Influence of renal function on the pharmacokinetics of diacerein after a single oral dose

The pharmacokinetics of diacerein (a new anti-inflammatory analgesic antipyretic drug) following a single oral dose of 50 mg was studied in 12 healthy volunteers and two groups of eight patients with mild or severe renal insufficiency. Statistical analysis using a Kruskal-Wallis rank sum test showed a significant difference between the three groups for the following parameters. In severely uraemic patients, median AUC0-infinity was multiplied by a factor of ca 2: 40.5 mg h/l versus 21.3 in healthy subjects, P = 0.04; and t1/2 was prolonged by the same factor: 9.6 h versus 4.3 in the control group, P = 0.003. Apparent drug availability and renal clearance assessed through urinary data decreased with renal failure, respectively: 14.5% and 0.045 l/h versus 35.4% (P = 0.01) and 0.13 l/h (P = 0.008) in healthy subjects. Amounts of glucuro and sulfo conjugates in urine were lower in severely uraemic patients. Intermediate values were observed for mildly uraemic patients. Other parameters: lag-time, Cmax, tmax, Vss/F, urinary glucuro- to sulphoconjugate ratios did not change significantly. Apparent total clearance of rhein was poorly correlated with creatinine clearance and this was related to a decrease of non-renal clearance of rhein in renal insufficiency. It was concluded that, from a pharmacokinetic point of view, a reduction (50%) in the maintenance dosage of diacerein should be considered in severe renal failure.

Pharmacokinetics of diacerein in patients with liver cirrhosis

The pharmacokinetics of diacerein following a single oral dose of 50 mg was studied in 12 healthy volunteers, 10 patients with a mild liver cirrhosis (Child Pugh's grade A), and 6 patients with a more severe liver cirrhosis (Child Pugh's grade B to C). Statistical analysis using a Kruskal-Wallis test showed no significant differences between the three groups for the following parameters: median Cmax was 3.9 mg l-1 for the cirrhotic patients group I (CPI) and 3.2 mg l-1 for the cirrhotic patients group II (CPII) versus 3.2 mg l-1 for the healthy volunteers (HV); median t1/2 was 4.9 h for CPI and 4.3 h for CPII versus 4.3 h for HV; median Cl/F was 2.1 l h-1 for CPI and 2.5 l h-1 for CPII versus 1.6 l h-1 for HV; median Vdss/F was 12.6 l for CPI and 14.0 l for CPII versus 13.21 for HV. The urinary parameters were comparable. It was concluded that, from a pharmacokinetic point of view, no reduction in the initial dosage of diacerein need be proposed in liver cirrhosis.

Thermal behavior and elastic properties of phospholipid bilayers under the effect of a synthetic flavonoid derivative, LEW-10

We have investigated the effect on phospholipidic bilayers of LEW-10, a synthetic flavonoid, derivative of diosmin. Two optical techniques, Quasi-elastic Light Scattering (QLS) and Fourier Transform Infrared Spectroscopy (FT-IR) were used. The results show that in the presence of LEW-10, the phase transition of the bilayers is lowered and that the elastic modulus is decreased. The FT-IR results indicate interactions in the aqueous interface regions of the bilayers. We also discuss LEW-10 comparatively with another derivative, LEW-7/S1, whose effect has been previously studied.

Pharmacokinetics and absolute rectal bioavailability of hydrocortisone acetate in distal colitis

The hydrocortisone pharmacokinetic profiles of hydrocortisone acetate foam (Proctocort) administered rectally was assessed in healthy volunteers and patients with ulcerative colitis or X-irradiation colitis. Endogenous production of hydrocortisone was suppressed by dexamethasone. Comparison of these data with those obtained after intravenous administration enabled assessment of absolute bioavailability, which was 30.0 +/- 15.1% in healthy volunteers vs. 16.4 +/- 14.8% in patients (P = 0.09). Maximal concentrations of hydrocortisone were also decreased in patients, 277 +/- 215 nmol/L vs. 610 +/- 334 nmol/L (P = 0.03). There was a nonsignificant tendency to faster absorption of hydrocortisone in patients vs. healthy volunteers, as the times to peak concentration were, respectively, 2.5 +/- 1.2 h vs. 2.8 +/- 0.8 h (P = 0.64), and the mean absorption times were 1.96 +/- 1.45 h vs. 2.54 +/- 1.62 h (P = 0.46). Thus, rectal inflammation resulted in a lower absorption of hydrocortisone. In addition systemic plasma levels remained in the physiological range, so that only minor side effects are to be expected.

Pharmacokinetics of glafenine and glafenic acid in patients with cirrhosis, compared to healthy volunteers

Pharmacokinetic parameters were evaluated in 12 patients with alcoholic cirrhosis and 12 healthy volunteers after a single 400 mg oral dose of glafenine. Glafenine (G) and its major active metabolite glafenic acid (GA) were measured at regular intervals using a specific high performance liquid chromatographic method. Glafenine absorption was significantly delayed in cirrhotic patients (CP) (Tmax = 2.8 +/- 1.3 hvs 1.5 +/- 0.4 h, p less than 0.01) and was dramatically reduced in 3 patients. The large hepatic 'first pass' effect observed in healthy volunteers was markedly reduced in CP (ratio Cmax GA/Cmax G = 3.6 +/- 2.9 vs 18.9 +/- 9.8, p less than 0.001; ratio areas under the curves AUC GA/AUC G = 2.3 +/- 2.3 vs 18.2 +/- 11.2, p less than 0.001). The elimination half-life of G was prolonged in the CP (13.0 +/- 13.1 h vs 1.5 +/- 0.5 h, p less than 0.01). In CP, GA elimination half-life was increased (12.0 +/- 13.4 h vs 4.3 +/- 1.3 h, NS) but the difference did not reach statistical significance because of large variability. The significant rise of G plasma concentrations (Cmax = 2.2 +/- 2.1 mg/L vs 0.7 +/- 0.2 mg/L, p less than 0.05) and its longer half-life would lead to an accumulation if the usual dosage regimen was prescribed for CP and could result in nephrotoxicity. On the other hand, lower dosage would be ineffective because only GA is active and nephrotoxic. Hence, G should be given with great caution to CP.

Amiodarone decreases cardiac beta-adrenoceptors through an antagonistic effect on 3,5,3' triiodothyronine

Because surprising similarities exist between the cardiac effects of amiodarone and those observed during hypothyroidism, we tested three different mechanisms of action in rats to determine whether amiodarone might act by inducing a tissular hypothyroidism: (a) a decrease in thyroid secretion, (b) an inhibiting effect on the conversion of thyroxine (T4) to 3,5,3' triiodothyronine (T3), and (c) a direct antagonistic effect on the cellular action of T3. Five groups of rats, treated orally for 7 or 13 days, were studied: I, control (0.5 ml saline for 7 or 13 days, n = 14); II, amiodarone (50 mg/kg for 7 days, n = 5); III, iopanoic acid (100 mg/kg for 13 days, n = 7); IV, control + T3 (0.5 ml saline for 13 days and 0.5 mg/kg T3 for the last 6 days, n = 5); V, amiodarone + T3 (amiodarone 50 mg/kg for 13 days and 0.5 mg/kg T3 for the last 6 days, n = 5). Cardiac beta-adrenoceptor density (CBARD) and heart rate (HR) were the two endpoint parameters investigated. Thyroid status was evaluated by serum thyrotropin (TSH), T4, T3, rT3 concentrations and liver type I 5'-deiodinase (5'D-I) activity. Amiodarone (group II) decreased CBARD (-22%, p less than 0.05) without altering thyroid secretion and T3 serum level, whereas 5'D-I was strongly inhibited (-90%, p less than 0.01). Iopanoic acid had no effect on CBARD and HR, but deeply inhibited 5'D-I.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo effects of macrolides on thyroid hormone serum levels and on hepatic type 1 5'-deiodinase in rat. A comparative study with amiodarone, phenobarbital and propranolol

Very often, an impact on the intracellular metabolism of iodothyronines and more precisely on microsomal deiodinases is evoked to explain thyroid hormone (TH) serum level alterations occurring with numerous drugs. Among them, three at least are also known to interfere with other hepatic microsomal enzymes, amiodarone (AMI), phenobarbital (PHE) and propranolol (PRO). Starting from this statement, we have examined the effects of 5 macrolides on TH serum level and on hepatic 5' type 1 deiodinase (5'DI) in vivo in rat. Rats were treated orally for eight days either with 200 mg/kg macrolides--erythromycine (ERY), troleandomycine (TRO), josamycine (JOS), midecamycine (MID) and spiramycine (SPI)--, or with AMI (45 mg/kg), PHE (50 mg/kg) or PRO (20 mg/kg), these 3 latter drugs for comparative purpose. Total T4, T3 and rT3 were determined by RIA. Hepatic 5'DI was evaluated by measuring released radioactive iodide from a reverse T3 monolabelled with 125I used substrate. Compared to control group, ERY and TRO decreased T4 (respectively by 28 and 16%) and from these two, only TRO decreased T3 (23%). With JOS, the only major modification was an increment of T3 (26%). AMI gave a typical alteration with a high T4 (130%), a low T3 (26%) and a high rT3 (376%). 5'DI was statistically inhibited by AMI (85%), JOS (49%), TRO (43%) and ERY (35%). The other drugs showed no significant effect. So, three macrolides have both altered TH serum level and 5'DI, findings which have never been reported before. The precise mechanism of this action remains unknown and the resulting effect, being far from the one observed with AMI, tends to demonstrate, for macrolides, an absence of correlation between the extent of 5'DI inhibition and TH serum profile. Besides, comparative analysis of the results observed with macrolides, AMI, PHE and PRO argues against any relationship between 5'DI and cytochrome-P450 monooxygenases.

Effect of nifedipine and nitrendipine on insulin release in non-diabetic obese patients: a double-blind, placebo-controlled study

Calcium antagonists are known to decrease insulin release in vitro. In vivo, their effects on insulin secretion and glucose tolerance are more controversial. We carried out a double-blind, double-dummy, controlled trial to study the effects of nifedipine (40 mg/day; n = 9), nitrendipine (20 mg/day; n = 9) and placebo (n = 10) on insulin release in 3 parallel groups of obese patients with mild or transient hypertension and a normal oral glucose tolerance test. The treatment lasted one week. Patients were asked not to modify their diet throughout the trial, and their body weight did not vary significantly. A 2-hour i.v. glucose tolerance test was performed twice in every patient, just before the first drug intake and one hour after the last one. The following parameters were measured or calculated during each test: basal, peak and early phase levels of blood glucose, insulin and C-peptide; glucose disappearance rate; and glucose, insulin and C-peptide incremental areas under the time-curves. On day 1, the 3 groups of patients were comparable for age, sex, body weight and every biological parameter. One-way analysis of variance did not show any significantly different evolution of those parameters between the 3 treatment groups, but calcium antagonists tended to slightly reduce the early phase of insulin release compared with placebo.

Effects of troleandomycin and josamycin on thyroid hormone and steroid serum levels, liver function tests and microsomal monooxygenases in healthy volunteers: a double blind placebo-controlled study

Serum TSH levels are moderately but significantly (P ANOVA: 0.05) decreased by troleandomycin (T; 1 g bid over a 10-day period) compared with josamycin (J) (same doses) and placebo (P) in healthy volunteers. T also significantly increases serum estradiol concentration (P ANOVA: 0.03). This effect may be related to a T-induced inhibition of some P450 monooxygenase isoenzymes and more specifically P 450 NF, determined in our study by a decrease in urinary excretion of 6-beta-hydroxy-cortisol. Troleandomycin and josamycin both show poor upper GI tolerance. Liver enzymes (SGOT, SGPT, alkaline phosphatase and gGT) are significantly altered by T compared with J and P (P ANOVA: 0.007, 0.001, 0.09 and 0.04 respectively). After J, liver function tests are very close to control values (placebo). Liver enzymes are significantly more altered by T than by J (P 0.004, 0.001 and 0.06 for SGOT, SGPT and gGT respectively). Using 6 volunteers in a latin-square designed study, some established effects of oral macrolides were confirmed (poor upper GI tolerance; liver toxicity of T). Some other effects of T were also elicited, which were either unknown (decrease in serum TSH) or expected but which had not previously been assessed in man (increase in serum estradiol; decreased urinary excretion of 6-beta-hydroxy-cortisol).

Amiodarone: influence of the route of administration on thyroid status and cardiac beta-adrenoceptors in the rat

The influence of 2 different routes of amiodarone (AMIO) administration, oral gavage (OG) and subcutaneous injection (SC), on the density of cardiac beta-adrenoceptors (Bmax), hepatic type I 5' iodothyronine deiodinase (5' DI) and thyroid hormone serum concentrations was studied. Compared with respective control values, AMIO treatment (50 mg/kg per day, 7 days) via both OG and SC routes significantly lowered Bmax (OG: 14.6 +/- 1.92 vs 18.2 +/- 1.03 fmol/mg and SC: 16.6 +/- 2.34 vs 19.1 +/- 2.05 fmol/mg) and 5' DI activity (from 409 to 85 and 340 to 47 fmol I-/mg per min, respectively). The SC route induced a fall in thyroid secretion and a generalized hypothyroidism (decreased serum FT4 and FT3, inhibition of body weight gain. The OG route did not modify thyroid secretion. These results demonstrated that the effects on cardiac beta-receptor density in the SC group might be due to the generalized hypothyroidism and that AMIO produced its specific cardiac effects only after oral route medication, suggesting that the oral route is the best choice for studying AMIO cardiac effects on beta-receptor density.

Diclofenac, paracetamol, and vidarabine removal during plasma exchange in polyarteritis nodosa patients

Since plasma exchange (PE) represents a major treatment for patients suffering from systemic diseases, its influence on the kinetics of three drugs was investigated: vidarabine, used in patients with polyarteritis nodosa associated with hepatitis B virus (eight subjects), and diclofenac and paracetamol for investigative purposes (five subjects). This study confirmed that vidarabine is so rapidly deaminated to form hypoxanthine arabinoside (Hx-Ara) that no detectable concentrations were measured. Hx-Ara levels were used to evaluate vidarabine kinetics; 19.5 +/- 14.6 mg of Hx-Ara were removed by one PE during the first week of treatment (15 mg kg-1 d-1, continuous infusion) and 7.8 +/- 10.2 mg were eliminated by one PE during the second week of treatment (7.5 mg kg-1 d-1, continuous infusion). Based on the vidarabine intake per hour and the resulting quantity of Hx-Ara removed per hour, PE recovery was quite important (ca. 30 per cent), during both the first and second weeks of continuous infusion. Data were subject to large interindividual variability. However, these results do not favor vidarabine dosage supplementation in this indication because the duration of PE is less than 8 per cent of a daily administration period. For paracetamol (1 g, single oral dose) and diclofenac (100 mg, single oral dose), the fractions of drug removed during PE effected within 2 h of drug intake, were respectively 5.0 +/- 3.1 per cent and 13.6 +/- 9.5 per cent, while plasmapheretic clearance reached, respectively, 13.0 +/- 10.7 per cent of the systemic clearance for paracetamol and 23.0 +/- 1.0 per cent for diclofenac.

Effect of nifedipine on thyrotropin, prolactin, and thyroid hormone release in man: a placebo-controlled study

Nifedipine (10 mg tid) or placebo was administered in a randomized double-blind trial for 1 wk to 2 groups of 10 mildly hypertensive euthyroid patients. Hormonal concentrations (thyrotropin [TSH], prolactin [PRL], thyroxin, triiodothyronine, and reverse triiodothyronine) before and during a TRH test were assessed in the 2 groups before (D0) and after (D7) each treatment. Parameters of the TRH test were determined (peak values, area under the curve [AUC], release [Kr], and elimination [Ke] rate constants) and their D7:D0 ratios were compared in the 2 groups. The TSH (peak values and Kr) and PRL (peak values and AUC) responses to TRH were significantly decreased in the nifedipine group compared to the placebo group. Neither basal nor TRH-stimulated thyroid hormone levels were modified. These results confirm experimental data but seem to be clinically irrelevant.

Effective high-performance liquid chromatographic determination of glafenine in plasma: pharmacokinetic application

A high-performance liquid chromatographic method for an effective determination of glafenine and its main metabolite, glafenic acid, is described. The assay involves separate extraction procedures for glafenine and for its metabolite, but the same internal standard (floctafenine) and the same chromatographic conditions (including a 5-micron C8 column, a quaternary solvent mixture of water-acetonitrile-diethylamine-acetic acid and an ultraviolet detector set at 360 nm). For 1 ml of plasma, the detection limit is 0.05 mg/l for glafenine and 0.25 mg/l for glafenic acid. Compared with previously described techniques, this assay uses a very low glafenine linearity range, which allows the true pharmacokinetics of this drug to be described for the first time.

Use of a pharmacokinetic model to characterize the thyrotropin (TSH) and prolactin (PRL) response to thyrotropin-releasing hormone (THR) in man

On the basis of a pharmacokinetic model using the data of a TRH test and without the use of radio-isotope tracers, a simple procedure of estimation of PRL and TSH TRH-stimulated release and elimination half-lives is presented. TRH tests were performed in 33 healthy subjects and their data were used to calculate the kinetic parameters of each subject. Elimination half-lives of TSH and PRL were found to be respectively (mean +/- SD in min) 63 +/- 7.4 and 35 +/- 2.8. Release half-lives were 8.2 +/- 1.3 for TSH and 5 +/- 0.4 for PRL. The usefulness of the procedure in the evaluation of drug effects on pituitary secretion in man and the comparison with the literature data are discussed.

Effect of diosmin upon red blood cell deformability and osmotic fragility. Relationship with lipid content

Rats were treated by ingesting forcibly 2 ml of a suspension of four different doses (100, 200, 300 and 400 mg/kg) of diosmin in carboxymethylcellulose (CMC) and were killed immediately or after 3 or 6 hours of fasting. Animals treated by CMC only in a similar way (gavage) exhibited a fall in red blood cell (RBC) membrane cholesterol and an increase in RBC rigidity at the third hour while osmotic fragility remained stable. Diosmin treatment opposed the rise in RBC rigidity evoked by the gavage and induced a dose-dependent decrease of the RBC membrane cholesterol over phospholipid ratio.

Remission of idiopathic nephrotic syndrome after treatment with cyclosporin A

Nephrotic syndrome in minimal change lipoid nephrosis and focal segmental glomerulosclerosis may be due to alteration of glomerular anionic sites by a lymphokine. Six adults with nephrotic syndrome who were resistant to treatment with corticosteroids and immunosuppressants were treated with cyclosporin A. In three patients with minimal change lipoid nephrosis who had been nephrotic for 3.5 to 23 years proteinuria resolved within 12 to 42 days. Subsequently, these patients became dependent on cyclosporin A. In three patients with focal segmental glomerulosclerosis who had been nephrotic for four to six years mean (SD) 24 hour urinary protein decreased from 14.7 (8.4) g to 3.6 (0.6) g within 20 to 25 days, serum albumin concentration rose, and oedema subsided. One patient died of myocardial infarction when still in partial remission after 11 weeks' treatment. Two patients remained proteinuric despite continuing treatment with cyclosporin A, but control of sodium balance was easy and serum albumin concentrations remained higher than without cyclosporin A. In all patients renal function improved during treatment. These preliminary results show that cyclosporin A may be effective in the treatment of patients with nephrotic syndrome that resists every other form of treatment and especially in the treatment of those with minimal change lipoid nephrosis. The results are in keeping with a T lymphocyte mediated mechanism of minimal change lipoid nephrosis and focal segmental glomerulosclerosis, but they also suggest that minimal change lipoid nephrosis and focal segmental glomerulosclerosis are separate entities.

Effect of a short-term oral administration of cimetidine and ranitidine on the basal and thyrotropin-releasing hormone-stimulated serum concentrations of prolactin, thyrotropin and thyroid hormones in healthy volunteers. A double-blind cross-over study

Cimetidine (400 mg b.d.), ranitidine (150 mg b.d.) and placebo were administered for 1 week to 6 healthy male volunteers in a randomized double-blind cross-over fashion. Hormonal concentrations before and after a TRH test were assessed before and after each treatment. A spontaneous decrease in the hormonal response to TRH was observed after placebo treatment. Both cimetidine and ranitidine induced a significant increase in basal prolactin (PRL) values. Neither TSH nor T3 were modified by cimetidine or by ranitidine. The basal concentration of reverse T3 was increased during cimetidine treatment. There was a significant rise in post-TRH T4 after cimetidine and ranitidine administration. These results suggest a role for histamine H2 receptors in the secretion of PRL and T4. Moreover, cimetidine affects the hepatic metabolism of thyroid hormones.