Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Abacavir is a nucleoside analogue reverse transcriptase inhibitor that inhibits clinical isolates of HIV in vitro with a potency similar to that of zidovudine. Resistance to abacavir develops relatively slowly. Cross-resistance between abacavir and didanosine, zalcitabine or lamivudine, but not zidovudine or stavudine, has been reported in vitro. Abacavir has good oral bioavailability, as demonstrated in animals, and penetrates the CNS. Treatment with abacavir, alone or in combination with other anti-HIV agents (zidovudine, lamivudine, nevirapine, amprenavir and/or other protease inhibitors), decreased viral load and increased CD4+ cell count in patients with HIV infection. Effectiveness was maintained for at least 48 weeks. In early phase I/II trials, headache, gastrointestinal disturbances, rash, malaise, fatigue and/or asthenia were the most common adverse events reported with abacavir alone or in combination with other anti-HIV agents. Hypersensitivity reactions lead to discontinuation of therapy in 2 to 3% of patients.
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PMID:Abacavir. 958 69

Abacavir (formerly 1592U89) is a carbocyclic nucleoside analog with potent anti-human immunodeficiency virus (anti-HIV) activity when administered alone or in combination with other antiretroviral agents. The population pharmacokinetics and pharmacodynamics of abacavir were investigated in 41 HIV type 1 (HIV-1)-infected, antiretroviral naive adults with baseline CD4(+) cell counts of >/=100/mm(3) and plasma HIV-1 RNA levels of >30,000 copies/ml. Data for analysis were obtained from patients who received randomized, blinded monotherapy with abacavir at 100, 300, or 600 mg twice-daily (BID) for up to 12 weeks. Plasma abacavir concentrations from sparse sampling were analyzed by standard population pharmacokinetic methods, and the effects of dose, combination therapy, gender, weight, and age on parameter estimates were investigated. Bayesian pharmacokinetic parameter estimates were calculated to determine the peak concentration of abacavir in plasma (C(max)) and the area under the concentration-time curve from time zero to infinity (AUC(0-infinity)) for individual subjects. The pharmacokinetics of abacavir were dose proportional over the 100- to 600-mg dose range and were unaffected by any covariates. No significant correlations were observed between the incidence of the five most common adverse events (headache, nausea, diarrhea, vomiting, and malaise or fatigue) and AUC(0-infinity). A significant correlation was observed between C(max) and nausea by categorical analysis (P = 0.019), but this was of borderline significance by logistic regression (odds ratio, 1.45; 95% confidence interval, 0.95 to 2.32). The log(10) time-averaged AUC(0-infinity) minus baseline (AAUCMB) values for HIV-1 RNA and CD4(+) cell count correlated significantly with C(max) and AUC(0-infinity), but with better model fits for AUC(0-infinity). The increase in AAUCMB values for CD4(+) cell count plateaued early for drug exposures that were associated with little change in AAUCMB values for plasma HIV-1 RNA. There was less than a 0.4 log(10) difference over 12 weeks in the HIV-1 RNA levels with the doubling of the abacavir AUC(0-infinity) from 300 to 600 mg BID dosing. In conclusion, pharmacodynamic modeling supports the selection of abacavir 300 mg twice-daily dosing.
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PMID:Population pharmacokinetics and pharmacodynamic modeling of abacavir (1592U89) from a dose-ranging, double-blind, randomized monotherapy trial with human immunodeficiency virus-infected subjects. 1089 75

Abacavir (1592U89), once thought to be a promising new nucleoside analog, has some troubling side effects and limitations. It is being made available on a compassionate use program both for children and for adults who meet specific criteria and are failing standard therapy. Little information is available on abacavir from early studies. Side effects have been observed in studies with only a small number of volunteers, and include increased fatigue, changes in liver function tests, and gastrointestinal distress. The drug does not enter cerebrospinal fluid, in spite of early encouraging tests that showed that it might be effective in crossing the blood-brain barrier. In addition, in patients who have developed resistance to other nucleoside analogs, the use of abacavir adds very little anti-HIV effect. Patients are cautioned to wait for new drugs to be developed, unless they are in an emergency situation.
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PMID:Abacavir for children and adults. 1136 30

Abacavir sulfate (Ziagen) received accelerated approval for treatment of HIV infection from the Food and Drug Administration (FDA). It is the fifteenth approved anti-HIV drug. Abacavir, manufactured by Glaxo Wellcome, is currently the most powerful of the nucleoside analogue reverse transcriptase inhibitors (NRTIs). Side effects include nausea, vomiting, fatigue, headache, and diarrhea. A serious hypersensitivity reaction occurs in approximately 5 percent of patients taking the drug. Patients who experience this reaction can never take the drug again, because subsequent reactions can be fatal. Drug interactions may be minimal, as abacavir is not metabolized by the same enzymes that metabolize several other anti-retrovirals. Resistance is also discussed and clinical data from studies are presented.
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PMID:Abacavir sulfate (Ziagen). 1136 89

Abacavir (Ziagen), a nucleoside analog used in combination therapy, can cause a hypersensitivity reaction in as many as five percent of patients. When this reaction occurs, the drug must be stopped immediately and never restarted. The hypersensitivity can cause fever, rash, gastrointestinal symptoms, fatigue, and life-threatening hypotension. The reaction generally occurs in the first six weeks of treatment. The risk of hypersensitivity has long been recognized, but it is often misdiagnosed as a respiratory ailment. Glaxo Wellcome sent out a letter in January 2000 to warn health care providers about the reaction and how to diagnose it; the full text of that letter is included. The manufacturer has also relabeled the drug with stronger warnings; the Web site address is provided for further information on the change in labeling.
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PMID:Abacavir warning: certain respiratory symptoms can indicate hypersensitivity reaction. 1136 10

Abacavir is a nucleoside reverse-transcriptase inhibitor that has been approved for use in combination with other retroviral agents in the treatment of HIV infection. Common adverse reactions include headache, fatigue, nausea, and rash. A fatal hypersensitivity reaction may occur in 5% of patients receiving abacavir; therefore, screening for HLA-B5701 should be performed before starting abacavir. Alopecia areata (AA) is infrequently reported in HIV-infected patients. Certain underlying conditions have been associated with AA, including a decreased CD4:CD8 ratio related to the progression of HIV infection, some opportunistic infections, and syphilis. Several antiretroviral drugs, such as zidovudine, indinavir, indinavir/ritonavir, lopinavir/ritonavir, and atazanavir/ritonavir have been implicated in the development of AA. At present, the occurrence of AA has not been associated with abacavir use. We cannot exclude that the use of abacavir and the development of AA could be coincidental. Nevertheless, patients given abacavir should be monitored for hair loss and the drug discontinued promptly if such signs appear.
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PMID:Alopecia areata associated with abacavir therapy. 2502 72