Hege Christensen

• Kvitne, Kine Eide; Hovd, Markus; Johnsen, Line Kristin; Wegler, Christine; Karlsson, Cecilia & Artursson, Per [Show all 14 contributors for this article] (2023). Digoxin Pharmacokinetics in Patients with Obesity Before and After a Gastric Bypass or a Strict Diet Compared with Normal Weight Individuals. Clinical Pharmacokinetics. ISSN 0312-5963. doi: 10.1007/s40262-023-01320-9. Full text in Research Archive
• Damsa, Crina I.; Henriksen, Lise Toft & Christensen, Hege (2023). Dialogue and Artefacts as Instruments in Peer Group Mentoring and Supervision of Problem-Based Learning in Higher Education, Faculty Peer Group Mentoring in Higher Education - Developing Collegiality through Organised Supportive Collaboration. Springer. ISSN 9783031374579. p. 63–77.
• Hovd, Markus Herberg; Robertsen, Ida; Johnson, Line Kristin; Krogstad, Veronica; Wegler, Christine & Kvitne, Kine Eide [Show all 16 contributors for this article] (2023). Neither Gastric Bypass Surgery Nor Diet-Induced Weight-Loss Affect OATP1B1 Activity as Measured by Rosuvastatin Oral Clearance. Clinical Pharmacokinetics. ISSN 0312-5963. 62(5), p. 725–735. doi: 10.1007/s40262-023-01235-5. Full text in Research Archive
• Kvitne, Kine Eide; Åsberg, Anders; Johnson, Line Kristin; Wegler, Christine; Hertel, Jens Kristoffer & Artursson, Per [Show all 14 contributors for this article] (2022). Impact of type 2 diabetes on in vivo activities and protein expressions of cytochrome P450 in patients with obesity. Clinical and Translational Science (CTS). ISSN 1752-8054. 15(11), p. 2685–2696. doi: 10.1111/cts.13394. Full text in Research Archive Show summary

  Previous studies have not accounted for the close link between type 2 diabetes mellitus (T2DM) and obesity when investigating the impact of T2DM on cytochrome P450 (CYP) activities. The aim was to investigate the effect of T2DM on in vivo activities and protein expressions of CYP2C19, CYP3A, CYP1A2, and CYP2C9 in patients with obesity. A total of 99 patients from the COCKTAIL study (NCT02386917) were included in this cross-sectional analysis; 29 with T2DM and obesity (T2DM-obesity), 53 with obesity without T2DM (obesity), and 17 controls without T2DM and obesity (controls). CYP activities were assessed after the administration of a cocktail of probe drugs including omeprazole (CYP2C19), midazolam (CYP3A), caffeine (CYP1A2), and losartan (CYP2C9). Jejunal and liver biopsies were also obtained to determine protein concentrations of the respective CYPs. CYP2C19 activity and jejunal CYP2C19 concentration were 63% (−0.39 [95% CI: −0.82, −0.09]) and 40% (−0.09 fmol/μg protein [95% CI: −0.18, −0.003]) lower in T2DM-obesity compared with the obesity group, respectively. By contrast, there were no differences in the in vivo activities and protein concentrations of CYP3A, CYP1A2, and CYP2C9. Multivariable regression analyses also indicated that T2DM was associated with interindividual variability in CYP2C19 activity, but not CYP3A, CYP1A2, and CYP2C9 activities. The findings indicate that T2DM has a significant downregulating impact on CYP2C19 activity, but not on CYP3A, CYP1A2, and CYP2C9 activities and protein concentrations in patients with obesity. Hence, the effect of T2DM seems to be isoform-specific.

• Hovd, Markus Herberg; Mariussen, Espen; Uggerud, Hilde Thelle; Lashkarivand, Aslan; Christensen, Hege & Ringstad, Geir [Show all 7 contributors for this article] (2022). Population pharmacokinetic modeling of CSF to blood clearance: prospective tracer study of 161 patients under work-up for CSF disorders. Fluids and Barriers of the CNS. ISSN 2045-8118. 19. doi: 10.1186/s12987-022-00352-w. Full text in Research Archive Show summary

  Background Quantitative measurements of cerebrospinal fluid to blood clearance has previously not been established for neurological diseases. Possibly, variability in cerebrospinal fluid clearance may affect the underlying disease process and may possibly be a source of under- or over-dosage of intrathecally administered drugs. The aim of this study was to characterize the cerebrospinal fluid to blood clearance of the intrathecally administered magnetic resonance imaging contrast agent gadobutrol (Gadovist, Bayer Pharma AG, GE). For this, we established a population pharmacokinetic model, hypothesizing that cerebrospinal fluid to blood clearance differs between cerebrospinal fluid diseases. Methods Gadobutrol served as a surrogate tracer for extra-vascular pathways taken by several brain metabolites and drugs in cerebrospinal fluid. We estimated cerebrospinal fluid to blood clearance in patients with different cerebrospinal fluid disorders, i.e. symptomatic pineal and arachnoid cysts, as well as tentative spontaneous intracranial hypotension due to cerebrospinal fluid leakage, idiopathic intracranial hypertension, or different types of hydrocephalus (idiopathic normal pressure hydrocephalus, communicating- and non-communicating hydrocephalus). Individuals with no verified cerebrospinal fluid disturbance at clinical work-up were denoted references. Results Population pharmacokinetic modelling based on 1,140 blood samples from 161 individuals revealed marked inter-individual variability in pharmacokinetic profiles, including differences in absorption half-life (time to 50% of tracer absorbed from cerebrospinal fluid to blood), time to maximum concentration in blood and the maximum concentration in blood as well as the area under the plasma concentration time curve from zero to infinity. In addition, the different disease categories of cerebrospinal fluid diseases demonstrated different profiles. Conclusions The present observations of considerable variation in cerebrospinal fluid to blood clearance between individuals in general and across neurological diseases, may suggest that defining cerebrospinal fluid to blood clearance can become a useful diagnostic adjunct for work-up of cerebrospinal fluid disorders. We also suggest that it may become useful for assessing clearance capacity of endogenous brain metabolites from cerebrospinal fluid, as well as measuring individual cerebrospinal fluid to blood clearance of intrathecal drugs.

• Kvitne, Kine Eide; Hole, Kristine; Krogstad, Veronica; Wollmann, Birgit Malene Tovik; Wegler, Christine & Johnson, Line Kristin [Show all 19 contributors for this article] (2022). Correlations between 4β-hydroxycholesterol and hepatic and intestinal CYP3A4: protein expression, microsomal ex vivo activity, and in vivo activity in patients with a wide body weight range. European Journal of Clinical Pharmacology. ISSN 0031-6970. 78(8), p. 1289–1299. doi: 10.1007/s00228-022-03336-9. Full text in Research Archive Show summary

  Purpose Variability in cytochrome P450 3A4 (CYP3A4) metabolism is mainly caused by non-genetic factors, hence providing a need for accurate phenotype biomarkers. Although 4β-hydroxycholesterol (4βOHC) is a promising endogenous CYP3A4 biomarker, additional investigations are required to evaluate its ability to predict CYP3A4 activity. This study investigated the correlations between 4βOHC concentrations and hepatic and intestinal CYP3A4 protein expression and ex vivo microsomal activity in paired liver and jejunum samples, as well as in vivo CYP3A4 phenotyping (midazolam) in patients with a wide body weight range. Methods The patients (n = 96; 78 with obesity and 18 normal or overweight individuals) were included from the COCKTAIL-study (NCT02386917). Plasma samples for analysis of 4βOHC and midazolam concentrations, and liver (n = 56) and jejunal (n = 38) biopsies were obtained. The biopsies for determination of CYP3A4 protein concentration and microsomal activity were obtained during gastric bypass or cholecystectomy. In vivo CYP3A4 phenotyping was performed using semi-simultaneous oral (1.5 mg) and intravenous (1.0 mg) midazolam. Results 4βOHC concentrations were positively correlated with hepatic microsomal CYP3A4 activity (ρ = 0.53, p < 0.001), and hepatic CYP3A4 concentrations (ρ = 0.30, p = 0.027), but not with intestinal CYP3A4 concentrations (ρ = 0.18, p = 0.28) or intestinal microsomal CYP3A4 activity (ρ = 0.15, p = 0.53). 4βOHC concentrations correlated weakly with midazolam absolute bioavailability (ρ =  − 0.23, p = 0.027) and apparent oral clearance (ρ = 0.28, p = 0.008), but not with systemic clearance (ρ =  − 0.03, p = 0.81). Conclusion These findings suggest that 4βOHC concentrations reflect hepatic, but not intestinal, CYP3A4 activity. Further studies should investigate the potential value of 4βOHC as an endogenous biomarker for individual dose requirements of intravenously administered CYP3A4 substrate drugs.

• Kvitne, Kine Eide; Krogstad, Veronica; Wegler, Christine; Johnson, Line Kristin; Kringen, Marianne K. & Hovd, Markus Herberg [Show all 19 contributors for this article] (2022). Short- and long-term effects of body weight, calorie restriction and gastric bypass on CYP1A2, CYP2C19 and CYP2C9 activity. British Journal of Clinical Pharmacology. ISSN 0306-5251. 88(9), p. 4121–4133. doi: 10.1111/bcp.15349. Full text in Research Archive Show summary

  Roux-en-Y gastric bypass (RYGB) may influence drug disposition due to surgery-induced gastrointestinal alterations and/or subsequent weight loss. The objective was to compare short- and long-term effects of RYGB and diet on the metabolic ratios of paraxanthine/caffeine (cytochrome P450 [CYP] 1A2 activity), 5-hydroxyomeprazole/omeprazole (CYP2C19 activity) and losartan/losartan carboxylic acid (CYP2C9 activity), and cross-sectionally compare these CYP-activities with normal-to-overweight controls. Methods This trial included patients with severe obesity preparing for RYGB (n = 40) or diet-induced (n = 41) weight loss, and controls (n = 18). Both weight loss groups underwent a 3-week low-energy diet (<1200 kcal/day, weeks 0-3) followed by a 6-week very-low-energy diet or RYGB (both <800 kcal/day, weeks 3-9). Follow-up time was 2 years, with four pharmacokinetic investigations. Results Mean ± SD weight loss from baseline was similar in the RYGB-group (13 ± 2.4%) and the diet group (10.5 ± 3.9%) at week 9, but differed at year 2 (RYGB −30 ± 6.9%, diet −3.1 ± 6.3%). From weeks 0 to 3, mean (95% confidence interval [CI]) CYP2C19 activity similarly increased in both groups (RYGB 43% [16, 55], diet 48% [22, 60]). Mean CYP2C19 activity increased by 30% (2.6, 43) after RYGB (weeks 3-9), but not in the diet-group (between-group difference −0.30 [−0.63, 0.03]). CYP2C19 activity remained elevated in the RYGB group at year 2. Baseline CYP2C19 activity was 2.7-fold higher in controls compared with patients with obesity, whereas no difference was observed in CYP1A2 and CYP2C9 activities. Conclusion Our findings suggest that CYP2C19 activity is lower in patients with obesity and increases following weight loss. This may be clinically relevant for drug dosing. No clinically significant effect on CYP1A2 and CYP2C9 activities was observed.

• Wegler, Christine; Wisniewski, Jacek R.; Robertsen, Ida; Christensen, Hege; Hertel, Jens Kristoffer & Hjelmesæth, Jøran Sture [Show all 10 contributors for this article] (2022). Drug disposition protein quantification in matched human jejunum and liver from donors with obesity. Clinical Pharmacology and Therapeutics. ISSN 0009-9236. 111(5), p. 1142–1154. doi: 10.1002/cpt.2558. Full text in Research Archive Show summary

  Mathematical models, such as physiologically based pharmacokinetic (PBPK) models, are used to predict e.g., drug disposition and toxicity. However, populations differ in the abundance of proteins involved in these processes. To improve the building and refinement of such models, they must take into account these inter-individual variabilities. In this study, we used global proteomics to characterize the protein composition of jejunum and liver from 37 donors with obesity enrolled in the COCKTAIL study. Liver protein levels from the 37 donors were further compared with those from donors without obesity. We quantified thousands of proteins and could present the expression of several drug-metabolizing enzymes, for the first time, in jejunum, many of which belong to the cytochrome P450 (e.g., CYP2U1) and the amine oxidase [flavin-containing] (e.g., MAOA) families. Although we show that many metabolizing enzymes had greater expression in liver, others had higher expression in jejunum (such as, MAOA and CES2), indicating the role of the small intestine in extrahepatic drug metabolism. We further show that proteins involved in drug disposition are not correlated in the two donor-matched tissues. These proteins also do not correlate with physiological factors such as BMI, age, and inflammation status in either tissue. Furthermore, the majority of these proteins are not differently expressed in donors with or without obesity. Nonetheless, inter-individual differences were considerable, with implications for personalized prediction models and systems pharmacology.

• Skauby, Ragnhild Kristine Heier; Bergan, Stein; Andersen, Anders Mikal; Vethe, Nils Tore & Christensen, Hege (2021). In vitro assessments predict that CYP3A4 contributes to a greater extent than CYP3A5 to prednisolone clearance. Basic & Clinical Pharmacology & Toxicology. ISSN 1742-7835. 129(6), p. 427–436. doi: 10.1111/bcpt.13645. Show summary

  Because several steroid hormones are metabolized to their respective 6β-hydroxy forms by CYP3A4 and CYP3A5, these isoenzymes have been assumed to metabolize the immunosuppressive drug prednisolone, with conflicting results in the literature with respect to their relative importance. A direct study of the metabolism of prednisolone by microsomal CYP3A4 and CYP3A5 is missing. The aim of this in vitro study was to investigate the relative importance of recombinant CYP3A4 and recombinant CYP3A5 in the metabolism of prednisolone and to compare the extent of formation of 6β-OH-prednisolone by the two enzymes. Through in vitro incubations using rCYP3A4 and rCYP3A5 enzymes, intrinsic clearance (CLint) of prednisolone was determined by the substrate depletion approach. Formation of the metabolite 6β-OH-prednisolone by rCYP3A4 and rCYP3A5, respectively, was compared. Prednisolone concentrations were measured, and its metabolite 6β-OH-prednisolone was identified using a HPLC-MS/MS in-house method. CLint for prednisolone by rCYP3A5 was less than 26% relative to rCYP3A4. Formation of 6β-OH-prednisolone by rCYP3A5 was less than 11% relative to rCYP3A4. The study indicates that 6β-hydroxylation of prednisolone assessed in vitro in recombinant CYP enzymes depends on rCYP3A4 rather than rCYP3A5 and that CYP3A5 may be responsible for the formation of other prednisolone metabolite(s) in addition to 6β-OH-prednisolone.

• Wegler, Christine; Matsson, Pär; Krogstad, Veronica; Urdzik, Jozef; Christensen, Hege & Andersson, Tommy B. [Show all 7 contributors for this article] (2021). Influence of Proteome Profiles and Intracellular Drug Exposure on Differences in CYP Activity in Donor-Matched Human Liver Microsomes and Hepatocytes. Molecular Pharmaceutics. ISSN 1543-8384. 18(4), p. 1792–1805. doi: 10.1021/acs.molpharmaceut.1c00053. Full text in Research Archive
• Kvitne, Kine Eide; Robertsen, Ida; Skovlund, Eva; Christensen, Hege Staaland; Krogstad, Veronica & Wegler, Christine [Show all 18 contributors for this article] (2021). Short- and long-term effects of body weight loss following calorie restriction and gastric bypass on CYP3A-activity – a non-randomized three-armed controlled trial. Clinical and Translational Science (CTS). ISSN 1752-8054. doi: 10.1111/cts.13142. Full text in Research Archive
• Eide, Per Kristian; Mariussen, Espen; Uggerud, Hilde Thelle; Pripp, Are Hugo; Lashkarivand, Aslan & Hassel, Bjørnar [Show all 8 contributors for this article] (2021). Clinical application of intrathecal gadobutrol for assessment of cerebrospinal fluid tracer clearance to blood. JCI Insight. ISSN 2379-3708. 6(9), p. 1–13. doi: 10.1172/jci.insight.147063. Full text in Research Archive
• Krogstad, Veronica; Peric, Alexandra; Robertsen, Ida; Kringen, Marianne K.; Vistnes, Maria & Hjelmesæth, Jøran [Show all 15 contributors for this article] (2020). Correlation of body weight and composition with hepatic activities of cytochrome P450 enzymes . Journal of Pharmaceutical Sciences. ISSN 0022-3549. 110(1), p. 432–437. doi: 10.1016/j.xphs.2020.10.027. Full text in Research Archive
• Egeland, Erlend Johannessen; Witczak, Bartlomiej J; Zare, Hasse Khiabani; Christensen, Hege Staaland; Åsberg, Anders & Robertsen, Ida (2020). Chronic Inhibition of CYP3A is Temporarily Reduced by Each Hemodialysis Session in Patients With End‐Stage Renal Disease. Clinical Pharmacology and Therapeutics. ISSN 0009-9236. 108(4), p. 866–873. doi: 10.1002/cpt.1875.
• Krogstad, Veronica; Peric, Alexandra; Robertsen, Ida; Kringen, Marianne K.; Wegler, Christine & Angeles, Philip Carlo Soriano [Show all 13 contributors for this article] (2019). A Comparative Analysis of Cytochrome P450 Activities in Paired Liver and Small Intestinal Samples from Patients with Obesity. Drug Metabolism And Disposition. ISSN 0090-9556. 48(1), p. 8–17. doi: 10.1124/DMD.119.087940.
• Krogstad, Veronica; Vethe, Nils Tore; Robertsen, Ida; Hasvold, Grete; Ose, Anne-Marthe Due & Hermann, Monica [Show all 12 contributors for this article] (2018). Determination of Tacrolimus Concentration and Protein Expression of P-Glycoprotein in Single Human Renal Core Biopsies. Therapeutic Drug Monitoring. ISSN 0163-4356. 40(3), p. 292–300. doi: 10.1097/FTD.0000000000000510.
• Hjelmesæth, Jøran; Åsberg, Anders; Andersson, Shalini; Sandbu, Rune; Robertsen, Ida & Johnson, Line Kristin [Show all 16 contributors for this article] (2018). Impact of body weight, low energy diet and gastric bypass on drug bioavailability, cardiovascular risk factors and metabolic biomarkers: protocol for an open, non-randomised, three-armed single centre study (COCKTAIL). BMJ Open. ISSN 2044-6055. 8:e021878(5), p. 1–10. doi: 10.1136/bmjopen-2018-021878. Full text in Research Archive
• Hermann, Monica; Robertsen, Ida & Christensen, Hege Staaland (2015). Immunologisk aktivitet og biologiske legemidler påvirker legemiddelmetabolisme og -transport. Norsk Farmaceutisk Tidsskrift. ISSN 0029-1935. 123(6), p. 22–25.
• Robertsen, Ida; Vethe, Nils Tore; Midtvedt, Karsten; Falck, Pål; Christensen, Hege Staaland & Åsberg, Anders (2015). Closer to the site of action: everolimus concentrations in peripheral blood mononuclear cells correlate well with whole blood concentrations. Therapeutic Drug Monitoring. ISSN 0163-4356. 37(5), p. 675–680. doi: 10.1097/FTD.0000000000000185.
• Lunde, Ingrid; Bremer, Sara; Midtvedt, Karsten; Mohebi, Beata Urbanczyk; Husvegg, Miriam Dahl & Bergan, Stein [Show all 8 contributors for this article] (2014). The influence of CYP3A, PPARA and POR genetic variants on the pharmacokinetics of tacrolimus and cyclosporine in renal transplant recipients. European Journal of Clinical Pharmacology. ISSN 0031-6970. 70(6), p. 685–693. doi: 10.1007/s00228-014-1656-3.
• Bräunlich, Paula Marie; Christensen, Hege Staaland; Johannesen, Siri; Slimestad, Rune; Wangensteen, Helle & Malterud, Karl Egil [Show all 7 contributors for this article] (2013). In Vitro Inhibition of Cytochrome P450 3A4 by Aronia melanocarpa Constituents. Planta Medica. ISSN 0032-0943. 79(2), p. 137–141. doi: 10.1055/s-0032-1328055.
• Jakobsen, Gunn Signe; Skottheim, Ine Blankenberg; Sandbu, Rune; Christensen, Hege Staaland; Røislien, Jo & Åsberg, Anders [Show all 7 contributors for this article] (2013). Long-term effects of gastric bypass and duodenal switch on systemic exposure of atorvastatin. Surgical Endoscopy. ISSN 0930-2794. 27(6), p. 2094–2101. doi: 10.1007/s00464-012-2716-3.
• Darwich, AS; Pade, D; Rowland-Yeo, K; Jamei, M; Åsberg, Anders & Christensen, Hege Staaland [Show all 8 contributors for this article] (2013). Application of an in silico physiologically based pharmacokinetic model to simulate oral drug bioavailability of atorvastatin and cyclosporine post bariatric surgery. Clinical Pharmacology and Therapeutics. ISSN 0009-9236. 2. doi: 10.1038/psp.2013.23.
• Robertsen, Ida; Falck, Pål; Andreassen, Arne K.; Næss, Nina Kaajal; Lunder, Niclas & Christensen, Hege Staaland [Show all 8 contributors for this article] (2013). Endomyocardial, intralymphocyte and whole blood concentrations of ciclosporin A in heart transplant recipients. Transplantation Research. ISSN 2047-1440. 2(5). doi: 10.1186/2047-1440-2-5.
• Ulvestad, Maria; Skottheim, Ine Blankenberg; Jakobsen, Gunn Signe; Bremer, Sara; Molden, Espen & Åsberg, Anders [Show all 10 contributors for this article] (2013). Impact of OATP1B1, MDR1, and CYP3A4 expression in liver and intestine on interpatient pharmacokinetic variability of atorvastatin in obese subjects. Clinical Pharmacology and Therapeutics. ISSN 0009-9236. 93(3), p. 275–282. doi: 10.1038/clpt.2012.261.
• Amundsen, Rune; Åsberg, Anders; Ohm, Ingrid Kristine & Christensen, Hege Staaland (2012). Cyclosporine A- and tacrolimus-mediated inhibition of CYP3A4 and CYP3A5 in vitro. Drug Metabolism And Disposition. ISSN 0090-9556. 40(4), p. 655–661. doi: 10.1124/dmd.111.043018.
• Christensen, Hege Staaland & Hermann, Monica (2012). Immunological response as a source to variability in drug metabolism and transport. Frontiers in Pharmacology. ISSN 1663-9812. 3(8), p. 1–10. doi: 10.3389/fphar.2012.00008.
• Christensen, Hege Staaland; Hestad, Anette Leirvik; Molden, Espen & Mathiesen, Liv (2011). CYP3A5-mediated metabolism of midazolam in recombinant systems is highly sensitive to NADPH-cytochrome P450 reductase activity. Xenobiotica. ISSN 0049-8254. 41(1), p. 1–5. doi: 10.3109/00498254.2010.523734.
• Amundsen, Rune; Christensen, Hege Staaland; Zabihyan, Behnaz & Åsberg, Anders (2010). Cyclosporine A, but Not Tacrolimus, Shows Relevant Inhibition of Organic Anion-Transporting Protein 1B1-Mediated Transport of Atorvastatin. Drug Metabolism And Disposition. ISSN 0090-9556. 38(9), p. 1499–1504. doi: 10.1124/dmd.110.032268.
• Skottheim, IB; Jakobsen, Gunn Signe; Stormark, Kjartan; Christensen, H; Hjelmesæth, Jøran & Jenssen, Trond Geir [Show all 8 contributors for this article] (2010). Significant Increase in Systemic Exposure of Atorvastatin After Biliopancreatic Diversion With Duodenal Switch. Clinical Pharmacology and Therapeutics. ISSN 0009-9236. 87(6), p. 699–705. doi: 10.1038/clpt.2010.32.
• Bakken, Gry Vibeke; Rudberg, Ida; Christensen, Hege Staaland; Molden, Espen; Refsum, Helge & Hermann, Monica (2009). Metabolism of quetiapine by CYP3A4 and CYP3A5 in presence or absence of cytochrome b5. Drug Metabolism And Disposition. ISSN 0090-9556. 37(2), p. 254–258. doi: 10.1124/dmd.108.023291.
• Waade, RB; Christensen, Hege Staaland; Rudberg, Ida; Refsum, H & Hermann, Monica (2009). Influence of Comedication on Serum Concentrations of Aripiprazole and Dehydroaripiprazole. Therapeutic Drug Monitoring. ISSN 0163-4356. 31(2), p. 233–238.
• Christensen, Hege Staaland; Mathiesen, Liv; Postvoll, Lillian Wåge; Winther, Bjørn & Molden, Espen (2009). Different Enzyme Kinetics of Midazolam in Recombinant CYP3A4 Microsomes from Human and Insect Sources. Drug Metabolism and Pharmacokinetics (DMPK). ISSN 1347-4367. 24(3), p. 261–268.
• Skottheim, IB; Stormark, KM; Stormark, Kjartan; Christensen, H; Jakobsen, GS & Hjelmesæth, Jøran [Show all 11 contributors for this article] (2009). Significantly Altered Systemic Exposure to Atorvastatin Acid Following Gastric Bypass Surgery in Morbidly Obese Patients. Clinical Pharmacology and Therapeutics. ISSN 0009-9236. 86(3), p. 311–318. doi: 10.1038/clpt.2009.82.
• Christensen, Hege Staaland & Åsberg, Anders (2008). Interaksjon mellom næringsmidler og legemidler. Norsk tidsskrift for ernæring (NTFE). ISSN 1503-5034. p. 16–21.
• Hermann, Monica; Kase, Eili Tranheim; Molden, Espen & Christensen, Hege Staaland (2006). Evaluation of microsomal incubation conditions on CYP3A4-mediated metabolism of cyclosporine A by a statistical experimental design. Current drug metabolism. ISSN 1389-2002. 7, p. 265–271.
• Christensen, Hege Staaland; Baker, Mark; Tucker, Geoffery T. & Rostami-Hodjegan, Amin (2006). Prediction of plasma protein binding displacement and its implications for quantitative assessment of metabolic drug-drug interactions from in vitro data. Journal of Pharmaceutical Sciences. ISSN 0022-3549. 95(12), p. 2778–2787.
• Hermann, Monica; Christensen, Hege Staaland & Reubsaet, Jan Leo (2005). Determination of atorvastatin and metabolites in human plasma with solid-phase extraction followed by LC-tandem MS. Analytical and Bioanalytical Chemistry. ISSN 1618-2642. 382, p. 1242–1249.
• Wangensteen, Helle; Molden, Espen; Christensen, Hege Staaland & Malterud, Karl Egil (2003). Identification of epoxybergamottin as a CYP3A4 inhibitor in grapefruit peel. European Journal of Clinical Pharmacology. ISSN 0031-6970. 58, p. 663–668.
• Molden, Espen; Bøe, Grethe Helen; Christensen, Hege Staaland & Reubsaet, Leon (2003). High-performance liquid chromatography - mass spectrometry analysis of diltiazem and 11 of its phase I metabolites. Journal of Pharmaceutical and Biomedical Analysis. ISSN 0731-7085. 33, p. 275–285.
• Molden, Espen; Johansen, Per Wiik; Bøe, Grethe Helen; Bergan, Stein; Christensen, Hege Staaland & Rugstad, Hans Erik [Show all 9 contributors for this article] (2002). Pharmacokinetics of diltiazem and its metabolites in relation to CYP2D6 genotype. Clinical Pharmacology and Therapeutics. ISSN 0009-9236. 72, p. 333–342.
• Christensen, Hege Staaland; Åsberg, Anders; Holmboe, Aase-Britt & Berg, Knut Joachim. (2002). Coadministration of grapefruit juice increases systemic exposure of diltiazem in healthy volunteers. European Journal of Clinical Pharmacology. ISSN 0031-6970. 58, p. 515–520.
• Hermann, Monica; Christensen, Hege Staaland & Reubsaet, Jan Leo (2002). Evaluation of essential parameters in the chromatographic determination of cyclosporin A and metabolites using a D-optimal design. Journal of Pharmaceutical and Biomedical Analysis. ISSN 0731-7085. 30, p. 1263–1276.
• Hermann, Monica; Åsberg, Anders; Reubsaet, Jan Leo; Berg, Knut Joachim.; Sæther, Stig & Christensen, Hege Staaland (2002). Intake of grapefruit juice alters the metabolic pattern of cyclosporin A in renal transplant recipients. International Journal of Clinical Pharmacology and Therapeutics. ISSN 0946-1965. 40, p. 451–456.
• Molden, Espen; Åsberg, Anders & Christensen, Hege Staaland (2002). Desacetyl-diltiazem displays severalfold higher affinity to CYP2D6 compared to CYP3A4. Drug Metabolism And Disposition. ISSN 0090-9556. 30, p. 1–3.

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• Thoresen, G. Hege; Simonsen, terje; Christensen, Hege; Johansen, Harald Thidemann; Kase, Eili Tranheim & Robertsen, Ida [Show all 9 contributors for this article] (2021). Basal farmakologi. Fagbokforlaget. ISBN 9788245033557. 405 p.
• Thoresen, G. Hege; Solberg, Rigmor; Johansen, Harald Thidemann; Kase, Eili Tranheim; Rustan, Arild Christian & Christensen, Hege [Show all 7 contributors for this article] (2020). Illustrert farmakologi. Fagbokforlaget. ISBN 9788245033564. 392 p.

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• Hovd, Markus Herberg; Mariussen, Espen; Uggerud, Hilde Thelle; Lashkarivand, Aslan; Christensen, Hege & Ringstad, Geir [Show all 7 contributors for this article] (2023). CSF to blood clearance differs substantially across individuals and patients with CSF disorders. Fluids and Barriers of the CNS. ISSN 2045-8118. 19. doi: 10.1186/s12987-022-00397-x.
• Christensen, Hege Staaland; Damsa, Crina I. & Henriksen, Lise Toft (2021). Kollegaveiledning for PBL-veiledere i farmasiutdanning. In Wittek, Anne Line & de Lange, Thomas (Ed.), Kollegaveiledning i høyere utdanning. Universitetsforlaget. ISSN 9788215048420.
• Ose, Anne M; Krogstad, Veronica; Hasvold, Grete; Robertsen, Ida; Egeland, Erlend Johannessen & Hermann, Monica [Show all 9 contributors for this article] (2017). Optimalisering av metode for kvantifisering av CYP3A5 og P_glykoprotein i små nyrebiopsier.
• Vu, Martin; Krogstad, Veronica; Johnson, Line Kristin; Angeles, Philip Carlo S; Hasvold, Grete & Hermann, Monica [Show all 13 contributors for this article] (2017). Effect of low calorie diet on the absolute bioavailability of midazolam in patients with severe obesity.
• Le, Peter Huy Vo; Robertsen, Ida; Åsberg, Anders; Christensen, Hege Staaland & Hermann, Monica (2016). Utvikling av en sensitiv LC-MS/MS-metode for å kvantifisere midazolam og metabolitter i pasienter med sykelig overvekt før og etter gastrisk bypass-operasjon.
• Myhrer, Marthe; Krogstad, Veronica; Christensen, Hege Staaland; Reubsaet, Leon & Hermann, Monica (2015). Kvantifisering av P-glykoprotein i lymfocytter ved bruk av LC-MS/MS.
• Ulvmoen, Anders; Robertsen, Ida; Åsberg, Anders; Christensen, Hege Staaland & Hermann, Monica (2015). Utvikling av en sensitiv LC-MS/MS-metode for å kvantifisere midazolam og metabolitter in vitro og i sykelig overvektige pasienter.
• Ho, Giang Thanh Thi; Braünlich, Marie; Wangensteen, Helle; Malterud, Karl Egil; Økstad, Ole Andreas Løchen & Christensen, Hege Staaland [Show all 9 contributors for this article] (2014). Spennende helseeffekter av aroniabær.
• Ahlsen, Kathrine; Robertsen, Ida; Midtvedt, Karsten; Åsberg, Anders & Christensen, Hege Staaland (2014). Aktivitet av P-glykoprotein i mononukleære celler fra perifert blod.
• Lilleengen, Anniken; Lunde, Ingrid; Sandbu, Rune; Åsberg, Anders & Christensen, Hege Staaland (2014). CYP3A4-aktivitet ex vivo i individuelle humane intestinale mikrosomer.
• Jensen, Ben Andre; Reubsaet, Leon; Christensen, Hege Staaland; Åsberg, Anders & Hermann, Monica (2013). Utvikling av kvantitativ proteomikkmetode for måling av P-glykoprotein i lymfocytter isolert fra pasienter.
• Dahl, Miriam; Lunde, Ingrid; Mohebi, Beata Urbanczyk; Bremer, Sara; Bergan, Stein & Midtvedt, Karsten [Show all 10 contributors for this article] (2013). Farmakokinetisk betydning av sekvensvarianter i CYP3A4, POR og PPAR-alpha.
• Bräunlich, Paula Marie; Christensen, Hege Staaland; Johannesen, Siri; Ho, Giang Thanh Thi; Wangensteen, Helle & Barsett, Hilde (2013). Complement fixing Activity and in vitro inhibition of cytochrome P450 3A4 by Aronia melanocarpa constituents.
• Barsett, Hilde; Bräunlich, Paula Marie; Wangensteen, Helle; Malterud, Karl Egil; Christensen, Hege Staaland & Johannesen, Siri [Show all 9 contributors for this article] (2013). Bioactive compounds in Aronia melanocarpa berries.
• Hotvedt, Tor Arne; Fleischer, Phillip; Molden, Espen; Åsberg, Anders & Christensen, Hege Staaland (2012). Cytokiners effekt på CYP3A4-mediert metabolisme av midazolam i THLE-celler.
• Robertsen, Ida; Falck, Pål; Næss, Nina Kaajal; Andreassen, Arne K.; Gullestad, Lars & Christensen, Hege Staaland [Show all 7 contributors for this article] (2012). Endomyovardial, intralymphocyte and whole blood concentrations of cyclosporine A in heart transplant recipients.
• Huynh, C; Nordeng, Marit; Skottheim, Ine Blankenberg; Sandbu, Rune; Åsberg, Anders & Christensen, Hege Staaland (2011). Individuell variasjon i P-glykoprotein uttrykk i ulike deler av mage- og tarmsystemet.
• Jensstuen, Ågot K; Robertsen, Ida; Amundsen, Rune & Christensen, Hege Staaland (2011). CYP3A4-mediert metabolisme av cyklosporin i insektsmikrosomer.
• Amundsen, Rune; Åsberg, Anders; Ohm, IK & Christensen, Hege Staaland (2011). Ciklosporin og takrolimus som hemmere av CYP3A4 og CYP3A5.
• Christensen, Hege Staaland; Amundsen, Rune & Åsberg, Anders (2011). Mechanisms involved in the pharmacokinetic interaction between atorvastatin and cyclosporine A.
• Vist, Solveig; Skottheim, Ine Blankenberg; Sandbu, Rune; Åsberg, Anders & Christensen, Hege Staaland (2010). Uttrykk av CYP3A4 og CYP3A5 i parrede prøver fra GI-traktus og lever fra overvektige personer.
• Amundsen, Rune; Christensen, Hege Staaland; Zabihyan, B & Åsberg, Anders (2010). Cyclosporin A, men ikke takrolimus, hemmer OATP1B1-mediert opptak av atorvastatin.
• Ohm, IK; Amundsen, Rune & Christensen, Hege Staaland (2010). Cyclosporin A som hemmer av CYP3A4 og CYP3A5.
• Amundsen, Rune; Christensen, Hege Staaland; Zabihyan, Behnaz & Åsberg, Anders (2010). Cyclosporine A, but not tacrolimus, shows relevant inhibition of OATP1B1-mediated transport of atorvastatin.
• Lund, Cathrine; Christensen, Hege Staaland; Frøyshov, Sten & Jacobsen, Dag (2010). Toxicokinetics of Diltiazem and Three Metabolites During Acute Life-Threatening Poisoning. Clinical Toxicology. ISSN 1556-3650. 48(3), p. 281–281.
• Amundsen, Rune; Zabihyan, Behnaz; Christensen, Hege Staaland & Åsberg, Anders (2009). CYCLOSPORINE A, BUT NOT TACROLIMUS, INHIBITS OATP1B1 MEDIATED TRANSPORT OF ATORVASTATIN. Journal of clinical pharmacology. ISSN 0091-2700. 49(9), p. 1112–1112.
• Christensen, Hege Staaland; Hestad, Anette L; Molden, Espen & Mathiesen, Liv (2009). Effect of NADPH-cytochrome P450 oxidoreductase on CYP3A5-mediated metabolism of midazolam.
• Skottheim, Ine Blankenberg; Kjartan, Stormark; Christensen, Hege Staaland; Jacobsen, Gunn Signe; Hjelmesæth, Jøran & Jensen, Trond [Show all 9 contributors for this article] (2009). Signifikant endret biotilgjengelighet av atorvastatin etter gastrisk bypass i sykelig overvektige pasienter.
• Amundsen, Rune; Zabihyan, Behnaz; Christensen, Hege Staaland & Åsberg, Anders (2009). CYCLOSPORINE A, BUT NOT TACROLIMUS, INHIBITS OATP1B1 MEDIATED TRANSPORT OF ATORVASTATIN.
• Skottheim, Ine Blankenberg; Christensen, Hege Staaland; Stormark, Kjartan; Hjelmesæth, Jøran; Jacobsen, Gunn Signe & Sandbu, Rune [Show all 7 contributors for this article] (2008). GASTRIC BYPASS SURGERY IN MORBIDLY OBESE PATIENTS ALTERS ATORVASTATIN ACID BIOAVAILABILITY.
• Christensen, Hege Staaland (2008). From drug interactions in patients to in vitro drug metabolism studies.
• Skottheim, Ine Blankenberg; Stormark, Kjartan; Christensen, Hege Staaland; Hjelmesæth, Jøran; Åsberg, Anders & Jacobsen, Gunn Signe [Show all 7 contributors for this article] (2008). Significantly altered bioavailability of atorvastatin acid following laparoscopic gastric bypass in morbidly obese patients.
• Bakken, Vibeke; Rudberg, Ida; Hermann, Monica; Molden, Espen & Christensen, Hege Staaland (2008). Metabolisme av quetiapin via CYP3A4 og CYP3A5 in vitro.
• Skottheim, Ine Blankenberg; Stormark, Kjartan; Åsberg, Anders; Christensen, Hege Staaland; Hjælmeseth, Jøran & Nergård, Bent Johnny [Show all 8 contributors for this article] (2007). Legemiddelabsorpsjon etter bariatrisk kirurgi.
• Christensen, Hege Staaland (2007). Visjoner for framtidens forskning innen farmasøytisk biovitenskap.
• Christensen, Hege Staaland; Postvoll, Lillian W; Mathiesen, Liv; Johannesen, Siri & Molden, Espen (2007). Different CYP3A4 enzyme kinetics of midazolam in different microsomal preparations.
• Christensen, Hege Staaland; Postvoll, Lillian W; Mathiesen, Liv; Johannesen, Siri & Molden, Espen (2007). Different microsomal preparations exhibit different CYP3A4 enzyme kinetics of midazolam.
• Christensen, Hege Staaland (2006). In vitro-in vivo extrapolation of metabolism based drug-drug interactions.
• Christensen, Hege Staaland (2006). Fortrengning fra plasmaproteiner: Ekstrapolering av legemiddelinteraksjoner fra in vitro data.
• Christensen, Hege Staaland; Baker, Mark; Tucker, Geoffery T. & Rostami-Hodjegan, Amin (2005). Prediction of plasma protein binding displacement and its implications for quantitative assessment of metabolic drug-drug interactions from in vitro data. Drug metabolism reviews (Softcover ed.). ISSN 0360-2532. 37, p. 19–19.
• Christensen, Hege Staaland; Baker, M; Tucker, G & Rostami-Hodjegan, A (2005). Plasma protein binding displacement: Prediction and implications for extrapolation of metabolic drug-drug interactions from in vitro data. Journal of clinical pharmacology. ISSN 0091-2700. 45.
• Christensen, Hege Staaland; Baker, Mark; Tucker, Geoffery T. & Rostami-Hodjegan, Amin (2005). Prediksjon av fortrengning fra plasmaproteiner og betydningen for in vitro-in vivo ekstrapolering av legemiddel-interaksjoner.
• Åsberg, Anders; Lemahieu, Wim P D; Hermann, Monica; Holdaas, Hallvard; Hartmann, Anders & Verbeke, K [Show all 10 contributors for this article] (2005). The mechanisms of the pharmacokinetic interaction between calcineurin inhibitors and statins.
• Christensen, Hege Staaland; Baker, Mark; Tucker, Geoffery T. & Rostami-Hodjegan, Amin (2005). Plasma protein binding displacement: prediction and implications for extrapolation of metabolic drug-drug interactions from in vitro data.
• Hermann, Monica; Åsberg, Anders; Christensen, Hege Staaland; Holdaas, Hallvard; Hartmann, Anders & Reubsaet, Jan Leo (2004). Substantially elevated levels of atorvastatin and metabolites in cyclosporine-treated renal transplant recipients. Clinical Pharmacology and Therapeutics. ISSN 0009-9236. 76, p. 388–391.
• Åsberg, Anders; Hermann, Monica; Christensen, Hege Staaland; Reubsaet, Jan Leo; Holdaas, Hallvard & Hartmann, Anders (2004). The substantially higher levels of atorvastatin and metabolites in cyclosporine A treated renal transplant recipients are mostly due to an effect on the acid forms compared to lactone forms.
• Åsberg, Anders; Hermann, Monica; Christensen, Hege Staaland; Reubsaet, Jan Leo; Holdaas, Hallvard & Hartmann, Anders (2004). Several-fold higher systemic exposure of atorvastatin and meabolites n cyclosporine treated renal transplant recipients compared with healthy volunteers.
• Hermann, Monica; Åsberg, Anders; Reubsaet, Leon; Christensen, Hege Staaland & Hartmann, Anders (2003). Kraftig økning i systemisk eksponering av atorvastatin og metabolitter ved samtidig inntak av cyclosporin hos nyretransplanterte pasienter.
• Arnesen, Petter; Molden, Espen; Malterud, Karl Egil & Christensen, Hege Staaland (2003). Substanser i rødvin hemmer CYP3A4-mediert legemiddelmetabolisme.
• Kase, Eili Tranheim; Hermann, Monica; Molden, Espen & Christensen, Hege Staaland (2003). Metabolism of cyclosporine A in microsomes isolated from CYP 3A4 transfected liver epithelial cells.
• Jensen, Ben Andre; Hermann, Monica; Reubsaet, Leon & Christensen, Hege Staaland (2013). Utvikling av kvantitativ proteomikkmetodefor P-glykoprotein i mononukleære celler fra perifert blod. Universitetet i Oslo.
• Bjøringsøy, Stine Karen; Barsett, Hilde & Christensen, Hege Staaland (2013). Ekstrakter av hageblåbær, skogsblåbær, tranebær og tyttebær hemmer CYP3A4 in vitro. Universitetet i Oslo.
• Nguyen, Maria; Barsett, Hilde & Christensen, Hege Staaland (2010). Hemming av CYP3A4-metabolisme av ulike bærekstrakter. Universitetet i Oslo.

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