Didanosine (original) (raw)
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Antiviral therapy
Objective: To compare the antiviral activity, safety and tolerability of didanosine dosed once and twice daily when administered in combination with stavudine dosed twice daily in human immunodeficiency virus type 1 (HIV-1)-infected individuals with little or no previous exposure to antiretroviral drugs. Design: Comparative, multicentre, randomized, openlabel, short-term study. Patients and Methods: Eighty-four HIV-1-infected adults with qualifying baseline CD4 cell counts of 200 to 500 cells/mm 3 were included in the study. Of these, 43 patients received once daily didanosine plus twice daily stavudine (group A) and 41 subjects received twice daily didanosine plus twice daily stavudine (group B). The primary efficacy analysis used was the time-averaged difference (TAD) between treatment regimens of variations in plasma HIV-1 RNA levels from baseline over the first 12 weeks of therapy. Plasma HIV-1 RNA levels, CD4 cell counts and adverse events were monitored. Results: At week 12, median HIV-1 RNA variations were -1.18 log 10 copies/ml in group A and -0.88 log 10 copies/ml in group B. For patients who were followed up to week 24, median variations of HIV-1 RNA levels from baseline were -1.21 log 10 copies/ml in group A and -0.78 log 10 copies/ml in group B. The TAD between the two treatment groups for variations from baseline plasma HIV-1 RNA levels over the first 12 weeks was 0.10 log 10 copies/ml (95% confidence interval, -0.19 to 0.40), indicating equivalence. Conclusion: Once daily didanosine plus twice daily stavudine and twice daily didanosine plus twice daily stavudine are equally effective in reducing plasma HIV-1 RNA levels and increasing CD4 cell counts. Both regimens are safe and well tolerated.
Didanosine enteric-coated capsule: current role in patients with HIV-1 infection
Drugs, 2007
Didanosine, which is a synthetic nucleoside analogue intracellularly phosphorylated to the active metabolite, inhibits the activity of HIV-1 reverse transcriptase by competing with the natural substrate. Currently, didanosine is mainly provided as an enteric-coated capsule. In vitro, the molecule is active against laboratory strains and clinical isolates of HIV-1 in resting and activated T cells and monocyte/macrophages. Didanosine may select for resistance mutations that may render the drug inactive against the virus; L74V and K65R remain as the main didanosine-related mutations. In vitro, phenotypic susceptibility to didanosine was decreased beyond a defined fold change clinical cut-off (1.7), and it is considered that genotypic resistance exists when five thymidine-associated mutations or four plus M184V are present. In vivo, clinical studies have shown that didanosine retains significant antiviral activity in patients who have up to five nucleoside analogue mutations at baseline...
Antiviral Chemistry and Chemotherapy, 1994
Lipophilic 6-halo-2′,3′-dideoxypurine nucleosides may be useful prodrugs for the targeting of 2′,3′-dideoxyinosine (ddl) to the central nervous system. The purpose of this study was to evaluate the potential effectiveness of 6-chloro-2′,3′-dideoxypurine (6-CI-ddP) for the targeting of ddl to the brain. In vitro studies indicated that the adenosine deaminase-mediated biotransformation of 6-CI-ddP to ddl was more rapid in mouse brain homogenate than in mouse serum. The brain distribution of 6-CI-ddP and ddl was assessed in vivo in mice following intravenous and oral administration of the prodrug or parent drug. Brain concentrations of ddl were similar after intravenous administration of 6-CI-ddP or ddl. However, after oral administration of the 6-CI-ddP prodrug, significantly greater concentrations of ddl were seen in the brain compared to those found after oral administration of ddl. The brain:serum AUG ratio (expressed as a percentage) of ddl after intravenous administration of 50 m...
Clinical Pharmacology and Therapeutics, 1991
Pharmacokinetics of didanosine in patients with acquired immunodeficiency syndrome or acquired immunodeficiency syndrome related complex The pharmacokinetics of didanosine (2',3'-dideoxyinosine) after intravenous and oral administration were evaluated in an open, escalating-dose phase I study in patients with acquired immunodeficiency syndrome (AIDS) or severe AIDS-related complex. Didanosine was administered twice a day for 2 weeks as an intravenous infusion of 60 minutes duration at doses ranging from 0.4 to 16.5 mg/kg, followed by 4 weeks of oral treatment at twice the intravenous dose. Serial blood and urine samples were obtained on the first and final day of intravenous administration and after the first oral dose, as well as at steady state. Didanosine demonstrated linear pharmacokinetic behavior over the dose ranges of 0.4 to 16.5 mg/kg intravenously and 0.8 to 10.2 mg/kg orally. There was no indication of significant changes in pharmacokinetic parameters with repeated administration. The apparent elimination half-life after oral administration was approximately 1.4 hour. Renal clearance values exceeded the glomerular filtration rate, indicating that active tubular secretion of didanosine occurs. Bioavailability of didanosine when administered as a solution with an antacid was approximately 43% for doses from 0.8 to 10.2 mg/kg in patients with AIDS and advanced AIDS-related complex. Bioavailability of didanosine from the citratephosphatebuffered solution, the formulation currently used in phase II and expanded access studies, was comparable to the formulation used in the phase I trials.
2014
Objectives: The disposition of antiretroviral agents into genital tissue and fluids is one of the factors implicated in the control of viral replication within the male genital tract and should be an objective of highly active antiretroviral therapy. We have investigated didanosine penetration in seminal plasma of 16 HIV-infected patients. Patients and methods: A total of 16 patients on didanosine (200 mg every 12 h or 400 mg once daily) participated in the pharmacokinetic study. After the didanosine morning dose, peripheral blood plasma and semen plasma were collected within the intervals 0–4, 4–8 and 8–12 h in the twice-daily regimen and 0–4, 4–12 and 12–24 h in the once-daily regimen. Results: Within each sampling time interval didanosine concentrations in seminal plasma were higher than in blood. The interquartile range of concentrations in seminal plasma was 292–1217 ng/mL, compared with 50–150 ng/mL in blood plasma. Didanosine could be detected in 14 of the 16 semen samples an...
Antimicrobial Agents and Chemotherapy, 1987
It is generally accepted that human immunodeficiency virus (HIV) is the etiologic agent of the acquired immunodeficiency syndrome and related diseases. In this report, we demonstrate the antiviral effect of nucleoside analogs 2',3'-didehydro-2',3'-dideoxythymidine (DHT) and 2',3'-didehydro-2',3'-dideoxycytidine (DHC) by using human T-cell lymphotropic virus type I-carrying MT-4 cells, which are extremely susceptible to HIV infection. These agents efficiently inhibited the cytopathic effects and expression of HIV-specific antigens in MT-4 cells after infection of the virus. Both DHT and DHC also strongly blocked viral replication as determined by our quantitative bioassay system using a plaque-forming assay. These antiviral effects were obtained at concentrations at which the drugs produced little or no toxicity and were comparable to those with 3'-azido-3'-deoxythymidine and 2',3'-dideoxynucleosides. These findings warrant further inve...