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Biomedical subjects

M Kurowski

Publications and source records attributed to M Kurowski.

At least 19 recordsLinked to original sources
PubMed2006

Pharmacokinetics and tolerability of a combination of indinavir, lopinavir and ritonavir in multiply pretreated HIV-1 infected adults.

OBJECTIVES: The authors evaluated the pharmacokinetics and tolerability of indinavir/lopinavir/ritonavir in a protease inhibitor only combination. METHODS: Plasma drug levels of patients taking indinavir/lopinavir/ritonavir 800/400/100mg twice daily (n = 24, group 1) were compared to patients taking either lopinavir/ritonavir 400/100mg (n = 35, group2) or indinavir/ritonavir 800/100mg (n = 33, group3) twice daily plus nucleos(t)ide reverse transcriptase inhibitors (NRTI). Steady-state drug concentrations were measured by LC/MS/MS. Minimum and maximum concentrations (C subsetmin, C subsetmax), area under the concentration-time curve (AUC subset0-12h), total clearance (CL subsettot) and half-life (t1/2) were calculated. HIV viral load, CD4 cell count and adverse events causing early termination of therapy were correlated over a period of 48 weeks. RESULTS: Plasma levels of lopinavir/ritonavir were significantly enhanced when combined with indinavir compared to a regimen of lopinavir/ritonavir+NRTI: Mean lopinavir AUC subset(0-12h) 80,912 ng*h/mL vs. 60,548 ng*h/mL; C subsetmin 4,633 ng/mL vs. 3,258 ng/mL; C subsetmax 8,023 ng/mL vs. 6,710 ng/mL. Mean ritonavir AUC(0-12h) 6,907 ng*h/mL vs. 3,467 ng*h/mL; Cmin 220 ng/mL vs. 125 ng/mL; C subsetmax 1,059 ng/mL vs. 522 ng/mL. Indinavir levels were comparable for both indinavir containing regimen. A significantly smaller number of patients stopped indinavir/lopinavir/ritonavir therapy (group1: 16.7%) than indinavir/ritonavir + NRTI treatment (group3: 45.5%) due to adverse events. Virological failure was the main reason for early termination of treatment with indinavir/lopinavir/ ritonavir before week 48 (group1: 50%). CONCLUSIONS: indinavir/lopinavir/ritonavir 800/400/ 100mg twice daily represents a therapy option with an adequate safety but only short term efficacy for extensively pretreated patients.

Adult↗
PubMed2005

Impact of rosiglitazone treatment on the bioavailability of antiretroviral compounds in HIV-positive patients.

OBJECTIVES: The insulin-sensitizer rosiglitazone is under investigation for therapy of HIV-associated lipodystrophy syndrome (LDS). Little is known about pharmacological interactions with antiretroviral (ARV) drugs. METHODS: Therapeutic drug monitoring (TDM) of ARV drugs was performed in a prospective study before and at day 28 after start of treatment with 4 mg of rosiglitazone for combined LDS. Drug levels were measured in the morning fasting, and 0.5, 1, 2, 4, 6 and 8 h after standardized drug intake. Values were log-transformed for analysis. RESULTS: Twelve males and six females were assessed; mean age was 50.7 years and mean CD4 cell count was 496 cells/mm(3). All patients had a viral load below 50 copies/mL, and backbone ARV therapy consisted of two or three nucleoside reverse transcriptase inhibitors in all cases. After administration of rosiglitazone, no significant differences in Cmax, Cmin and AUC were found in cases treated with efavirenz (n = 10) and lopinavir (n = 4). Mean Cmax of nevirapine (n = 4) was reduced significantly [-0.44; 95% confidence interval (CI) -0.86 to -0.01]. Furthermore, there was a consistent trend to a reduction in the geometric mean ratio (GMR) of Cmax, Cmin and AUC (GMR of Cmax 0.95; 95% CI 0.9-1.0; GMR of Cmin 0.89; 95% CI 0.65-1.13; GMR of AUC 0.96; 95% CI 0.91-1.01). CONCLUSIONS: Treatment with 4 mg of rosiglitazone for HIV-associated LDS is likely to reduce the bioavailability of nevirapine. Thus, routine TDM is recommended for patients treated with rosiglitazone and nevirapine. A therapy consisting of efavirenz or lopinavir seems to be without negative impact. Further studies on the interaction of rosiglitazone with ARV drugs are necessary.

Anti-HIV Agents↗
PubMed2004

Long-term pharmacokinetics of amprenavir in combination with delavirdine in HIV-infected children.

Five heavily pretreated HIV-infected children were put on amprenavir and delavirdine plus two nucleoside inhibitors to reverse transcriptase to boost amprenavir levels and to use the antiretroviral activity of a non-nucleoside reverse transcriptase inhibitor. No data are available about this combination in children. It w;as well tolerated, and the median reduction in viral load was 1.5 log after 18 months. Delavirdine boosted amprenavir trough levels more than 10-fold, and delavirdine trough levels remained i several fold above susceptible HIV strains.

Adolescent↗
PubMed2004

Impact of amphotericin B on the cytochrome P450 system in HIV-infected patients.

OBJECTIVE: To investigate whether cytochrome P450-dependent enzymes are influenced by amphotericin B (Am-B) during the treatment of Candida oesophagitis in HIV-infected patients. METHODS: Twelve HIV-infected, antiretroviral-naive patients (CDC/WHO stage C3) with Candida oesophagitits were enrolled into a prospective clinical trial. The patients were treated with Am-B (0.4 mg/kg body weight) for two weeks. At baseline and after Am-B therapy the clearance of antipyrine and its metabolites were investigated by high-performance liquid chromatography. In addition, the urinary excretion of 6-beta-hydroxycortisol and 17-hydroxycorticosteroids was assessed by means of a radioimmunoassay. RESULTS: The following significant changes were observed after Am-B treatment (P < 0.01): increase of antipyrine half-life (12.4 h vs 16.8 h) and the area under the plasma concentration-time curve (27.9 mg min/ml vs 38.1 mg min/ml); decrease of the total body clearance (61.2 ml/min vs 43.7 ml/min); decrease of the renal clearance of antipyrine metabolites - norantipyrine (7.45 ml/min vs 5.31 ml/min), 4-hydroxyantipyrine (15.4 ml/min vs 10.3 ml/min), hydroxymethylantipyrine (4.31 ml/min vs 3.65 ml/min); decrease of urinary 6-beta-hydroxycortisol excretion (453 microg/24h vs 298 microg/24h) and the ratio of 6-beta-hydroycortisol to 17-hydroxycorticosteroids (8.8% vs 6.4%). CONCLUSIONS: Our data indicate that Am-B therapy has an inhibitory effect on cytochrome P450-dependent enzymes in HIV-infected patients. These results are of particular significance for HIV-infected patients who are concomitantly treated with drugs that are predominantly metabolised in the liver. A careful drug monitoring system seems advisable, especially for proteinase inhibitor experienced HIV-1-infected subjects.

17-Hydroxycorticosteroids↗
PubMed2004

Montelukast plus cetirizine in the prophylactic treatment of seasonal allergic rhinitis: influence on clinical symptoms and nasal allergic inflammation.

BACKGROUND: The aim of our study was to investigate effects of 6-week pretreatment of seasonal allergic rhinitis (AR) with cetirizine, and montelukast, alone and in combination. Antihistamine/antileukotriene treatment is effective in AR. Antihistamines may prevent AR symptoms while prophylactic activity of antileukotrienes remains unclear. METHODS: Sixty AR patients, aged 18-35 years, were randomized to receive placebo, montelukast only, cetirizine only, or montelukast plus cetirizine, 6 weeks prior and 6 weeks after the beginning of grass pollen season. Mean self-recorded in-season symptom scores and mean weekly all-symptom scores were analyzed. In 31 patients, nasal lavages were performed before treatment, and at the end of the study, i.e. 12 weeks after the treatment initiation. Eosinophil and basophil counts, eosinophil cationic protein (ECP), and mast cell tryptase (MCT) levels were evaluated in lavage samples. RESULTS: Combined montelukast/cetirizine pretreatment significantly reduced in-season symptom score for sneezing, eye itching, nasal itching, rhinorrhea, and congestion. Montelukast plus cetirizine were more effective than cetirizine alone in preventing eye itching, rhinorrhea, and nasal itching. Moreover, combined pretreatment with montelukast and cetirizine delayed appearance of AR symptoms. Eosinophil nasal lavage fluid counts were significantly increased during pollen season in placebo and montelukast-only groups. No differences were observed in basophil counts. The in-season ECP level was significantly increased in all groups except montelukast-plus-cetirizine group. In-season MCT levels were not increased. CONCLUSION: Combined antihistamine and antileukotriene treatment started 6 weeks before the pollen season is effective in preventing AR symptoms and reduces allergic inflammation in nasal mucosa during natural allergen exposure.

Acetates↗
PubMed2004

A prospective, controlled study assessing the effect of lopinavir on amprenavir concentrations boosted by ritonavir.

In a controlled, prospective study, the efficacy of ritonavir 200 mg twice daily (bid) in inhibiting the decrease of amprenavir plasma concentrations caused by co-administration of lopinavir was assessed. Twelve HIV-seropositive patients were enrolled, and nine patients completed the 28-day study. At day 14, plasma concentrations of amprenavir 600 mg bid and ritonavir 200 mg bid were determined over 12 h. At day 15, lopinavir 400 mg bid was added. At day 28, plasma concentrations of amprenavir, ritonavir and lopinavir were assessed. Co-administration of lopinavir was found to decrease the amprenavir concentration, determined as the median area under the curve over 12 h (AUC12), by 25% (AUC12 24.9 microg/h/mL vs. 18.5 microg/h/mL; P<0.01), despite the presence of ritonavir 200 mg bid. Eight participants discontinued the study regimen during the first 6 weeks because of adverse gastrointestinal events. In conclusion, gastrointestinal tolerance of a regimen containing an increased dose of ritonavir 200 mg bid was low, while the regimen did not prevent a decrease of amprenavir and possibly lopinavir plasma concentrations.

Anti-HIV Agents↗
PubMed2003

Pharmacokinetic and tolerability profile of twice-daily saquinavir hard gelatin capsules and saquinavir soft gelatin capsules boosted with ritonavir in healthy volunteers.

OBJECTIVE: To evaluate the pharmacokinetics and safety of a boosted saquinavir (SQV)/ritonavir (RTV) combination, administered as either the hard gelatin capsule (HGC) or soft gelatin capsule (SGC) formulation of SQV, in 24 healthy volunteers. METHODS: This was a single-centre, open-label, randomized, 2 x 2 crossover study. Twelve subjects were randomized to receive SQV/RTV 1000 mg/100 mg twice daily (BID) orally for 10 days, as either the HGC or SGC formulation. The pharmacokinetic profile of SQV was determined on day 10. Subjects then crossed over to the opposite SQV formulation, and the pharmacokinetic profile was determined again on day 20. The primary analysis was the assessment of bioequivalence based on logarithmically transformed values for AUC(0-24 h) and Cmax for the two formulations. RESULTS: There was a statistically significant increase in the geometric means of all the pharmacokinetic variables evaluated for SQV-HGC/RTV compared with SQV-SGC/RTV. A mean AUC0-24 h-value of 15.798 micro g/mL/h was reported for the HGC formulation compared with 11.655 micro g/mL/h for the SGC formulation (P = 0.0043). The SQV-HGC/RTV combination was better tolerated in terms of gastrointestinal system disorders. Furthermore, no elevations in triglycerides or total cholesterol were reported with SQV/RTV during the entire study period. CONCLUSION: In healthy volunteers, RTV boosting of SQV-HGC produces plasma exposures at least comparable to SQV-SGC, which is accompanied by an improvement in gastrointestinal system disorders.

Adult↗
PubMed2002

Predictors of treatment failure during highly active antiretroviral therapy (racing trial).

PURPOSE: To determine factors associated with virological failure during long-term treatment with the triple combination of saquinavir soft gel capsule, zalcitabine and zidovudine. METHOD: Open-label, prospective, multicentre study undertaken in private practices and the outpatient department of the Auguste-Viktoria-Hospital. A total of 95 patients with plasma HIV RNA > 5000 copies/ml who had received no more than 6 months pre-treatment with NRTIs and no prior PI therapy received saquinavir soft gel, zalcitabine and zidovudine for 52 weeks, before being randomly assigned to either remain on therapy or switch to nelfinavir, lamivudine and zidovudine for further 52 weeks. RESULTS: Combination therapy with saquinavir, zalcitabine and zidovudine was found to be effective and well tolerated, with virological response to therapy maintained for up to 2 years. In patients responding to therapy, switching to a novel triple regimen did not result in a virological or immunological worsening, but it did not confer an additional clinical benefit. Factors predictive of early treatment failure (virological failure within 16 weeks of treatment initiation) included high viral load and presence of RT mutations at baseline (OR: 0.30, 95% CI 0.11 0.83 and OR 0.13, 95% CI 0.03 0.52, respectively), with baseline viral load and the development of genotypic mutations on therapy being predictive of late treatment failure (16 52 weeks; OR: 0.15, 95% 0.05 0.46 and OR: 0.26, 95% CI < 0.001 1.16, respectively). Plasma saquinavir concentration < 50 mg/ml at 4 weeks was also found to be an independent risk factor for both early and late treatment failure (OR: 1.80, 95% CI 1.23 2.64 and OR: 1.16, 95% CI 0.84 1.60, respectively). CONCLUSIONS: While antiretroviral drug resistance appears to be a principal cause of treatment failure, other factors such as inadequate drug plasma concentrations also play a role.

Adult↗
PubMed2002

Initiation of HAART in drug-naive HIV type 1 patients prevents viral breakthrough for a median period of 35.5 months in 60% of the patients.

The introduction of potent combinations of antiviral drugs is a major breakthrough in the treatment of HIV. We investigated the long-term virologic outcome and the development of resistance after initiating highly active antiretroviral therapy (HAART) in drug-naive patients in daily clinical practice. Twenty-five treatment-naive HIV-1 patients were started on HAART. Fifteen patients responded with a drop in viral load below the limit of detection during 35.5 (interquartile range: 7) months of therapy. In 6 of 10 patients with virologic failure, virus with resistance-related mutations against the received drugs emerged. Compared with responders (R), nonresponding (NR) patients were in a later disease stage at therapy start (p = 0.0089) with lower CD4 cell counts at baseline (p = 0.040), and a lower proportion of nonresponders showed protease inhibitor (PI) levels above C(min) (p = 0.049). More NR patients showed secondary PI mutations at baseline (p = 0.079), and the CCR2-64I coreceptor polymorphism was absent among NR patients, compared with 38.5% of R patients displaying CCR2-64I (p = 0.053), although the differences were not significant. In conclusion, starting HAART in antiretroviral drug-naive HIV-infected patients followed in daily clinical practice prevented viral breakthrough for up to 44 months in 60% of the patients. Virologic failure was associated with the development of resistance-related mutations, a later stage of disease at start of therapy and lower PI drug levels.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Phenotypic HIV-1 resistance correlates with treatment outcome of nelfinavir salvage therapy.

In order to analyse whether drug sensitivity testing would be beneficial for clinical decision-making in heavily pretreated patients, we retrospectively studied viral genotype and phenotypic drug resistance in 12 HIV-1-infected patients, each of them with a history of failing at least one therapeutic regimen including one or two protease inhibitors (PIs). The salvage therapy included nelfinavir as new PI in all cases. Four patients showed a sustained and five patients a transient viral load decrease. Three patients failed to show a significant decline of plasma HIV-1 RNA. In the baseline samples of these cases, resistance against all components of their combination therapy could be detected, whereas at least one antiretroviral drug was still active in the cases with transient treatment response. All patients with sustained therapy response harboured viruses that were either fully sensitive or resistant to only one of the drugs administered. In our study, phenotypic drug resistance was predictive for the success of antiretroviral salvage regimens.

Amino Acid Sequence↗
PubMed1999

Single daily doses of saquinavir achieve HIV-inhibitory concentrations when combined with baby-dose ritonavir.

Dual protease inhibitor (PI) therapy has been established either in order to increase plasma concentrations of one PI or to combine synergistic effects of two PI's on viral load. Studies with saquinavir (SQV) and small doses of ritonavir (RTV) as well as experiences from our therapeutic drug monitoring suggest that single daily doses may result in sufficient SQV serum levels throughout an interval of 24 h. A controlled, randomized trial with 20 healthy men was conducted for the comparison of serum levels with 1600 mg SQV (group 1) or 1600 mg SQV/200 mg RTV (group 2). The dosages were selected in order to use RTV as an inhibitor of cytochrome P450 3A4 and SQV as protease inhibitor. The volunteers received single daily doses following a standardized breakfast on 3 consecutive days. Serum samples were analyzed for SQV and RTV employing LC-tandem mass spectrometry. The minimum concentration of saquinavir after 24 hours, the AUC, the maximum concentration and the serum half-lives on day 3 served as target parameters. The minimum SQV concentration amounted to 469.4 ng/ml, when combined with RTV and proved to be significantly higher (p <0.05) than the corresponding concentration with SQV alone (127.3 ng/ml). The SQV maximum concentration was raised approximately 6fold and the AUC 9fold when RTV was coadministered. In combination with 200 mg of RTV the predominant elimination half-life of SQV increased from 2.6 to 6.45 hours. These data prove that under single daily doses of 1600 mg SQV/200 mg RTV HIV-inhibitory concentrations of SQV can be achieved for 24 hours. Due to the high variability of the concentrations, which can be seen with all PI s, we recommend continuous therapeutic drug monitoring of serum trough levels.

Adult↗
PubMed1997

Is Helicobacter pylori infection a risk or protective factor for mucosal lesions development in patients chronically treated with acetylsalicylic acid?

The interaction between ASA and H.p. as the strongest irritants to gastric mucosa has not been sufficiently documented to date. The aim of our study was to evaluate the frequency of mucosal lesions in stomach and duodenum and the frequency of H.p. infection in patients suffering from IHD and chronically taking ASA. We evaluated the number of mucosal lesions and the incidence rate in relation to the daily dose of ASA. We examined 96 with IHD treated with ASA in doses: 75, 150 or 300 mg per day. We assessed the number of mucosal lesions and H.p. status. The control groups included 80 patients treated for IHD who did not take ASA and 50 patients who did not suffer from IHD. The highest rate of mucosal lesions we found in the group of patients with IHD treated with ASA: 62% vs 41% in patients not using ASA and 8% in the control group. We did not find any essential difference in mucosal lesions occurrence between patients treated with 75 or 150 and 300 mg per day. In patients with IHD using ASA the frequency of H.p. infection was higher in comparison to patients not receiving ASA (68% vs 47%) and to control group (68% vs 26%). ASA users infected with H.p. had more mucosal lesions (75%) in comparison to those not using ASA (47%). Our results confirm the synergistic harmful influence of ASA and H.p. infection on gastric and duodenal mucosa. It seems to us that the frequency of mucosal lesions development does not depend on the daily dose of ASA.

Adult↗