Pregnancy-induced changes in pharmacokinetics: a mechanistic-based approach

Pharmacotherapy of obsessive-compulsive disorder during pregnancy: a clinical approach

Obsessive-compulsive disorder (OCD) is a relatively common psychiatric disorder in the perinatal period. However, specific pharmacological treatment approaches for patients with OCD during pregnancy have not been satisfactorily discussed in the literature. In addition, there are no randomized controlled studies on the treatment of this disorder during pregnancy. The present paper discusses the pharmacological treatment of OCD in the light of data on the safety of antipsychotics and serotonergic antidepressants during pregnancy and their efficacy in the non-perinatal period. Treatment decisions should be individualized because the risk-benefit profile of pharmacotherapy is an important issue in the treatment of pregnant women with any psychiatric diagnosis.

Rationale and design for an investigation to optimize selective serotonin reuptake inhibitor treatment for pregnant women with depression

The physiological changes of pregnancy can affect the pharmacokinetics of a drug, thereby affecting its dose requirements. Because pharmacokinetic (PK) studies in pregnant women have rarely been conducted, evidence-based dosing adjustments are seldom available. In particular, despite the fact that the use of antidepressants has become increasingly common, pregnancy-associated PK changes of the selective serotonin reuptake inhibitors (SSRIs) are largely unknown.

Preconception Counseling for Women with Congenital Heart Disease

With advances that have been made over the recent decades in transcatheter and surgical interventions, most patients with congenital heart disease (CHD) can survive into adulthood. Overall, probably half of these surviving patients are female. When these female CHD patients reach childbearing age, however, pregnancy management will be a major issue. In order to meet the demands of fetal growth, the maternal cardiovascular system starts a series of adaptations beginning in early pregnancy. These adaptations include: decreased systemic and pulmonary vascular resistances, decreased blood pressure, expansion of the blood volume, increased heart rate and increased cardiac output. For women with CHD, this hemodynamic alteration may increase the risks of adverse cardiovascular events as well as the fetal and neonatal complications. Therefore, proper risk stratification and effective counseling for women with CHD who are planning their pregnancies is an important undertaking.

KEY WORDS

Congenital heart disease; Pregnancy.

Use of anticancer agents in gynecological oncology during pregnancy: a systematic review of maternal pharmacokinetics and transplacental transfer

INTRODUCTION

Cancer affects one in a thousand pregnant women and gynecological cancers are one of the most frequent malignancies. Chemotherapy remains the cornerstone treatment for gynecological cancer. Although all chemotherapeutic agents can cross the placental barrier, the extent of placental transfer varies considerably. Furthermore, the significant physiological variations observed in pregnant women may have an impact on pharmacokinetic parameters. Given the complexity of predicting placental transfer, in vivo and ex vivo studies are essential in this context. In view of the paucity of data on chemotherapy during pregnancy, the objective of the present study was to summarize all the available data on the transplacental transfer of anticancer drugs used to treat gynecological cancers.

AREAS COVERED

In order to evaluate the in vivo and ex vivo transplacental transfer of the anticancer drugs most frequently used in gynecological malignancies, we carried out a comprehensive review of the literature published from 1967 to 2015. Lastly, we summarized recent clinical guidelines on the treatment of gynecological cancers in pregnant patients.

EXPERT OPINION

The preclinical and scarce clinical data must now be extrapolated to define the maternofetal toxicity/efficacy profile and thus guide the physicians to choose anticancer drugs more efficiently in this complex situation.

Blood Biomarkers of Late Pregnancy Exposure to Trihalomethanes in Drinking Water and Fetal Growth Measures and Gestational Age in a Chinese Cohort

BACKGROUND

Previous studies have suggested that elevated exposure to disinfection by-products (DBPs) in drinking water during gestation may result in adverse birth outcomes. However, the findings of these studies remain inconclusive.

OBJECTIVE

The purpose of our study was to examine the association between blood biomarkers of late pregnancy exposure to trihalomethanes (THMs) in drinking water and fetal growth and gestational age.

METHODS

We recruited 1,184 pregnant women between 2011 and 2013 in Wuhan and Xiaogan City, Hubei, China. Maternal blood THM concentrations, including chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (TBM), were measured as exposure biomarkers during late pregnancy. We estimated associations with gestational age and fetal growth indicators [birth weight, birth length, and small for gestational age (SGA)].

RESULTS

Total THMs (TTHMs; sum of TCM, BDCM, DBCM, and TBM) were associated with lower mean birth weight (-60.9 g; 95% CI: -116.2, -5.6 for the highest vs. lowest tertile; p for trend = 0.03), and BDCM and DBCM exposures were associated with smaller birth length (e.g., -0.20 cm; 95% CI: -0.37, -0.04 for the highest vs. lowest tertile of DBCM; p for trend = 0.02). SGA was increased in association with the second and third tertiles of TTHMs (OR = 2.91; 95% CI: 1.32, 6.42 and OR = 2.25; 95% CI: 1.01, 5.03; p for trend = 0.08).

CONCLUSIONS

Our results suggested that elevated maternal THM exposure may adversely affect fetal growth.

CITATION

Cao WC, Zeng Q, Luo Y, Chen HX, Miao DY, Li L, Cheng YH, Li M, Wang F, You L, Wang YX, Yang P, Lu WQ. 2016. Blood biomarkers of late pregnancy exposure to trihalomethanes in drinking water and fetal growth measures and gestational age in a Chinese cohort. Environ Health Perspect 124:536-541; http://dx.doi.org/10.1289/ehp.1409234.

Maternal Pharmacokinetics and Fetal Disposition of (±)-Citalopram during Mouse Pregnancy

While selective-serotonin reuptake inhibitor (SSRI) antidepressants are commonly prescribed in the treatment of depression, their use during pregnancy leads to fetal drug exposures. According to recent reports, such exposures could affect fetal development and long-term offspring health. A central question is how pregnancy-induced physical and physiological changes in mothers, fetuses, and the placenta influence fetal SSRI exposures during gestation. In this study, we examined the effects of gestational stage on the maternal pharmacokinetics and fetal disposition of the SSRI (±)-citalopram (CIT) in a mouse model. We determined the maternal and fetal CIT serum concentration-time profiles following acute maternal administration on gestational days (GD)14 and GD18, as well as the fetal brain drug disposition. The results show that pregnancy affects the pharmacokinetics of CIT and that maternal drug clearance increases as gestation progresses. The data further show that CIT and its primary metabolite desmethylcitalopram (DCIT) readily cross the placenta into the fetal compartment, and fetal exposure to CIT exceeds that of the mother during gestation 2 h after maternal administration. Enzymatic activity assays revealed that fetal drug metabolic capacity develops in late gestation, resulting in elevated circulating and brain concentrations of DCIT at embryonic day (E)18. Fetal exposure to the SSRI CIT in murine pregnancy is therefore influenced by both maternal gestational stage and embryonic development, suggesting potential time-dependent effects on fetal brain development.

Toward Earlier Inclusion of Pregnant and Postpartum Women in Tuberculosis Drug Trials: Consensus Statements From an International Expert Panel

Tuberculosis is a major cause of morbidity and mortality in women of childbearing age (15-44 years). Despite increased tuberculosis risk during pregnancy, optimal clinical treatment remains unclear: safety, tolerability, and pharmacokinetic data for many tuberculosis drugs are lacking, and trials of promising new tuberculosis drugs exclude pregnant women. To advance inclusion of pregnant and postpartum women in tuberculosis drug trials, the US National Institutes of Health convened an international expert panel. Discussions generated consensus statements (>75% agreement among panelists) identifying high-priority research areas during pregnancy, including: (1) preventing progression of latent tuberculosis infection, especially in women coinfected with human immunodeficiency virus; (2) evaluating new agents/regimens for treatment of multidrug-resistant tuberculosis; and (3) evaluating safety, tolerability and pharmacokinetics of tuberculosis drugs already in use during pregnancy and postpartum. Incorporating pregnant women into clinical trials would extend evidence-based tuberculosis prevention and treatment standards to this special population.

Issues for Women with Epilepsy

Epilepsy and antiepileptic drugs affect the menstrual cycle, aspects of contraception, reproductive health, pregnancy, and menopause through alteration of sex steroid hormone pathways. Sex steroid hormones often have an effect on seizure frequency and may alter the level of some antiepileptic drugs. Approximately one-third of women experience an increase in perimenstrual and/or periovulatory seizure frequency. Some women experience an increase in seizure frequency during pregnancy. Balancing maternal seizure control and the risk of congenital malformations associated with fetal antiepileptic drug exposure may be challenging. Some antiepileptic drugs are associated with cognitive and behavioral teratogenesis and should be avoided if possible during pregnancy.

Influence of gestational diabetes on the stereoselective pharmacokinetics and placental distribution of metoprolol and its metabolites in parturients

AIM

To investigate the influence of gestational diabetes mellitus (GDM) on the kinetic disposition and transplacental and amniotic fluid distribution of metoprolol and its metabolites O-desmethylmetoproloic acid and α-hydroxymetoprolol stereoisomers in hypertensive parturients receiving a single dose of the racemic drug.

METHODS

The study was conducted on hypertensive parturients with well-controlled GDM (n = 11) and non-diabetic hypertensive parturients (n = 24), all receiving a single 100 mg oral dose of racemic metoprolol tartrate before delivery. Serial maternal blood samples (0-24 h) and umbilical blood and amniotic fluid samples were collected for the quantitation of metoprolol and its metabolite stereoisomers using LC-MS/MS or fluorescence detection.

RESULTS

The kinetic disposition of metoprolol and its metabolites was stereoselective in the diabetic and control groups. Well-controlled GDM prolonged tmax for both enantiomers of metoprolol (1.5 vs. 2.5 h R-(+)-MET; 1.5 vs. 2.75 h S-(-)-MET) and O-desmethylmetoproloic acid (2.0 vs. 3.5 h R-(+)-AOMD; 2.0 vs. 3.0 h S-(-)-OAMD), and for the four stereoisomers of α-hydroxymetoprolol (2.0 vs. 3.0 h for 1'S,2R-, 1'R,2R- and 1'R,2S-OHM; 2.0 vs. 3.5 h for 1'S,2S-OHM) and reduced the transplacental distribution of 1'S,2S-, 1'R,2R-, and 1'R,2S-OHM by approximately 20%.

CONCLUSIONS

The kinetic disposition of metoprolol was enantioselective, with plasma accumulation of the S-(-)-MET eutomer. Well-controlled GDM prolonged the tmax of metoprolol and O-desmethylmetoproloic acid enantiomers and the α-hydroxymetoprolol stereoisomers and reduced by about 20% the transplacental distribution of 1'S,2S-, 1'R,2R-, and 1'R,2S-OHM. Thus, well-controlled GDM did not change the activity of CYP2D6 and CYP3A involved in metoprolol metabolism.

Pregnancy-induced changes in the pharmacokinetics of caffeine and its metabolites

This study sought to assess the pharmacokinetic (PK) changes of caffeine and its CYP1A2 metabolites across the 3 trimesters of pregnancy. A prospective, multicenter PK study was conducted among 59 pregnant women (93.2% white) who were studied once during a trimester. One beverage with 30-95 mg caffeine was consumed, and a blood/urine sample was collected within 1 hour postingestion. Concentrations of caffeine and its primary metabolites were quantified from serum and urine by LC-MS/MS. There was a significant increase in dose-normalized caffeine serum and urine concentrations between the first and third trimesters (P < .05 and P < .01, respectively). Normalized theophylline concentrations also increased significantly in the third trimester in serum (P < .001) and in urine (P < .05). The caffeine urine/serum concentration ratio also increased in the last trimester (P < .05). No significant difference was found in normalized paraxanthine or theobromine concentrations. This study identified decreased caffeine metabolism and an increase in the active metabolite theophylline concentrations during pregnancy, especially in the third trimester, revealing evidence of the large role that pregnancy plays in influencing caffeine metabolism.

Artemether-Lumefantrine Pharmacokinetics and Clinical Response Are Minimally Altered in Pregnant Ugandan Women Treated for Uncomplicated Falciparum Malaria

Artemether-lumefantrine is a first-line regimen for the treatment of uncomplicated malaria during the second and third trimesters of pregnancy. Previous studies have reported changes in the pharmacokinetics and clinical outcomes following treatment with artemether-lumefantrine in pregnant women compared to nonpregnant adults; however, the results are inconclusive. We conducted a study in rural Uganda to compare the pharmacokinetics of artemether-lumefantrine and the treatment responses between 30 pregnant women and 30 nonpregnant adults with uncomplicated Plasmodium falciparum malaria. All participants were uninfected with HIV, treated with a six-dose regimen of artemether-lumefantrine, and monitored clinically for 42 days. The pharmacokinetics of artemether, its metabolite dihydroartemisinin, and lumefantrine were evaluated for 21 days following treatment. We found no significant differences in the overall pharmacokinetics of artemether, dihydroartemisinin, or lumefantrine in a direct comparison of pregnant women to nonpregnant adults, except for a statistically significant but small difference in the terminal elimination half-lives of both dihydroartemisinin and lumefantrine. There were seven PCR-confirmed reinfections (5 pregnant and 2 nonpregnant participants). The observation of a shorter terminal half-life for lumefantrine may have contributed to a higher frequency of reinfection or a shorter posttreatment prophylactic period in pregnant women than in nonpregnant adults. While the comparable overall pharmacokinetic exposure is reassuring, studies are needed to further optimize antimalarial efficacy in pregnant women, particularly in high-transmission settings and because of emerging drug resistance. (This study is registered at ClinicalTrials.gov under registration no. NCT01717885.)

Population Pharmacokinetics of Rifampin in Pregnant Women with Tuberculosis and HIV Coinfection in Soweto, South Africa

Effective treatment of tuberculosis during pregnancy is essential for preventing maternal and fetal mortality, but little is known about the effects of pregnancy on the disposition of antituberculosis drugs. We explored the effects of pregnancy on the pharmacokinetics of rifampin, the key sterilizing drug in tuberculosis treatment, in Tshepiso, a prospective cohort study involving pregnant HIV-infected women with or without tuberculosis in Soweto, South Africa. Participants receiving standard first-line tuberculosis treatment underwent sparse sampling for rifampin at 37 weeks' gestation or delivery and then postpartum. Cord blood was collected when possible. A population pharmacokinetic model was developed to investigate the effects of pregnancy on rifampin pharmacokinetics. Among the 48 participants, median age and weight were 28 years and 67 kg, respectively. A one-compartment model with first-order elimination, transit compartment absorption, and allometric scaling described the data well. Pregnancy reduced rifampin clearance by 14%. The median (interquartile range) model-estimated rifampin area under the concentration-time curve over 24 h (AUC0-24) during pregnancy or intrapartum was 40.8 h · mg/liter (27.1 to 54.2 h · mg/liter) compared to 37.4 h · mg/liter (26.8 to 50.3 h · mg/liter) postpartum. The maximum concentrations were similar during pregnancy and postpartum. Rifampin was detectable in 36% (8/22) of cord blood samples, and 88% (42/48) of the women had successful treatment outcomes. There was one case of perinatal tuberculosis. In conclusion, rifampin clearance is modestly reduced during the last trimester of pregnancy. Exposures are only slightly increased, so dose adjustment during pregnancy is not needed. Rifampin was detected in cord blood samples when delivery occurred soon after dosing. The consequences of exposure to this potent inducer of metabolizing enzymes among HIV-exposed infants are unclear.

Impact of physiological, pathological and environmental factors on the expression and activity of human cytochrome P450 2D6 and implications in precision medicine

With only 1.3-4.3% in total hepatic CYP content, human CYP2D6 can metabolize more than 160 drugs. It is a highly polymorphic enzyme and subject to marked inhibition by a number of drugs, causing a large interindividual variability in drug clearance and drug response and drug-drug interactions. The expression and activity of CYP2D6 are regulated by a number of physiological, pathological and environmental factors at transcriptional, post-transcriptional, translational and epigenetic levels. DNA hypermethylation and histone modifications can repress the expression of CYP2D6. Hepatocyte nuclear factor-4α binds to a directly repeated element in the promoter of CYP2D6 and thus regulates the expression of CYP2D6. Small heterodimer partner represses hepatocyte nuclear factor-4α-mediated transactivation of CYP2D6. GW4064, a farnesoid X receptor agonist, decreases hepatic CYP2D6 expression and activity while increasing small heterodimer partner expression and its recruitment to the CYP2D6 promoter. The genotypes are key determinants of interindividual variability in CYP2D6 expression and activity. Recent genome-wide association studies have identified a large number of genes that can regulate CYP2D6. Pregnancy induces CYP2D6 via unknown mechanisms. Renal or liver diseases, smoking and alcohol use have minor to moderate effects only on CYP2D6 activity. Unlike CYP1 and 3 and other CYP2 members, CYP2D6 is resistant to typical inducers such as rifampin, phenobarbital and dexamethasone. Post-translational modifications such as phosphorylation of CYP2D6 Ser135 have been observed, but the functional impact is unknown. Further functional and validation studies are needed to clarify the role of nuclear receptors, epigenetic factors and other factors in the regulation of CYP2D6.

Maraviroc Pharmacokinetics in HIV-1-Infected Pregnant Women

OBJECTIVE

To describe the pharmacokinetics of maraviroc in human immunodeficiency virus (HIV)-infected women during pregnancy and post partum.

METHODS

HIV-infected pregnant women receiving maraviroc as part of clinical care had intensive steady-state 12-hour pharmacokinetic profiles performed during the third trimester and ≥2 weeks after delivery. Cord blood samples and matching maternal blood samples were taken at delivery. The data were collected in 2 studies: P1026 (United States) and PANNA (Europe). Pharmacokinetic parameters were calculated.

RESULTS

Eighteen women were included in the analysis. Most women (12; 67%) received 150 mg of maraviroc twice daily with a protease inhibitor, 2 (11%) received 300 mg twice daily without a protease inhibitor, and 4 (22%) had an alternative regimen. The geometric mean ratios for third-trimester versus postpartum maraviroc were 0.72 (90% confidence interval, .60-.88) for the area under the curve over a dosing interval (AUCtau) and 0.70 (0.58-0.85) for the maximum maraviroc concentration. Only 1 patient showed a trough concentration (Ctrough) below the suggested target of 50 ng/mL, both during pregnancy and post partum. The median ratio of maraviroc cord blood to maternal blood was 0.33 (range, 0.03-0.56). The viral load close to delivery was <50 copies/mL in 13 women (76%). All children were HIV negative at testing.

CONCLUSIONS

Overall maraviroc exposure during pregnancy was decreased, with a reduction in AUCtau and maximum concentration of about 30%. Ctrough was reduced by 15% but exceeded the minimum Ctrough target concentration. Therefore, the standard adult dose seems sufficient in pregnancy.

CLINICAL TRIALS REGISTRATION

NCT00825929 and NCT000422890.

Pharmacogenomics of preterm birth prevention and treatment

Pharmacogenomics and personalised medicine incorporate genetic factors, historical data, and environmental exposures to predict individual variation in response to medications. The study of pharmacology and pharmacogenomics is challenging in obstetrics, and our knowledge in this area lags behind other disciplines of medicine. Some preliminary data, however, suggest that some of the interindividual variation seen in response to medications given for the prevention (progesterone) and the treatment (nifedipine, terbutaline, and others) of preterm labour may be caused by pharmacogenomic effects. A comprehensive approach, integrating clinical data, environmental factors, including concomitant medications and genotype, to optimise the prevention and treatment strategies for preterm birth, is urgently needed.

TWEETABLE ABSTRACT

Some of the variation to meds for prematurity prevention/treatment may arise from pharmacogenomic effects.

Cardiac Arrest in Pregnancy

This is the first scientific statement from the American Heart Association on maternal resuscitation. This document will provide readers with up-to-date and comprehensive information, guidelines, and recommendations for all aspects of maternal resuscitation. Maternal resuscitation is an acute event that involves many subspecialties and allied health providers; this document will be relevant to all healthcare providers who are involved in resuscitation and specifically maternal resuscitation.

No Need for Lopinavir Dose Adjustment during Pregnancy: a Population Pharmacokinetic and Exposure-Response Analysis in Pregnant and Nonpregnant HIV-Infected Subjects

Lopinavir-ritonavir is frequently prescribed to HIV-1-infected women during pregnancy. Decreased lopinavir exposure has been reported during pregnancy, but the clinical significance of this reduction is uncertain. This analysis aimed to evaluate the need for lopinavir dose adjustment during pregnancy. We conducted a population pharmacokinetic analysis of lopinavir and ritonavir concentrations collected from 84 pregnant and 595 nonpregnant treatment-naive and -experienced HIV-1-infected subjects enrolled in six clinical studies. Lopinavir-ritonavir doses in the studies ranged between 400/100 and 600/150 mg twice daily. In addition, linear mixed-effect analysis was used to compare the area under the concentration-time curve from 0 to 12 h (AUC0-12) and concentration prior to dosing (Cpredose) in pregnant women and nonpregnant subjects. The relationship between lopinavir exposure and virologic suppression in pregnant women and nonpregnant subjects was evaluated. Population pharmacokinetic analysis estimated 17% higher lopinavir clearance in pregnant women than in nonpregnant subjects. Lopinavir clearance values postpartum were 26.4% and 37.1% lower than in nonpregnant subjects and pregnant women, respectively. As the tablet formulation was estimated to be 20% more bioavailable than the capsule formulation, no statistically significant differences between lopinavir exposure in pregnant women receiving the tablet formulation and nonpregnant subjects receiving the capsule formulation were identified. In the range of lopinavir AUC0-12 or Cpredose values observed in the third trimester, there was no correlation between lopinavir exposure and viral load or proportion of subjects with virologic suppression. Similar efficacy was observed between pregnant women and nonpregnant subjects receiving lopinavir-ritonavir at 400/100 mg twice daily. The pharmacokinetic and pharmacodynamic results support the use of a lopinavir-ritonavir 400/100-mg twice-daily dose during pregnancy.

Changes in the rate of nicotine metabolism across pregnancy: a longitudinal study

AIMS

Increased nicotine metabolism during pregnancy could explain why nicotine replacement therapy (NRT) appears to be less effective on smoking cessation in pregnancy than in non-pregnant smokers, but little is known about nicotine metabolism across pregnancy. This study was conducted to determine when changes in nicotine metabolism occur during pregnancy and to describe the magnitude of these changes.

DESIGN

Longitudinal cohort study of pregnant smokers' nicotine metabolite ratio (NMR).

SETTING AND PARTICIPANTS

101 pregnant smokers recruited from hospital antenatal clinics in Nottingham, UK were asked to provide saliva samples at 8-14 weeks (n = 98), 18-22 weeks (n = 65), 32-36 weeks gestation (n = 47), 4 weeks postpartum (n = 44) and 12 weeks postpartum (n = 47).

MEASUREMENTS

Nicotine metabolite ratio (NMR) was measured using the ratio of cotinine to its primary metabolite trans-3'-hydroxycotinine. Multi-level modelling was used to detect any overall difference in NMR between time points. The 12 week postpartum NMR was compared with the NMRs collected antenatally and 4 weeks postpartum.

FINDINGS

NMR changed over time (p = 0.0006). Compared with NMR at 12 weeks postpartum, NMR was significantly higher at 18-22 weeks (26% higher, 95% CI 12% to 38%) and 32-36 weeks (23% higher, 95% CI 9% to 35%). There was no significant difference between the 8-14 weeks gestation or 4 weeks postpartum NMR and 12 weeks postpartum.

CONCLUSIONS

Nicotine metabolism appears to be faster during pregnancy; this faster metabolism is apparent from 18 to 22 weeks of pregnancy and appears to fall by 4 weeks after childbirth.

The importance of studying antimicrobials in pregnancy

Pregnant women and their unborn fetuses are a population with unique and heightened risks from a variety of infectious conditions. Sizable percentages of pregnant women receive antimicrobials during pregnancy for various indications. Despite this, many of the available antimicrobials in current use have inadequate data to fully inform evidence-based dosage recommendations to optimize clinical impact. Because of non-inclusion of pregnant women in clinical trials this situation exists and challenges the obstetric providers' ability to provide evidence-based treatment. Examples of the impact of the current status of exclusion of pregnant women from participation in clinical trials will be highlighted. In addition, successful models of research permitting safe and informative investigations of various antimicrobials in pregnancy will be discussed.

Pharmacologic studies in vulnerable populations: Using the pediatric experience

Historically, few data exist to guide dosing in children and pregnant women. Multiple barriers to inclusion of these vulnerable populations in clinical trials have led to this paucity of data. However, federal legislation targeted at pediatric therapeutics, innovative clinical trial design, use of quantitative clinical pharmacology methods, pediatric thought leadership, and collaboration have successfully overcome many existing barriers. This success has resulted in improved knowledge on pharmacokinetics, safety, and efficacy of therapeutics in children. To date, research in pregnant women has not been characterized by similar success. Wide gaps in knowledge remain despite the common use of therapeutics in pregnancy. Given the similar barriers to drug research and development in pediatric and pregnant populations, the route toward success in children may serve as a model for the advancement of drug development and appropriate drug administration in pregnant women.

Epidemiology of medications use in pregnancy

The use of prescribed and over-the-counter medications in pregnancy is on the rise. Many women become pregnant at an older age and with preexisting medical conditions that require pharmacotherapy. In addition, pregnancy is associated with profound changes in the physiology of virtually every organ in the body, which affect medications' pharmacokinetics and pharmacodynamics. Despite all of these, pregnant women are still considered therapeutic orphans, as the majority of current therapeutics were never studied in pregnancy. The goals of this review are to synthesize the available information regarding the epidemiology of medications use and the state of drug research in pregnancy, in an effort to highlight the need for pharmacologic research in pregnancy.

Pharmacokinetics of drugs in pregnancy

Pregnancy is a complex state where changes in maternal physiology have evolved to favor the development and growth of the placenta and the fetus. These adaptations may affect preexisting disease or result in pregnancy-specific disorders. Similarly, variations in physiology may alter the pharmacokinetics or pharmacodynamics that determines drug dosing and effect. It follows that detailed pharmacologic information is required to adjust therapeutic treatment strategies during pregnancy. Understanding both pregnancy physiology and the gestation-specific pharmacology of different agents is necessary to achieve effective treatment and limit maternal and fetal risk. Unfortunately, most drug studies have excluded pregnant women based on often-mistaken concerns regarding fetal risk. Furthermore, over two-thirds of women receive prescription drugs while pregnant, with treatment and dosing strategies based on data from healthy male volunteers and non-pregnant women, and with little adjustment for the complex physiology of pregnancy and its unique disease states. This review will describe basic concepts in pharmacokinetics and their clinical relevance and highlight the variations in pregnancy that may impact the pharmacokinetic properties of medications.

Modified renal function in pregnancy: impact on emtricitabine pharmacokinetics

AIMS

The aims were to describe emtricitabine (FTC) pharmacokinetics in a large population of pregnant women during the different trimesters of pregnancy, and to explain FTC pharmacokinetic variability during pregnancy.

METHODS

FTC plasma concentrations were measured in 103 non-pregnant and 83 pregnant women, including women in the different trimesters of pregnancy and on the day of delivery. A total of 457 plasma concentrations were available for analysis. A population pharmacokinetic model was developed with Monolix 4.1.3.

RESULTS

FTC pharmacokinetics was best described by a two compartment model. The effect of creatinine clearance on apparent elimination clearance (CL/F) was significant. CL/F in pregnant women was significantly higher compared with non-pregnant women (geometric mean 24.1 vs 20.5 l h(-1) , P < 0.001), reflecting a modified renal function. FTC daily exposures (AUC) during pregnancy were lower than AUC in non-pregnant women, regardless of the trimester of pregnancy. FTC AUC geometric means were 8.38 mg l(-1 ) h in the second trimester of pregnancy, 8.16 mg l(-1 ) h in the third trimester of pregnancy, 8.30 mg l(-1 ) h on the day of delivery and 9.77 mg l(-1 ) h in non-pregnant women. FTC concentrations 24 h after administration were lower in pregnant women compared with non-pregnant women (0.054 vs. 0.079 mg l(-1) , P < 0.001) but still above the inhibitory concentration 50%.

CONCLUSIONS

FTC CL/F was increased by 18% during pregnancy, reflecting a modified renal function with 50% increase in estimated glomerular filtration rate. However, the impact of this modified renal function on FTC pharmacokinetics was not sufficiently large to consider dose adjustments during pregnancy.

Lumefantrine and Desbutyl-Lumefantrine Population Pharmacokinetic-Pharmacodynamic Relationships in Pregnant Women with Uncomplicated Plasmodium falciparum Malaria on the Thailand-Myanmar Border

Artemether-lumefantrine is the most widely used antimalarial artemisinin-based combination treatment. Recent studies have suggested that day 7 plasma concentrations of the potent metabolite desbutyl-lumefantrine correlate better with treatment outcomes than those of lumefantrine. Low cure rates have been reported in pregnant women with uncomplicated falciparum malaria treated with artemether-lumefantrine in northwest Thailand. A simultaneous pharmacokinetic drug-metabolite model was developed based on dense venous and sparse capillary lumefantrine and desbutyl-lumefantrine plasma samples from 116 pregnant patients on the Thailand-Myanmar border. The best model was used to evaluate therapeutic outcomes with a time-to-event approach. Lumefantrine and desbutyl-lumefantrine concentrations, implemented in an Emax model, both predicted treatment outcomes, but lumefantrine provided better predictive power. A combined model including both lumefantrine and desbutyl-lumefantrine did not improve the model further. Simulations suggested that cure rates in pregnant women with falciparum malaria could be increased by prolonging the treatment course. (These trials were registered at controlled-trials.com [ISRCTN 86353884].).

Physiologically-based pharmacokinetic modeling of renally excreted antiretroviral drugs in pregnant women

AIM

Physiological changes during pregnancy can affect drug disposition. Anticipating these changes will help to maximize drug efficacy and safety in pregnant women. Our objective was to determine if physiologically-based pharmacokinetics (PBPK) can accurately predict changes in the disposition of renally excreted antiretroviral drugs during pregnancy.

METHODS

Whole body PBPK models were developed for three renally excreted antiretroviral drugs, tenofovir (TFV), emtricitabine (FTC) and lamivudine (3TC). To assess the impact of pregnancy on PK, time-varying pregnancy-related physiological parameters available within the p-PBPK Simcyp software package were used. Renal clearance during pregnancy followed glomerular filtration changes with or without alterations in secretion. PK profiles were simulated and compared with observed data, i.e. area under the curves (AUC), peak plasma concentrations (Cmax ) and oral clearances (CL/F).

RESULTS

PBPK models successfully predicted TFV, FTC and 3TC disposition for non-pregnant and pregnant populations. Both renal secretion and filtration changed during pregnancy. Changes in renal clearance secretion were related to changes in renal plasma flow. The maximum clearance increases were approximately 30% (TFV 33%, FTC 31%, 3TC 29%).

CONCLUSIONS

Pregnancy PBPK models are useful tools to quantify a priori the drug exposure changes during pregnancy for renally excreted drugs. These models can be applied to evaluate alternative dosing regimens to optimize drug therapy during pregnancy.

Opposite malaria and pregnancy effect on oral bioavailability of artesunate - a population pharmacokinetic evaluation

Aim

The aim was to compare the pharmacokinetic properties of artesunate and dihydroartemisinin in the same women: i) pregnant with acute uncomplicated malaria on day 1 and 2, ii) pregnant with convalescent malaria on day 7 and iii) in a healthy state 3 months post-partum on day 1, 2 and 7.

Methods

Non-linear mixed-effects modelling was used to compare plasma concentration–time profiles of artesunate and dihydroartemisinin over 7 days of treatment following oral and intravenous artesunate administration to pregnant women with uncomplicated Plasmodium falciparum malaria during their second or third trimesters of pregnancy. The same women were restudied 3 months after delivery when fully recovered. Non-compartmental results of the same study have been published previously.

Results

Twenty pregnant patients on the Thailand-Myanmar border were studied and 15 volunteered to be restudied 3 months post-partum. Malaria and pregnancy had no effect on the pharmacokinetic properties of artesunate or dihydroartemisinin after intravenous artesunate administration. However, malaria and pregnancy had opposite effects on the absorption of orally administered artesunate. Malaria increased the absolute oral bioavailability of artesunate by 87%, presumably by inhibiting first pass effect, whereas pregnancy decreased oral bioavailability by 23%.

Conclusions

The population pharmacokinetic analysis demonstrated opposite effects of malaria and pregnancy on the bioavailability of orally administered artesunate. Lower drug exposures during the second and third trimesters of pregnancy may contribute to lower cure rates and thus the development of drug resistance. Dose optimization studies are required for artesunate containing artemisinin-based combination therapies (ACTs) in later pregnancy.

Therapeutic drug monitoring in HIV-infected pregnant women with a focus on protease inhibitors

The goals of HIV therapy in pregnant patients are to ensure health of mother and to prevent mother to child transmission of HIV to the unborn child. Pregnancy is a time of significant physiological alterations that affect all pharmacological aspects of the antiretroviral (ARV) drugs. Studies point toward lower levels of ARVs in maternal blood especially during late stages of pregnancy. Therapeutic drug monitoring is a strategy to ensure that maternal blood contains adequate level of ARVs to achieve these targets. Pharmacokinetics and therapeutic drug monitoring studies of protease inhibitors are reviewed in this article with emphasis on darunavir which is a newer protease inhibitor gaining popularity as a therapeutic choice in pregnant patients.

Analysis of nifedipine in human plasma and amniotic fluid by liquid chromatography-tandem mass spectrometry and its application to clinical pharmacokinetics in hypertensive pregnant women

Nifedipine is a dihydropyridine calcium channel blocker used for the treatment of hypertension in pregnant women. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for analysis of nifedipine in human plasma and amniotic fluid. Separation of nifedipine and nitrendipine (IS) was performed using a LiChroCART(®) RP-Select B column and a mixture of water:acetonitrile:glacial acetic acid (30:70:0.5 v/v) as the mobile phase. Aliquots of 500μL of biological samples were extracted at pH 13 using dichloromethane:n-pentane (3:7 v/v). The validated method was applied to a study of the pharmacokinetics of nifedipine in human plasma and amniotic fluid samples collected up to 12h after administration of the last slow-release nifedipine (20mg/12h) dose to 12 hypertensive pregnant women. The estimated pharmacokinetic parameters of nifedipine showed a mean AUC(0-12) of 250.2ngh/mL, ClT/F of 89.2L/h, Vd/F of 600.0L and t1/2 5.1h. The mean amniotic fluid/plasma concentration ratio was 0.05. The methods proved to be highly sensitive by showing a lower quantification limit of 0.1ng/mL for both matrices. And this study reports for the first time the complete development and validation of the method to quantify nifedipine in amniotic fluid using LC-MS-MS.

A pharmacological approach to panic disorder during pregnancy

Anxiety disorders and pregnancy may occur concurrently in some women. Although, several epidemiological or clinical studies about anxiety disorders in pregnancy exist, data on their treatment are very limited. Similar to other anxiety disorders, specific pharmacological treatment approaches in pregnant women with panic disorder (PD) have not been discussed in the literature. An important issue in the treatment of pregnant women with any psychiatric diagnosis is the risk-benefit profile of pharmacotherapy. Therefore, the treatment should be individualized. Untreated PD seems to be associated with several negative outcomes in the pregnancy. When the results of current study regarding the safety of pharmacological agents on the fetus and their efficacy in PD were gathered, sertraline, citalopram, imipramine and clomipramine at low doses for pure PD, and venlafaxine appeared to be more favorable than the other potential drugs. However, controlled studies examining optimum dosing, efficacy of antipanic medications and risk-benefit profile of intrauterine exposure to treated or untreated PD are urgently needed.

Population pharmacokinetics, tolerability, and safety of dihydroartemisinin-piperaquine and sulfadoxine-pyrimethamine-piperaquine in pregnant and nonpregnant Papua New Guinean women

The tolerability, safety, and disposition of dihydroartemisinin (DHA) and piperaquine (PQ) were assessed in 32 pregnant (second/third trimester) and 33 nonpregnant Papua New Guinean women randomized to adult treatment courses of DHA-PQ (three daily doses) or sulfadoxine-pyrimethamine (SP)-PQ (three daily PQ doses, single dose of SP). All dose adminstrations were observed, and subjects fasted for 2 h postdose. Plasma PQ was assayed by using high-performance liquid chromatography, and DHA was assessed by using liquid chromatography-mass spectrometry. Compartmental pharmacokinetic models were developed using a population-based approach. Both regimens were well tolerated. There was an expected increase in the rate-corrected electrocardiographic QT interval which was independent of pregnancy and treatment. Two pregnant and two nonpregnant women had Plasmodium falciparum parasitemia which cleared within 48 h, and no other subject became slide positive for malaria during 42 days of follow-up. Of 30 pregnant women followed to delivery, 27 (90%) delivered healthy babies and 3 (10%) had stillbirths; these obstetric outcomes are consistent with those in the general population. The area under the plasma PQ concentration-time curve (AUC0-∞) was lower in the pregnant patients (median [interquartile range], 23,721 μg · h/liter [21,481 to 27,951 μg · h/liter] versus 35,644 μg · h/liter [29,546 to 39,541 μg · h/liter]; P < 0.001) in association with a greater clearance relative to bioavailability (73.5 liters/h [69.4 to 78.4] versus 53.8 liters/h [49.7 to 58.2]; P < 0.001), but pregnancy did not influence the pharmacokinetics of DHA. The apparent pharmacokinetic differences between the present study and results from other studies of women with uncomplicated malaria that showed no effect of pregnancy on the AUC0-∞ of PQ and greater bioavailability may reflect differences in postdose fat intake, proportions of women with malaria, and/or racial differences in drug disposition.

Raltegravir in HIV-1-Infected Pregnant Women: Pharmacokinetics, Safety, and Efficacy

BACKGROUND

The use of raltegravir in human immunodeficiency virus (HIV)-infected pregnant women is important in the prevention of mother-to-child HIV transmission, especially in circumstances when a rapid decline of HIV RNA load is warranted or when preferred antiretroviral agents cannot be used. Physiological changes during pregnancy can reduce antiretroviral drug exposure. We studied the effect of pregnancy on the pharmacokinetics of raltegravir and its safety and efficacy in HIV-infected pregnant women.

METHODS

An open-label, multicenter, phase 4 study in HIV-infected pregnant women receiving raltegravir 400 mg twice daily was performed (Pharmacokinetics of Newly Developed Antiretroviral Agents in HIV-Infected Pregnant Women Network). Steady-state pharmacokinetic profiles were obtained in the third trimester and postpartum along with cord and maternal delivery concentrations. Safety and virologic efficacy were evaluated.

RESULTS

Twenty-two patients were included, of which 68% started raltegravir during pregnancy. Approaching delivery, 86% of the patients had an undetectable viral load (<50 copies/mL). None of the children were HIV-infected. Exposure to raltegravir was highly variable. Overall area under the plasma concentration-time curve (AUC) and plasma concentration at 12 hours after intake (C12h) plasma concentrations in the third trimester were on average 29% and 36% lower, respectively, compared with postpartum: Geometric mean ratios (90% confidence interval) were 0.71 (.53-.96) for AUC0-12h and 0.64 (.34-1.22) for C12h. The median ratio of raltegravir cord to maternal blood was 1.21 (interquartile range, 1.02-2.17; n = 9).

CONCLUSIONS

Raltegravir was well tolerated during pregnancy. The pharmacokinetics of raltegravir showed extensive variability. The observed mean decrease in exposure to raltegravir during third trimester compared to postpartum is not considered to be of clinical importance. Raltegravir can be used in standard dosages in HIV-infected pregnant women.

CLINICAL TRIALS REGISTRATION

NCT00825929.

Effects of Clozapine and other Atypical Antipsychotics on Infants Development Who Were Exposed to as Fetus: A Post-Hoc Analysis

OBJECTIVE

To investigate the developmental effects of clozapine and other atypical antipsychotics on infants who were exposed to as fetus.

METHOD

The developmental progress of 33 infants who were exposed to clozapine as fetus was compared to 30 infants who were exposed to risperidone, olanzapine or quetiapine as fetus by assessing Apgar scoring, birth weight at birth, body weight, height, and the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III) at months 2, 6 and 12 of age. Five subscale scores of BSID-III including cognitive, language, motor, social-emotional, and adaptive behavior were also compared. Student's t test and Chi-square analysis were used as appropriate. Repeated measurements were evaluated by analysis of covariance.

RESULTS

Of the 63 infants, 58 (92.1%) completed a 12-month study period. At the age of 2 and 6 months, mean adaptive behavior scores of BSID-III were significantly lower in clozapine-exposed infants than infants who exposed to other atypical antipsychotic at 2 and 6 months of age. More clozapine-exposed infants had delayed development (defined as the subscale score of <85) for adaptive behavior at 2 and 6 months of age. There was no difference between the two groups for cognitive, language, motor, social and emotional at 2, 6 and 12 months of age. More infants who were exposed to clozapine as fetus (25 of 33, 75.8%) had disturbed sleep and a labile state than those who were exposed to other atypical antipsychotics (8 of 30, 26.7%) during 2 months of age (P<0.001).

CONCLUSION

These results suggest that clozapine has more adaptive behavior effects on infants who were exposed to as a fetus than other atypical antipsychotics at 2 and 6 months of age.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01479400.

Acute myeloid leukemia in the pregnant patient

Although acute myeloid leukemia (AML) mostly occurs in older patients, it could be seen in women of childbearing age. It is therefore not surprising that in some patients, the management of AML will be complicated by a coexistent pregnancy. However, the association of leukemia and pregnancy is uncommon. Its incidence is estimated to be 1 in 75,000-100,000 pregnancies. During pregnancy, most leukemias are acute: two-thirds are myeloid and one-third are lymphoblastic. There is no standard approach for this clinical dilemma, in part because of variables such as the type of AML, the seriousness of the symptoms, and the patient's personal beliefs. In many cases, the diagnostic workup has to be altered because of the pregnancy, and often available treatments have varying risks to the fetus. While chemotherapy is reported to have some risks during the first trimester, it is admitted that it can be administered safely during the second and the third trimesters.

EPMA position paper in cancer: current overview and future perspectives

At present, a radical shift in cancer treatment is occurring in terms of predictive, preventive, and personalized medicine (PPPM). Individual patients will participate in more aspects of their healthcare. During the development of PPPM, many rapid, specific, and sensitive new methods for earlier detection of cancer will result in more efficient management of the patient and hence a better quality of life. Coordination of the various activities among different healthcare professionals in primary, secondary, and tertiary care requires well-defined competencies, implementation of training and educational programs, sharing of data, and harmonized guidelines. In this position paper, the current knowledge to understand cancer predisposition and risk factors, the cellular biology of cancer, predictive markers and treatment outcome, the improvement in technologies in screening and diagnosis, and provision of better drug development solutions are discussed in the context of a better implementation of personalized medicine. Recognition of the major risk factors for cancer initiation is the key for preventive strategies (EPMA J. 4(1):6, 2013). Of interest, cancer predisposing syndromes in particular the monogenic subtypes that lead to cancer progression are well defined and one should focus on implementation strategies to identify individuals at risk to allow preventive measures and early screening/diagnosis. Implementation of such measures is disturbed by improper use of the data, with breach of data protection as one of the risks to be heavily controlled. Population screening requires in depth cost-benefit analysis to justify healthcare costs, and the parameters screened should provide information that allow an actionable and deliverable solution, for better healthcare provision.

Alteration in cytochrome P450 3A4 activity as measured by a urine cortisol assay in HIV-1-infected pregnant women and relationship to antiretroviral pharmacokinetics

OBJECTIVES

Pregnancy results in physiological changes altering the pharmacokinetics of drugs metabolized by cytochrome P450 3A4 (CYP3A4). The urinary ratio of 6-β hydroxycortisol to cortisol (6βHF : F) is a marker of CYP3A4 induction. We sought to evaluate its change in antiretroviral (ARV)-treated HIV-1-infected women and to relate this change to ARV pharmacokinetics.

METHODS

Women receiving various ARVs had pharmacokinetic evaluations during the third trimester of pregnancy (>30 weeks) and postpartum with determination of 6βHF : F carried out on the same days. The Wilcoxon signed rank test was used to compare the ratio antepartum to postpartum. The relationship between the change in ratio and the change in pharmacokinetics was analysed using Kendall's tau.

RESULTS

6βHF : F ratios were available for 107 women antepartum, with 54 having postpartum values. The ratio was higher antepartum (P=0.033) (median comparison 1.35; 95% confidence interval 1.01, 1.81). For 71 women taking a protease inhibitor (PI), the antepartum vs. postpartum 6βHF : F comparison was marginally significant (P=0.058). When the change in the 6βHF : F ratio was related to the change in the dose-adjusted ARV area under the plasma concentration vs. time curve (AUC) between antepartum and postpartum, the 35 subjects in the lopinavir/ritonavir (LPV/r) arms demonstrated an inverse relationship (P=0.125), albeit this correlation did not reach statistical significance.

CONCLUSIONS

A 35% increase in the urinary 6βHF : F ratio was measured during late pregnancy compared with postpartum, indicating that CYP3A induction occurs during pregnancy. The trend towards an inverse relationship between the change in the 6βHF : F ratio and the change in the LPV AUC antepartum vs. postpartum suggests that CYP3A induction may be one mechanism behind altered LPV exposure during pregnancy.

Pharmacogenetics of pregnancy-induced changes in efavirenz pharmacokinetics

Pregnancy-induced physiological changes alter many drugs' pharmacokinetics. We investigated pregnancy-induced changes in efavirenz pharmacokinetics in 25 pregnant and 19 different postpartum women stratified from 211 HIV-positive women in whom a preliminary pharmacogenetic study had been undertaken. Despite significant changes in CL/F during pregnancy (42.6% increase; P = 0.023), median (range) Cmin was 1,000 ng/mL (429-5,190) with no significant change in Cmax (P = 0.072). However, when stratified for CYP2B6 516G>T (rs3745274) genotype, efavirenz AUC0-24 , Cmax and Cmin were 50.6% (P = 0.0013), 17.2% (P = 0.14), and 61.6% (P = 0.0027) lower during pregnancy (n = 8) compared with postpartum (n = 6) in 516G homozygotes, with values of 25,900 ng.h/mL (21,700-32,600), 2,640 ng/mL (1,260-3,490), and 592 ng/mL (429-917), respectively, and CL/F was 100% higher (P = 0.0013). No changes were apparent in CYP2B6 516 heterozygotes (14 pregnant vs. 7 postpartum). The clinical implications of these findings warrant further investigation.

Ondansetron pharmacokinetics in pregnant women and neonates: towards a new treatment for neonatal abstinence syndrome

Ondansetron is the drug of choice to prevent nausea in women undergoing cesarean surgery and can be used to prevent neonatal abstinence syndrome (NAS). The pharmacokinetics of ondansetron have not been characterized in pregnant women or in newborns. A nonlinear mixed-effects modeling approach was used to analyze plasma samples obtained from 20 nonpregnant and 40 pregnant women following a single administration of 4 or 8 mg ondansetron, from umbilical cord blood at delivery, and from neonates after birth. The analysis indicates that: ondansetron disposition is not affected by pregnancy (P > 0.05), but influenced by dose (P < 0.05), and is characterized by rapid transplacental transfer and longer elimination half-life in neonates compared to their mother. A dosing regimen for prevention of NAS was designed based on the model. The regimen involves IV administration of 4 mg to the mothers shortly before cord clamping, or oral administration of 0.07 mg/kg (or equivalently 0.04 mg/kg IV) to neonates.