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Stika CS, Hebert MF. Design Considerations for Pharmacokinetic Studies During Pregnancy. J Clin Pharmacol 2023; 63 Suppl 1:S126-S136. [PMID: 37317491 PMCID: PMC10350295 DOI: 10.1002/jcph.2238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/28/2023] [Indexed: 06/16/2023]
Abstract
Most of the interventions performed by obstetric providers involve the administration of drugs. Pregnant patients are pharmacologically and physiologically different from nonpregnant young adults. Therefore, dosages that are effective and safe for the general public may be inadequate or unsafe for the pregnant patient and her fetus. Establishing dosing regimens appropriate for pregnancy requires evidence generated from pharmacokinetic studies performed in pregnant people. However, performing these studies during pregnancy often requires special design considerations, evaluations of both maternal and fetal exposures, and recognition that pregnancy is a dynamic process that changes as gestational age advances. In this article, we address design challenges unique to pregnancy and discuss options for investigators, including timing of drug sampling during pregnancy, appropriate selection of control groups, pros and cons of dedicated and nested pharmacokinetic studies, single-dose and multiple-dose analyses, dose selection strategies, and the importance of integrating pharmacodynamic changes into these protocols. Examples of completed pharmacokinetic studies in pregnancy are provided for illustration.
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Affiliation(s)
- Catherine S. Stika
- Northwestern University, Department of Obstetrics and Gynecology, Chicago IL
| | - Mary F. Hebert
- University of Washington, Departments of Pharmacy and Obstetrics and Gynecology, Seattle WA
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Stika CS. Principles of Obstetric Pharmacology: Maternal Physiologic and Hepatic Metabolism Changes. Obstet Gynecol Clin North Am 2023; 50:1-15. [PMID: 36822695 DOI: 10.1016/j.ogc.2022.10.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Since the recognition of pregnancy as a special pharmacokinetic population in the late 1990s, investigations have expanded our understanding of obstetric pharmacology. Many of the basic physiologic changes that occur during pregnancy impact on drug absorption, distribution, or clearance. Activities of hepatic metabolizing enzymes are variably altered by pregnancy, resulting in concentrations sufficiently different for some drugs that efficacy or toxicity may be affected. Understanding these unique pharmacologic changes will better inform our use of medications for our pregnant patients.
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Affiliation(s)
- Catherine S Stika
- Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, 250 East Superior Street, Suite 03-2303, Chicago, IL 60611, USA.
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Abstract
During pregnancy, there are several physiological changes during each trimester that can affect the absorption, distribution, metabolism, and elimination of drugs. Although there is a potential need to understand the pharmacokinetics and pharmacodynamics of drugs in pregnant patients, therapeutic drug monitoring is not well established for various drug classes due to ethical and safety concerns regarding the neonate. Potential risks from in utero drug exposure to the fetus may impact growth and development and may cause malformations or teratogenesis. The clinician must consider the benefits of drug treatment for the pregnant mother versus the risk to the fetus, before prescribing medications during pregnancy. The objective of this review is to aid clinicians, pharmacists, and laboratorians in understanding the pharmacokinetic and pharmacodynamic changes during pregnancy, to provide drug class recommendations for monitoring therapy throughout pregnancy via therapeutic drug monitoring, and to highlight the recent directives of governing agencies on maternal and fetal health.
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Lin YS, Thummel KE, Thompson BD, Totah RA, Cho CW. Sources of Interindividual Variability. Methods Mol Biol 2021; 2342:481-550. [PMID: 34272705 DOI: 10.1007/978-1-0716-1554-6_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The efficacy, safety, and tolerability of drugs are dependent on numerous factors that influence their disposition. A dose that is efficacious and safe for one individual may result in sub-therapeutic or toxic blood concentrations in others. A significant source of this variability in drug response is drug metabolism, where differences in presystemic and systemic biotransformation efficiency result in variable degrees of systemic exposure (e.g., AUC, Cmax, and/or Cmin) following administration of a fixed dose.Interindividual differences in drug biotransformation have been studied extensively. It is recognized that both intrinsic factors (e.g., genetics, age, sex, and disease states) and extrinsic factors (e.g., diet , chemical exposures from the environment, and the microbiome) play a significant role. For drug-metabolizing enzymes, genetic variation can result in the complete absence or enhanced expression of a functional enzyme. In addition, upregulation and downregulation of gene expression, in response to an altered cellular environment, can achieve the same range of metabolic function (phenotype), but often in a less predictable and time-dependent manner. Understanding the mechanistic basis for variability in drug disposition and response is essential if we are to move beyond the era of empirical, trial-and-error dose selection and into an age of personalized medicine that will improve outcomes in maintaining health and treating disease.
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Affiliation(s)
- Yvonne S Lin
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA.
| | - Kenneth E Thummel
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Brice D Thompson
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Rheem A Totah
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - Christi W Cho
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
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Abduljalil K, Badhan RKS. Drug dosing during pregnancy-opportunities for physiologically based pharmacokinetic models. J Pharmacokinet Pharmacodyn 2020; 47:319-340. [PMID: 32592111 DOI: 10.1007/s10928-020-09698-w] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 06/20/2020] [Indexed: 12/15/2022]
Abstract
Drugs can have harmful effects on the embryo or the fetus at any point during pregnancy. Not all the damaging effects of intrauterine exposure to drugs are obvious at birth, some may only manifest later in life. Thus, drugs should be prescribed in pregnancy only if the expected benefit to the mother is thought to be greater than the risk to the fetus. Dosing of drugs during pregnancy is often empirically determined and based upon evidence from studies of non-pregnant subjects, which may lead to suboptimal dosing, particularly during the third trimester. This review collates examples of drugs with known recommendations for dose adjustment during pregnancy, in addition to providing an example of the potential use of PBPK models in dose adjustment recommendation during pregnancy within the context of drug-drug interactions. For many drugs, such as antidepressants and antiretroviral drugs, dose adjustment has been recommended based on pharmacokinetic studies demonstrating a reduction in drug concentrations. However, there is relatively limited (and sometimes inconsistent) information regarding the clinical impact of these pharmacokinetic changes during pregnancy and the effect of subsequent dose adjustments. Examples of using pregnancy PBPK models to predict feto-maternal drug exposures and their applications to facilitate and guide dose assessment throughout gestation are discussed.
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Affiliation(s)
- Khaled Abduljalil
- Certara UK Limited, Simcyp Division, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK.
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Abstract
Pharmacologic interventions play a major role in obstetrical care throughout pregnancy, labor and delivery and the postpartum. Traditionally, obstetrical providers have utilized standard dosing regimens developed for non-obstetrical indications based on pharmacokinetic knowledge from studies in men or non-pregnant women. With the recognition of pregnancy as a special pharmacokinetic population in the late 1990s, investigators have begun to study drug disposition in this unique patient dyad. Many of the basic physiologic changes that occur during pregnancy have significant impact on drug absorption, distribution and clearance. Activity of Phase I and Phase II drug metabolizing enzymes are differentially altered by pregnancy, resulting in drug concentrations sufficiently different for some medications that efficacy or toxicity is affected. Placental transporters play a major dynamic role in determining fetal drug exposure. In the past two decades, we have begun to expand our understanding of obstetrical pharmacology; however, to truly optimize pharmacologic care of our pregnant patients and their developing fetus, additional research is critically needed.
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Dallmann A, Ince I, Coboeken K, Eissing T, Hempel G. A Physiologically Based Pharmacokinetic Model for Pregnant Women to Predict the Pharmacokinetics of Drugs Metabolized Via Several Enzymatic Pathways. Clin Pharmacokinet 2019; 57:749-768. [PMID: 28924743 DOI: 10.1007/s40262-017-0594-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Physiologically based pharmacokinetic modeling is considered a valuable tool for predicting pharmacokinetic changes in pregnancy to subsequently guide in-vivo pharmacokinetic trials in pregnant women. The objective of this study was to extend and verify a previously developed physiologically based pharmacokinetic model for pregnant women for the prediction of pharmacokinetics of drugs metabolized via several cytochrome P450 enzymes. METHODS Quantitative information on gestation-specific changes in enzyme activity available in the literature was incorporated in a pregnancy physiologically based pharmacokinetic model and the pharmacokinetics of eight drugs metabolized via one or multiple cytochrome P450 enzymes was predicted. The tested drugs were caffeine, midazolam, nifedipine, metoprolol, ondansetron, granisetron, diazepam, and metronidazole. Pharmacokinetic predictions were evaluated by comparison with in-vivo pharmacokinetic data obtained from the literature. RESULTS The pregnancy physiologically based pharmacokinetic model successfully predicted the pharmacokinetics of all tested drugs. The observed pregnancy-induced pharmacokinetic changes were qualitatively and quantitatively reasonably well predicted for all drugs. Ninety-seven percent of the mean plasma concentrations predicted in pregnant women fell within a twofold error range and 63% within a 1.25-fold error range. For all drugs, the predicted area under the concentration-time curve was within a 1.25-fold error range. CONCLUSION The presented pregnancy physiologically based pharmacokinetic model can quantitatively predict the pharmacokinetics of drugs that are metabolized via one or multiple cytochrome P450 enzymes by integrating prior knowledge of the pregnancy-related effect on these enzymes. This pregnancy physiologically based pharmacokinetic model may thus be used to identify potential exposure changes in pregnant women a priori and to eventually support informed decision making when clinical trials are designed in this special population.
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Affiliation(s)
- André Dallmann
- Department of Pharmaceutical and Medical Chemistry, Clinical Pharmacy, Westfälische Wilhelms-University Münster, 48149, Münster, Germany.
| | - Ibrahim Ince
- Clinical Pharmacometrics, Bayer AG, 51368, Leverkusen, Germany
| | - Katrin Coboeken
- Clinical Pharmacometrics, Bayer AG, 51368, Leverkusen, Germany
| | - Thomas Eissing
- Clinical Pharmacometrics, Bayer AG, 51368, Leverkusen, Germany
| | - Georg Hempel
- Department of Pharmaceutical and Medical Chemistry, Clinical Pharmacy, Westfälische Wilhelms-University Münster, 48149, Münster, Germany
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Patil AS, Sheng JS, Dotters-Katz SK, Schmoll MS, Onslow ML. Principles of Anti-infective Dosing in Pregnancy. Clin Ther 2016; 38:2006-15. [DOI: 10.1016/j.clinthera.2016.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 08/11/2016] [Accepted: 08/12/2016] [Indexed: 01/25/2023]
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Yu T, Campbell SC, Stockmann C, Tak C, Schoen K, Clark EAS, Varner MW, Spigarelli MG, Sherwin CMT. Pregnancy-induced changes in the pharmacokinetics of caffeine and its metabolites. J Clin Pharmacol 2015; 56:590-6. [PMID: 26358647 DOI: 10.1002/jcph.632] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 09/08/2015] [Indexed: 01/18/2023]
Abstract
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.
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Affiliation(s)
- Tian Yu
- Division of Clinical Pharmacology, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Sarah C Campbell
- Division of Clinical Pharmacology, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Chris Stockmann
- Division of Clinical Pharmacology, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Casey Tak
- Clinical Trials Office, Department of Pediatrics, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Katherine Schoen
- Division of Clinical Pharmacology, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Erin A S Clark
- Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Michael W Varner
- Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, School of Medicine, University of Utah, Salt Lake City, UT, USA.,Intermountain Healthcare, Women and Newborns Clinical Programs, Salt Lake City, Utah, USA
| | - Michael G Spigarelli
- Division of Clinical Pharmacology, School of Medicine, University of Utah, Salt Lake City, UT, USA.,Clinical Trials Office, Department of Pediatrics, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Catherine M T Sherwin
- Division of Clinical Pharmacology, School of Medicine, University of Utah, Salt Lake City, UT, USA.,Clinical Trials Office, Department of Pediatrics, School of Medicine, University of Utah, Salt Lake City, UT, USA
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Malek A, Mattison DR. Drug development for use during pregnancy: impact of the placenta. ACTA ACUST UNITED AC 2014. [DOI: 10.1586/eog.10.29] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Ke AB, Nallani SC, Zhao P, Rostami-Hodjegan A, Isoherranen N, Unadkat JD. A physiologically based pharmacokinetic model to predict disposition of CYP2D6 and CYP1A2 metabolized drugs in pregnant women. Drug Metab Dispos 2013; 41:801-13. [PMID: 23355638 DOI: 10.1124/dmd.112.050161] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Conducting pharmacokinetic (PK) studies in pregnant women is challenging. Therefore, we asked if a physiologically based pharmacokinetic (PBPK) model could be used to evaluate different dosing regimens for pregnant women. We refined and verified our previously published pregnancy PBPK model by incorporating cytochrome P450 CYP1A2 suppression (based on caffeine PK) and CYP2D6 induction (based on metoprolol PK) into the model. This model accounts for gestational age-dependent changes in maternal physiology and hepatic CYP3A activity. For verification, the disposition of CYP1A2-metabolized drug theophylline (THEO) and CYP2D6-metabolized drugs paroxetine (PAR), dextromethorphan (DEX), and clonidine (CLO) during pregnancy was predicted. Our PBPK model successfully predicted THEO disposition during the third trimester (T3). Predicted mean postpartum to third trimester (PP:T3) ratios of THEO area under the curve (AUC), maximum plasma concentration, and minimum plasma concentration were 0.76, 0.95, and 0.66 versus observed values 0.75, 0.89, and 0.72, respectively. The predicted mean PAR steady-state plasma concentration (Css) ratio (PP:T3) was 7.1 versus the observed value 3.7. Predicted mean DEX urinary ratio (UR) (PP:T3) was 2.9 versus the observed value 1.9. Predicted mean CLO AUC ratio (PP:T3) was 2.2 versus the observed value 1.7. Sensitivity analysis suggested that a 100% induction of CYP2D6 during T3 was required to recover the observed PP:T3 ratios of PAR Css, DEX UR, and CLO AUC. Based on these data, it is prudent to conclude that the magnitude of hepatic CYP2D6 induction during T3 ranges from 100 to 200%. Our PBPK model can predict the disposition of CYP1A2, 2D6, and 3A drugs during pregnancy.
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Affiliation(s)
- Alice Ban Ke
- Department of Pharmaceutics, University of Washington, Box 357610, Seattle, WA 98195, USA
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Abduljalil K, Furness P, Johnson TN, Rostami-Hodjegan A, Soltani H. Anatomical, Physiological and Metabolic Changes with Gestational Age during Normal Pregnancy. Clin Pharmacokinet 2012; 51:365-96. [DOI: 10.2165/11597440-000000000-00000] [Citation(s) in RCA: 220] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Cazzola M, Page CP, Calzetta L, Matera MG. Pharmacology and therapeutics of bronchodilators. Pharmacol Rev 2012; 64:450-504. [PMID: 22611179 DOI: 10.1124/pr.111.004580] [Citation(s) in RCA: 307] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Bronchodilators are central in the treatment of of airways disorders. They are the mainstay of the current management of chronic obstructive pulmonary disease (COPD) and are critical in the symptomatic management of asthma, although controversies around the use of these drugs remain. Bronchodilators work through their direct relaxation effect on airway smooth muscle cells. at present, three major classes of bronchodilators, β(2)-adrenoceptor (AR) agonists, muscarinic receptor antagonists, and xanthines are available and can be used individually or in combination. The use of the inhaled route is currently preferred to minimize systemic effects. Fast- and short-acting agents are best used for rescue of symptoms, whereas long-acting agents are best used for maintenance therapy. It has proven difficult to discover novel classes of bronchodilator drugs, although potential new targets are emerging. Consequently, the logical approach has been to improve the existing bronchodilators, although several novel broncholytic classes are under development. An important step in simplifying asthma and COPD management and improving adherence with prescribed therapy is to reduce the dose frequency to the minimum necessary to maintain disease control. Therefore, the incorporation of once-daily dose administration is an important strategy to improve adherence. Several once-daily β(2)-AR agonists or ultra-long-acting β(2)-AR-agonists (LABAs), such as indacaterol, olodaterol, and vilanterol, are already in the market or under development for the treatment of COPD and asthma, but current recommendations suggest the use of LABAs only in combination with an inhaled corticosteroid. In addition, some new potentially long-acting antimuscarinic agents, such as glycopyrronium bromide (NVA-237), aclidinium bromide, and umeclidinium bromide (GSK573719), are under development, as well as combinations of several classes of long-acting bronchodilator drugs, in an attempt to simplify treatment regimens as much as possible. This review will describe the pharmacology and therapeutics of old, new, and emerging classes of bronchodilator.
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Affiliation(s)
- Mario Cazzola
- Università di Roma Tor Vergata, Dipartimento di Medicina Interna, Via Montpellier 1, 00133 Roma, Italy.
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The human placental perfusion model: a systematic review and development of a model to predict in vivo transfer of therapeutic drugs. Clin Pharmacol Ther 2011; 90:67-76. [PMID: 21562489 DOI: 10.1038/clpt.2011.66] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Dual perfusion of a single placental lobule is the only experimental model to study human placental transfer of substances in organized placental tissue. To date, there has not been any attempt at a systematic evaluation of this model. The aim of this study was to systematically evaluate the perfusion model in predicting placental drug transfer and to develop a pharmacokinetic model to account for nonplacental pharmacokinetic parameters in the perfusion results. In general, the fetal-to-maternal drug concentration ratios matched well between placental perfusion experiments and in vivo samples taken at the time of delivery of the infant. After modeling for differences in maternal and fetal/neonatal protein binding and blood pH, the perfusion results were able to accurately predict in vivo transfer at steady state (R² = 0.85, P < 0.0001). Placental perfusion experiments can be used to predict placental drug transfer when adjusting for extra parameters and can be useful for assessing drug therapy risks and benefits in pregnancy.
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Abstract
Asthma is the most common significant chronic medical condition affecting young adults and it is therefore often encountered in pregnancy. Approximately 3% of women of child-bearing age suffer some degree of asthma and this prevalence is increasing. Some of the apparent increase is due to heightened awareness of the condition, although air pollution and increased childhood exposure to house dust mite may also be contributing.
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Cragan JD, Friedman JM, Holmes LB, Uhl K, Green NS, Riley L. Ensuring the safe and effective use of medications during pregnancy: planning and prevention through preconception care. Matern Child Health J 2006; 10:S129-35. [PMID: 16850277 PMCID: PMC1592140 DOI: 10.1007/s10995-006-0102-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Accepted: 04/20/2006] [Indexed: 11/27/2022]
Affiliation(s)
- Janet D Cragan
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, MS E-86, 1600 Clifton Road, N.E., Atlanta, Georgia 30333, USA.
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Liccardi G, Cazzola M, Canonica GW, D'Amato M, D'Amato G, Passalacqua G. General strategy for the management of bronchial asthma in pregnancy. Respir Med 2003; 97:778-89. [PMID: 12854627 DOI: 10.1016/s0954-6111(03)00031-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Epidemiological studies showed that bronchial asthma is one of the most common diseases which can complicate pregnancy (1-7%). In about 0.05-2% of the cases, asthma occurs as a life-threatening event. In the common medical practice a waiting strategy or, even, the complete refusal for drug therapies are frequently observed. This is justified by the fear of the possible adverse effects of drugs on developing fetus. On the contrary, several studies have demonstrated that severe and uncontrolled asthma may produce serious maternal and fetal complications, such as gestational hypertension and eclampsia, fetal hypoxemia and an increased risk of perinatal death. Therefore, all pregnant women suffering from bronchial asthma should be considered as potentially at high risk of complications and adequately treated. Since asthma is a chronic disease with acute exacerbations, a continuous treatment is mandatory to control symptoms, to prevent acute episodes and to reduce the degree of airway inflammation. The global strategy for asthma management in pregnancy includes five main topics: (1) objective evaluation of maternal/ fetal clinical conditions; (2) avoidance/control of triggering factors; (3) pharmacological treatment; (4) educational support; (5) psychological support. As far as drug therapy is concerned, the International Guidelines and Recommendations suggest that the general strategy does not differ significantly from management outside pregnancy. We herein review and discuss the available data and the criteria for the management of asthma in pregnant patients.
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Affiliation(s)
- G Liccardi
- Unit of Pneumology and Allergology, Department of Chest Diseases, A.Cardarelli Hospital, Piazza Arenella no 7/h, Naples 80128, Italy.
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Dorne JL, Walton K, Renwick AG. Uncertainty factors for chemical risk assessment. human variability in the pharmacokinetics of CYP1A2 probe substrates. Food Chem Toxicol 2001; 39:681-96. [PMID: 11397515 DOI: 10.1016/s0278-6915(01)00005-9] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A 100-fold uncertainty factor is used to derive acceptable daily intakes for compounds causing thresholded toxicity. The 10-fold factor for human variability can be further subdivided into two factors of 10(0.5) (3.16) to allow for toxicokinetics and toxicodynamics. The validity of the human kinetic subfactor has been analysed in relation to CYP1A2 metabolism using published in vivo pharmacokinetic parameters selected to reflect chronic exposure (metabolic and total clearances and area under the plasma concentration-time curve: CLm, CL and AUC) and acute exposure (the peak plasma concentration, C(max)). The variability in CYP1A2 activity in healthy adults, based on data after oral and intravenous dosage (CLm, CL and AUC), ranged from 34 to 42%. The variability in C(max) was 21%. The default kinetic factor of 3.16 would cover at least 99% of the healthy adult population, assuming that the data were log-normally distributed, but would give lower protection for some subgroups (pregnant women at term, healthy elderly, patients with liver disease), and was inadequate for neonates. This analysis of in vivo kinetic data for CYP1A2 substrates illustrates the importance of quantifying human variability in specific metabolic pathways, and of identifying potentially susceptible subgroups of the human population, in order to determine the scientific validity of uncertainty factors.
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Affiliation(s)
- J L Dorne
- Clinical Pharmacology Group, Biomedical Sciences Building, University of Southampton, Bassett Crescent East, SO16 7PX, Southampton, UK
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Abstract
Asthma may be the most common potentialy serious medical problem to complicate pregnancy. Because severe uncontrolled asthma may cause both maternal and fetal morbidity and mortality, pharmacological asthma therapy is often necessary during pregnancy. Only 1 published randomized controlled clinical trial has evaluated the efficacy of an asthma medication (inhaled beclomethasone) during pregnancy. Human data bearing on the safety of medications during pregnancy are usually limited to observational studies, because experimental studies on the use of medications during human pregnancy would generally be unethical. Existing observational cohort data do not associate an increased risk of preeclampsia, total congenital malformations, preterm birth, or low birth weight infants with maternal exposures to inhaled beta agonists, theophylline, cromolyn, or inhaled corticosteroids. Maternal use of oral corticosteroids has been associated with reduced birth weight, an increased risk of preeclampsia, and an increased risk of oral clefts (first trimester use). Based on this information, benefit-risk considerations suggest that inhaled asthma medications and theophylline should be used when indicated for the treatment of asthma during pregnancy. Moreover, although some increased risks may be associated with the gestational use of oral corticosteroids, these risks are probably still less than the potential risks to the mother and the fetus of severe uncontrolled asthma. This articles describes recently published consensus recommendations regarding the pharmacological management of asthma during pregnancy.
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Affiliation(s)
- M Schatz
- Department od Allergy, Kaiser-Permanente Medical Center, San Diego, CA 92111, USA
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Abstract
Changes in maternal physiology occur normally during pregnancy and have the potential to alter the absorption, distribution, and elimination of drugs used therapeutically in pregnant women. These physiologic changes include: plasma volume expansion and increases in extracellular fluid space and total body water; decreased plasma albumin concentration; a compensated respiratory alkalosis; increased cardiac output with regional blood flow changes; increased renal blood flow associated with increased glomerular filtration; changes in hepatic drug metabolizing enzymes; and changes in gastrointestinal function. These changes begin in early gestation but are most pronounced in the third trimester of pregnancy. Further maternal physiologic changes occur intrapartum with some normalizing themselves within 24 hours of delivery, while others are sustained only returning to normal some 12 weeks postpartum. These physiologic changes form the basis for the need for pharmacokinetic studies during pregnancy.
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Affiliation(s)
- M C Frederiksen
- Department of Obstetrics and Gynecology, Northwestern University, Chicago, IL, USA.
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Hakkola J, Tanaka E, Pelkonen O. Developmental expression of cytochrome P450 enzymes in human liver. PHARMACOLOGY & TOXICOLOGY 1998; 82:209-17. [PMID: 9646325 DOI: 10.1111/j.1600-0773.1998.tb01427.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Drug-metabolizing cytochrome P450 enzymes, the major phase I enzymes, are active in human liver already at very early stages of intrauterine development, although presumably at fairly low concentrations and in low numbers. During maturation, these enzymes go through various developmental programmes towards adulthood. The major increase both in abundance as well as in number of different enzymes takes place after birth, probably during the first year of life. Detailed information concerning these developmental changes is still limited. The major drug-metabolizing P450 enzymes appear to be primarily members of the CYP3A subfamily in all stages of development. The balance between different members of this subfamily, however, undergoes significant switches from the foetal predominant CYP3A7 to the major adult form CYP3A4. The ontogeny of the other cytochrome P450 enzymes is less well characterized, but the major switch-on appears to occur mainly after birth. Developmental expression of P450 enzymes is one of the key factors determining the pharmacokinetic status of developing individuals both pre- and postnatally.
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Affiliation(s)
- J Hakkola
- Department of Pharmacology and Toxicology, University of Oulu, Finland
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Cristòfol C, Franquelo C, Navarro M, Carretero A, Ruberte J, Arboix M. Comparative pharmacokinetics of netobimin metabolites in pregnant ewes. Res Vet Sci 1997; 62:117-20. [PMID: 9243708 DOI: 10.1016/s0034-5288(97)90131-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The pharmacokinetics of netobimin (NTB) metabolites has been investigated in ewes. Non-pregnant ewes and ewes in the first and last third of pregnancy were dosed orally with 20 mg kg bodyweight of NTB. Blood samples were collected from the jugular vein from 30 minutes to 72 hours after administration and plasma samples were analysed by high performance liquid chromatography. Neither NTB nor albendazole (ABZ) were detected in any of the samples analysed. No statistically significant differences were found between the pharmacokinetic parameters of albendazole suphoxide (ABZSO) and albendazole sulphone (ABZSO2) among the three groups of ewes. The peak plasma concentrations (Cmax) ABZSO and ABZSO2 were reached about 10 and 20 hours respectively after administration in all three groups. The ratios of ABZSO/ABZSO2 for Cmax and the areas under the curve (AUCzero-infinity) were 6 and 3, respectively, in each group and suggest a low rate of oxidation of sulfoxide to sulphone.
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Affiliation(s)
- C Cristòfol
- Facultat de Veterinària, Universitat Autònoma de Barcelona, Spain
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Schatz M. ASTHMA AND PREGNANCY. Radiol Clin North Am 1996. [DOI: 10.1016/s0033-8389(22)00250-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Omarini D, Barzago MM, Bortolotti A, Lucchini G, Stellari F, Efrati S, Bonati M. Placental transfer of theophylline in an in vitro closed perfusion system of human placenta isolated lobule. Eur J Drug Metab Pharmacokinet 1993; 18:369-74. [PMID: 8020536 DOI: 10.1007/bf03190187] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Theophylline (TH) is a methylated xanthine widely used in the treatment of asthmatic pregnant women. Because of the scant available information on the transplacental profile, the time course of TH transfer was studied by an in vitro human placental perfusion. 6 placentas were perfused with Earle's enriched bicarbonate buffer for 180 min using recirculating maternal and fetal circuits. The physiological and biochemical properties of the tissue were well maintained. TH data were compared to those of antipyrine (AP), an usual marker in placental perfusions. The disappearance of TH from the maternal circuit was studied after administration of 15 mg/l in maternal perfusate. TH appeared in the fetal circuit within 5 min. Equilibrium was achieved in both circuits. TH fetomaternal mass ratio became constant (FMM = 0.45 +/- 0.01) after 80 min of perfusion and maternal to fetal clearance was 2.59 +/- 0.24 ml/min. About 16% of TH maternal dose was recovered in the tissue, while 18% appeared in fetal circulation. TH recovery was 89 +/- 9%. On the basis of our results, similar concentrations could be predicted in mother and fetus after maternal TH intake. The TH transfer profile is consistent with in vivo values reported in humans and animals at delivery.
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Affiliation(s)
- D Omarini
- Laboratory for Mother and Child Health, Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
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Omarini D, Barzago MM, Bortolotti A, Aramayona J, Bonati M. Placental transfer of theophylline during in situ perfusion in the rabbit. JOURNAL OF PHARMACOLOGICAL METHODS 1991; 25:263-73. [PMID: 1886413 DOI: 10.1016/0160-5402(91)90026-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Many physiological changes take place during pregnancy, and the disposition profile of endogenous and exogenous compounds may change, too. Thus knowledge of the disposition pattern of a compound may be useful in relation to its therapeutic effect(s) and its potential toxicity on the fetus and the newborn. Because the amount of a compound received by the fetus is a product of placental transfer rate, and available maternal amount, and because it is difficult to control and evaluate the factors that may affect such a transfer in women, we set up an in situ perfused placental model in the rabbit. The reliability of the model was borne out by comparing the placental transfer of theophylline with antipyrine, a commonly used marker of placental exchange, at steady state after a two-step infusion at mean arterial plasma concentrations of 8 and 5 mg/L, respectively for theophylline and antipyrine. The rabbit placenta was perfused in situ with a modified Earle's buffer at a 1-mL/min flow rate. During perfusion, maternal plasma, placental perfusate, biochemical parameters, gas exchange, body temperature, and electrocardiogram were carefully monitored. The maternal plasma and perfusate drug concentrations over time were fitted by appropriate models and kinetic parameters were calculated. Umbilical vein/maternal artery concentration ratios reached equilibrium soon after the loading infusion was stopped for both drugs. Placental clearance averaged 0.62 and 0.77 mL/min for theophylline and antipyrine, respectively, and the clearance index of theophylline was 0.81 +/- 0.07. Although human and rabbit placentas are structurally dissimilar, the rabbit placenta perfused in situ appears to be a useful preparation for measuring the transfer processes and the related and governing factors, of different compounds.
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Affiliation(s)
- D Omarini
- Perinatal Clinical Pharmacology Unit, Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
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Atkinson AJ, Ruo TI, Frederiksen MC. Physiological basis of multicompartmental models of drug distribution. Trends Pharmacol Sci 1991; 12:96-101. [PMID: 2053193 DOI: 10.1016/0165-6147(91)90515-t] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Although most pharmacokinetic studies are conducted in normal subjects, their clinical utility depends on the reliability with which the results can be extrapolated to patients. This reliability can be improved by increased understanding of how drug absorption and disposition mechanisms are affected by physiological changes or by disease. In recent years, important insight has been gained regarding the effects of altered renal function on drug elimination by the kidneys. There has also been considerable progress in defining the interaction of hemodynamic and metabolic factors that affect the hepatic elimination of drugs. Although comparatively little progress has been made in elucidating the underlying basis of changes in the rate and extent of drug distribution, Arthur Atkinson and colleagues analyse methods of compartmental pharmacokinetic analysis that may provide physiological insight into the factors affecting drug distribution.
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Affiliation(s)
- A J Atkinson
- Clinical Pharmacology Center, Northwestern University Medical School, Chicago, IL 60611
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Schatz M, Zeiger RS. Drug Therapy in the Allergic Pregnant Patient. Immunol Allergy Clin North Am 1991. [DOI: 10.1016/s0889-8561(22)00312-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Gaspari F, Bonati M. Interspecies metabolism and pharmacokinetic scaling of theophylline disposition. Drug Metab Rev 1990; 22:179-207. [PMID: 2272287 DOI: 10.3109/03602539009041084] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- F Gaspari
- Laboratory of Clinical Pharmacology, Instituto di Ricerche Farmacologiche Mario Negri Bergamo & Milano, Italy
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Affiliation(s)
- J L Carson
- Department of Medicine, University of Medicine and Dentistry of New Jersey/Robert Wood Johnson Medical School, New Brunswick 08903
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Abstract
The purpose of this investigation was to determine whether the neurotoxicity of theophylline is altered in advanced pregnancy. Sprague-Dawley rats that were 20 days pregnant and nonpregnant rats of the same age and strain received infusions of aminophylline until onset of maximal seizures which occurred after 28 and 30 minutes respectively. Theophylline concentrations at this endpoint in serum (total) and CSF were similar but serum (free) and brain concentrations were slightly different in pregnant rats. Theophylline serum protein binding determined by equilibrium dialysis was lower in pregnant rats. Fetal serum concentrations at onset of seizures in the mother were similar to maternal brain and CSF concentrations and correlated significantly with the former. It is concluded that advanced pregnancy has a negligible effect on the neurotoxic response to theophylline in rats.
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Affiliation(s)
- I Ramzan
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pennsylvania 15261
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Affiliation(s)
- E Perucca
- Department of Internal Medicine and Therapeutics, University of Pavia, Italy
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