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Vider E, Gavioli EM. Clinical Safety Considerations of Integrase Strand Transfer Inhibitors in the Older Population Living with HIV. Drugs Aging 2021; 38:967-975. [PMID: 34494229 DOI: 10.1007/s40266-021-00894-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/20/2021] [Indexed: 10/20/2022]
Abstract
There are approximately 40 million people living with HIV globally, and 21% (7.9 million) are older adults (aged > 50 years) as of 2019. The average age of HIV-positive patients is predicted to increase to 58 by 2035. The favorable clinical efficacy of integrase strand transfer inhibitors has led to high rates of viral suppression and have now become the preferred agents by the AIDS guideline when initiating antiretroviral therapy. There are concerns of increasing adverse effects from HIV medications, such as integrase strand transfer inhibitors, as a result of changes in pharmacodynamic and pharmacokinetic parameters within the older population. The authors aim to describe the safety concerns of the current integrase strand transfer inhibitors based upon a narrative literature review, including recommendations for drug-drug interactions, and relevant comorbidities to consider for selection of the most appropriate integrase strand transfer inhibitor for older people living with HIV. Raltegravir is a well-tolerated option with minor adverse events; however, adherence to a twice-daily regimen may be difficult in older patients who are also taking many other medications for various comorbidities. Elvitegravir is also well tolerated with limited adverse effects, but has many drug-drug interactions that may pose problems for older patients with polypharmacy. Dolutegravir has been associated with more frequent adverse events, such as neuropsychiatric disorders.
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Affiliation(s)
- Etty Vider
- LIU Pharmacy (Arnold & Marie Schwartz College of Pharmacy and Health Sciences), 1 University Plaza, Brooklyn, NY, 11201, USA
| | - Elizabeth Marie Gavioli
- LIU Pharmacy (Arnold & Marie Schwartz College of Pharmacy and Health Sciences), 1 University Plaza, Brooklyn, NY, 11201, USA.
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Elliot ER, Wang X, Singh S, Simmons B, Vera JH, Miller RF, Fitzpatrick C, Moyle G, McClure M, Boffito M. Increased Dolutegravir Peak Concentrations in People Living With Human Immunodeficiency Virus Aged 60 and Over, and Analysis of Sleep Quality and Cognition. Clin Infect Dis 2020; 68:87-95. [PMID: 29771285 DOI: 10.1093/cid/ciy426] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 05/12/2018] [Indexed: 12/12/2022] Open
Abstract
Background Demographic data show an increasingly aging human immunodeficiency virus (HIV) population worldwide. Recent concerns over dolutegravir-related neuropsychiatric toxicity have emerged, particularly amongst older people living with HIV (PLWH). We describe the pharmacokinetics (PK) of dolutegravir (DTG) 50 mg once daily in PLWH aged 60 and older. Additionally, to address calls for prospective neuropsychiatric toxicodynamic data, we evaluated changes in sleep quality and cognitive functioning in this population after switching to abacavir (ABC)/lamivudine (3TC)/DTG over 6 months. Methods PLWH ≥60 years with HIV-viral load <50 copies/mL on any non-DTG-based antiretroviral combination were switched to ABC/3TC/DTG. On day 28, 24-hour PK sampling was undertaken. Steady-state PK parameters were compared to a published historical control population aged ≤50 years. We administered 6 validated sleep questionnaires and neurocognitive (Cogstate) testing pre-switch and over 180 days. Results In total, 43 participants enrolled, and 40 completed the PK phase. Overall, 5 discontinued (2 due to sleep-related adverse events, 4.6%). DTG maximum concentration (Cmax) was significantly higher in patients ≥60 years old versus controls (geometric mean 4246 ng/mL versus 3402 ng/mL, P = .005). In those who completed day 180 (n = 38), sleep impairment (Pittsburgh Sleep Quality Index) was marginally higher at day 28 (P = .02), but not at days 90 or 180. Insomnia, daytime functioning, and fatigue test scores did not change statistically over time. Conclusions DTG Cmax was significantly higher in older PLWH. Our data provides clinicians with key information on the safety of prescribing DTG in older PLWH.
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Affiliation(s)
- Emilie R Elliot
- St. Stephen's AIDS Trust-Chelsea and Westminster Hospital, London
| | | | - Suveer Singh
- Imperial College, London.,Chelsea and Westminster Hospital, London
| | | | - Jaime H Vera
- Brighton and Sussex Med School, University College London, United Kingdom
| | - Robert F Miller
- Mortimer Market Centre, Institute for Global Health, University College London, United Kingdom
| | - Colin Fitzpatrick
- Brighton and Sussex Med School, University College London, United Kingdom
| | | | | | - Marta Boffito
- St. Stephen's AIDS Trust-Chelsea and Westminster Hospital, London.,Imperial College, London
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Saidijam M, Karimi Dermani F, Sohrabi S, Patching SG. Efflux proteins at the blood-brain barrier: review and bioinformatics analysis. Xenobiotica 2017; 48:506-532. [PMID: 28481715 DOI: 10.1080/00498254.2017.1328148] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
1. Efflux proteins at the blood-brain barrier provide a mechanism for export of waste products of normal metabolism from the brain and help to maintain brain homeostasis. They also prevent entry into the brain of a wide range of potentially harmful compounds such as drugs and xenobiotics. 2. Conversely, efflux proteins also hinder delivery of therapeutic drugs to the brain and central nervous system used to treat brain tumours and neurological disorders. For bypassing efflux proteins, a comprehensive understanding of their structures, functions and molecular mechanisms is necessary, along with new strategies and technologies for delivery of drugs across the blood-brain barrier. 3. We review efflux proteins at the blood-brain barrier, classified as either ATP-binding cassette (ABC) transporters (P-gp, BCRP, MRPs) or solute carrier (SLC) transporters (OATP1A2, OATP1A4, OATP1C1, OATP2B1, OAT3, EAATs, PMAT/hENT4 and MATE1). 4. This includes information about substrate and inhibitor specificity, structural organisation and mechanism, membrane localisation, regulation of expression and activity, effects of diseases and conditions and the principal technique used for in vivo analysis of efflux protein activity: positron emission tomography (PET). 5. We also performed analyses of evolutionary relationships, membrane topologies and amino acid compositions of the proteins, and linked these to structure and function.
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Affiliation(s)
- Massoud Saidijam
- a Department of Molecular Medicine and Genetics , Research Centre for Molecular Medicine, School of Medicine, Hamadan University of Medical Sciences , Hamadan , Iran and
| | - Fatemeh Karimi Dermani
- a Department of Molecular Medicine and Genetics , Research Centre for Molecular Medicine, School of Medicine, Hamadan University of Medical Sciences , Hamadan , Iran and
| | - Sareh Sohrabi
- a Department of Molecular Medicine and Genetics , Research Centre for Molecular Medicine, School of Medicine, Hamadan University of Medical Sciences , Hamadan , Iran and
| | - Simon G Patching
- b School of BioMedical Sciences and the Astbury Centre for Structural Molecular Biology, University of Leeds , Leeds , UK
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Vanhove T, Bouillon T, de Loor H, Annaert P, Kuypers D. Fexofenadine, a Putative In Vivo P-glycoprotein Probe, Fails to Predict Clearance of the Substrate Tacrolimus in Renal Recipients. Clin Pharmacol Ther 2017; 102:989-996. [PMID: 28437851 DOI: 10.1002/cpt.718] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 04/12/2017] [Accepted: 04/17/2017] [Indexed: 01/22/2023]
Abstract
Whether the combined use of probe drugs for CYP3A4 and P-glycoprotein can clarify the relative contribution of these proteins to pharmacokinetic variability of a dual substrate like tacrolimus has never been assessed. Seventy renal recipients underwent simultaneous 8-h pharmacokinetic profiles for tacrolimus, the CYP3A4 probe midazolam, and the putative P-glycoprotein probe fexofenadine. Patients were genotyped for polymorphisms in CYP3A5, CYP3A4, ABCB1, ABCC2 and SLCO2B1, -1B1, and 1B3. Carriers of the ABCB1 2677G>A polymorphism displayed lower fexofenadine Cmax (-66%; P = 0.012) and a trend toward higher clearance (+157%; P = 0.078). Predictors of tacrolimus clearance were CYP3A5 genotype, midazolam clearance, hematocrit, weight, and age (R2 = 0.61). Fexofenadine pharmacokinetic parameters were not predictive of tacrolimus clearance. In conclusion, fexofenadine pharmacokinetics varied considerably between renal recipients but most of this variability remained unexplained, with only minor effects of genetic polymorphisms. Fexofenadine cannot be used to assess in vivo CYP3A4-P-glycoprotein interplay in tacrolimus-treated renal recipients.
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Affiliation(s)
- T Vanhove
- Department of Microbiology and Immunology, KU Leuven - University of Leuven, and Department of Nephrology and Renal Transplantation, University Hospitals Leuven, Leuven, Belgium
| | - T Bouillon
- Drug Delivery and Disposition, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven - University of Leuven, Leuven, Belgium
| | - H de Loor
- Department of Microbiology and Immunology, KU Leuven - University of Leuven, and Department of Nephrology and Renal Transplantation, University Hospitals Leuven, Leuven, Belgium
| | - P Annaert
- Drug Delivery and Disposition, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven - University of Leuven, Leuven, Belgium
| | - Drj Kuypers
- Department of Microbiology and Immunology, KU Leuven - University of Leuven, and Department of Nephrology and Renal Transplantation, University Hospitals Leuven, Leuven, Belgium
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Reeve E, Trenaman SC, Rockwood K, Hilmer SN. Pharmacokinetic and pharmacodynamic alterations in older people with dementia. Expert Opin Drug Metab Toxicol 2017; 13:651-668. [DOI: 10.1080/17425255.2017.1325873] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Emily Reeve
- NHMRC Cognitive Decline Partnership Centre, Kolling Institute of Medical Research, Northern Clinical School, Faculty of Medicine, University of Sydney, Sydney, Australia
- Geriatric Medicine Research, Faculty of Medicine, Dalhousie University and Nova Scotia Health Authority, Halifax, NS, Canada
| | - Shanna C Trenaman
- Dalhousie University and Nova Scotia Health Authority, Halifax, NS, Canada
| | - Kenneth Rockwood
- Geriatric Medicine Research, Faculty of Medicine, Dalhousie University and Nova Scotia Health Authority, Halifax, NS, Canada
- Division of Geriatric Medicine, Dalhousie University, Halifax, NS, Canada
- DGI Clinical Inc., Halifax, Canada
| | - Sarah N Hilmer
- NHMRC Cognitive Decline Partnership Centre, Kolling Institute of Medical Research, Northern Clinical School, Faculty of Medicine, University of Sydney, Sydney, Australia
- Departments of Aged Care and Clinical Pharmacology, Royal North Shore Hospital, St Leonards, NSW, Australia
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Merchant HA, Liu F, Orlu Gul M, Basit AW. Age-mediated changes in the gastrointestinal tract. Int J Pharm 2016; 512:382-395. [DOI: 10.1016/j.ijpharm.2016.04.024] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 03/22/2016] [Accepted: 04/12/2016] [Indexed: 12/21/2022]
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Understanding alterations in drug handling with aging: a focus on the pharmacokinetics of maintenance immunosuppressants in the elderly. Curr Opin Organ Transplant 2015; 20:424-30. [PMID: 26126198 DOI: 10.1097/mot.0000000000000220] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW This review presents current knowledge of the impact of age on the pharmacokinetics of maintenance immunosuppressants. RECENT FINDINGS Over the past decade, there has been a steady increase in older patients on organ transplant waiting lists. As a result, the average age of transplant recipients has significantly increased. The survival and quality-of-life benefits of transplantation in the elderly population have been demonstrated. Advancing age is associated with changes in immune responses, as well as changes in drug handling. Immunosenescence is a physiological part of aging and is linked to reduced rejection rates, but also higher rates of diabetes, infections and malignancies. Physiologic changes associated with age can have a significant impact on the pharmacokinetics of the maintenance immunosuppressive agents. Taken together, these age-related changes impact older transplant candidates and may have significant implications for managing immunosuppression in the elderly. SUMMARY Despite the lack of formal efficacy, safety and pharmacokinetic studies of individual immunosuppressants in the elderly transplant population, there are enough data available for practitioners to be able to adequately manage their older patients. A proficient understanding of the factors that impact the pharmacokinetics of the immunosuppressants in the elderly is essential to managing these patients successfully.
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Reeve E, Wiese MD, Mangoni AA. Alterations in drug disposition in older adults. Expert Opin Drug Metab Toxicol 2015; 11:491-508. [DOI: 10.1517/17425255.2015.1004310] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Guo M, Bughio S, Sun Y, Zhang Y, Dong L, Dai X, Wang L. Age-related P-glycoprotein expression in the intestine and affecting the pharmacokinetics of orally administered enrofloxacin in broilers. PLoS One 2013; 8:e74150. [PMID: 24066110 PMCID: PMC3774662 DOI: 10.1371/journal.pone.0074150] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 07/27/2013] [Indexed: 01/02/2023] Open
Abstract
Bioavailability is the most important factor for the efficacy of any drug and it is determined by P- glycoprotein (P-gp) expression. Confirmation of P-gp expression during ontogeny is needed for understanding the differences in therapeutic efficacy of any drug in juvenile and adult animals. In this study, Abcb1 mRNA levels in the liver and intestine of broilers during ontogeny were analysed by RT qPCR. Cellular distribution of P-gp was detected by immunohistochemstry. Age-related differences of enrofloxacin pharmacokinetics were also studied. It was found that broilers aged 4 week-old expressed significantly (P<0.01) higher levels of P-gp mRNA in the liver, jejunum and ileum, than at other ages. However, there was no significant (P>0.05) age-related difference in the duodenum. Furthermore, the highest and lowest levels of Abcb1 mRNA expression were observed in the jejunum, and duodenum, respectively. P-gp immunoreactivity was detected on the apical surface of the enterocytes and in the bile canalicular membranes of the hepatocytes. Pharmacokinetic analysis revealed that the 8 week-old broilers, when orally administrated enrofloxacin, exhibited significantly higher Cmax (1.97 vs. 0.98 μg•ml-1, P=0.009), AUC(14.54 vs. 9.35 μg•ml-1•h, P=0.005) and Ka (1.38 vs. 0.43 h-1, P=0.032), as well as lower Tpeak (1.78 vs. 3.28 h, P=0.048) and T1/2ka (0.6 vs. 1.64 h, P=0.012) than the 4 week-old broilers. The bioavailability of enrofloxacin in 8 week-old broilers was increased by 15.9%, compared with that in 4 week-old birds. Interestingly, combining verapamil, a P-gp modulator, significantly improved pharmacokinetic behaviour of enrofloxacin in all birds. The results indicate juvenile broilers had a higher expression of P-gp in the intestine, affecting the pharmacokinetics and reducing the bioavailability of oral enrofloxacin in broilers. On the basis of our results, it is recommended that alternative dose regimes are necessary for different ages of broilers for effective therapy.
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Affiliation(s)
- Mengjie Guo
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, P. R. China
| | - Shamsuddin Bughio
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, P. R. China
| | - Yong Sun
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, P. R. China
| | - Yu Zhang
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, P. R. China
| | - Lingling Dong
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, P. R. China
| | - Xiaohua Dai
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, P. R. China
| | - Liping Wang
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, P. R. China
- * E-mail:
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COX SR, LIAO S, PAYNE-JOHNSON M, ZIELINSKI RJ, STEGEMANN MR. Population pharmacokinetics of mavacoxib in osteoarthritic dogs. J Vet Pharmacol Ther 2011; 34:1-11. [DOI: 10.1111/j.1365-2885.2010.01183.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Jeannesson E, Siest G, Herbeth B, Albertini L, Shahabi P, Pfister M, Visvikis-Siest S. Biological and genetic factors associated with ABCB1 and pregnane-X-receptor expressions in peripheral blood mononuclear cells in the STANISLAS cohort. ACTA ACUST UNITED AC 2011; 26:27-32. [DOI: 10.1515/dmdi.2011.102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Modric S, Martinez M. Patient variation in veterinary medicine--part II--influence of physiological variables. J Vet Pharmacol Ther 2010; 34:209-23. [PMID: 21083665 DOI: 10.1111/j.1365-2885.2010.01249.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In veterinary medicine, the characterization of a drug's pharmacokinetic properties is generally based upon data that are derived from studies that employ small groups of young healthy animals, often of a single breed. In Part I of the series, we focused on the potential influence of disease processes, stress, pregnancy and lactation on drug pharmacokinetics. In this Part II of the series, we consider other covariates, such as gender, heritable traits, age, body composition, and circadian rhythms. The impact of these factors with respect to predicting the relationship between dose and drug exposure characteristics within an animal population is illustrated through the use of Monte Carlo simulations. Ultimately, an appreciation of these potential influences will improve the prediction of situations when dose adjustments may be appropriate.
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Affiliation(s)
- S Modric
- Center for Veterinary Medicine (CVM), Office of New Animal Drug Evaluation, Food and Drug Administration (FDA), Rockville, MD 20855, USA
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Blood–brain barrier P-glycoprotein function decreases in specific brain regions with aging: A possible role in progressive neurodegeneration. Neurobiol Aging 2009; 30:1818-24. [DOI: 10.1016/j.neurobiolaging.2008.02.002] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Revised: 01/11/2008] [Accepted: 02/05/2008] [Indexed: 11/22/2022]
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Pekcec A, Schneider EL, Baumgärtner W, Stein VM, Tipold A, Potschka H. Age-dependent decline of blood-brain barrier P-glycoprotein expression in the canine brain. Neurobiol Aging 2009; 32:1477-85. [PMID: 19836857 DOI: 10.1016/j.neurobiolaging.2009.08.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 08/12/2009] [Accepted: 08/25/2009] [Indexed: 11/18/2022]
Abstract
The efflux transporter P-glycoprotein serves as a major molecular gatekeeper at the blood-brain barrier. It has been suggested that a reduction of P-glycoprotein activity with aging might enhance exposure of brain tissue to exogenous and endogenous compounds thereby contributing to the development of neurodegenerative diseases. Brain tissue from owner-kept dogs renders an excellent tool to study the impact of aging on the background of variable environmental and genetic influencing factors. Therefore, we determined expression rates of P-glycoprotein in canine post-mortem tissue from 23 non-laboratory dogs. P-glycoprotein expression in the parahippocampal cortex exhibited a negative correlation with age. Analysis of the area labeled for P-glycoprotein in dogs aged >100 months revealed a 72% drop in P-glycoprotein expression as compared to young adults aged 23-36 months. Respective data from the dentate hilus and dentate gyrus indicated an earlier drop with a reduction by 77 and 80% in dogs aged 37-99 months in comparison with younger individuals. In contrast to the decline observed with aging in dogs without plaques, P-glycoprotein expression rates rather tended to increase with further aging in dogs with plaque formation. In conclusion, the thorough analysis of P-glycoprotein expression rates in non-laboratory dogs revealed a significant decline with aging. The data strongly support the concept that age-dependent changes might predispose to neurodegenerative diseases. In the early pathogenesis of Alzheimer's disease which is modelled by diffuse plaques in the canine brain, an up-regulation of P-glycoprotein might act as a compensatory mechanism to enhance Abeta efflux from the brain. Future studies are necessary to further evaluate the correlation between Abeta deposits and P-glycoprotein expression in different phases of the disease.
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Affiliation(s)
- A Pekcec
- Inst. of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Koeniginstr. 16, 80539 Munich, Germany
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Imaging the function of P-glycoprotein with radiotracers: pharmacokinetics and in vivo applications. Clin Pharmacol Ther 2009; 86:368-77. [PMID: 19625998 DOI: 10.1038/clpt.2009.138] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
P-glycoprotein (P-gp), an efflux transporter, controls the pharmacokinetics of various compounds under physiological conditions. P-gp-mediated drug efflux has been suggested as playing a role in various disorders, including multidrug-resistant cancer and medication-refractory epilepsy. However, P-gp inhibition has had, to date, little or no clinically significant effect in multidrug-resistant cancer. To enhance our understanding of its in vivo function under pathophysiological conditions, substrates of P-gp have been radiolabeled and imaged using single-photon emission computed tomography (SPECT) and positron emission tomography (PET). To accurately quantify P-gp function, a radiolabeled P-gp substrate should be selective for P-gp, produce a large signal after P-gp blockade, and generate few radiometabolites that enter the target tissue. Furthermore, quantification of P-gp function via imaging requires pharmacological inhibition of P-gp, which requires knowledge of P-gp density at the target site. By meeting these criteria, imaging can elucidate the function of P-gp in various disorders and improve the efficacy of treatments.
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The clinical implications of ageing for rational drug therapy. Eur J Clin Pharmacol 2008; 64:183-99. [PMID: 18180915 DOI: 10.1007/s00228-007-0422-1] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Accepted: 11/16/2007] [Indexed: 12/22/2022]
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