Influence of food on the presystemic metabolism of drugs.
Explore the source record for details and available documents.
Biological Availability↗
Biomedical subjects
A Melander
Publications and source records attributed to A Melander.
Sulphonylureas in the treatment of non-insulin-dependent diabetes.
Explore the source record for details and available documents.
Diabetes Mellitus, Type 2↗
Equianalgesic effects of paracetamol and indomethacin in rheumatoid arthritis.
The therapeutic and adverse effects of 2 weeks of treatment with high-dose indomethacin (150 mg/day) were compared with those of low-dose indomethacin (50 mg/day) combined with paracetamol (4 g/day) in a double-blind, double-dummy, cross-over study in 17 patients with active rheumatoid arthritis. Grip strength, Ritchie's index, joint circumference, joint pain, and patient's and physician's global assessments were estimated, and conventional laboratory parameters were followed. In addition, the time-concentration profiles of indomethacin and paracetamol were assessed during steady state. All patients had measurable plasma drug levels, indicating adequate compliance, and responders and nonresponders (five on each treatment) had equal drug levels, indicating that the variation in therapeutic efficacy was not secondary to pharmacokinetic differences. While there were fewer and milder side-effects during treatment with the drug combination, there was no difference in therapeutic efficacy. Hence, it appears that the main therapeutic profit of indomethacin in daily doses greater than 50 mg is enhanced analgesia. As such dosage involves pronounced side-effects, it seems more appropriate to employ the combination of 50 mg indomethacin and 4 g paracetamol, whereby similar analgesia can be obtained without an increase in side-effects.
Acetaminophen↗
Efficacy of dietary regulation in primary health care patients with hyperglycaemia detected by screening.
The efficacy of dietary regulation was examined in 38 consecutive primary health care patients with hyperglycaemia detected on screening. Ten weeks of dietary regulation reduced overall mean fasting blood glucose from 8.2 to 6.5 mmol l-1. Fasting blood glucose fell more (from 12.3 to 7.6 mmol l-1 and from 8.4 to 6.6 mmol l-1) in the two quartiles initially above the median (7.15 mmol l-1), than in the lower quartiles (6.7 to 6.1 mmol l-1 and 5.7 to 5.8 mmol l-1), even though weight reduction was similar. The reduction in blood glucose correlated (r = 0.87) with the degree of fasting hyperglycaemia before treatment. Sixteen patients (42%) reached or maintained fasting blood glucose less than or equal to 6.0 mmol l-1, and they had a milder degree of glucose intolerance, a higher insulin response to a meal and a greater reduction in weight than the 22 patients (58%) who did not reach less than or equal to 6.0 mmol l-1. Nine patients (24%) maintained fasting blood glucose less than or equal to 6.0 mmol l-1 for greater than 5 years, and showed a considerable improvement of insulin action. Dietary regulation improved glucose control mainly by reducing fasting hyperglycaemia; neither the delay in early insulin release nor the associated elevation and prolongation of the post-prandial glucose excursions were reduced.
Aged↗
Do sulfonylureas influence hepatic insulin clearance?
Explore the source record for details and available documents.
Animals↗
Physiotherapy after total hip replacement for primary arthrosis.
Organized physiotherapy starting two months after uncomplicated total hip replacements for primary arthrosis did not improve the rehabilitation. Six months after surgery there were no significant differences between 14 patients with and 16 patients without physiotherapy regarding improvement of passive hip motion, or hip or knee muscle strength of the operated limb. Neither were there any differences in walking ability or activities of daily living.
Activities of Daily Living↗
Atrial natriuretic peptide and blood pressure in a geographically defined population.
Plasma atrial natriuretic peptide (ANP) was measured in 717 subjects in a cross-sectional study of patients with hypertension (treated and untreated) and normotensive controls, representatives of a geographically defined population. ANP concentrations did not differ between the groups and there was no correlation with blood pressure. These results do not support the view that hypertensive and normotensive subjects have different ANP concentrations; they also call into question the role of ANP in the development of high blood pressure.
Adult↗
Lack of primary effect of sulphonylurea (glipizide) on plasma lipoproteins and insulin action in former type 2 diabetics with attenuated insulin secretion.
A double-blind, placebo-controlled investigation has been made into the effects of 8 weeks of glipizide treatment in diabetics previously classified as Type 2 but with subsequent attenuation of insulin secretion and thence maintained on exogenous insulin. Although all patients were exposed to therapeutic plasma concentrations of glipizide, fasting blood glucose, haemoglobin A1 and plasma lipoproteins (HDL, LDL, total cholesterol and triglycerides) did not show any consistent improvement following this treatment. It appears unlikely that SU (glipizide) has any primary effect on insulin action or on plasma lipoproteins. Its primary action is to augment insulin release and availability, so, its use should be restricted to Type 2 diabetics who retain insulin secretion.
Blood Glucose↗
Clinical pharmacology of sulfonylureas.
Sulfonylureas seem to have similar mechanisms of action, including an acceleration and increase of insulin secretion, an increase of the systemic availability of insulin, and probably indirectly, an increase of insulin action. Sulfonylureas may postpone the development of impaired glucose tolerance (IGT) to manifest non-insulin-dependent diabetes mellitus (NIDDM), and all NIDDM subjects should benefit from sulfonylurea treatment except those in whom insulin secretion has been attenuated. The most effective use is the combination of diet restriction and sulfonylurea introduced in NIDDM subjects soon after transition from IGT to NIDDM. A simple screening procedure has been devised to find the subjects at this early stage. Newer sulfonylureas, such as glipizide and glyburide, are more potent than the older ones, such as tolbutamide and chlorpropamide. During chronic treatment, glipizide and glyburide seem to be equally effective in reducing blood glucose levels, and they do so without causing a chronic elevation of insulin secretion, signifying that they do not increase the risk of pancreatic B cell exhaustion. Glipizide has rapid and complete absorption, as well as a rapid distribution and elimination. This may explain why it is less liable than other sulfonylureas to provoke long-lasting hypoglycemia, which is the major danger when using sulfonylureas. Despite its rapid elimination, 7.5 to 15 mg glipizide can be administered once daily without loss of therapeutic efficacy. This may be due in part to enterohepatic recirculation of the drug in response to meals. The therapeutic efficacy is increased if glipizide is received half an hour before breakfast.
Diabetes Mellitus, Type 2↗
3,4-Dihydroxypyridine: a potential antithyroid drug.
3,4-Dihydroxypyridine (3,4-DHP), a goitrogenic derivative of the plant amino acid mimosine, has no SH-group, in contrast to conventional antithyroid agents such as methimazole (MMI) and propylthiouracil (PTU). The current in vitro study shows that 3,4-DHP, like MMI and PTU, inhibits iodination of human thyroglobulin and interferes with mitogenic activation of human lymphocytes. This, together with a very low murine bone marrow toxicity, probably related to the absence of an SH-group, makes 3,4-DHP a potential antithyroid drug.
Antithyroid Agents↗
Different effects of glyburide and glipizide on insulin secretion and hepatic glucose production in normal and NIDDM subjects.
Glyburide (GB) and glipizide (GZ) differ in their pharmacokinetics, but it is not known whether they also differ in mode of action. To examine this question, 10 young healthy subjects and 6 non-insulin-dependent diabetic (NIDDM) patients participated in each of three studies: 1) infusion of saline for 120 min followed by a 100-min hyperglycemic (125 mg/dl) clamp; 2) 120-min primed continuous infusion of GZ followed by a 100-min hyperglycemic clamp; and 3) 120-min primed continuous infusion of GB followed by a 100-min hyperglycemic clamp. The GB and GZ infusions were continued throughout the hyperglycemic clamp. Similar plasma concentrations of GB and GZ were obtained in both groups. All studies were performed with [3-3H]glucose to allow quantification of hepatic glucose production. When administered under basal conditions of glycemia, the acute phase (0-10 min) of plasma insulin and C-peptide increase in both control and NIDDM subjects was twice as great with GZ compared with GB (P less than .01). During the hyperglycemic-clamp studies performed in normal subjects, both GB and GZ increased the first- (1.6-fold) and second- (2.2-fold) phase plasma insulin responses more than hyperglycemia alone. During the hyperglycemic clamp in NIDDM subjects, the first-phase plasma insulin response was absent, and the second-phase insulin response was markedly impaired. Neither GB nor GZ improved first-phase insulin secretion in the NIDDM patients. In both NIDDM and control subjects, the effects of hyperglycemia and sulfonylurea drugs (both GB and GZ) on the first- and second-phase plasma insulin responses were simply additive.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Influence of wheat bran and of a bulk-forming ispaghula cathartic on the bioavailability of digoxin in geriatric in-patients.
The present randomized study compared the influence of a gel-forming wheat bran with a nongel-forming bulk cathartic (an ispaghula formulation, Vi-Siblin S) on the steady state concentrations of digoxin in plasma in 30 geriatric in-patients treated with either combination (16 with wheat bran + digoxin, 14 with ispaghula + digoxin) for 4 weeks. After 2 but not after 4 weeks, wheat bran reduced the digoxin levels, although the levels were still within the therapeutic range. Ispaghula had no influence at any time. It is concluded that neither wheat bran nor the ispaghula formulation has any clinically relevant influence on therapeutic digoxin levels in geriatric patients.
Aged↗
Influence of food intake on the bioavailability of zuclopenthixol.
The single-dose kinetics of the neuroleptic thioxanthene zuclopenthixol was assessed in 12 healthy volunteers who ingested 10 mg of the drug orally, both on an empty stomach and together with a standardized breakfast of 1840 kj (440 kcal). The serum concentrations of zuclopenthixol were measured by HPLC. Concomitant food intake did not influence the peak concentration nor the time to reach the peak concentration or the elimination half-life of zuclopenthixol, but the AUC values were significantly increased. Hence it seems likely that concomitant food intake enhances the bioavailability of zuclopenthixol, without influencing its absorption rate. The most likely mechanism is that food reduces the presystemic clearance of the drug. As the increase in AUC was only 26%, it is doubtful whether zuclopenthixol has to be administered in a standardized relation to meals.
Adult↗
Therapeutic equivalence of once- and thrice-daily glipizide.
Two cross-over studies were carried out in 23 patients with Type 2 diabetes, to examine whether glipizide, a potent sulphonylurea with fast and complete absorption and rapid elimination (t1/2 less than 5 h), can be given once-daily without loss of therapeutic effect. In both studies, patients were randomly assigned to an initial dose of 7.5 mg once daily or 2.5 mg three-times daily, which was increased to 15 mg o.d. or 5 mg t.i.d. if the fasting plasma glucose remained over 10 mmol/l on the lower dosage. In Study 1 (n = 11), administration once a day before breakfast was compared with intake before breakfast, lunch and early dinner (5 p.m.) and in Study 2 (n = 12) the comparison was between intake once-daily before breakfast and dosing before breakfast, lunch, and at bedtime (10 p.m.). Neither the 24-hour urinary glucose excretion nor HbA1, fasting plasma glucose, insulin or C-peptide levels differed between the once and three times daily administration with the third dose given before early dinner. The nadir plasma levels of glipizide were not significantly different and were often too low to be detected. Postponing the third dose until 10 p.m. did not produce any improvement in HbA1 or in fasting plasma glucose, insulin or C-peptide. The mean nadir glipizide levels following this schedule were twice as high as those after once-daily administration. As expected, the plasma glipizide after breakfast was higher when the whole dose was taken before breakfast than when it was divided. The corresponding plasma level of insulin was higher and that of plasma glucose was lower.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Concomitant food intake can increase the bioavailability of propranolol by transient inhibition of its presystemic primary conjugation.
The influence of concomitant food intake on the bioavailability and presystemic primary conjugation of propranolol (80 mg) was studied in 11 healthy women. Food increased the maximum serum concentration and serum AUC of propranolol (P less than 0.05) and reduced those of conjugated propranolol (P less than 0.05). The mean AUC ratio of conjugated/unchanged propranolol was 13:1 in the fasting state but only about 6:1 in the nonfasting state (P less than 0.001). The time to maximum serum concentration and the t1/2 were not affected by food. There was no influence of food on any kinetic parameter of propranolol or conjugated propranolol when a slow-release formulation was used. We conclude that concomitant food intake can evoke a short-lasting, delivery rate-dependent inhibition of the presystemic primary conjugation of propranolol. This is one, but not the sole, mechanism by which food can enhance propranolol bioavailability.
Absorption↗
Pharmacokinetics and metabolic effects of glibenclamide and glipizide in type 2 diabetics.
Fifteen Type 2 diabetics were treated for 4-week periods with once daily (10 mg) glibenclamide, glipizide and placebo according to a double-blind cross-over protocol. Post-dose glipizide concentrations were three times higher than those of glibenclamide, due to the incomplete bioavailability of the latter. On the other hand, pre-dose drug levels were similar, as an expression of the slower absorption and/or elimination of glibenclamide. Both active treatments reduced postprandial blood glucose concentrations and 24-hour urinary glucose excretion to a similar degree, but fasting blood glucose concentrations were slightly lower during glibenclamide treatment. Both active treatments enhanced fasting and postprandial insulin and C-peptide concentrations, the C-peptide response being greater after glipizide than after glibenclamide. Plasma glucagon and GIP concentrations were not significantly affected. Insulin sensitivity was increased by glibenclamide but not by glipizide. Neither therapy affected insulin binding to erythrocytes. It appears that both glibenclamide and glipizide improved glucose metabolism by sustained stimulation of insulin secretion, which was most pronounced with glipizide. Only glibenclamide improved insulin sensitivity and was slightly more active than glipizide on fasting blood glucose levels. The differences may be consequences of the pharmacokinetics, but differences in pharmacodynamics cannot be excluded.
Aged↗
Concomitant food intake does enhance the bioavailability and effect of hydralazine.
Explore the source record for details and available documents.
Biological Availability↗
Pharmacokinetic interaction of acetylsalicylic acid and dipyridamole.
It is often recommended that acetylsalicylic acid (ASA) and dipyridamole should be given together in order to obtain secondary prophylaxis against certain ischaemic diseases. Therefore, the possible pharmacokinetic interactions between these agents were assessed following single-dose exposures in 14 healthy volunteers. The plasma concentrations of ASA, salicylic acid (SA) and dipyridamole were measured by selective h.p.l.c. techniques. It was found that, while dipyridamole kinetics were unaffected by concurrent ASA, concurrent dipyridamole significantly enhanced the peak concentration (24%) and AUC (27%) of ASA. Thus, co-administered dipyridamole might influence the anti-platelet effect of ASA.
Adult↗