Biomedical subjects

E Lukkari

Publications and source records attributed to E Lukkari.

10 recordsLinked to original sources

PubMed2000

A randomized controlled trial comparing the efficacy of controlled-release oxybutynin tablets (10 mg once daily) with conventional oxybutynin tablets (5 mg twice daily) in patients whose symptoms were stabilized on 5 mg twice daily of oxybutynin.

OBJECTIVE: To compare the efficacy of a controlled-release (CR) formulation of oxybutynin with that of conventional oxybutynin in patients with detrusor instability or detrusor hyper-reflexia whose symptoms were stabilized on conventional oral oxybutynin tablets. PATIENTS AND METHODS: The study comprised a randomized, double-blind, parallel-group trial involving 130 patients drawn from 15 centres in the UK. The study was of 6 weeks' duration, i.e. 2 weeks of screening whilst taking conventional oxybutynin tablets (5 mg twice daily) followed by 4 weeks of double-blind treatment with either CR oxybutynin tablets (10 mg once daily) or conventional oxybutynin tablets (5 mg twice daily). Outcome measures were changes in 24-h frequency and 24-h incontinence episodes recorded throughout the study on diary charts. Adverse events were recorded by patients in their diary charts and serum concentrations of oxybutynin and its active metabolite, N-desethyloxybutynin, were measured at baseline and at completion of the study to detect possible drug accumulation. RESULTS: The treatments did not differ significantly in any of the outcome measures. The primary efficacy criterion was the daytime continence at completion of the study; 53% and 58% of patients were continent on CR and conventional oxybutynin treatments, respectively (the 95% confidence interval of the difference in the proportion being - 22% to 13%; P = 0.62). The total number of side-effects experienced by those patients receiving treatment with the CR formulation was 57% of that for patients receiving treatment with conventional oxybutynin. Individual side-effects showed a similar distribution within treatment groups. There was no evidence of the accumulation of oxybutynin or N-desethyloxybutynin during the multiple dosing of CR or conventional oxybutynin tablets. CONCLUSION: The CR and conventional formulations of oxybutynin did not differ in their efficacy, and the CR formulation was associated with fewer side-effects. In addition, CR oxybutynin appeared to maintain therapeutic blood levels over the 24 h dosing interval with no accumulation of oxybutynin or its active metabolite. Once-daily dosing with a CR tablet is seen as convenient for the patient and is expected to result in improved compliance in patients already stabilized on conventional oxybutynin treatment.

Adolescent↗

PubMed1998

The pharmacokinetics of oxybutynin is unaffected by gender and contraceptive steroids.

OBJECTIVE AND METHODS: The effect of gender and concomitant use of contraceptive steroids on the absorption and metabolism of oxybutynin was investigated in 49 healthy volunteers, 24 females and 25 males. Serum concentrations of oxybutynin and its active metabolite, N-desethyloxybutynin, were measured for up to 48 h after ingestion of a single dose of 10 mg oxybutynin. RESULTS: Intake of oral contraceptive steroids had no significant effect on the pharmacokinetic parameters of oxybutynin or its metabolite. Both in males and females, the mean area under the curve (AUC0-t) of N-desethyloxybutynin was about 13 times higher and the peak concentration (Cmax) 15 to 19 times higher than the AUC0-t and Cmax of the parent oxybutynin, with no significant differences between males and females. CONCLUSIONS: The pharmacokinetics of orally administered oxybutynin shows a considerable interindividual variability, but is unaffected by gender and use of contraceptive steroids.

Administration, Oral↗

PubMed1998

Cytochrome P450 specificity of metabolism and interactions of oxybutynin in human liver microsomes.

Oxybutynin has an extensive first pass metabolism after oral administration, the main active metabolite being N-desethyloxybutynin. The purpose of this study was to investigate the CYP isoform specificity of oxybutynin N-deethylation and possible interactions. Oxybutynin N-deethylation in human liver microsomes in vitro was potently inhibited by ketoconazole (IC50 4.5 microM), less and variably by itraconazole and not by quinidine or several other reference inhibitors, suggesting that CYP3A enzymes are predominant catalysts of the reaction. Recombinant CYP3A5 enzyme had higher activity in oxybutynin N-deethylation than recombinant CYP3A4. Ketoconazole inhibited oxybutynin N-deethylation by the recombinant CYP3A4 and CYP3A5 almost completely, whereas itraconazole inhibited the activity of CYP3A4 more potently than that of CYP3A5. Oxybutynin inhibited CYP3A4- and CYP2D6- associated activities (testosterone 6 beta-hydroxylase and dextromethorphan O- demethylase, respectively) in human liver microsomes. CYP1A1/2-, CYP2A6-, CYP2C9- and CYP2E1-associated activities were inhibited less potently or not at all by oxybutynin when compared with reference inhibitors. Although the reasons for the weak and variable inhibition by itraconazole remain to be studied, it seems that oxybutynin is predominantly metabolized by CYP3A4 and CYP3A5 but not by CYP2D6. However, it seems to have some affinity also to the latter enzyme.

Antifungal Agents↗

PubMed1997

Comparison of a 10-mg controlled release oxybutynin tablet with a 5-mg oxybutynin tablet in urge incontinent patients.

Oxybutynin has long been used for the treatment of patients with detrusor overactivity and urinary urge incontinence. The short half-life of oxybutynin administered as a conventional tablet formulation or syrup requires 2-3 times daily dosage to be effective. A new controlled release (CR) tablet for once-daily administration has been developed. The efficacy and tolerability of this new controlled release tablet was compared to that of a 5-mg conventional oxybutynin tablet administered twice daily. Seventeen female incontinent patients were studied in a double-dummy crossover trial. Efficacy and tolerability were assessed by using a voiding diary, pad-weighing test, visual-analogue scale (VAS), and questionnaire. Adverse events were recorded spontaneously on a questionnaire by the patients themselves throughout the study. Serum concentrations of oxybutynin and its active metabolite N-desethyloxybutynin were studied after both a single dose and multiple dosage. There was no difference in efficacy between the two formulations. Depending on the parameters tested, the change from baseline values in a positive direction ranged from 15 to 53%. The incidence of adverse events was similar with both formulations. Oxybutynin or its metabolite showed no cumulation during the multiple dosage with a 10-mg CR tablet. The controlled release tablet formulation is as effective and as well-tolerated as the conventional one, but has the advantage of only once-a-day dosage, enhancing treatment compliance.

Adult↗

PubMed1997

Itraconazole moderately increases serum concentrations of oxybutynin but does not affect those of the active metabolite.

OBJECTIVE: Oxybutynin has low oral bioavailability due to an extensive presystemic metabolism. It has been suggested that the biotransformation of oxybutynin is dependent on CYP3A. Because itraconazole, a widely used mycotic, is a potent inhibitor of CYP3A4, we wanted to study a possible interaction between oxybutynin and itraconazole. METHODS: In this double-blind, randomized, two-phase cross-over study, ten healthy volunteers received either 200 mg itraconazole or placebo for 4 days. On day 4, each volunteer ingested a single dose of 5 mg oxybutynin. Serum concentrations of oxybutynin, its active metabolite N-desethyloxybutynin, and itraconazole were monitored over 24 h. RESULTS: Itraconazole significantly increased both the area under the serum drug concentration-time curve (AUC0-t) and the peak concentration of oxybutynin twofold. The AUC0-t and the peak concentration of N-desethyloxybutynin were not significantly affected by itraconazole. Itraconazole did not change the peak time or the elimination half-life of either oxybutynin or N-desethyloxybutynin. The occurrence of adverse events after oxybutynin administration was not increased by itraconazole. CONCLUSIONS: Itraconazole moderately increases serum concentrations of oxybutynin, probably by inhibiting the CYP3A-mediated metabolism. However, the concentrations of N-desethyloxybutynin were practically unchanged. Since about 90% of the antimuscarinic activity of oxybutynin is attributable to N-desethyloxybutynin, any interaction of oxybutynin with CYP3A4 inhibiting drugs has only minor clinical significance.

Adolescent↗

PubMed1997

Effect of time interval between food and drug ingestion on the absorption of oxybutynin from a controlled-release tablet.

The effect of time interval between food and drug ingestion on the bioavailability of oxybutynin was investigated in a randomized, three-phase cross-over study in 31 healthy volunteers. The serum concentrations of oxybutynin and the metabolite, N-desethyloxybutynin were measured up to 48 hr after ingestion of a controlled-release 10 mg oxybutynin tablet either in fasting state, 2 hr after breakfast or 1 hr before. The Cmax of both oxybutynin (P < 0.0001) and N-desethyloxybutynin (P < 0.0001) and the AUC0-1 of N-desethyloxybutynin (P < 0.05) were significantly larger when oxybutynin was ingested 2 hr after breakfast, than during the fasting, but the AUC0-1 of oxybutynin remained unchanged. Breakfast ingested 1 hr after oxybutynin did not affect the pharmacokinetic parameters of oxybutynin or N-desethyloxybutynin. The saliva secretion rate decreased slightly more (P < 0.05), when oxybutynin was administered 2 hr after breakfast than during fasting. The effect of food ingestion on the serum concentrations of oxybutynin and N-desethyloxybutynin is expected to have minor clinical significance only. However, ingestion of the controlled-release tablet 1 hr before meal increases the likelihood of obtaining constant drug levels with lower peak concentrations during the dosage interval, and thus ingestion of the controlled-release tablet 0.5-1 hr before food may well improve tolerability and compliance in patients who suffer from adverse reactions.

Adult↗

PubMed1996

Effect of food on the bioavailability of oxybutynin from a controlled release tablet.

OBJECTIVE: The effect of food on the bioavailability of oxybutynin was assessed in a randomised cross-over study in 23 healthy volunteers. A single oral 10 mg dose of a controlled release oxybutynin tablet was administered after a high fat breakfast and to fasting subjects. The AUC, Cmax, tmax, t1/2 and MRT of oxybutynin and its active metabolite N-desethyloxybutynin were determined. RESULTS: Breakfast did not change the AUC of oxybutynin but increased the AUC of N-desethyloxybutynin by about 20%. The Cmax of oxybutynin and N-desethyloxybutynin were two-fold higher when the drug was administered after breakfast compared to the fasting state. CONCLUSION: Breakfast significantly reduced the MRT of oxybutynin and N-desethyloxybutynin.

Adult↗

PubMed1985

Does beta-blockade provoke intermittent claudication?

Intermittent claudication has been claimed to be a side-effect of beta-adrenoceptor blocking drugs. The confounding effect of coronary heart disease has not been controlled in earlier studies. In this case-control study, the cases were selected from a hospital material of patients with verified intermittent claudication and the controls from a nationwide health survey. The pool of potential cases and controls consisted of persons who had been treated with antihypertensives, but did not have coronary heart disease. The controls and cases were matched for age, sex, place of residence and time of examination. Comparison of current or previous use of beta-blocking drugs among our 55 case-control pairs revealed no association between intermittent claudication and beta-blockade. beta-Blockade is not a risk factor for intermittent claudication.

Adrenergic beta-Antagonists↗

PubMed1983

Characterization and elimination of a factor in serum that interferes with turbidimetry and nephelometry of lipase.

We studied a serum component ("pseudolipase") that interferes with both turbidimetric and nephelometric lipase measurements. Pseudolipase activity in serum was found in the presence of rheumatoid factor and in other disorders of active immune processes. The incidence of this interferent in sera seems to be greater than reported previously. We describe a method for eliminating its effect without affecting pancreatic lipase activity, by precipitating some of the proteins, including IgM, with polyethylene glycol.

False Positive Reactions↗

PubMed1983

The effect of taurocholate on canine bile flow, biliary excretion and concentration of ioglycamide.

The bile acid taurocholate increases the biliary excretion of organic anions, such as sulfobromophthalein (BSP), bilirubin and iopanoic acid. In the present study has been investigated the effect of taurocholate on 1. Canine biliary excretion and concentration of the i.v. contrast medium ioglycamide and 2. Canine bile flow. The experimental model consisted of cholecystectomized, anaesthetized dogs with a fistula, through which the common bile duct could be catheterized and drained. One hour after cannulation, i.v. infusion of ioglycamide at a rate of 4 mumol/min./kg. was started. Two hours after the infusion start a control group received i.v. infusion of saline, while in another a 1.5% sodium taurocholate infusion was started with stepwise increases with 30 min. intervals from 0.4 to 0.8, 1.6 and 3.2 mumol/min./kg. Compared with control, all rates of taurocholate infusion increased bile flow and decreased biliary ioglycamide concentration. Although the bile flow with increasing taurocholate infusion rates was enhanced, the biliary ioglycamide excretion did not increase. The results indicate that ioglycamide and taurocholate are excreted into bile by separate excretion mechanisms. As taurocholate increases the biliary excretion of some other organic anions, it supports the hypothesis that organic anions are excreted into bile by more than two excretion mechanisms, taurocholate affecting only some of them.

Animals↗