The effects of fasting on drug metabolism

Introduction: There is considerable variability in the rates and extent of drug metabolism between patients due to physiological, genetic, pharmacologic, environmental and nutritional factors such as fasting. This variability in drug metabolism may result in treatment failure or, conversely, in increased side effects or toxicity. Preclinical studies have shown that fasting alters drug metabolism by modulating the activity of drug metabolizing enzymes involved. However, until recently little was known about the effects of fasting on drug metabolism in humans.Areas covered: This review describes the effects of fasting on drug metabolism based on both preclinical studies and studies performed in humans.Expert opinion: A better understanding of the effects of fasting may improve the efficacy and safety of pharmacotherapy for individual patients. Fasting contributes to variability in human drug metabolism by differentially affecting drug metabolizing enzymes. Although the effects of fasting on drug metabolism appear to be small (between 10-20%), fasting may be relevant for drugs with a small therapeutic range and/or in combination with other factors that contribute to variability in drug metabolism such as physiological, genetic or pharmacological factors. Therefore, additional research on this topic is warranted.

Sorafenib for Patients with Hepatocellular Carcinoma and Child-Pugh B Liver Cirrhosis: Lessons Learned from a Terminated Study

Lessons Learned

Recruitment of patients with advanced hepatocellular carcinoma and Child‐Pugh B for sorafenib treatment and additional pharmacokinetic studies is challenging.

Patients with Child‐Pugh B liver cirrhosis have high rates of cirrhosis‐related adverse events.

Background

Few data are available on the pharmacokinetics (PK) of sorafenib in patients with advanced hepatocellular carcinoma (HCC) and Child‐Pugh B liver cirrhosis. This study aimed to explore the sorafenib PK and its relationship with efficacy and toxicity in these patients.

Methods

Patients with advanced HCC and Child‐Pugh B7‐8 liver function were prospectively recruited at a tertiary center. Adverse events (AEs), progression‐free survival (PFS), and overall survival (OS) were recorded. Patients received a starting dose of 200 b.i.d. with toxicity‐adjusted dose escalation to a target dose of 400 mg b.i.d. with PK sampling at fixed time points.

Results

Between May 2014 and March 2017, 12 patients were screened, of whom 7 progressed to a terminal stage during the screening (n = 6) or shortly after recruitment (n = 1). The five included patients had median PFS of 3.8 months (range, 1.7–10.8) and OS of 7.4 months (range, 1.7–25.8). Three patients had severe AEs and one patient had a partial response with an OS of 25.8 months. In 2017, the trial was aborted for lack of accrual.

Conclusion

Because of low accrual, no conclusion can be drawn on the sorafenib PK in patients with advanced HCC and Child‐Pugh B liver cirrhosis. The poor survival and frequent cirrhosis‐related AEs suggest limited benefit for most of these patients.

Differential effects of a 40-hour fast and bile acid supplementation on human GLP-1 and FGF19 responses

Bile acids, glucagon-like peptide-1 (GLP-1), and fibroblast growth factor 19 (FGF19) play an important role in postprandial metabolism. In this study, we investigated the postprandial bile acid response in plasma and its relation to insulin, GLP-1, and FGF19. First, we investigated the postprandial response to 40-h fast. Then we administered glycine-conjugated deoxycholic acid (gDCA) with the meal. We performed two separate observational randomized crossover studies on healthy, lean men. In experiment 1: we tested 4-h mixed meal after an overnight fast and a 40-h fast. In experiment 2, we tested a 4-h mixed meal test with and without gDCA supplementation. Both studies measured postprandial glucose, insulin, bile acids, GLP-1, and FGF19. In experiment 1, 40 h of fasting induced insulin resistance and increased postprandial GLP-1 and FGF19 concentrations. After an overnight fast, we observed strong correlations between postprandial insulin and gDCA levels at specific time points. In experiment 2, administration of gDCA increased GLP-1 levels and lowered late postprandial glucose without effect on FGF19. Energy expenditure was not affected by gDCA administration. Unexpectedly, 40 h of fasting increased both GLP-1 and FGF19, where the former appeared bile acid independent and the latter bile acid dependent. Second, a single dose of gDCA increased postprandial GLP-1. Therefore, our data add complexity to the physiological regulation of the enterokines GLP-1 and FGF19 by bile acids.

Nutritional Status Differentially Alters Cytochrome P450 3A4 (CYP3A4) and Uridine 5'-Diphospho-Glucuronosyltransferase (UGT) Mediated Drug Metabolism: Effect of Short-Term Fasting and High Fat Diet on Midazolam Metabolism

BACKGROUND AND OBJECTIVES

Previous studies have shown that nutritional status can alter drug metabolism which may result in treatment failure or untoward side effects. This study assesses the effect of two nutritional conditions, short-term fasting, and a short-term high fat diet (HFD) on cytochrome P450 3A4 (CYP3A4) and uridine 5'-diphospho-glucuronosyltransferase (UGT) mediated drug metabolism by studying the pharmacokinetics of midazolam and its main metabolites.

METHODS

In a randomized-controlled cross-over trial, nine healthy subjects received a single intravenous administration of 0.015 mg/kg midazolam after: (1) an overnight fast (control); (2) 36 h of fasting; and (3) an overnight fast after 3 days of a HFD consisting of 500 ml of cream supplemented to their regular diet. Pharmacokinetic parameters were analyzed simultaneously using non-linear mixed-effects modeling.

RESULTS

Short-term fasting increased CYP3A4-mediated midazolam clearance by 12% (p < 0.01) and decreased UGT-mediated metabolism apparent 1-OH-midazolam clearance by 13% (p < 0.01) by decreasing the ratio of clearance and the fraction metabolite formed (ΔCL_1-OH-MDZ/f_1-OH-MDZ). Furthermore, short-term fasting decreased apparent clearance of 1-OH-midazolam-O-glucuronide (CL_{1-OH-MDZ-glucuronide}/(f_{1-OH-MDZ-glucuronide} × f_1-OH-MDZ)) by 20% (p < 0.01). The HFD did not affect systemic clearance of midazolam or metabolites.

CONCLUSIONS

Short-term fasting differentially alters midazolam metabolism by increasing CYP3A4-mediated metabolism but by decreasing UGT-mediated metabolism. In contrast, a short-term HFD did not affect systemic clearance of midazolam.

Short-Term Fasting Alters Pharmacokinetics of Cytochrome P450 Probe Drugs: Does Protein Binding Play a Role?

Background and Objectives

Short-term fasting differentially alters cytochrome P450 (CYP) mediated drug metabolism. This has been established by using CYP-enzyme selective probe drugs. However, the observed effects of fasting on the pharmacokinetics of these probe drugs may also include the effects of altered plasma protein binding of these drugs. Therefore, we studied the effect of short-term fasting on protein binding of five commonly used probe drugs [caffeine (CYP1A2), metoprolol (CYP2D6), midazolam (CYP3A4), omeprazole (CYP2C19) and S-warfarin (CYP2C9)].

Methods

The free and total plasma concentrations of the five probe drugs were analyzed by LC–MS/MS in samples retrieved in a cross-over study in which nine healthy subjects received an intravenous administration of the cocktail after an overnight fast (control) and after 36 h of fasting.

Results

Short-term fasting increased plasma free fatty acid concentrations from 0.48 mmol/L (control) to 1.29 mmol/L (36 h fasting) (p = 0.012). Short-term fasting did not alter the free fractions of caffeine, metoprolol and omeprazole compared to the control intervention (p > 0.05). Power to detect a difference for midazolam and S-warfarin was low since the majority of free concentrations were below the limit of quantification.

Conclusions

This study demonstrates that short-term fasting does not alter protein binding of the probe drugs caffeine, metoprolol and omeprazole.

Electronic supplementary material

The online version of this article (doi:10.1007/s13318-017-0437-7) contains supplementary material, which is available to authorized users.

Effect of Short-Term Fasting on Systemic Cytochrome P450-Mediated Drug Metabolism in Healthy Subjects: A Randomized, Controlled, Crossover Study Using a Cocktail Approach

Background and Objective

Short-term fasting can alter drug exposure but it is unknown whether this is an effect of altered oral bioavailability and/or systemic clearance. Therefore, the aim of our study was to assess the effect of short-term fasting on oral bioavailability and systemic clearance of different drugs.

Methods

In a randomized, controlled, crossover trial, 12 healthy subjects received a single administration of a cytochrome P450 (CYP) probe cocktail, consisting of caffeine (CYP1A2), metoprolol (CYP2D6), midazolam (CYP3A4), omeprazole (CYP2C19) and warfarin (CYP2C9), on four occasions: an oral (1) and intravenous (2) administration after an overnight fast (control) and an oral (3) and intravenous (4) administration after 36 h of fasting. Pharmacokinetic parameters of the probe drugs were analyzed using the nonlinear mixed-effects modeling software NONMEM.

Results

Short-term fasting increased systemic caffeine clearance by 17% (p = 0.04) and metoprolol clearance by 13% (p < 0.01), whereas S-warfarin clearance decreased by 19% (p < 0.01). Fasting did not affect bioavailability.

Conclusion

The study demonstrates that short-term fasting alters CYP-mediated drug metabolism in a non-uniform pattern without affecting oral bioavailability.

Fasting-Induced Changes in Hepatic P450 Mediated Drug Metabolism Are Largely Independent of the Constitutive Androstane Receptor CAR

Introduction

Hepatic drug metabolism by cytochrome P450 enzymes is altered by the nutritional status of patients. The expression of P450 enzymes is partly regulated by the constitutive androstane receptor (CAR). Fasting regulates the expression of both P450 enzymes and CAR and affects hepatic drug clearance. We hypothesized that the fasting-induced alterations in P450 mediated drug clearance are mediated by CAR.

Methods

To investigate this we used a drug cocktail validated in humans consisting of five widely prescribed drugs as probes for specific P450 enzymes: caffeine (CYP1A2), metoprolol (CYP2D6), omeprazole (CYP2C19), midazolam (CYP3A4) and s-warfarin (CYP2C9). This cocktail was administered to wild type (WT, C57Bl/6) mice or mice deficient for CAR (CAR^-/-) that were either fed ad libitum or fasted for 24 hours. Blood was sampled at predefined intervals and drug concentrations were measured as well as hepatic mRNA expression of homologous/orthologous P450 enzymes (Cyp1a2, Cyp2d22, Cyp3a11, Cyp2c37, Cyp2c38 and Cyp2c65).

Results

Fasting decreased Cyp1a2 and Cyp2d22 expression and increased Cyp3a11 and Cyp2c38 expression in both WT and CAR^-/- mice. The decrease in Cyp1a2 was diminished in CAR^-/- in comparison with WT mice. Basal Cyp2c37 expression was lower in CAR^-/- compared to WT mice. Fasting decreased the clearance of all drugs tested in both WT and CAR^-/- mice. The absence of CAR was associated with an decrease in the clearance of omeprazole, metoprolol and midazolam in fed mice. The fasting-induced reduction in clearance of s-warfarin was greater in WT than in CAR^-/-. The changes in drug clearance correlated with the expression pattern of the specific P450 enzymes in case of Cyp1a2-caffeine and Cyp2c37-omeprazole.

Conclusion

We conclude that CAR is important for hepatic clearance of several widely prescribed drugs metabolized by P450 enzymes. However the fasting-induced alterations in P450 mediated drug clearance are largely independent of CAR.

A short-term high fat diet increases exposure to midazolam and omeprazole in healthy subjects

OBJECTIVES

Knowledge of factors contributing to variation in drug metabolism is of vital importance to optimize drug treatment. This study assesses the effects of a short-term hypercaloric high fat diet on metabolism of five oral drugs, which are each specific for a single P450 isoform: midazolam (CYP3A4), omeprazole (CYP2C19), metoprolol (CYP2D6), S-warfarin (CYP2C9) and caffeine (CYP1A2).

METHODS

In 9 healthy volunteers, pharmacokinetics of the five drugs were assessed after an overnight fast at two separate occasions: after a regular diet and after 3 days of a hypercaloric high fat diet (i.e. regular diet supplemented with 500 mL cream [1715 kcal, 35% fat]). Pharmacokinetic parameters (mean [SEM]) were estimated by non-compartmental analysis.

RESULTS

The high fat diet increased exposure to midazolam by 19% from 24.7 (2.6) to 29.5 (3.6) ng ml-1h-1 (p=0.04) and exposure to omeprazole by 31% from 726 (104) to 951 (168) ng ml-1h-1 (p=0.05). Exposure to metoprolol, caffeine and S-warfarin was not affected by the high fat diet.

CONCLUSION

A short-term hypercaloric high fat diet increases exposure to midazolam and omeprazole, possibly reflecting modulation of CYP3A4 and CYP2C19.

Short-term fasting alters cytochrome P450-mediated drug metabolism in humans

Experimental studies indicate that short-term fasting alters drug metabolism. However, the effects of short-term fasting on drug metabolism in humans need further investigation. Therefore, the aim of this study was to evaluate the effects of short-term fasting (36 h) on P450-mediated drug metabolism. In a randomized crossover study design, nine healthy subjects ingested a cocktail consisting of five P450-specific probe drugs [caffeine (CYP1A2), S-warfarin (CYP2C9), omeprazole (CYP2C19), metoprolol (CYP2D6), and midazolam (CYP3A4)] on two occasions (control study after an overnight fast and after 36 h of fasting). Blood samples were drawn for pharmacokinetic analysis using nonlinear mixed effects modeling. In addition, we studied in Wistar rats the effects of short-term fasting on hepatic mRNA expression of P450 isoforms corresponding with the five studied P450 enzymes in humans. In the healthy subjects, short-term fasting increased oral caffeine clearance by 20% (P = 0.03) and decreased oral S-warfarin clearance by 25% (P < 0.001). In rats, short-term fasting increased mRNA expression of the orthologs of human CYP1A2, CYP2C19, CYP2D6, and CYP3A4 (P < 0.05), and decreased the mRNA expression of the ortholog of CYP2C9 (P < 0.001) compared with the postabsorptive state. These results demonstrate that short-term fasting alters cytochrome P450-mediated drug metabolism in a nonuniform pattern. Therefore, short-term fasting is another factor affecting cytochrome P450-mediated drug metabolism in humans.

Clustering of additional autoimmunity behaves differently in Hashimoto's patients compared with Graves' patients

OBJECTIVE

It is unclear whether Hashimoto's thyroiditis and Graves' disease (often referred to as autoimmune thyroid disease, AITD) cluster to the same extent with other autoimmune disorders.

METHODS

We assessed adrenal, β-cell, celiac and gastric antibodies in a cohort of 523 adult patients with Graves' disease and 359 patients with Hashimoto's disease and compared their clustering.

RESULTS

Adrenal autoimmunity associated more often with Hashimoto's disease (9.0%) than with Graves' disease (3.3%, P=0.001). β-cell autoimmunity was seen more frequently in Hashimoto's disease (25.4%) than in Graves' disease (15.6%, P=0.001) patients. We found low prevalences of celiac autoimmunity (1.2% for Graves' and 1.2% for Hashimoto's disease). Celiac and gastric autoimmunity were not statistically different in Hashimoto's and Graves' disease patients. Although gastric autoimmunity itself was equally prevalent (around 20%), Hashimoto's disease often showed significantly more clustering of adrenal autoimmunity with gastric autoimmunity (5.3%) than Graves' disease (1.2%, P=0.001). Similarly, clustering of adrenal autoimmunity was seen with β-cell autoimmunity in Hashimoto's patients (3.2%), while such clustering was much less encountered in 359 Graves' patients (0.9%, P=0.029).

CONCLUSION

In conclusion, Hashimoto's disease shows a markedly higher clustering of additional autoimmunity, especially with adrenal and β-cell autoimmunity. Combined clustering of gastric and adrenal autoimmunity and combined clustering of adrenal and β-cell autoimmunity were both seen more often in Hashimoto's patients. Clustering with celiac disease appears to be low. These findings indicate that Hashimoto's and Graves' disease differ in their clinical expression regarding additional autoimmunity, which argues against the indiscriminate use of AITD as an entity.

Implementation of preconceptional carrier screening for cystic fibrosis and haemoglobinopathies: a sociotechnical analysis

OBJECTIVE

To obtain more insight into the process of potential implementation of a screening program, which aims to identify carriers of cystic fibrosis and haemoglobinopathies before pregnancy, in order to enable couples at high risk of having a child with these disorders, to make informed reproductive decisions.

METHODS

Use of sociotechnical analysis, based on a model of co-evolution between technology and society, and, for comparison, the study of the implementation processes of two already existing health care programs with similar aspects to the screening program at issue.

RESULTS

Factors important for success appeared to be the existence of sociotechnical niches, in which technological options can be developed and studied in an experimental setting; a structural approach of providing information to future parents; a party that can articulate demand; governmental involvement in the attunement between various stakeholders; and a screening infrastructure in which large-scale DNA diagnostic services are available.

CONCLUSIONS

Successful implementation of preconceptional carrier screening for cystic fibrosis and haemoglobinopathies will depend on changes at both regime and landscape level, including the establishment of a new preconceptional health care setting and a clearly visible public health authority which can coordinate, monitor and evaluate such an initiative in public health care.