Abstract
There are several clinical scenarios in which knowledge of zidovudine disposition may be important. This study evaluated the clinical utility of pharmacokinetic parameters for zidovudine derived from sparse serum concentration data obtained in an outpatient setting. Twelve human immunodeficiency virus-infected participants had two serum zidovudine concentrations determinations obtained on two different clinic visits, 2 to 38 days apart. Zidovudine concentrations were measured by radioimmunoassay. A one-compartment oral absorption model was used to describe zidovudine disposition. Three different approaches were used to estimate pharmacokinetic parameters: Bayesian estimation with one or two concentrations and least squares with one concentration. The ability of these parameters to predict concentrations measured during the second clinic visit was assessed by calculation of precision and bias and compared with predictions using standard fixed or weight-adjusted parameters. Estimated pharmacokinetic parameters for zidovudine were consistent with literature values; there was no statistically significant difference among the parameters calculated with the three estimation strategies. Absorptive phase concentrations were poorly predicted by all methods (mean percent bias, 157 to 249%; mean percent precision, 389 to 537%). Predictive ability for concentrations obtained in the elimination phase was strikingly improved: mean percent bias, -17 to 70%; mean percent precision, 40 to 95%. Bayesian and least-squares estimated parameters were statistically better than fixed-parameter values for predicting concentrations in the elimination phase. These observations provide a modeling framework to determine pharmacokinetic disposition of zidovudine in an individual, screen for the existence of a drug interaction, and conduct concentration-controlled clinical trials.
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Selected References
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- Blum M. R., Liao S. H., Good S. S., de Miranda P. Pharmacokinetics and bioavailability of zidovudine in humans. Am J Med. 1988 Aug 29;85(2A):189–194. [PubMed] [Google Scholar]
- Burger D. M., Meenhorst P. L., Koks C. H., Beijnen J. H. Pharmacokinetic interaction between rifampin and zidovudine. Antimicrob Agents Chemother. 1993 Jul;37(7):1426–1431. doi: 10.1128/aac.37.7.1426. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Burger D. M., Meenhorst P. L., ten Napel C. H., Mulder J. W., Neef C., Koks C. H., Bult A., Beijnen J. H. Pharmacokinetic variability of zidovudine in HIV-infected individuals: subgroup analysis and drug interactions. AIDS. 1994 Dec;8(12):1683–1689. doi: 10.1097/00002030-199412000-00007. [DOI] [PubMed] [Google Scholar]
- Cappell M. S., Schwartz M. S., Biempica L. Clinical utility of liver biopsy in patients with serum antibodies to the human immunodeficiency virus. Am J Med. 1990 Feb;88(2):123–130. doi: 10.1016/0002-9343(90)90460-u. [DOI] [PubMed] [Google Scholar]
- Collart L., Blaschke T. F., Boucher F., Prober C. G. Potential of population pharmacokinetics to reduce the frequency of blood sampling required for estimating kinetic parameters in neonates. Dev Pharmacol Ther. 1992;18(1-2):71–80. [PubMed] [Google Scholar]
- D'Argenio D. Z., Schumitzky A., Wolf W. Simulation of linear compartment models with application to nuclear medicine kinetic modeling. Comput Methods Programs Biomed. 1988 Jul-Aug;27(1):47–54. doi: 10.1016/0169-2607(88)90102-2. [DOI] [PubMed] [Google Scholar]
- Drusano G. L., Balis F. M., Gitterman S. R., Pizzo P. A. Quantitative relationships between zidovudine exposure and efficacy and toxicity. Antimicrob Agents Chemother. 1994 Aug;38(8):1726–1731. doi: 10.1128/aac.38.8.1726. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fischl M. A., Parker C. B., Pettinelli C., Wulfsohn M., Hirsch M. S., Collier A. C., Antoniskis D., Ho M., Richman D. D., Fuchs E. A randomized controlled trial of a reduced daily dose of zidovudine in patients with the acquired immunodeficiency syndrome. The AIDS Clinical Trials Group. N Engl J Med. 1990 Oct 11;323(15):1009–1014. doi: 10.1056/NEJM199010113231501. [DOI] [PubMed] [Google Scholar]
- Fischl M. A., Richman D. D., Grieco M. H., Gottlieb M. S., Volberding P. A., Laskin O. L., Leedom J. M., Groopman J. E., Mildvan D., Schooley R. T. The efficacy of azidothymidine (AZT) in the treatment of patients with AIDS and AIDS-related complex. A double-blind, placebo-controlled trial. N Engl J Med. 1987 Jul 23;317(4):185–191. doi: 10.1056/NEJM198707233170401. [DOI] [PubMed] [Google Scholar]
- Fischl M. A., Richman D. D., Hansen N., Collier A. C., Carey J. T., Para M. F., Hardy W. D., Dolin R., Powderly W. G., Allan J. D. The safety and efficacy of zidovudine (AZT) in the treatment of subjects with mildly symptomatic human immunodeficiency virus type 1 (HIV) infection. A double-blind, placebo-controlled trial. The AIDS Clinical Trials Group. Ann Intern Med. 1990 May 15;112(10):727–737. doi: 10.7326/0003-4819-112-10-727. [DOI] [PubMed] [Google Scholar]
- Fletcher C. V., Rhame F. S., Beatty C. C., Simpson M., Balfour H. H., Jr Comparative pharmacokinetics of zidovudine in healthy volunteers and in patients with AIDS with and without hepatic disease. Pharmacotherapy. 1992;12(6):429–434. [PubMed] [Google Scholar]
- Gitterman S. R., Drusano G. L., Egorin M. J., Standiford H. C. Population pharmacokinetics of zidovudine. The Veterans Administration Cooperative Studies Group. Clin Pharmacol Ther. 1990 Aug;48(2):161–167. doi: 10.1038/clpt.1990.131. [DOI] [PubMed] [Google Scholar]
- Hedaya M. A., Elmquist W. F., Sawchuk R. J. Probenecid inhibits the metabolic and renal clearances of zidovudine (AZT) in human volunteers. Pharm Res. 1990 Apr;7(4):411–417. doi: 10.1023/a:1015835826114. [DOI] [PubMed] [Google Scholar]
- Kotler D. P., Gaetz H. P., Lange M., Klein E. B., Holt P. R. Enteropathy associated with the acquired immunodeficiency syndrome. Ann Intern Med. 1984 Oct;101(4):421–428. doi: 10.7326/0003-4819-101-4-421. [DOI] [PubMed] [Google Scholar]
- Lake-Bakaar G., Tom W., Lake-Bakaar D., Gupta N., Beidas S., Elsakr M., Straus E. Gastropathy and ketoconazole malabsorption in the acquired immunodeficiency syndrome (AIDS). Ann Intern Med. 1988 Sep 15;109(6):471–473. doi: 10.7326/0003-4819-109-6-471. [DOI] [PubMed] [Google Scholar]
- Mentré F., Escolano S., Diquet B., Golmard J. L., Mallet A. Clinical pharmacokinetics of zidovudine: inter and intraindividual variability and relationship to long term efficacy and toxicity. Eur J Clin Pharmacol. 1993;45(5):397–407. doi: 10.1007/BF00315509. [DOI] [PubMed] [Google Scholar]
- Rao T. K., Friedman E. A., Nicastri A. D. The types of renal disease in the acquired immunodeficiency syndrome. N Engl J Med. 1987 Apr 23;316(17):1062–1068. doi: 10.1056/NEJM198704233161705. [DOI] [PubMed] [Google Scholar]
- Sahai J., Gallicano K., Ormsby E., Garber G., Cameron D. W. Relationship between body weight, body surface area and serum zidovudine pharmacokinetic parameters in adult, male HIV-infected patients. AIDS. 1994 Jun;8(6):793–796. doi: 10.1097/00002030-199406000-00011. [DOI] [PubMed] [Google Scholar]
- Sahai J., Gallicano K., Pakuts A., Cameron D. W. Effect of fluconazole on zidovudine pharmacokinetics in patients infected with human immunodeficiency virus. J Infect Dis. 1994 May;169(5):1103–1107. doi: 10.1093/infdis/169.5.1103. [DOI] [PubMed] [Google Scholar]
- Sale M., Sheiner L. B., Volberding P., Blaschke T. F. Zidovudine response relationships in early human immunodeficiency virus infection. Clin Pharmacol Ther. 1993 Nov;54(5):556–566. doi: 10.1038/clpt.1993.188. [DOI] [PubMed] [Google Scholar]
- Sande M. A., Carpenter C. C., Cobbs C. G., Holmes K. K., Sanford J. P. Antiretroviral therapy for adult HIV-infected patients. Recommendations from a state-of-the-art conference. National Institute of Allergy and Infectious Diseases State-of-the-Art Panel on Anti-Retroviral Therapy for Adult HIV-Infected Patients. JAMA. 1993 Dec 1;270(21):2583–2589. doi: 10.1001/jama.270.21.2583. [DOI] [PubMed] [Google Scholar]
- Sheiner L. B., Beal S. L. Some suggestions for measuring predictive performance. J Pharmacokinet Biopharm. 1981 Aug;9(4):503–512. doi: 10.1007/BF01060893. [DOI] [PubMed] [Google Scholar]
- Ullrich R., Zeitz M., Heise W., L'age M., Höffken G., Riecken E. O. Small intestinal structure and function in patients infected with human immunodeficiency virus (HIV): evidence for HIV-induced enteropathy. Ann Intern Med. 1989 Jul 1;111(1):15–21. doi: 10.7326/0003-4819-111-1-15. [DOI] [PubMed] [Google Scholar]
- Volberding P. A., Lagakos S. W., Koch M. A., Pettinelli C., Myers M. W., Booth D. K., Balfour H. H., Jr, Reichman R. C., Bartlett J. A., Hirsch M. S. Zidovudine in asymptomatic human immunodeficiency virus infection. A controlled trial in persons with fewer than 500 CD4-positive cells per cubic millimeter. The AIDS Clinical Trials Group of the National Institute of Allergy and Infectious Diseases. N Engl J Med. 1990 Apr 5;322(14):941–949. doi: 10.1056/NEJM199004053221401. [DOI] [PubMed] [Google Scholar]