Efficacy of glyburide in diabetics poorly controlled on first-generation oral hypoglycemics

Twenty-four type II (non-insulin-dependent) diabetic patients poorly controlled on maximum doses of first-generation oral hypoglycemic agents were switched to glyburide. There was a significant decrease in glycosylated hemoglobin, but the level was normalized in only four patients; there was no correlation with age, weight, or duration of diabetes. The best predictor for improvement was initial failure on tolbutamide, as opposed to the other first-generation drugs. Patients not controlled with 500 mg/day of chlorpropamide were less likely to benefit from glyburide therapy.

Effect on rat embryos of in vitro culture in sera from human diabetic patients

Recently conditions have been established whereby rat embryos can be cultured in vitro in human serum over the period of their major morphogenesis. By standardizing the amount of glucose in sera from diabetic subjects prior to culture, it has been possible to investigate factors other than hyperglycemia which might account for the increased incidence of congenital defects seen in infants of diabetic mothers. The incidence of abnormalities in rat embryos cultured in sera from chlorpropamide-treated diabetics was not significantly different from that using control sera from normal subjects. On the other hand, sera from insulin-dependent diabetics produced more defects in rat embryos than sera from either normal subjects or diabetics on oral agents. The incidence of abnormal rat embryos does not appear to be correlated with patient age, with the original blood glucose concentration or with the concentration of hemoglobin A1 or, in the insulin group, with the total daily insulin dosage.

Effect of short- and long-term chlorpropamide therapy on oral glucose tolerance and erythrocyte insulin receptors in non-obese non-insulin dependent diabetes mellitus

Erythrocyte (RBC) insulin receptors and the insulin response to glucose load (oGTT) were evaluated in ten male, non-obese, non-insulin dependent diabetic patients (NIDDM) before and after 14 and 90 days of 250 mg/day of chlorpropamide administration. In addition, as a control group, twelve healthy non-obese subjects were studied. Diabetic patients with fasting plasma glucose level higher than 14 mmol/l (group A), presented a significant improvement in the incremental glucose area only after 90 days of therapy. There was an evident reduction in insulin secretion, in comparison to normals, which however increased progressively during drug administration. No alterations in insulin binding to RBC receptors were observed either before or after the use of chlorpropamide, but the normalization of the initially low number of receptors per cell (N) and an increased high affinity constant (Ke) were achieved. In group B with fasting glucose less than 14 mmol/l there was a significant reduction in plasma glucose levels during oGTT without changes in glucose areas and a significant improvement of the insulin secretion was noted only in the early samples. Except for transient alterations in N and Ke no significant changes were observed in insulin-RBC binding parameters. We conclude that the improvement in the glucose tolerance in NIDDM is associated both to a greater insulin secretion and to the correction of the alterations in receptor parameters which could be related, at least partially, to proportionate changes in reticulocyte count.

[Comparative evaluation of the hypoglycemic activity of the vegetal complex of Phaseolus vulgaris and chlorpropamide in experimental diabetes]

Experiments on rabbits with alloxan diabetes showed that the plant complex (PC) reduced the level of glycemia after single administration for 6-8 h by 27-32%. A similar effect was demonstrated with chlorpropamide. However the PC produced a longer hypoglycemic effect. In course treatment the PC returned the blood level of glucose (5.14 +/- 0.62 mmol/l) to normal on the 11th day whereas with chlorpropamide this indicator was almost normal (6.6 +/- 1.1 mmol/l) on the 15th day only. A rapid decrease in the blood glucose concentration caused by the PC was observed in AIS induced hyperglycemia. The PC demonstrated its sugar reducing action by extrapancreatic means.

Chlorpropamide-induced pure white cell aplasia

We investigated the mechanism for isolated agranulocytosis and marrow pure white cell aplasia in an elderly man receiving 0.5 to 1.0 g per day of chlorpropamide (Chl) without other toxic drug exposure or overt systemic illness. Patient marrow revealed an absence of recognizable granulocytic precursors; megakaryocytes and erythroid precursors were normal. The WBC count was 1800/mm3 on admission with only 2% neutrophils; the absolute neutrophil count first exceeded 500/mm3 on the 17th day following cessation of Chl. A serum Chl level on admission was 100 micrograms/mL (acute phase, AP); no Chl was detected in serum (convalescent phase, CP) assessed on the 22nd hospital day. Antineutrophil antibodies were not detected, and T cell depletion failed to augment patient in vitro granulopoiesis. Patient AP serum produced potent complement-mediated inhibition (87% +/- 7%) of autologous granulocyte progenitors (CFU-GM) with minimal inhibition of erythroid (11% +/- 5%) or multipotent (5% +/- 4%) progenitor cells. Selective inhibition by patient AP serum of CFU-GM (74% +/- 11%) was also seen against two allogeneic marrows. Patient CP serum no longer inhibited (6% +/- 4%) autologous CFU-GM. Addition of Chl (5 to 120 micrograms/mL) to CP serum but not to control serum resulted in potent drug concentration-dependent complement-mediated inhibition of autologous and allogeneic CFU-GM. Inhibition of CFU-GM in the presence of Chl was no longer demonstrable following immunoabsorbent removal of IgG from patient serum. Patient serum in the presence of Chl had limited activity against morphologically recognizable marrow granulocytic precursors in a microimmunofluorescence assay. These results are most consistent with the development of Chl-dependent, selective antibody-mediated immune inhibition of granulopoiesis.

Erythrocyte aldehyde dehydrogenase, plasma chlorpropamide concentrations and the chlorpropamide alcohol flush

Erythrocyte aldehyde dehydrogenase activity (EALDH) was measured in 21 diabetics on long-term chlorpropamide therapy. Median EALDH was 0.362 units, range 0.108 to 0.750 units and correlated neither with previously assessed chlorpropamide alcohol flushing nor with coincident plasma or erythrocyte chlorpropamide concentration. The hypothesis that genetic or permanently acquired reduction in EALDH correlates with CPAF status was not supported. There was no concentration-related inhibition of the enzyme by prevailing plasma or erythrocyte chlorpropamide.

Pharmacokinetics of chlorpropamide in epileptic patients: effects of enzyme induction and urine pH on chlorpropamide elimination

The effects of liver enzyme induction and of urine pH on the pharmacokinetics of chlorpropamide have been studied. A single oral dose of chlorpropamide 250 mg was administered to 8 patients on antiepileptic drugs (phenytoin, carbamazepine) and to 8 healthy volunteers. The half-life of chlorpropamide was significantly shorter in the patients (34.4 h) than in the healthy volunteers (50.2 h), but the difference between the groups in the half-life of antipyrine was even more pronounced (5.1 vs 11.4 h). The clearance and volume of distribution of total chlorpropamide were significantly higher in the patients (2.99 ml X h-1 X kg-1 and 126 ml X kg-1) than in the healthy volunteers (1.60 ml X h-1 X kg-1 and 106 ml X kg-1). The unbound fraction of chlorpropamide in serum was also higher in the patients (5.7%) than in the healthy subjects (4.4%). Neither the volume of distribution nor the clearance of the free fraction of chlorpropamide differed significantly between the groups. There was a significant correlation between the half-lives of chlorpropamide and antipyrine, and the half-life of chlorpropamide also had at least as good an inverse correlation with the urinary excretion of unchanged chlorpropamide. The renal clearance of chlorpropamide correlated well with urine pH and was almost 100-fold higher at pH 7 than at pH 5. Both the metabolic and renal clearances of chlorpropamide are important in its elimination. At urine pH higher than 6.5-7, the renal clearance of chlorpropamide represents more than half its total clearance regardless the degree of induction of liver enzymes.

No glycemic benefit from guar administration in NIDDM

A randomized crossover study of 5-g guar minitablets against placebo, given three times per day with main meals for 8 wk, was done in 29 non-insulin-dependent diabetes mellitus (NIDDM) patients who had near-normal fasting plasma glucose concentrations on treatment with diet alone, additional sulfonylurea, or ultralente insulin. Guar did not reduce the excessive postprandial glycemic excursion, glycosylated hemoglobin values, basal plasma glucose concentrations, basal or incremental plasma C-peptide values, or body weight. There were few side effects with either guar or placebo therapy. Mean low-density lipoprotein cholesterol levels were significantly reduced (P less than .001) by guar administration (116 +/- 23 vs. 104 +/- 19 mg/dl). Guar additives did not improve the excessive postprandial glycemia found in NIDDM patients in whom near-normal fasting plasma glucose levels had been obtained.

Diabetes mellitus and primary hepatocellular carcinoma

In view of the increasing incidence of primary hepatocellular carcinoma in western Europe and concern that this may in part be related to long-term use of drugs which cause hepatic microsomal enzyme induction, we undertook a comparison of long-term drug use in 105 patients with hepatocellular carcinoma and equal numbers of age and sex-matched patients with colorectal tumours and with fractures of femur. We found no patients with hepatocellular carcinoma who were long-term anticonvulsant users and only one who used oral contraceptives. However, we observed a four-fold excess of diabetic patients among the group with hepatocellular carcinoma. This association did not appear to be due to pre-existing haemochromatosis, alcoholic cirrhosis or viral hepatitis. The association was strongest in patients receiving drug treatment for diabetes, but the data, although suggestive, were insufficient to determine whether any specific anti-diabetic agent could be responsible. Further studies are required to elucidate the nature of this unexpected association. An association of this magnitude with diabetes mellitus could account at least in part for the increasing incidence of hepatocellular carcinoma in western Europe.

Selective osmoreceptor dysfunction presenting as intermittent hypernatremia following surgery for a pituitary chromophobe adenoma

Intermittent hypernatremia following hypothalamic surgery or trauma is usually attributed to the triphasic dysfunction of vasopressin release (diabetes insipidus, inappropriate vasopressin release, and diabetes insipidus). A 39-year-old patient had hypodipsia and intermittent hypernatremia following hypothalamic surgery for a chromophobe adenoma. Mean arterial pressure fell by 25 percent during orthostasis testing and was associated with an increase in vasopressin levels from 1.3 microU/ml to 12 microU/ml. Plasma renin activity and aldosterone increased from 1.1 to 16 ng/ml per hour and from 6.7 to 39 ng/dl, respectively, and remained elevated for three and a half hours after tilt testing. Hypertonic saline infusion, on the other hand, increased serum osmolality from 290 to 304 mOsm/kg but did not result in a significant rise in vasopressin levels (all were less than 1 microU/ml). These results are consistent with a selective dysfunction of the osmoreceptor pathways of vasopressin release and intact volume receptor-mediated pathways. Patients with intermittent hypernatremia following hypothalamic surgery or trauma should be questioned specifically regarding thirst. If it is impaired or absent, these patients should be watched carefully, not only for the development of triphasic dysfunction of vasopressin release, but also for a selective osmoreceptor dysfunction associated with thirst deficits as found in patients with "essential hypernatremia."

Diabetes insipidus in a quadriplegic patient

An incomplete quadriplegic patient underwent investigation for production of copious amounts of dilute urine. Serum osmolality, electrolytes, BUN, glucose, and serum antidiuretic hormone (ADH) were recorded, as well as urinary osmolality, electrolytes, glucose, and pH. In response to subcutaneous vasopressin during the dehydration test, the patient's urinary osmolality increased by 12%, from 620 mOsm/l to 695 mOsm/l. A definitive diagnosis of partial central diabetes insipidus was made. Physicians involved in the care of patients with spinal cord injuries should be aware of the method of evaluating polyuric conditions, particularly while the patient is undergoing catheterization.

Opuntia streptacantha: a coadjutor in the treatment of diabetes mellitus

This report describes the effect produced by the complementary daily administration of Opuntia streptacantha sap to a diabetic volunteer being under treatment with chlorpropamide. The plant product improved remarkably the general symptomatology of the patient as well as his insulin and glucose blood levels.

Once-daily use of glyburide

Ideally, metabolic control with sulfonylureas should be maintained for 24 hours. To determine an optimal glyburide dosage schedule, the effects of glyburide once (every morning) or twice daily and chlorpropamide once daily (every morning) were compared in 18 men with non-insulin-dependent diabetes mellitus in a randomized, double-blind fashion. After discontinuation of previous hypoglycemic agents for 10 days, patients were admitted to a metabolic ward for two weeks (Study A). Glycemic measurements were performed on Day 14. Subjects were readmitted after 12 weeks of outpatient therapy for another two weeks (Study B), and glycemic determinations were repeated. Weight was kept constant during and between Studies A and B. Effective hypoglycemic action of each drug regimen was demonstrated. When six glycemic parameters were compared, there was no significant difference between groups. Thus, over a 14-week period, both glyburide regimens were similar and as effective as chlorpropamide once daily.

Review of glyburide after one year on the market

After one year on the American market, glyburide, a second-generation sulfonylurea, seems well accepted by physicians. If the hyperglycemia of patients with type II diabetes mellitus is not corrected by diet and exercise, glyburide can be used as adjunctive therapy. The drug is comparable in efficacy to the first-generation sulfonylurea chlorpropamide, but it has fewer reported side effects. Additionally, glyburide does not appear to interact with other medications and is well absorbed from the gastrointestinal tract. Although the drug had been reported to produce hypoglycemia, increased clinical experience--along with use of judicious dosages in appropriate patients--has decreased the incidence of hypoglycemia. Although still in the investigational stage, combination insulin/glyburide therapy may also benefit subgroups of type II diabetic patients. Glyburide is a useful and rational addition to therapy in properly selected patients with type II diabetes mellitus.

Treatment strategies for patients with non-insulin-dependent diabetes mellitus

Strategies for the treatment of patients with non-insulin-dependent diabetes mellitus are discussed. In order to achieve treatment goals, diet and exercise remain important components of an overall treatment program that may include sulfonylurea drugs, especially in cases where patients are of normal weight or only slightly obese, have had the disease less than five years, and are taking little or no insulin. Failure to control blood sugar levels with sulfonylurea drugs may lead to combining this therapy with insulin or administering insulin alone, regardless of patients' weights.

Effects of oral sulfonylureas on the spectrum of defects in non-insulin-dependent diabetes mellitus

Blood glucose and plasma insulin responses to hypoglycemic agents in normal subjects and patients with non-insulin-dependent diabetes mellitus are presented. The responses of the normal subjects and the diabetic patients show differences in response to different hypoglycemic agents. Interim data from the United Kingdom's prospective study of non-insulin-dependent diabetes mellitus are presented. About half of the anticipated subjects (approximately 2,000) have been enrolled in that clinical trial as of December 1984. It is concluded that sulfonylurea drugs have a role in the treatment of non-insulin-dependent diabetes mellitus, but that each patient must be treated individually since the disease is heterogeneous. Furthermore, more studies than are now customary should be performed on each patient to determine which of several available agents is most appropriate.

U.K. prospective diabetes study. II. Reduction in HbA1c with basal insulin supplement, sulfonylurea, or biguanide therapy in maturity-onset diabetes. A multicenter study

Newly presenting maturity-onset diabetic subjects were put on diet and if, after 3-4 mo, their fasting plasma glucose continued greater than 6 mmol/L, they were randomized to three therapies: (1) continuing diet alone, (2) with additional sulfonylurea, or (3) with additional basal insulin supplement provided by ultralente insulin. Obese patients were also randomized to metformin therapy. The aim was to lower the fasting plasma glucose to less than 6 mmol/L and the degree to which this reduced the hemoglobin A1C (HbA1C) concentration was studied in 195 patients over 1 yr. Sulfonylurea and insulin similarly reduced (P less than 0.001) the fasting plasma glucose from 8.3 +/- 1.9 to 6.7 +/- 1.3 mmol/L (mean +/- 1 SD) and 8.6 +/- 2.2 to 6.8 +/- 1.4 mmol/L, respectively. This was accompanied by a significant reduction (P less than 0.001) of the HbA1C to the high normal range, from 9.1 +/- 2.1% to 7.8 +/- 1.2%, and from 9.1 +/- 1.9% to 8.1 +/- 1.3%, respectively, both values at 1 yr being significantly (P less than 0.05) lower than in patients randomized to diet alone. Patients randomized to diet alone had little change in fasting plasma glucose (8.6 +/- 1.8 to 9.3 +/- 2.3 mmol/L) or HbA1C (8.8 +/- 1.7% to 9.1 +/- 1.6%, respectively). Thus, the simple therapeutic aim of trying to reduce the fasting plasma glucose to less than 6 mmol/L is an effective means of reducing the HbA1C to a high-normal level. The HbA1C and fasting plasma glucose concentrations were similarly related for all three therapies (HbA1C [%] = 0.47 X fasting plasma glucose [mmol/L] + 4.7).(ABSTRACT TRUNCATED AT 250 WORDS)

A case of chronic liver disease due to tolazamide

Although chlorpropamide and tolbutamide are well recognized as causes of hepatotoxicity, there are only 3 reported cases of hepatic injury caused by a third oral hypoglycemic agent, tolazamide. In 2 of these cases, the liver-function tests returned to normal when the drug was discontinued. In the third case, the patient had cholestasis from chlorpropamide before administration of tolazamide and developed chronic liver disease. We are reporting the second instance of chronic liver disease induced by tolazamide. Our patient had been taking chlorpropamide, but she had no evidence of liver disease before administration of tolazamide. Tolazamide should be considered as a drug capable of producing hepatotoxicity that on occasion may be chronic.

Long-range implications for the mother. The Aberdeen experience

One hundred twelve women with impaired glucose tolerance (IGT) diagnosed by intravenous glucose tolerance test (IVGTT) after pregnancy were followed up for a period of up to 22 yr (mean 12.9 yr). About one-third have been treated with chlorpropamide and the others by diet only. At the final assessment, approximately 35% had abnormal intravenous glucose tolerance and less than 7% overt diabetes. Chlorpropamide did not prove significantly more effective than diet only. Factors associated with deterioration in glucose tolerance were age at diagnosis and follow-up and the initial fasting plasma glucose (FPG) level (greater than or equal to 5.8 mM), but obesity was less important, although it was associated with an increased rate of vascular complications. Tests for islet cell antibodies (ICA) were weakly positive in 12.5% of 72 subjects and in only 0.5% of an unselected population; they did not correlate with the final state of glucose tolerance. Only three patients developed insulin-dependent diabetes (IDDM) and did so before the ICA study was started. A comparison is made between the results reported by O'Sullivan in patients diagnosed as having gestational diabetes, only 2% of whom still had abnormal oral glucose tolerance postpartum, and the results of our patients, all of whom had IGT after pregnancy. In spite of differences of technique and in the populations studied, the prevalence of IGT and overt diabetes at follow-up was significantly less in the Aberdeen series, who were initially a higher risk group. It seems probable that this is mainly attributable to dietary treatment in the follow-up period as O'Sullivan's cases were treated only during pregnancy.

Medication compliance in non-insulin-dependent diabetes: a randomized comparison of chlorpropamide and insulin

Medication compliance may be a problem in the management of patients with diabetes. Some physicians initially treat patients having non-insulin-dependent diabetes with oral sulfonylureas because they fear greater compliance problems with insulin therapy. We compared compliance with insulin and chlorpropamide in patients newly beginning medication for NIDDM. Seventy-seven adults with hyperglycemia despite diet therapy were randomly assigned to chlorpropamide or insulin. Compliance was measured four times over 24 wk. Patients then crossed over to the other medication and were followed for 24 additional weeks. Overall, there were no differences in compliance with the two medications in terms of percent of prescription used, proportion taking at least 80% of prescribed medication, self-report of medication or diet compliance, or protocol dropout rates. However, treatment satisfaction was higher with chlorpropamide, and most patients preferred chlorpropamide to insulin (P less than 0.0001). While such differences in satisfaction may affect long-term compliance, physicians should not assume that their patients will be less compliant with insulin than with oral sulfonylureas.

The 24-hour effects of glyburide and chlorpropamide after chronic treatment of type II diabetic patients

A single-blind, randomized, comparative evaluation of glyburide (GL) and chlorpropamide (CP) therapy was performed in twenty previously untreated patients with non-insulin dependent diabetes mellitus (NIDDM) of about two years duration. Only newly diagnosed patients who were never treated and whose fasting blood glucose (FBS) levels were greater than 140 mg/dl after a six to eight week trial of dietary restriction were evaluated. Metabolic studies were performed before and after four months of therapy. GL and CP produced essentially the same effects on serum levels of glucose, insulin, glucagon (IRG), growth hormone (GH), cholesterol, and triglyceride. The mean 24-hour glucose levels for both the GL and CP groups were significantly lower than the pretherapy values (p less than 0.001). The mean 24-hour insulin levels did not change significantly during therapy (p greater than 0.05). Excellent control of plasma glucose was possible during the entire day without producing nocturnal hypoglycemia. Neither GL nor CP therapy influenced the mean 24-hour levels of IRG, GH, or cholesterol. However, mean 24-hour levels of triglyceride were lower in both groups. IRG levels were elevated and the pattern of change in the insulin and IRG levels paralleled each other, which suggested that glucagon may play a role in the resistance of insulin action in NIDDM. GH levels were normal and remained unchanged during therapy. It was concluded that detailed 24-hour studies are important for better understanding the spectrum of abnormalities in newly diagnosed patients with NIDDM who were never treated.(ABSTRACT TRUNCATED AT 250 WORDS)