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Pernaute-Lau L, Camara M, Nóbrega de Sousa T, Morris U, Ferreira MU, Gil JP. An update on pharmacogenetic factors influencing the metabolism and toxicity of artemisinin-based combination therapy in the treatment of malaria. Expert Opin Drug Metab Toxicol 2022; 18:39-59. [PMID: 35285373 DOI: 10.1080/17425255.2022.2049235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Artemisinin-based combination therapies (ACTs) are recommended first-line antimalarials for uncomplicated Plasmodium falciparum malaria. Pharmacokinetic/pharmacodynamic variation associated with ACT drugs and their effect is documented. It is accepted to an extent that inter-individual variation is genetically driven, and should be explored for optimized antimalarial use. AREAS COVERED We provide an update on the pharmacogenetics of ACT antimalarial disposition. Beyond presently used antimalarials, we also refer to information available for the most notable next-generation drugs under development. The bibliographic approach was based on multiple Boolean searches on PubMed covering all recent publications since our previous review. EXPERT OPINION The last 10 years have witnessed an increase in our knowledge of ACT pharmacogenetics, including the first clear examples of its contribution as an exacerbating factor for drug-drug interactions. This knowledge gap is still large and is likely to widen as a new wave of antimalarial drug is looming, with few studies addressing their pharmacogenetics. Clinically useful pharmacogenetic markers are still not available, in particular, from an individual precision medicine perspective. A better understanding of the genetic makeup of target populations can be valuable for aiding decisions on mass drug administration implementation concerning region-specific antimalarial drug and dosage options.
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Affiliation(s)
- Leyre Pernaute-Lau
- Department of Microbiology, Tumor and Cell biology, Karolinska Institutet, Solna, Sweden.,Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, University of Lisbon, Lisbon, 1749-016, Portugal
| | - Mahamadou Camara
- Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Malaria Research and Training Center, University of Science, Techniques and Technologies of Bamako, Bamako, Mali
| | - Taís Nóbrega de Sousa
- Molecular Biology and Malaria Immunology Research Group, Instituto René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Brasil
| | - Ulrika Morris
- Department of Microbiology, Tumor and Cell biology, Karolinska Institutet, Solna, Sweden
| | - Marcelo Urbano Ferreira
- Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, University of Lisbon, Lisbon, 1749-016, Portugal.,Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - José Pedro Gil
- Department of Microbiology, Tumor and Cell biology, Karolinska Institutet, Solna, Sweden.,Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, University of Lisbon, Lisbon, 1749-016, Portugal.,Global Health and Tropical Medicine, Institute of Hygiene and Tropical Medicine, Nova University of Lisbon, Portugal
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Chalon S, Chughlay MF, Abla N, Marie Tchouatieu A, Haouala A, Hutter B, Lorch U, Macintyre F. Unanticipated CNS Safety Signal in a Placebo-Controlled, Randomized Trial of Co-Administered Atovaquone-Proguanil and Amodiaquine. Clin Pharmacol Ther 2021; 111:867-877. [PMID: 34453327 PMCID: PMC9291514 DOI: 10.1002/cpt.2404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 07/29/2021] [Indexed: 01/28/2023]
Abstract
Atovaquone‐proguanil (ATV‐PG) plus amodiaquine (AQ) has been considered as a potential replacement for sulfadoxine‐pyrimethamine plus AQ for seasonal malaria chemoprevention in African children. This randomized, double‐blind, placebo‐controlled, parallel group study assessed the safety, tolerability, and pharmacokinetics (PKs) of ATV‐PG plus AQ in healthy adult males and females of Black sub‐Saharan African origin. Participants were randomized to four treatment groups: ATV‐PG/AQ (n = 8), ATV‐PG/placebo (n = 12), AQ/placebo (n = 12), and placebo/placebo (n = 12). Treatments were administered orally once daily for 3 days (days 1–3) at daily doses of ATV‐PQ 1000/400 mg and AQ 612 mg. Co‐administration of ATV‐PG/AQ had no clinically relevant effect on PK parameters for ATV, PG, the PG metabolite cycloguanil, AQ, or the AQ metabolite N‐desethyl‐amodiaquine. Adverse events occurred in 8 of 8 (100%) of participants receiving ATV‐PG/AQ, 11 of 12 (91.7%) receiving ATV‐PG, 11 of 12 (91.7%) receiving AQ, and 3 of 12 (25%) receiving placebo. The safety and tolerability profiles of ATV‐PG and AQ were consistent with previous reports. In the ATV‐PG/AQ group, 2 of 8 participants experienced extrapyramidal adverse effects (EPAEs) on day 3, both psychiatric and physical, which appeared unrelated to drug plasma PKs or cytochrome P450 2C8 phenotype. Although rare cases are reported with AQ administration, the high incidence of EPAE was unexpected in this small study. Owing to the unanticipated increased frequency of EPAE observed, the combination of ATV‐PQ plus AQ is not recommended for further evaluation in prophylaxis of malaria in African children.
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Affiliation(s)
| | | | - Nada Abla
- Medicines for Malaria Venture, Geneva, Switzerland
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Munoz-Tello P, Lin H, Khan P, de Vera IMS, Kamenecka TM, Kojetin DJ. Assessment of NR4A Ligands That Directly Bind and Modulate the Orphan Nuclear Receptor Nurr1. J Med Chem 2020; 63:15639-15654. [PMID: 33289551 PMCID: PMC8006468 DOI: 10.1021/acs.jmedchem.0c00894] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Nurr1/NR4A2 is an orphan nuclear receptor transcription factor implicated as a drug target for neurological disorders including Alzheimer's and Parkinson's diseases. Previous studies identified small-molecule NR4A nuclear receptor modulators, but it remains unclear if these ligands affect transcription via direct binding to Nurr1. We assessed 12 ligands reported to affect NR4A activity for Nurr1-dependent and Nurr1-independent transcriptional effects and the ability to bind the Nurr1 ligand-binding domain (LBD). Protein NMR structural footprinting data show that amodiaquine, chloroquine, and cytosporone B bind the Nurr1 LBD; ligands that do not bind include C-DIM12, celastrol, camptothecin, IP7e, isoalantolactone, ethyl 2-[2,3,4-trimethoxy-6-(1-octanoyl)phenyl]acetate (TMPA), and three high-throughput screening hit derivatives. Importantly, ligands that modulate Nurr1 transcription also show Nurr1-independent effects on transcription in a cell type-specific manner, indicating that care should be taken when interpreting the functional response of these ligands in transcriptional assays. These findings should help focus medicinal chemistry efforts that desire to optimize Nurr1-binding ligands.
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Affiliation(s)
- Paola Munoz-Tello
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, FL, 33458, USA
| | - Hua Lin
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, Florida 33458, USA
| | - Pasha Khan
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, Florida 33458, USA
| | - Ian Mitchelle S. de Vera
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, FL, 33458, USA
| | - Theodore M. Kamenecka
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, Florida 33458, USA
| | - Douglas J. Kojetin
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, FL, 33458, USA
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, Florida 33458, USA
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Adepiti AO, Adeagbo BA, Adehin A, Bolaji OO, Elujoba AA. Influence of MAMA decoction, an Herbal Antimalarial, on the Pharmacokinetics of Amodiaquine in Mice. Eur J Drug Metab Pharmacokinet 2019; 45:81-88. [PMID: 31642009 DOI: 10.1007/s13318-019-00583-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND AND OBJECTIVE MAMA decoction (MD) is an antimalarial product prepared from the leaves of Mangifera indica L. (Anacardiaceae), Alstonia boonei De Wild (Apocynaceae), Morinda lucida Benth (Rubiaceae) and Azadirachta indica A. Juss (Meliaceae). A previous report showed that MD enhanced the efficacy of amodiaquine (AQ) in malaria-infected mice, thus suggesting a herb-drug interaction. The present study hence evaluated the effect of MD on the disposition of AQ in mice with a view to investigating a possible pharmacokinetic interaction. METHODS In a 3-period study design, three groups of mice (n = 72) were administered oral doses of AQ (10 mg/kg/day) alone, concurrently with MD (120 mg/kg/day), and in the 3rd period, mice were given AQ after a 3-day pre-treatment with MD. Blood samples were collected between 0 and 96 h for quantification of AQ and its major metabolite, desethylamodiaquine, by a validated high-performance liquid chromatography method. RESULTS Maximum concentrations of AQ increased by 12% with the concurrent dosing of MD and by 85% in the group of mice pre-treated with MD. The exposure and half-life of desethylamodiaquine increased by approximately 11% and 21%, respectively, with concurrent administration. Corresponding increases of approximately 20% and 33% of desethylamodiaquine were also observed in mice pre-treated with MD. CONCLUSION MD influenced the pharmacokinetics of AQ and desethylamodiaquine, its major metabolite. The increase in the half-life and systemic exposure of AQ following its co-administration with MD may provide a basis for the enhanced pharmacological effect of the combination in an earlier study in Plasmodium-infected mice.
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Affiliation(s)
- Awodayo O Adepiti
- Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, 220005, Osun State, Nigeria.
| | - Babatunde A Adeagbo
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, 220005, Nigeria
| | - Ayorinde Adehin
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, 220005, Nigeria
| | - Oluseye O Bolaji
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, 220005, Nigeria
| | - Anthony A Elujoba
- Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, 220005, Osun State, Nigeria
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Abstract
CONTEXT Co-administration of amodiaquine with MAMA decoction (MD), an herbal antimalarial drug comprising the leaves of Mangifera indica L. (Anacardiaceae), Alstonia boonei De Wild (Apocynaceae), Morinda lucida Benth (Rubiaceae) and Azadirachta indica A. Juss (Meliaceae) was investigated. The practice of concurrent administration of herbal medicines with orthodox drugs is currently on the increase globally. OBJECTIVE The study was designed to investigate the possible enhancement of the antimalarial potency as well as possible herb-drug interaction resulting from concurrent administration of MAMA decoction with amodiaquine (AQ). MATERIALS AND METHODS Combinations of MD with AQ were investigated in chloroquine (CQ)-sensitive Plasmodium berghei NK 65 in varying oral doses (mg/kg) at: sub-therapeutic [MD30 + AQ1.25], therapeutic [MD120 + AQ10] and median effective [MD40 + AQ3.8], using chemosuppressive and curative antimalarial test models. Secondly, P. berghei ANKA (CQ-resistant)-infected mice were orally treated with MD 120, 240, [MD120 + AQ10] and [MD240 + AQ10] mg/kg, using both models. The survival times of mice were monitored for 28 d. RESULTS ED50 values of MD and AQ were 48.8 and 4.1 mg/kg, respectively. A total parasite clearance of CQ-sensitive P. berghei NK65 was obtained with the therapeutic combination dose in the curative test giving an enhanced survival time. In CQ-resistant P. berghei ANKA-infected mice, [MD120 + AQ10] and [MD240 + AQ10] mg/kg gave comparable activities with AQ (10 mg/kg) in both models. CONCLUSION The therapeutic combination dose gave total parasite clearance of CQ-sensitive P. berghei NK65, whereas none of the doses tested showed notable activity against CQ-resistant P. berghei ANKA.
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Affiliation(s)
- Awodayo O Adepiti
- a Department of Pharmacognosy , Obafemi Awolowo University , Ile-Ife , Nigeria
| | - Anthony A Elujoba
- a Department of Pharmacognosy , Obafemi Awolowo University , Ile-Ife , Nigeria
| | - Oluseye O Bolaji
- b Department of Pharmaceutical Chemistry , Obafemi Awolowo University , Ile-Ife , Nigeria
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Adedeji ON, Bolaji OO, Falade CO, Osonuga OA, Ademowo OG. Validation and pharmacokinetic application of a high-performance liquid chromatographic technique for determining the concentrations of amodiaquine and its metabolite in plasma of patients treated with oral fixed-dose amodiaquine-artesunate combination in areas of malaria endemicity. Antimicrob Agents Chemother 2015; 59:5114-22. [PMID: 25896711 DOI: 10.1128/AAC.04957-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 04/05/2015] [Indexed: 11/20/2022] Open
Abstract
Artemisinin-based combination therapies (ACTs) have been adopted by most African countries, including Nigeria, as first-line treatments for uncomplicated falciparum malaria. Fixed-dose combinations of these ACTs, amodiaquine-artesunate (FDC AQAS) and artemether-lumefantrine (AL), were introduced in Nigeria to improve compliance and achieve positive outcomes of malaria treatment. In order to achieve clinical success with AQAS, we developed and validated a simple and sensitive high-performance liquid chromatography (HPLC) method with UV detection for determination of amodiaquine (AQ) and desethylamodiaquine (DAQ) in plasma using liquid-liquid extraction of the drugs with diethyl ether following protein precipitation with acetonitrile. Chromatographic separation was achieved using an Agilent Zorbax C18 column and a mobile phase consisting of distilled water-methanol (80:20 [vol/vol]) with 2% (vol/vol) triethylamine, pH 2.2, at a flow rate of 1 ml/min. Calibration curves in spiked plasma were linear from 100 to 1,000 ng/ml (r > 0.99) for both AQ and DAQ. The limit of detection was 1 ng (sample size, 20 μl). The intra- and interday coefficients of variation at 150, 300, and 900 ng/ml ranged from 1.3 to 4.8%, and the biases were between 6.4 and 9.5%. The mean extraction recoveries of AQ and DAQ were 80.0% and 68.9%, respectively. The results for the pharmacokinetic parameters of DAQ following oral administration of FDC AQAS (612/200 mg) for 3 days in female and male patients with uncomplicated falciparum malaria showed that the maximum plasma concentrations (C max) (740 ± 197 versus 767 ± 185 ng/ml), areas under the plasma concentration-time curve (AUC) (185,080 ± 20,813 versus 184,940 ± 16,370 h · ng/ml), and elimination half-life values (T 1/2) (212 ± 1.14 versus 214 ± 0.84 h) were similar (P > 0.05).
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Yu DS. A study of an effective sunitinib–chemotherapeutic combination regimen for bladder cancer treatment using a mouse model. Urological Science 2014. [DOI: 10.1016/j.urols.2013.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Abstract
Cerebral malaria (CM), caused by Plasmodium falciparum infection, is a prevalent neurological disorder in the tropics. Most of the patients are children, typically with intractable seizures and high mortality. Current treatment is unsatisfactory. Understanding the pathogenesis of CM is required in order to identify therapeutic targets. Here, we argue that cerebral energy metabolic defects are probable etiological factors in CM pathogenesis, because malaria parasites consume large amounts of glucose metabolized mostly to lactate. Monocarboxylate transporters (MCTs) mediate facilitated transfer, which serves to equalize lactate concentrations across cell membranes in the direction of the concentration gradient. The equalizing action of MCTs is the basis for lactate’s role as a volume transmitter of metabolic signals in the brain. Lactate binds to the lactate receptor GPR81, recently discovered on brain cells and cerebral blood vessels, causing inhibition of adenylyl cyclase. High levels of lactate delivered by the parasite at the vascular endothelium may damage the blood–brain barrier, disrupt lactate homeostasis in the brain, and imply MCTs and the lactate receptor as novel therapeutic targets in CM.
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Affiliation(s)
- Shelton T Mariga
- Department of Neuroscience and Pharmacology, University of Copenhagen Copenhagen, Denmark
| | - Miriam Kolko
- Department of Neuroscience and Pharmacology, University of Copenhagen Copenhagen, Denmark ; Department of Ophthalmology, Roskilde Hospital Roskilde, Denmark
| | - Albert Gjedde
- Department of Neuroscience and Pharmacology, University of Copenhagen Copenhagen, Denmark
| | - Linda H Bergersen
- Department of Neuroscience and Pharmacology, University of Copenhagen Copenhagen, Denmark ; The Brain and Muscle Energy Group and SN-Lab, Department of Anatomy and Department of Oral Biology, Institute of Basic Medical Sciences and Centre for Molecular Biology and Neuroscience/SERTA Healthy Brain Aging Centre, University of Oslo Oslo, Norway
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Ongarora DS, Gut J, Rosenthal PJ, Masimirembwa CM, Chibale K. Benzoheterocyclic amodiaquine analogues with potent antiplasmodial activity: Synthesis and pharmacological evaluation. Bioorg Med Chem Lett 2012; 22:5046-50. [DOI: 10.1016/j.bmcl.2012.06.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 06/01/2012] [Accepted: 06/04/2012] [Indexed: 11/27/2022]
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Wu CL, Ping SY, Yu CP, Yu DS. Tyrosine kinase receptor inhibitor-targeted combined chemotherapy for metastatic bladder cancer. Kaohsiung J Med Sci 2012; 28:194-203. [DOI: 10.1016/j.kjms.2011.06.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 12/13/2010] [Indexed: 11/29/2022] Open
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Abstract
INTRODUCTION Plasmodium falciparum malaria is one of the world's most lethal infectious diseases, commanding millions of drug administrations per year. The pharmacogenetics of these drugs is poorly known, although its application can be pivotal for the optimized management of this disease. AREAS COVERED The main components of artemisinin combination therapy (ACT), the worldwide main antimalarial strategy, are metabolized by the polymorphic CYP3A4 (mefloquine, artemether, lumefantrine), CYP2C8 (amodiaquine), CYP2A6 (artesunate) and CYP1A1/2 (amodiaquine/desethylamodiaquine), with dihydroartemisinin being acted by Phase II UDP-glucuronosyltransferases. The worldwide adoption of ACT is leading to a large number of antimalarial treatments. Simultaneously, the feared development of parasite drug resistance might drive dosing increases. In these scenarios of increased drug exposure, pharmacogenetics can be a key tool supporting evidence-based medicine aiming for the longest possible useful lifespan of this important chemotherapy. EXPERT OPINION Translation in this moment is not operationally possible at an individual level, but large population studies are achievable for: i) the development of robust pharmacogenetics markers; and ii) the parallel development of a pharmacogenetic cartography of malaria settings. Advances in the understanding of antimalarial pharmacogenetics are urgent in order to protect the exposed populations, enhance the effectiveness of ACT and, consequently, contributing for the long aimed elimination of the disease.
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Affiliation(s)
- Rita Piedade
- Karolinska Institute, Division of Pharmacogenetics, Department of Physiology and Pharmacology, Stockholm, Sweden
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Kerb R, Fux R, Mörike K, Kremsner PG, Gil JP, Gleiter CH, Schwab M. Pharmacogenetics of antimalarial drugs: effect on metabolism and transport. The Lancet Infectious Diseases 2009; 9:760-74. [DOI: 10.1016/s1473-3099(09)70320-2] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Abstract
Amodiaquine is a central drug in the new global strategy of combination therapies for the control of malaria. Amodiaquine is mainly metabolized hepatically towards its major active metabolite desethylamodiaquine, by the polymorphic P450 isoform CYP2C8. Amodiaquine is associated with rare but serious side effects, as well as with relatively frequent mild ones. These are expected to be at least partially related to CYP2C8 alleles. Pharmacogenetic knowledge of amodiaquine exposed populations is important for pharmacovigilance issues and in being a first step for future realistic applications from a personal medicine perspective.
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Affiliation(s)
- Jose Pedro Gil
- Malaria Research, Karolinska Institutet, Retzius väg 10, plan 5, 171 77 Stockholm, Sweden
- Centre of Molecular and Structural Biomedicine, Institute of Biotechnology and Bioengineering, University of Algarve, Portugal
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Hietala SF, Bhattarai A, Msellem M, Röshammar D, Ali AS, Strömberg J, Hombhanje FW, Kaneko A, Björkman A, Ashton M. Population pharmacokinetics of amodiaquine and desethylamodiaquine in pediatric patients with uncomplicated falciparum malaria. J Pharmacokinet Pharmacodyn 2007; 34:669-86. [PMID: 17620000 DOI: 10.1007/s10928-007-9064-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Accepted: 05/24/2007] [Indexed: 10/23/2022]
Abstract
The study aimed to characterize the population pharmacokinetics of amodiaquine (AQ) and its major metabolite N-desethylamodiaquine (N-DEAQ), and to assess the correlation between exposure to N-DEAQ and treatment outcome. Blood samples from children in two studies in Zanzibar and one in Papua New Guinea were included in the pharmacokinetic analysis (n = 86). The children had been treated with AQ in combination with artesunate or sulphadoxine-pyrimethamine. The population pharmacokinetics of AQ and N-DEAQ were modeled using the non-linear mixed effects approach as implemented in NONMEM. Bayesian post-hoc estimates of individual pharmacokinetic parameters were used to generate individual profiles of N-DEAQ exposure. The correlation between N-DEAQ exposure and effect was studied in 212 patients and modeled with logistic regression in NONMEM. The pharmacokinetics of AQ and N-DEAQ were best described by two parallel two-compartment models with a central and a peripheral compartment for each compound. The systemic exposure to AQ was low in comparison to N-DEAQ. The t(1/2 lambda) of N-DEAQ ranged from 3 days to 12 days. There was a statistically significant, yet weak, association between N-DEAQ concentration on day 7 and treatment outcome. The age-based dosing schedule currently recommended in Zanzibar appeared to result in inadequate exposure to N-DEAQ in many patients.
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Affiliation(s)
- Sofia Friberg Hietala
- Unit for Pharmacokinetics and Drug Metabolism, Department of Pharmacology, Sahlgrenska Academy at Göteborg University, Box 431, Göteborg 405 30, Sweden
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Abstract
Malaria is a major infectious disease. In the last 10 years it has killed more than 20 million people, mainly small children in Africa. The highly efficacious artemisinine combination therapy is being launched globally, constituting the main hope for fighting the disease. Amodiaquine is a main partner in these combinations. Amodiaquine is almost entirely metabolized by the polymorphic cytochrome P450 (CYP) isoform 2C8 to the pharmacologically active desethylamodiaquine. The question remains whether the efficacy of amodiaquine is affected by the gene polymorphism. Genotype-inferred low metabolizers are found in 1-4% of African populations, which corresponds to millions of expected exposures to the drug. In vivo pharmacokinetic data on amodiaquine is limited. By combining it with published in vitro pharmacodynamic and drug metabolism information, we review and predict the possible relevance, or lack of, of CYP2C8 polymorphisms in the present and future efficacy of amodiaquine. Chloroquine and dapsone, both substrates of CYP2C8, are also discussed in the same context.
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Affiliation(s)
- J P Gil
- Karolinska Institute, Malaria Research Unit, Division of Infectious Diseases, Department of Medicine, Karolinska University Hospital, M9:02, KS 17176 Stockholm, Sweden.
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Bell A. Antimalarial drug synergism and antagonism: mechanistic and clinical significance. FEMS Microbiol Lett 2005; 253:171-84. [PMID: 16243458 DOI: 10.1016/j.femsle.2005.09.035] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Revised: 09/22/2005] [Accepted: 09/22/2005] [Indexed: 11/18/2022] Open
Abstract
Interactions between antimicrobial agents provide clues as to their mechanisms of action and influence the combinations chosen for therapy of infectious diseases. In the treatment of malaria, combinations of drugs, in many cases acting synergistically, are increasingly important in view of the frequency of resistance to single agents. The study of antimalarial drug interactions is therefore of great significance to both treatment and research. It is therefore worrying that the analysis of drug-interaction data is often inadequate, leading in some cases to dubious conclusions about synergism or antagonism. Furthermore, making mechanistic deductions from drug-interaction data is not straightforward and of the many reported instances of antimalarial synergism or antagonism, few have been fully explained biochemically. This review discusses recent findings on antimalarial drug interactions and some pitfalls in their analysis and interpretation. The conclusions are likely to have relevance to other antimicrobial agents.
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Affiliation(s)
- Angus Bell
- Department of Microbiology, Moyne Institute of Preventive Medicine, University of Dublin--Trinity College, Dublin 2, Ireland.
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