Lamivudine

Tramadol is a synthetic opioid agonist used extensively in human and, to a lesser extent, veterinary medicine throughout the world. The clinical efficacy and pharmacokinetic profile of intravenous (i.v.) and extradural (e.d.) tramadol (2 mg/kg) and its o-desmethyl metabolite were studied in dogs undergoing tibial plateau levelling osteotomy (TPLO). Intra-operative cardiorespiratory variables were monitored and post-operative pain was assessed using the short form of the Glasgow Composite Pain Scale. A rapid (<5 min) and effective production of o-desmethyl tramadol was recorded. The pharmacokinetic profile was similar for tramadol and its metabolite irrespective of the route of administration. E.d. tramadol provided sufficient intra- and post-operative analgesia without significant clinical side-effects, but the post-operative analgesia was comparable to that following i.v. administration and the e.d. route could therefore not be considered a practical alternative to the i.v. route.

There are few data on plasma and intracellular pharmacokinetics (PK) of once-daily (q24h) nucleoside analogues in HIV-infected children. Children aged 2-13 years receiving combination treatment containing lamivudine (3TC) (4 mg/kg) and/or abacavir (ABC) (8 mg/kg) twice daily (q12h) were included in this single-arm, open-label, crossover study. Intensive plasma PK sampling was performed at steady state, after which children switched to q24h dosing and PK sampling was repeated 4 weeks later. Daily area under the curve (AUC0-24) and peak level (Cmax) of q24h and q12h regimens were compared by geometric mean ratios (GMRs) with 90% confidence intervals (CIs). Children were followed for 24 weeks to evaluate safety and virological response. 24 children were enrolled, of whom 20 [median age (range) 5.6 (2.1-12.8) years] had evaluable PK data for 3TC (n=19) and/or ABC (n=14). GMRs of 3TC and ABC AUC0-24 and Cmax q24h versus q12h significantly exceeded 1.0. GMRs were not significantly differe...

The effect of peer support on virologic and immunologic treatment outcomes among HIVinfected patients receiving antiretroviral therapy (ART) was assessed in a cluster randomized controlled trial in Vietnam. Seventy-one clusters (communes) were randomized in intervention or control, and a total of 640 patients initiating ART were enrolled. The intervention group received peer support with weekly home-visits. Both groups received first-line ART regimens according to the National Treatment Guidelines. Viral load (VL) (ExaVir™ Load) and CD4 counts were analyzed every 6 months. The primary endpoint was virologic failure (VL >1000 copies/ml). Patients were followed up for 24 months. Intention-to-treat analysis was used. Cluster longitudinal and survival analyses were used to study time to virologic failure and CD4 trends. Of 640 patients, 71% were males, mean age 32 years, 83% started with stavudine/lamivudine/nevirapine regimen. After a mean of 20.8 months, 78% completed the study, an...

High shear wet granulation is a preferred manufacturing method of tablets. It allowed for rapid production of compressible granulations. The resultant granulation characteristics depend on a combination of formulation properties and processing parameters. Fully pregelatinized starches are currently being used as binders in wet granulated formulations. But due to the gelatinization, much of the disintegration properties are lost. Partially pregelatinized starches (starch 1,500) have a mixture of properties of both native and fully gelatinized starches; made them useful as both a binder and a disintegrant in wet granulated formulations. Starch 1,500 performed as an excellent binder producing a granulation that was compressible and produced lamivudine tablets of improved hardness and friability compared with those prepared with povidone. The formulation of lamivudine tablets with starch 1,500 exceeded the disintegration and dissolution performance of the povidone formulation that utili...

Lamivudine [(-)-beta-L-2',3'-dideoxy-3'-thiacytidine] reduces woodchuck hepatitis virus (WHV) titers in the sera of chronically infected woodchucks by inhibiting viral DNA synthesis. However, after 6 to 12 months, WHV titers begin to increase toward pretreatment levels. Three WHV variants with mutations in the active site of the DNA polymerase gene are present at this time (W. S. Mason et al., Virology 245:18-32, 1998). We have asked if these mutant viruses were responsible for the lamivudine resistance and if their emergence caused an immediate rise in virus titers. Cell cultures studies implied that the mutants were resistant to lamivudine. Emergence of mutant WHV was not always associated, however, with an immediate rise in virus titers in the serum. One of the three types of mutant viruses became prominent in serum up to 7 months before titers in serum actually began to increase, at a time when wild-type virus was still predominant in the liver. The two other mutants...

The use of hepatitis B immunoglobulin (HBIg) combined with nucleos(t)ide analogues (NUCs) has improved outcomes in post-hepatitis B (PHB) liver transplant (LT), reducing the 1-year recurrence rate below 10%. The aim of this study was to evaluate efficacy and pharmacokinetics of prophylaxis with NUC(s) and intravenous (iv-) or intramuscular (im-) HBIg in 33 PHBLTs, transplanted for more than 1 year. During the first six months of the study, 18 subjects received 5000 IU of iv-HBIg every four weeks and 15 patients 2160 IU/12 mL of im-HBIg every two weeks. In the following six months, 31 subjects were switched to two different concentrations of im-HBIg, 2160/12 mL (16 patients) or 2000 IU/6 mL every two weeks (15 patients). All patients remained HBsAg-negative and 30/31 maintained anti-HBs >100 IU/L. Overall mean anti-HBs titer during treatment was 363 IU/mL. Mean HBIg half-life was 21.4, 27.3 and 26 days with intravenous, diluted or concentrated im-preparations, respectively. These ...

Retroviruses may cause diseases in their vertebrate hosts. They are distinguished by their common means of replication involving reverse transcription, a process inhibited by nucleoside reverse transcriptase inhibitors (NRTIs) and other compounds used in antiretroviral chemotherapy. Previous work on NRTIs has been limited to their effect on human immunodeficiency virus (HIV) (for review see Ho & Hitchcock, 1989; Weller, 1999) and little information exists regarding the efficacy and therapeutic potential of these drugs against other retroviruses. We have tested all six NRTIs licensed for HIV treatment [didanosine (ddI), zalcitabine (ddC), lamivudine (3TC), stavudine (d4T), zidovudine (AZT) and abacavir (ABC)] against seven retroviruses representative of the traditional subfamilies: Spumavirinae, Lentivirinae and the Oncovirinae. As expected, each drug showed a range of activities against the panel of retroviruses, some drugs inhibiting other viruses at concentrations well below those...