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[Adherence to antiretroviral treatments with a protease inhibitor in HIV-infected patients].

OBJECTIVE: Long-term therapeutic success of powerful antiretroviral treatments dependent on patient adherence. This study was conducted to assess the difficulties HIV-infected patients with advanced-stage disease encounter in adhering to antiretroviral treatments with a protease inhibitor. PATIENTS AND METHODS: A prospective self-administered questionnaire survey was conducted at our outpatient clinic for 2 months. CD4 counts and HIV viral loads were also determined. RESULTS: Seventy-one percent of the study population which included 262 responded to the questionnaire. The survey was made a median 215 days after initiating the antiprotease treatment with indinavir (71% of the cases), ritonavir (13%), saquinavir (6%), or a combination of protease inhibitors (10%). At onset of antiprotease treatment, mean CD4 count was 171+/-150/mm(3) and mean HIV viral load was 75,000 copies/ml. The treatment was considered to be difficult to take by 43% of the patients; 66% stated they had forgotten to take their drugs at least once a month. It was most difficult to take the drugs prescribed for the afternoon. Shifts of 1 hour were observed in 58% of patients. Non-adherence was frequent (1 failure to take drugs per week), observed in 13% of patients. Most often, the patients stated they had forgotten to take their drugs because of occupational or relational difficulties (52%). Non-adherence increased with duration of treatment. The drug most often associated with non-adherence was indinavir (73%). Age and sex did not influence adherence. Mean RNA HIV serum level was lower than at onset of the antiprotease treatment in the most non-adherent patients. At the time of the questionnaire, there was no difference in serum RNA HIV level or in the percentage of patients with an undetectable level between non-adherent and adherent patients. CONCLUSION: This survey confirmed difficulties in adherence are frequent and worsen with time. No relationship was found between non-adherence and reduction in viral load, suggesting that a short-term effect of these very active drugs despite lack of perfect adherence. Other factors (pharmacology, sensitivity to antiretroviral drugs.) also play a major role in therapeutic success.

Adult↗

Case report. Intestinal infarction due to vascular catastrophe in an HIV-infected patient.

A 40-year-old HIV-infected woman developed nausea, vomiting, and epigastric pain and died following her third dose (per study protocol) of interleukin (IL)-2. Her HIV infection was diagnosed in 1996. Her last CD4 cell count was 390/microL, and her viral load was negligible (as of November 28, 1998). She had no known general risk factors for thrombosis other than HIV infection, injection drug abuse, and antiretroviral therapy with indinavir. Abdominal films showed no sign of mechanical obstruction but a generalized gas distention of the bowel, which was suggestive of paralytic ileus. Autopsy revealed dilation of the small bowel with extensive necrosis and hemorrhage involving all the segments. The superior and inferior mesenteric arteries revealed severe atherosclerosis. The stenotic celiac artery was occluded by a recent thrombus at the aortic ostium. Clinicians need to be aware of the potential for thrombosis and accelerated atherosclerosis in HIV-infected patients. Both injection drug abuse and protease inhibitors, such as indinavir, have been shown to be risk factors for thrombosis. However, it is likely IL-2 contributed to the severe thrombosis in this patient, although definitive proof is lacking. An acute awareness of intestinal infarction in HIV-infected patients is warranted.

Adult↗

Adherence to antiretroviral therapy and outcomes in HIV-infected patients enrolled in an induction/maintenance randomized trial.

OBJECTIVE: To examine the effect of adherence to therapy on early virological response, later virological failure, and occurrence of adverse events in HIV-infected patients. DESIGN: A randomized trial of 3-month induction period of zidovudine/lamivudine/indinavir followed by a maintenance phase of zidovudine/lamivudine/indinavir, zidovudine/lamivudine or zidovudine/indinavir. MAIN OUTCOMES: Adherence was assessed by pill count. In the induction phase, early virological response was defined as plasma HIV-RNA<500 copies/ml at month 2 and in the maintenance phase, virological failure was defined as plasma HIV-RNA >500 copies/ml in two consecutive specimens. RESULTS: The median adherence rate was 97% in both induction (n=366) and maintenance phase (n=237). In the maintenance phase, pairwise comparisons showed a lower adherence rate in zidovudine/lamivudine/indinavir versus zidovudine/lamivudine (P=0.03), or versus zidovudine/indinavir (P=0.05). Only 13% of patients had an adherence over the maintenance phase of 80% or lower, while 40% of patients occasionally had an adherence rate of 80% or lower during this phase. Among the 362 patients with documented HIV-RNA at month 2, 86% had an early virological response. Adherence of 80% or greater was the only variable statistically predictive to early virological response (P<0.001), while baseline CD4, baseline HIV-RNA, and adherence of 95% or greater were not associated to virological response. In the maintenance phase, adherence, baseline HIV-RNA, HIV-RNA at month 3 and treatment groups were independently predictive to time to virological failure. Analysis by randomized groups indicated that difficulty in adherence (<80%) was predictive to time to failure (P<0.001) only in both indinavir-containing regimens. Occurrence of two or more severe adverse events (grade 3 and 4) was higher in patients with poor adherence although not statistically associated (P=0.12), while no association was found with minor adverse events. CONCLUSION: Adherence rate was globally lower in patients maintaining the original triple-drug therapy compared with those receiving less intensive regimens. Adherence rate was a time-dependent variable. Adherence to antiviral regimen of 80% or greater was predictive to early virological response, and adherence rate lower than 80% or 95% was predictive to virological failure, especially in indinavir-containing regimens. Occurrence of adverse events was not clearly associated to adherence.

Adult↗

Effect of various cytochrome P450 3A and P-glycoprotein modulators on the biliary clearance of bromosulphaphthalein in male wistar rats.

The main aim of this study was to investigate the effect of various selective cytochrome P4503A (CYP3A) and/or P-glycoprotein (P-gp) modulators on biliary clearance of bromosulphaphthalein (BSP) in male albino wistar rats. Male albino wistar rats were divided into different groups, treated with CYP3A and P-gp modulators and BSP was administered intravenously (bolus or infusion) to each treated group. BSP in serum and bile samples was analyzed using spectrophotometric analysis at 580 nm. There was a statistically significant (p < 0.05) increase in serum BSP levels with CYP3A and P-gp substrates and/or inhibitors, cyclosporine-A, nitrendipine, quinidine, indinavir, daxorubicin, etoposide and erythromycin by 27%, 35%, 32%, 12%, 5%, 22%, and 106%, respectively. There was a slight increase (4%, p > 0.05) observed in serum BSP levels in the presence of ketoconazole, whereas CYP3A and P-gp inducers, rifampicin and sodium butyrate significantly (p < 0,05) decreased the serum BSP levels by 30% and 14% respectively, when compared to control group after 62 min of BSP i.v. bolus administration. In BSP infusion studies, Cyclosporine A, nitrendipine, quinidine, indinavir, ketoconazole, doxorubicin, etoposide, and erythromycin significantly decreased the bile BSP levels by 23%, 22%, 17%, 59%, 3%, 15%, 10%, 29%, respectively. Upon 60 min of BSP infusion, rifampicin and sodium butyrate significantly (p < 0.05) increased bile BSP levels by 33% and 25%, respectively. Finally, we observed that the P-gp and CYP3A inducers significantly decreased the total serum BSP levels and increased the total biliary levels of BSP, this could be by inducing P-gp in biliary canalicular membrane in male wistar rats. P-gp and CYP3A inhibitors and substrates significantly increased the total serum BSP levels and reduced the biliary excretion of BSP by inhibiting P-gp in biliary pathway. There was no significant difference observed between inhibitors and substrates of P-gp on BSP disposition. We suggest that the biliary transport of BSP could be useful as a simple and economical in vivo screening model for identifying P-gp and CYP3A substrates and/or inhibitors and/or inducers in wistar rats.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Contribution of cellular HIV-1 DNA quantification to the efficacy analysis of antiretroviral therapy: a randomized comparison of 2 regimens, including 3 drugs from 2 or 3 classes (TRIANON, ANRS 081).

Cellular HIV-1 DNA level was sequentially measured by quantitative polymerase chain reaction in 141 patients not previously treated with highly active antiretroviral therapy (HAART), who were enrolled in a 72-week randomized trial (ANRS 081 "Trianon") comparing 2 regimens, including 3 drugs from 2 classes (indinavir + stavudine + lamivudine, group 1) or 3 classes (indinavir + stavudine + nevirapine, group 2). The median decrease from baseline to week 72 in cellular HIV-1 DNA level was not significantly different between the 2 groups (0.54 and 0.45 log10 copies/10 peripheral blood mononuclear cells [PBMCs] in groups 1 and 2, respectively), whereas a higher proportion of patients maintained a plasma HIV-1 RNA level less than 20 copies/mL at week 72 in group 1 than in group 2 (79% and 52%; P = 0.0009). Furthermore, the difference in cellular HIV-1 DNA decrease from baseline to week 72 between patients who achieved a plasma HIV-1 RNA level less than 20 copies/mL at week 72 and those who did not was not statistically significant (0.54 and 0.45 log10 copies/10 PBMCs, respectively; P = 0.14). The decay in cellular HIV-1 DNA from baseline to week 72 was higher in antiretroviral-naive patients than in pretreated patients (0.55 and 0.23 log10 copies/10 PBMCs, respectively; P = 0.0008). The cellular HIV-1 DNA level change under therapy was best fitted to a 2-phase decay model with a junction point at week 16, from which its half-life was estimated at 18 weeks during the initial phase and at 104 weeks thereafter. In conclusion, the changes under therapy in cellular HIV-1 DNA level, which were mostly coincident to those of plasma HIV-1 RNA, did not add significant information to the comparison of the viral efficacy of the 2 studied regimens.

Adult↗

Altered adipokine response in murine 3T3-F442A adipocytes treated with protease inhibitors and nucleoside reverse transcriptase inhibitors.

BACKGROUND: Abnormal levels of tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and adiponectin have been observed in HIV patients with lipodystrophy. However, because these patients have long drug and disease histories, it is unclear which drugs are responsible for these abnormalities. We have therefore investigated the effects of individual antiretrovirals on adipokine expression and adipogenesis using a murine cell line in vitro. METHODS: Differentiating murine 3T3-F442A adipocytes were incubated with 20 microM nucleoside reverse transcriptase inhibitors (NRTIs) zidovudine or stavudine, or protease inhibitors (PIs) indinavir, ritonavir, saquinavir or nelfinavir, in the presence and absence of rosiglitazone (10 microM). Adipogenesis was assessed using glycerol-3-phosphate dehydrogenase activity, while expression of TNF-alpha, IL-6 and adiponectin at protein and mRNA levels was assessed by ELISA and quantitative real-time PCR, respectively. RESULTS: Nelfinavir, ritonavir and saquinavir inhibited adipogenesis and up-regulated the expression of TNF-alpha and IL-6, but this effect was not seen with indinavir, zidovudine and stavudine. Adiponectin expression was significantly reduced in both NRTI- and PI-treated cells, although the most profound reductions were found with ritonavir and saquinavir. Co-incubation with rosiglitazone led to a partial attenuation of the change in TNF-alpha, IL-6 and adiponectin secretion. CONCLUSIONS: Our data suggest that the PIs nelfinavir, ritonavir and saquinavir have potent effects in inhibiting adipocyte differentiation whilst up-regulating TNF-alpha and IL-6 mRNA levels and decreasing adiponectin levels. These changes were partially attenuated by rosiglitazone. Taken together, the data show that antiretrovirals have complex effects on adipocyte function, which may be mediated by an altered adipokine response.

3T3 Cells↗

HIV associated arthritis: case report and review of the literature.

HIV infection can be associated with different types of arthropathies which are often underdiagnosed. We present the case of a 52 year old HIV positive man on highly active antiretroviral therapy including indinavir who developed an acute painful oligoarthritis. We present this case on HIV associated arthritis and include a review on other HIV specific types of arthritis (acute symmetric arthritis and painful articular syndrome) which are assumed as entities exclusively apparent in HIV patients. The pathophysiology of arthritis in HIV infected patients is not yet completely understood but a direct role of the HIV on the initiation of synovitis is suspected in some of them. Additionally, there is evidence that antiretroviral drugs, in particular the protease inhibitor indinavir, can lead to arthritic complications as well.

Antiretroviral Therapy, Highly Active↗

Co-treatment with grapefruit juice inhibits while chronic administration activates intestinal P-glycoprotein-mediated drug efflux.

P-Glycoprotein (P-gp) mediated efflux is recognized as a significant biochemical barrier affecting oral absorption for a number of drugs. Various conflicting reports have been published regarding the effects of grapefruit juice (GFJ) on P-gp-mediated drug efflux, in which GFJ has been shown both to inhibit and activate it. Hence, the present study adopted a two-way approach, involving both co-treatment and chronic administration. Bi-directional transport of paclitaxel (PCL) was carried out in the absence and presence of GFJ extract, in rat everted ileum sac. Further, the effect of chronic administration of GFJ to rats was characterized by permeability studies with indinavir (INDI). Co-treatment of GFJ extract at 100% concentration reduced the asymmetric transport of PCL (efflux ratio = 20.8) by increasing absorptive (A --> B) transport by 921% and reducing secretory (B --> A) transport by 41%. Further, GFJ showed a concentration dependent effect on PCL permeability. Imipramine, a passive permeability marker with absorptive permeability of 15.33 +/- 4.26 x 10(-6) cm/s showed no asymmetric transport and also no significant (P < 0.05) change in permeability in the presence of GFJ. Chronic administration of GFJ resulted in a significant decrease in absorptive transport of indinavir, which was even greater than that produced by rifampicin pretreatment. No change in permeability of propranolol, a passive permeability marker, was observed. Further, the decrease in absorptive transport of INDI was reversed by the P-gp inhibitor verapamil. In conclusion, GFJ extract inhibited P-gp-mediated efflux in co-treatment, whereas chronic administration led to increased levels of P-gp expression, thus having a profound effect on intestinal absorption and GFJ-drug interactions in vivo.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Incidence of and risk factors for insulin resistance in treatment-naive HIV-infected patients 48 weeks after starting highly active antiretroviral therapy.

OBJECTIVES: to assess the incidence and risk factors for insulin resistance (IR) in a cohort of naive HIV-infected patients 48 weeks after starting highly active antiretroviral therapy (HAART). DESIGN: prospective, two centre, observational, cohort study. METHODS: One-hundred and thirty-seven patients who started HAART and maintained the same regimen for 48 weeks were included. IR was determined by the homeostasis model assessment (HOMA-IR) method. Individuals with a HOMA-IR value >3.8 were defined as insulin resistant. Independent associations with the development of IR at 48 weeks were evaluated. RESULTS: Seventeen (12.4%) individuals showed a HOMA-IR value >3.8 at baseline and were excluded for incidence analyses. Fifteen patients developed IR at 48 weeks of HAART, giving an incidence of 13%. Independent predictors of the development or IR were indinavir exposure (beta-coefficient 5.45, 95% confidence interval [CI] 1.30-22.8; P=0.02), and hepatitis C virus (HCV) antibody positivity (beta-coefficient 5.22, 95% CI 1.34-20.33; P=0.01). The appearance of IR was associated with a higher BMI (beta-coefficient 1.72 for each 2 kg/m2 increase, 95% CI 1.54-1.94; P=0.02) and with the presence of lipodystrophy at 48 weeks (beta-coefficient 5.59, 95% CI 1.45-21.5; P=0.01). CONCLUSIONS: HAART induces the development of IR in previously naive non-insulin-resistant HIV-infected individuals, with an incidence of 13% in the first year of therapy. Indinavir exposure, and HCV coinfection are associated with an increased risk of developing IR.

Adult↗

Selective biotransformation of the human immunodeficiency virus protease inhibitor saquinavir by human small-intestinal cytochrome P4503A4: potential contribution to high first-pass metabolism.

Saquinavir is a HIV protease inhibitor used in the treatment of patients with acquired immunodeficiency syndrome, but its use is limited by low oral bioavailability. The potential of human intestinal tissue to metabolize saquinavir was assessed in 17 different human small-intestinal microsomal preparations. Saquinavir was metabolized by human small-intestinal microsomes to numerous mono- and dihydroxylated species with K(M) values of 0.3-0.5 microM. The major metabolites M-2 and M-7 were single hydroxylations on the octahydro-2-(1H)-isoquinolinyl and (1,1-dimethylethyl)amino groups, respectively. Ketoconazole and troleandomycin, selective inhibitors of cytochrome P4503A4 (CYP3A4), were potent inhibitors for all oxidative metabolites of saquinavir. The cytochrome P450-selective inhibitors furafylline, fluvoxamine, sulfaphenazole, mephenytoin, quinidine, and chlorzoxazone had little inhibitory effect. All saquinavir metabolites were highly correlated with testosterone 6beta-hydroxylation and with each other. Human hepatic microsomes and recombinant CYP3A4 oxidized saquinavir to the same metabolic profile observed with human small-intestinal microsomes. Indinavir, a potent HIV protease inhibitor and a substrate for human hepatic CYP3A4, was a comparatively poor substrate for human intestinal microsomes and inhibited the oxidative metabolism of saquinavir to all metabolites with a Ki of 0.2 microM. In addition, saquinavir inhibited the human, small-intestinal, microsomal CYP3A4-dependent detoxication pathway of terfenadine to its alcohol metabolite with a Ki value of 0.7 microM. These data indicate that saquinavir is metabolized by human intestinal CYP3A4, that this metabolism may contribute to its poor oral bioavailability, and that combination therapy with indinavir or other protease inhibitors may attenuate its low relative bioavailability.

Anti-HIV Agents↗

Protease inhibitors as inhibitors of human cytochromes P450: high risk associated with ritonavir.

Four protease inhibitor antiviral agents (ritonavir, indinavir, nelfinavir, saquinavir) were evaluated as in vitro inhibitors of the activity of six human cytochromes using an in vitro model based on human liver microsomes. Ritonavir was a highly potent inhibitor of P450-3A activity (triazolam hydroxylation), having inhibitory potency slightly less than ketoconazole. Indinavir was also a potent 3A inhibitor, while nelfinavir and saquinavir were less potent. Ritonavir had high inhibition potency against cytochrome P450-2C9 (tolbutamide hydroxylation), -2C19 (S-mephenytoin hydroxylation), and -2D6 (dextromethorphan O-demethylation and desipramine hydroxylation), while the other protease inhibitors had one or more orders of magnitude lower inhibitory activity against these reactions. None of the protease inhibitors had important inhibitory potency against P450-1A2 (phenacetin O-deethylation) or -2E1 (chlorzoxazone hydroxylation). Thus, among available protease inhibitors, ritonavir carries the highest risk of incurring drug interactions due to inhibition of cytochrome P450 activity.

Antiviral Agents↗

Drug interactions between HIV protease inhibitors based on physiologically-based pharmacokinetic model.

A Physiologically-based pharmacokinetic (PB-PK) model was developed to describe the aspects of pharmacokinetic interactions between five HIV protease inhibitors (ritonavir, amprenavir, nelfinavir, saquinavir, indinavir) in rats. To increase usefulness of this BP-PK model, liver, intestinal tissue and other organ were assumed as compartments in this model. Each compartment was linked with the blood flow and the blood-to-plasma concentration ratios of those drugs, and the absorption process in the intestinal tract was presumed as a first-order kinetics. In addition, this PB-PK model incorporates two elimination processes due to hepatic and intestinal metabolism constructed by in vitro metabolic clearance rates and inhibition constants between HIV protease inhibitors. Excellent agreements were obtained between the predicted and observed concentrations of HIV protease inhibitors in rat plasma after a 20 mg/kg oral dose or co-administration of two kinds of HIV protease inhibitors (amprenavir/indinavir, nelfinavir/amprenavir, saquinavir/amprenavir, amprenavir/ritonavir, indinavir/ritonavir, nelfinavir/ritonavir, and saquinavir/ritonavir) with each 20 mg/kg oral dose. However, underestimates in the predicted plasma concentrations of saquinavir, indinavir and amprenavir were observed during the terminal phase after co-administration with ritonavir or amprenavir, suggesting that a term of other inhibitory process, such as a mechanism-based inhibition, might be incorporated into this PB-PK model. This BP-PK model enables us to know useful information about pharmacokinetic interaction when HIV infected patients would receive double protease therapy.

Administration, Oral↗

Failure of HIV-1 protease inhibitors to fully suppress viral replication. Implications for salvage therapy.

When used as initial therapy in combination with two nucleoside reverse transcriptase inhibitors, indinavir, ritonavir, nelfinavir and possible saquinavir-soft gel capsule (saquinavir-sgc) are highly effective agents. Patients who have been extensively pretreated, have advanced immunodeficiency or are unable to adhere with therapy are at high risk of failing protease inhibitor therapy. Although relevant prospective, randomized controlled clinical trails have not been reported, failure of a first protease inhibitor appears to compromise future therapeutic options. After resistance to indinavir or ritonavir emerges, salvage therapy with a protease inhibitor-containing regimen may be difficult. Preliminary data indicate that salvage therapy after resistance to saquinavir or nelfinavir emerges may be possible; however, this requires further investigation. The activity of newer agents, such as amprenavir or ABT 378, in salvage regimens is unknown. Until these issues are addressed in large prospective studies, clinicians should assume that cross-resistance will be common among all protease inhibitors.

Acquired Immunodeficiency Syndrome↗

Prognostic factors in the treatment of human immunodeficiency virus-associated non-Hodgkin's lymphoma.

Chemotherapy regimens similar to those used for non-Hodgkin's lymphoma (NHL) not associated with human immunodeficiency virus (HIV) infection have been used for patients with HIV-associated NHL with less success. In a recent trial, patients with intermediate or high-grade NHL were randomized to either low-dose chemotherapy with methotrexate, bleomycin, doxorubicin, vincristine and dexamethasone (m-BACOD) or to standard-dose m-BACOD with sargramostim (granulocyte-macrophage colony-stimulating factor, GM-CSF). With low-dose m-BACOD 41% of patients achieved a complete remission and the median survival was 35 weeks. With standard-dose m-BACOD and sargramostim, the percentage of complete remissions was 52% with a median survival of 31 weeks (P=n.s.). Myelosuppression was greater with standard-dose chemotherapy. In univariate and multivariate analyses of 21 pretreatment features of patients in this trial, four factors emerged as adversely prognostic with respect to survival: age >35 years, intravenous drug use, CD4 counts < 100/mm3 and stage III/IV disease. In an analysis using the proportional hazards model, a "favorable" group was defined by patients with 0 or 1 adverse factor (median survival 46 weeks, survival at 144 weeks 29.5%) as compared with an unfavorable group with 3 or 4 adverse factors (median survival 18 weeks, survival at 144 weeks 0). The outcome of these patients may be improving with the use of highly active antiretroviral therapy (HAART), which seems to improve immune function and tolerance of chemotherapy. A recent trial of the AIDS Malignancy Consortium found that low-dose chemotherapy (cyclophosphamide, doxorubicin, vincristine and prednisone: CHOP) and standard-dose chemotherapy had similar response rates, acceptable toxicity and minimal alterations in cyclophosphamide, doxorubicin and indinavir pharmacokinetics in HIV-associated lymphoma patients also on HAART (stavudine, lamivudine and indinavir). There is a suggestion that Burkitt-type lymphomas may tend to occur in HIV-infected patients with relatively well preserved immune function and CD4 cell counts. Recent results from our institution suggest that similar outcomes are achievable with intensive chemotherapy in patients with Burkitt's lymphomas with or without HIV infection. With improved immune status and improved bone marrow function with the use of HAART, it will probably become more possible to treat many patients with aggressive HIV-associated NHL with more intensive treatment regimens.

Adult↗

[Acute hypopyon uveitis with rifabutin therapy of systemic Mycobacterium avium complex (MAC) infection in AIDS].

BACKGROUND: Hypopyon-uveitis has been identified as a dosage-dependent side effect in patients with acquired immunodeficiency syndrome who are treated for Mycobacterium avium complex (MAC) infection with systemic rifabutin. PATIENTS AND METHODS: We report a 38-year-old female AIDS patient with bilateral hypopyon uveitis under therapy with rifabutin in combination with clarithromycin and indinavir. RESULTS: At the time of presentation of the bilateral hypopyon uveitis the patient was treated with rifabutin (300 mg/day), clarithromycin (1000 mg/day) and ethambutol (1000 mg/day) for an M. avium complex infection. Also, the patient received the protease inhibitor indinavir. The rifabutin dose was reduced to 150 mg/day. Hypopyon and inflammation resolved under therapy with steroids. CONCLUSIONS: The concomitant use of rifabutin, clarithromycin, and protease inhibitors may lead to hypopyon uveitis. Reduction of dosage of rifabutin (150 mg/day) and treatment with topical steroids are required.

AIDS-Related Opportunistic Infections↗

Anti-adenoviral effect of anti-HIV agents in vitro in serotypes inducing keratoconjunctivitis.

BACKGROUND: Around one million people are affected by adenoviral keratoconjunctivitis a year in Japan, and it is recognized as one of the major pathogens of ophthalmological nosocomial infection worldwide. Although cidofovir can be used systemically for immunocompromised patients with disseminated adenoviral infection, no specific anti-adenoviral agent has been established for the treatment of adenoviral infection. We evaluated the anti-adenoviral effect of anti-HIV (human immunodeficiency virus) agents in this study. METHODS: Five anti-HIV agents (zalcitabine, stavudine, nevirapine, indinavir and amprenavir) were subjected to in vitro evaluation. A549 cells were used for viral cell culture, and adenovirus serotypes 3, 4, 8, 19 and 37 were used. After calculating CC(50) (50% cytotoxic concentration) of each agent by MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) method, we cultured adenovirus with the agents for seven days and quantitatively measured extracted adenoviral DNA by real-time PCR. RESULTS: Among the anti-HIV drugs, zalcitabine and stavudine, both nucleoside reverse transcriptase inhibitors, showed significant anti-adenoviral activity. In contrast, nevirapine, a non-nucleoside reverse transcriptase inhibitor, and indinavir and amprenavir, which are both protease inhibitors, were ineffective against adenovirus. CONCLUSIONS: These results indicate that zalcitabine and stavudine are possible candidates for the local and systemic treatment of adenoviral infection, and the anti-adenoviral effect might depend on the pharmacological properties of anti-HIV agents. The chemical properties on the clinical safety for systemic and local application need to be determined in order to for these drugs to be accepted for the treatment of adenovirus in clinical settings.

Adenovirus Infections, Human↗

Quantitative assessment of HIV-1 protease inhibitor interactions with drug efflux transporters in the blood-brain barrier.

PURPOSE: To quantitatively characterize the drug efflux interactions of various HIV-1 protease inhibitors in an in vitro model of the blood-brain barrier (BBB) and to compare that with HIV-1 protease inhibitor stimulated P-glycoprotein (P-gp)-ATPase activity. METHODS: Cellular accumulation of the P-gp sensitive probe, rhodamine 123 (R123), and the mixed P-gp/multidrug resistance-associated protein (MRP) probe, 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF), were evaluated in primary cultured bovine brain microvessel endothelial cells (BBMEC) in the presence of various concentrations of HIV-1 protease inhibitors. The potency (IC50) and efficacy (Imax) of the drugs in the cell accumulation assays for P-gp and/or MRP was determined and compared to activity in a P-gp ATPase assay. RESULTS: For R123 (P-gp probe), the rank order potency for inhibiting R123 accumulation in the BBMEC was saquinavir=nelfinavir>ritonavir=amprenavir>indinavir. This correlated well with the rank order affinity in the P-gp ATPase assay. The rank order potency for MRP-related drug efflux transporters, was nelfinavir>ritonavir>saquinavir>amprenavir>indinavir. CONCLUSIONS: HIV-1 protease inhibitors potently interact with both P-gp and MRP-related transporters in BBMEC. Characterization of the interactions between the HIV-1 protease inhibitors and drug efflux transporters in brain microvessel endothelial cells will provide insight into potential drug-drug interactions and permeability issues in the BBB.

ATP Binding Cassette Transporter, Subfamily B↗

Determination of the new HIV-protease inhibitor atazanavir by liquid chromatography after solid-phase extraction.

An HPLC method previously described for the simultaneous assay of amprenavir, ritonavir, indinavir, saquinavir, nelfinavir and efavirenz is proposed here for the simultaneous analysis of the new HIV protease inhibitor atazanavir (ATV) in human plasma, by off-line solid-phase extraction (SPE) followed by HPLC coupled with UV-diode array detection. After viral inactivation by heat (60 degrees C for 60 min), plasma (600 microl) with clozapine (internal standard) is diluted 1 + 1 with phosphate buffer pH 7 and subjected to a SPE on a C18 cartridge. Matrix components are eliminated with 2 x 500 microl of a solution of 0.1% H(3)PO(4) neutralised with NaOH to pH 7. ATV is eluted with 3 x 500 microl MeOH. The resulting eluate is evaporated under nitrogen at room temperature and is reconstituted in 100 microl MeOH/H(2)O 50/50. A 40 microl volume is injected onto a Nucleosil 100-5 microm C18 AB column. ATV is analysed by UV detection at 201 nm using a gradient elution program with solvents constituted of MeCN and phosphate buffer adjusted to pH 5.14. The mobile phase also contains 0.02% sodium heptanesulfonate, enabling an excellent separation of ATV from the other HIV protease inhibitors (PIs) amprenavir, indinavir, saquinavir, ritonavir, lopinavir, nelfinavir and the non-nucleoside reverse transcriptase inhibitors (NNRTIs) efavirenz and nevirapine. The calibration curves are linear up to 10 microg/ml, with a lower limit of quantification of 0.2 microg/ml. The mean absolute recovery of ATV is 96.4 +/- 3.2%. The method is precise with mean inter-day CVs within 1.1-6.1%, and accurate (range of inter-day deviations +0.3 to +2.3%). The method has been validated and is currently applied to the monitoring of ATV in HIV patients.

Atazanavir Sulfate↗