subgroups of patients with a high placebo mortality. The present study shows that these patients are target groups for secondary prevention, as they benefit most from timolol treatment after myocardial infarction. In patients 65-75 years of age, the number of cardiac deaths and reinfarctions prevented by timolol treatment is twice as high as that of patients below 65 years of age. Timolol treatment is well tolerated in the older age group and the contraindications for timolol treatment are independent of age up to 75 years. The reduction in mortality and reinfarction is independent of heart size at baseline. However, in patients with cardiomegaly and compensated heart failure on treatment with digitalis and diuretics, timolol treatment may be of special importance because of the very high incidence of cardiac death in this group of patients. In patients with compensated heart failure on treatment with digitalis and diuretics, timolol treatment does not precipitate heart failure. Patients with stable diabetes mellitus basically behave like nondiabetic patients regarding inclusion rate, side effects, and timolol-related reduction in mortality and reinfarction. Decisions concerning secondary prevention with timolol should be independent of preinfarction and postinfarction angina. In conclusion, 70-80% of all the patients below 75 years of age surviving myocardial infarction, without contraindication to beta-blocker treatment, can be treated with timolol 10 mg twice daily to reduce mortality and reinfarction. In contrast to previous routines, secondary prevention with beta blockers should be especially directed to high-risk patients.

Wide variation in serum chlorpropamide concentration in outpatients

Serum chlorpropamide concentrations (s-CPA) were determined and related to clinical findings in 83 outpatients with maturity onset diabetes. The daily doses of CPA (mg/kg) varied six-fold, but s-CPA ranged 18-fold between the patients. There was a significant correlation between dose and s-CPA (r = 0.61), which rose to 0.75 in the 30 patients who had prescribed no other drugs. Patients given other drugs concomitantly were over-represented amongst subjects with extreme values of apparent plasma clearance of CPA. There was no correlation either between serum creatinine or age and s-CPA. Of the 83 patients 40 (48%) had acceptable blood and urinary glucose values according to our criteria; but as 17 were overweight, only 23 patients (28%) had acceptable clinical control. Of the remaining 60 patients, too low a dose was being given to only 12, and dietary failure was the most probable explanation in the others. Thirteen patients (16%) probably did not need CPA. It is likely that this is a partial explanation for the high utilisation of oral antidiabetic drugs in Sweden. There was no general correlation between dose or s-CPA and blood glucose values, but analysis of s-CPA may still be of value in explaining unexpected changes in clinical control.

Reversible mild diabetes in children after treatment with chlorpropamide

In 9 patients with juvenile-onset chemical diabetes treated with oral chlorpropamide, oral or intravenous assessments of carbohydrate tolerance were made regularly three weeks after withdrawal of therapy. 6 patients with sequential intravenous tests achieved statistically significant reversal of their carbohydrate intolerance and have remained normal for an average of 5.6 years (range 1-11 years). 2 patients who subsequently required insulin therapy were maintained in remission for 3.5 years and 5 years, respectively. There appears to be a group of young patients with chemical diabetes who achieve significant remission with sulphonylurea therapy.