Efficacy and safety of nifedipine tablets for the acute treatment of severe hypertension in pregnancy

Long-acting nifedipine in the management of essential hypertension: a review for cardiologists

Calcium channel antagonists, specifically long-acting nifedipine formulations, play a crucial role in treating hypertension and angina. Originally used for angina, nifedipine has been widely employed as an antihypertensive medication for over 40 years. It offers rapid action and oral bioavailability with minimal maternal or fetal side effects, making it suitable for treating hypertensive crises during pregnancy. However, it can cause a sudden drop in blood pressure and tachycardia. Long-acting formulations, such as gastrointestinal therapeutic systems, gradually release nifedipine over 24 hours, mitigating these issues. This review aims to assess the clinical efficacy and safety of long-acting nifedipine formulations in managing essential hypertension, with a focus on improving blood pressure control and addressing challenges in uncontrolled and resistant hypertension. Furthermore, long-acting nifedipine provides therapeutic advantages beyond hypertension management, showing efficacy in treating comorbid conditions such as chronic kidney disease and diabetes. Global studies support its efficacy, suggesting that a shift toward the use of long-acting nifedipine can help address the global hypertension problem and enhance the quality of life for hypertensive patients.

Comparative efficacy and safety of oral nifedipine with other antihypertensive medications in the management of hypertensive disorders of pregnancy: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Hypertensive disorders of pregnancy are the most frequently occurring medical condition during pregnancy, resulting in fetal and/or maternal morbidity and mortality. This meta-analysis compared the efficacy and safety of nifedipine with other antihypertensive medications used in hypertensive disorders of pregnancy.

METHODOLOGY

A comprehensive search was performed using PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Google Scholar. The meta-analysis was carried out using Review Manager Software, and the pooled effect estimate was generated as standardized mean difference and odds ratio with 95% confidence interval and two-sided P -value.

RESULTS

The meta-analysis was comprised of 22 randomized control trials with 2595 participants. It was found that meantime and number of doses required to achieve target blood pressure were lower in the nifedipine group ( P  < 0.05). Even though it is statistically insignificant, fetal APGAR (Appearance, Pulse, Grimace, Activity, and Respiration) scores less than seven favors nifedipine intervention. Furthermore, none of the fetal or maternal secondary outcomes were found significant.

CONCLUSION

Nifedipine was found to be more effective than other antihypertensive medications to reduce blood pressure, particularly in patients with severe hypertension. However, future clinical studies, including real-world data are necessary to establish the safety profile of nifedipine concerning the fetal outcomes in hypertensive pregnant women.

Best Practices for Managing Postpartum Hypertension

Purpose of Review

Patients remain at risk for persistent and de novo postpartum hypertension related to pregnancy. This review aims to summarize the current definitions, clinical practices, and novel systems innovations and therapies for postpartum hypertension.

Recent Findings

Recent changes to the definitions of hypertension outside of pregnancy have not yet impacted definitions or management of hypertensive disorders of pregnancy (HDP), though research examining the implications of these new definitions on risks of developing HDP and the resultant sequelae is ongoing. The administration of diuretics has been shown to reduce postpartum hypertension among women with HDP. Widespread implementation of telemedicine models and remote assessment of ambulatory blood pressures has increased data available on postpartum blood pressure trajectories, which may impact clinical management. Additionally, policy changes such as postpartum Medicaid extension and an increasing emphasis on building bridges to primary care in the postpartum period may improve long-term outcomes for women with postpartum hypertension. Prediction models utilizing machine learning are an area of ongoing research to assist with risk assessment in the postpartum period.

Summary

The clinical management of postpartum hypertension remains focused on blood pressure control and primary care transition for cardiovascular disease risk reduction. In recent years, systemic innovations have improved access through implementation of new care delivery models. However, the implications of changing definitions of hypertension outside of pregnancy, increased data assessing blood pressure trajectories in the postpartum period, and the creation of new risk prediction models utilizing machine learning remain areas of ongoing research.

Clinical Applicability of Monitoring Antihypertensive Drug Levels in Blood

Dried blood spot (DBS) analysis is a novel analytical method for therapeutic drug monitoring to identify nonadherence to antihypertensive drugs. This study was conducted to evaluate the clinical applicability of measuring drug concentrations of 8 antihypertensive drugs, using DBS and venipuncture. Furthermore, this study aimed to provide more insight into the between-patient variability in drug concentrations. False-negative values from DBS compared with a venipuncture were determined to assess drug adherence. A generalized estimating equation was used to estimate the model parameters, including sex, dose, age, weight, and the time interval, between drug intake and sampling, on the C_plasma (drug concentration in plasma). No false-negative values were found when measuring nonadherence using DBS compared with venipuncture. A high variability in C_plasma between patients was observed, especially at peak concentrations with a fold change reaching from 2.3 to 35.2. The time of intake was significantly related to the height of the C_plasma in 7 of the 8 measured drugs with a P<0.05, but the influence of dose, weight, age, and sex on drug levels differed largely between the measured drugs. DBS is a reliable and convenient method to assess nonadherence to antihypertensive drugs in clinical practice. The C_plasma of the 8 antihypertensive drugs in this study show a large interindividual difference, and therefore, low plasma concentrations do not necessarily mean nonadherence. Nonadherence can only be confirmed if drug levels are undetectable, that is, values below the lower limit of detection.

Oral antihypertensive regimens (nifedipine retard, labetalol, and methyldopa) for management of severe hypertension in pregnancy: an open-label, randomised controlled trial

BACKGROUND

Hypertension is the most common medical disorder in pregnancy, complicating one in ten pregnancies. Treatment of severely increased blood pressure is widely recommended to reduce the risk for maternal complications. Regimens for the acute treatment of severe hypertension typically include intravenous medications. Although effective, these drugs require venous access and careful fetal monitoring and might not be feasible in busy or low-resource environments. We therefore aimed to compare the efficacy and safety of three oral drugs, labetalol, nifedipine retard, and methyldopa for the management of severe hypertension in pregnancy.

METHODS

In this multicentre, parallel-group, open-label, randomised controlled trial, we compared these oral antihypertensives in two public hospitals in Nagpur, India. Pregnant women were eligible for the trial if they were aged at least 18 years; they were pregnant with fetuses that had reached a gestational age of at least 28 weeks; they required pharmacological blood pressure control for severe hypertension (systolic blood pressure ≥160 mm Hg or diastolic blood pressure ≥110 mm Hg); and were able to swallow oral medications. Women were randomly assigned to receive 10 mg oral nifedipine, 200 mg oral labetalol (hourly, in both of which the dose could be escalated if hypertension was maintained), or 1000 mg methyldopa (a single dose, without dose escalation). Masking of participants, study investigators, and care providers to group allocation was not possible because of different escalation protocols in the study groups. The primary outcome was blood pressure control (defined as 120-150 mm Hg systolic blood pressure and 70-100 mm Hg diastolic blood pressure) within 6 h with no adverse outcomes. This study is registered with ClinicalTrials.gov, number NCT01912677, and the Clinical Trial Registry, India, number ctri/2013/08/003866.

FINDINGS

Between April 1, 2015, and Aug 21, 2017, we screened 2307 women for their inclusion in the study. We excluded 1413 (61%) women who were ineligible, declined to participate, had impending eclampsia, were in active labour, or had a combination of these factors. 11 (4%) women in the nifedipine group, ten (3%) women in the labetalol group, and 11 (4%) women in the methyldopa group were ineligible for treatment (because they had only one qualifying blood pressure measurement) or had treatment stopped (because of delivery or transfer elsewhere). 894 (39%) women were randomly assigned to a treatment group and were included in the intention-to-treat analysis: 298 (33%) women were assigned to receive nifedipine, 295 (33%) women were assigned to receive labetalol, and 301 (33%) women were assigned to receive methyldopa. The primary outcome was significantly more common in women in the nifedipine group than in those in the methyldopa group (249 [84%] women vs 230 [76%] women; p=0·03). However, the primary outcome did not differ between the nifedipine and labetalol groups (249 [84%] women vs 228 [77%] women; p=0·05) or the labetalol and methyldopa groups (p=0·80). Seven serious adverse events (1% of births) were reported during the study: one (<1%) woman in the labetalol group had an intrapartum seizure and six (1%) neonates (one [<1%] neonate in the nifedipine group, two [1%] neonates in the labetalol group, and three [1%] neonates in the methyldopa group) were stillborn. No birth had more than one adverse event.

INTERPRETATION

All oral antihypertensives reduced blood pressure to the reference range in most women. As single drugs, nifedipine retard use resulted in a greater frequency of primary outcome attainment than labetalol or methyldopa use. All three oral drugs-methyldopa, nifedipine, and labetalol-are viable initial options for treating severe hypertension in low-resource settings.

FUNDING

PREEMPT (University of British Columbia, Vancouver, BC, Canada; grantee of Bill & Melinda Gates Foundation).

Safety of Antihypertensive Medications in Pregnancy: Living With Uncertainty

See Article by Mito et al.

Treatment and Prevention of Hypertensive Disorders During Pregnancy

This article reviews the pharmacology of the most commonly used antihypertensive medications during pregnancy; their mechanism of action; and the effects on the mother, the fetus, and lactation. Each class of antihypertensive pharmacologic agents have specific mechanisms of action by which they exert their antihypertensive effect. β-Adrenoreceptor antagonists block these receptors in the peripheral circulation. Calcium channel blockers result in arterial vasodilation. α-Agonists inhibit vasoconstriction. Methyldopa is a centrally acting adrenoreceptor antagonist. Vasodilators have a direct effect on vascular smooth muscle. Diuretics decrease intravascular volume. Medications acting on the angiotensin pathway are avoided during pregnancy because of fetotoxic effects.

Pharmacotherapy for hypertension in pregnant patients: special considerations

INTRODUCTION

Hypertensive disorders of pregnancy (HDP) represent a major cause of maternal, fetal and neonatal morbidity and mortality and identifies women at risk for cardiovascular and other chronic diseases later in life. When antihypertensive drugs are used during pregnancy, their benefit and harm to both mother and fetus should be evaluated.

AREAS COVERED

This review summarizes the pharmacological characteristics of the recommended antihypertensive drugs and their impact on mother and fetus when administered during pregnancy and/or post-partum. Drugs were identified using MEDLINE and the main international Guidelines for the management of HDP.

EXPERT OPINION

Although there is a consensus that severe hypertension should be treated, treatment of mild hypertension without end-organ damage (140-159/90-109 mmHg) remains controversial and there is no agreement on when to initiate therapy, blood pressure targets or recommended drugs in the absence of robust evidence for the superiority of one drug over others. Furthermore, the long-term outcomes of in-utero antihypertensive exposure remain uncertain. Therefore, evidence-based data regarding the treatment of HDP is lacking and well designed randomized clinical trials are needed to resolve all these controversial issues related to the management of HDP.

State-of-the-Art Diagnosis and Treatment of Hypertension in Pregnancy

Hypertension complicates up to 10% of pregnancies worldwide. Pregnancy hypertension is defined as systolic blood pressure (BP) equal to or greater than 140 mm Hg or diastolic BP equal to or greater than 90 mm Hg, usually on the basis of measurements in office/clinic settings and using various BP devices. Hypertensive disorders of pregnancy are classified into (1) chronic hypertension diagnosed before pregnancy or before 20 weeks' gestation, (2) gestational hypertension diagnosed at equal to or greater than 20 weeks, or (3) preeclampsia, defined restrictively as gestational hypertension with proteinuria or broadly as gestational hypertension with proteinuria or an end-organ manifestation consistent with preeclampsia. Absolute BP values equal to or greater than 140/90 mm Hg are associated with increased maternal and perinatal risks, particularly with preeclampsia. This review focuses on antihypertensive therapy of hypertensive disorders of pregnancy as a specific management strategy. Underpinning this therapy is the need for accurate measurement of BP, agreed-upon classification of pregnancy hypertension, agreed-upon BP thresholds for enhanced surveillance and antihypertensive treatment, and collaborative teamwork in management. Challenges relate to the methodology of studies on which care is based, as well as aspects of the care itself, particularly the unregulated use of home BP monitoring. Pitfalls include the unsubstantiated belief that nifedipine and magnesium sulfate cannot be used together and the perception that severe hypertension and nonsevere hypertension are separate entities rather than lying along a spectrum of BP values. The following must be addressed by future research: guidance for nuanced care as women transition between severe and nonsevere hypertension, personalized antihypertensive therapy, and incorporation of women's values into research priorities and clinical practice when antihypertensive care is chosen.

In-utero exposure to antihypertensive medication and neonatal and child health outcomes: a systematic review

BACKGROUND

Although medication is generally avoided wherever possible during pregnancy, pharmacotherapy is required for the treatment of pregnancy associated hypertension, which remains a leading cause of maternal and fetal morbidity and mortality. The long-term effects to the child of in-utero exposure to antihypertensive agents remains largely unknown.

OBJECTIVE

The aim of this study was to systematically review published studies on adverse outcomes to the child associated with in-utero exposure to antihypertensive medications.

METHODS

OVID, Scopus, EBSCO Collections, the Cochrane Library, and Web of Science databases were searched for relevant publications published between January 1950 and October 2016 and a total of 688 potentially eligible studies were identified.

RESULTS

Following review, 47 primary studies were eligible for inclusion. The Critical Appraisal Skills Programme checklist was used to assess study quality. Five studies were of excellent quality; the remainder were either mediocre or poor. Increased risk of low birth weight, low size for gestational age, preterm birth, and congenital defects following in-utero exposure to all antihypertensive agents were identified. Two studies reported an increased risk of attention deficit hyperactivity disorder following exposure to labetalol, and an increased risk of sleep disorders following exposure to methyldopa and clonidine.

CONCLUSION

The current systematic review demonstrates a paucity of relevant published high-quality studies. A small number of studies suggest possible increased risk of adverse child health outcomes; however, most published studies have methodological weaknesses and/or lacked statistical power thus preventing any firm conclusions being drawn.

Labetalol for hypertension in pregnancy

INTRODUCTION

Labetalol is one of the most commonly used antihypertensive medications for the treatment of hypertension during pregnancy, an increasingly common and leading cause of maternal mortality and morbidity worldwide.

AREAS COVERED

The literature reviewed included the 2014 Canadian national pregnancy hypertension guideline and its references. The additional published literature was retrieved through searches of Medline, CINAHL, and The Cochrane Library using appropriate controlled vocabulary (e.g., pregnancy, hypertension, pre-eclampsia, pregnancy toxemias) and key words (e.g., diagnosis, evaluation, classification, prediction, prevention, prognosis, treatment, and postpartum follow-up).Results were restricted to systematic reviews, randomized controlled trials, controlled clinical trials, and observational studies published in French or English, Jan-Mar/14. The unpublished literature was identified by searching websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. We evaluated the impact of interventions on substantive clinical outcomes for mothers and babies.

EXPERT OPINION

Labetalol is a reasonable choice for treatment of severe or non-severe hypertension in pregnancy. However, we should continue our search for other therapeutic options.

Use and impact of cardiac medication during pregnancy

ABSTRACT 

Cardiovascular disease is the most encountered cause of maternal death during pregnancy in the western world and an increase in maternal mortality due to cardiac causes has been observed. More women with congenital or acquired heart disease have the desire to become pregnant. Pregnancy is known to impose a major hemodynamic burden and also has impacts on the coagulation system. The risk of developing complications is clearly increased as compared with the normal population. For optimal management, it is crucial to have information on the effects of cardiac medications on the fetus. The focus of this article is to discuss the management of cardiac disease in pregnancy, as well as the known safety of cardiac medications for the mother and/or fetus.

Assessment of clinical outcomes and prescribing behavior among inpatients with severe preeclampsia and eclampsia: an Indian experience

Objectives:

The study aims to evaluate the management, maternal-fetal outcomes, and prescription behavior among inpatients with severe preeclampsia and eclampsia.

Materials and Methods:

This prospective cohort study in a tertiary referral center was conducted in 164 inpatient pregnant women who fulfilled the inclusion criteria. The study was conducted between November 2005 and February 2007. The patients were followed-up till delivery. Antepartum and intrapartum care and maternal and perinatal outcome were noted. Chief outcome measures were maternal and perinatal mortality and drug use indicators.

Results:

Median age at delivery of the women was 25 (22-28) years. Majority were suffering from antepartum eclampsia (52.5%), followed by preeclampsia (31%) and postpartum eclampsia (16.5%). Nulliparity (61.6%) was more common in eclampsia, while multiparity in preclamptic group. A total of 48% had preterm delivery. Most presented with headache (50%) and hyperreflexia (29%). Only 15% presented with all three prodromal symptoms and 86% had hypertension. There was increased morbidity, operative intervention, and admission to intensive care unit. Most babies (67%) weighed <2.5 kg and had poor outcome. The maternal mortality was 0.4/1000. Average number of drugs prescribed in patients of preeclampsia, antepartum eclampsia, and postpartum eclampsia were 13.2, 14.9, and 14.2, respectively. Antibiotics (24.6%) were the most common class of the drugs prescribed in all the groups, followed by vitamin and calcium supplements (22.7%) and antihypertensives (13.5%). Most common antihypertensive used were calcium channel blockers and anticonvulsant magnesium sulphate.

Conclusions:

There was increased maternal and perinatal morbidity. Protocols for the management of eclampsia, including antihypertensive and anticonvulsant therapies, should be available and reviewed regularly to improve the standard of care and reduce the prevalence of this dangerous condition.

Drug treatment of hypertension in pregnancy: a critical review of adult guideline recommendations

This review evaluates the guideline recommendations for the management of hypertension in pregnancy as presented by 25 national/international guidelines developed for the management of arterial hypertension in adults. There is a general consensus that oral α-methyldopa and parenteral labetalol are the drugs of choice for nonsevere and severe hypertension in pregnancy, respectively. Long-acting nifedipine is recommended by various guidelines as an alternative for first-line and second-line therapy in nonsevere and severe hypertension. The safety of β-blockers, atenolol in particular, in early and late stages of pregnancy is unresolved; their use is contraindicated according to several guidelines. Diuretic-associated harmful effects on maternal and fetal outcomes are controversial: their use is discouraged in pregnancy. It is important to develop specific guidelines for treating hypertension in special groups such as adult females of childbearing age and sexually active female adolescents to minimize the risk of adverse effects of drugs on the fetus. In several guidelines, the antihypertensive classes, recommended drug(s), intended drug formulation, and route of administration are not explicit. These omissions should be addressed in future guideline revisions in order to enhance the guidelines' utility and credibility in clinical practice.

Oral antihypertensive therapy for severe hypertension in pregnancy and postpartum: a systematic review

BACKGROUND

Pregnant and postpartum women with severe hypertension are at increased risk of stroke and require blood pressure (BP) reduction. Parenteral antihypertensives have been most commonly studied, but oral agents would be ideal for use in busy and resource-constrained settings.

OBJECTIVES

To review systematically, the effectiveness of oral antihypertensive agents for treatment of severe pregnancy/postpartum hypertension.

SEARCH STRATEGY

A systematic search of MEDLINE, EMBASE and the Cochrane Library was performed.

SELECTION CRITERIA

Randomised controlled trials in pregnancy and postpartum with at least one arm consisting of a single oral antihypertensive agent to treat systolic BP ≥ 160 mmHg and/or diastolic BP ≥ 110 mmHg.

DATA COLLECTION AND ANALYSIS

Cochrane RevMan 5.1 was used to calculate relative risk (RR) and weighted mean difference by random effects.

MAIN RESULTS

We identified 15 randomised controlled trials (915 women) in pregnancy and one postpartum trial. Most trials in pregnancy compared oral/sublingual nifedipine capsules (8-10 mg) with another agent, usually parenteral hydralazine or labetalol. Nifedipine achieved treatment success in most women, similar to hydralazine (84% with nifedipine; relative risk [RR] 1.07, 95% confidence interval [95% CI] 0.98-1.17) or labetalol (100% with nifedipine; RR 1.02, 95% CI 0.95-1.09). Less than 2% of women treated with nifedipine experienced hypotension. There were no differences in adverse maternal or fetal outcomes. Target BP was achieved ~ 50% of the time with oral labetalol (100 mg) or methyldopa (250 mg) (47% labetelol versus 56% methyldopa; RR 0.85 95% CI 0.54-1.33).

CONCLUSIONS

Oral nifedipine, and possibly labetalol and methyldopa, are suitable options for treatment of severe hypertension in pregnancy/postpartum.

Diagnosis, evaluation, and management of the hypertensive disorders of pregnancy

OBJECTIVE

This guideline summarizes the quality of the evidence to date and provides a reasonable approach to the diagnosis, evaluation and treatment of the hypertensive disorders of pregnancy (HDP).

EVIDENCE

The literature reviewed included the previous Society of Obstetricians and Gynaecologists of Canada (SOGC) HDP guidelines from 2008 and their reference lists, and an update from 2006. Medline, Cochrane Database of Systematic Reviews (CDSR), Cochrane Central Registry of Controlled Trials (CCRCT) and Database of Abstracts and Reviews of Effects (DARE) were searched for literature published between January 2006 and March 2012. Articles were restricted to those published in French or English. Recommendations were evaluated using the criteria of the Canadian Task Force on Preventive Health Care and GRADE.

Drugs for treatment of very high blood pressure during pregnancy

BACKGROUND

Very high blood pressure during pregnancy poses a serious threat to women and their babies. The aim of antihypertensive therapy is to lower blood pressure quickly but safety, to avoid complications. Antihypertensive drugs lower blood pressure but their comparative effectiveness and safety, and impact on other substantive outcomes is uncertain.

OBJECTIVES

To compare different antihypertensive drugs for very high blood pressure during pregnancy.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (9 January 2013).

SELECTION CRITERIA

Studies were randomised trials. Participants were women with severe hypertension during pregnancy. Interventions were comparisons of one antihypertensive drug with another.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and assessed trial quality. Two review authors extracted data and checked them for accuracy.

MAIN RESULTS

Thirty-five trials (3573 women) with 15 comparisons were included. Women allocated calcium channel blockers were less likely to have persistent high blood pressure compared to those allocated hydralazine (six trials, 313 women; 8% versus 22%; risk ratio (RR) 0.37, 95% confidence interval (CI) 0.21 to 0.66). Ketanserin was associated with more persistent high blood pressure than hydralazine (three trials, 180 women; 27% versus 6%; RR 4.79, 95% CI 1.95 to 11.73), but fewer side-effects (three trials, 120 women; RR 0.32, 95% CI 0.19 to 0.53) and a lower risk of HELLP (haemolysis, elevated liver enzymes and lowered platelets) syndrome (one trial, 44 women; RR 0.20, 95% CI 0.05 to 0.81).Labetalol was associated with a lower risk of hypotension compared to diazoxide (one trial 90 women; RR 0.06, 95% CI 0.00 to 0.99) and a lower risk of caesarean section (RR 0.43, 95% CI 0.18 to 1.02), although both were borderline for statistical significance.Both nimodipine and magnesium sulphate were associated with a high incidence of persistent high blood pressure, but this risk was lower for nimodipine compared to magnesium sulphate (one trial, 1650 women; 47% versus 65%; RR 0.84, 95% CI 0.76 to 0.93). Nimodipine was associated with a lower risk of respiratory difficulties (RR 0.28, 95% CI 0.08 to 0.99), fewer side-effects (RR 0.68, 95% CI 0.55 to 0.85) and less postpartum haemorrhage (RR 0.41, 95% CI 0.18 to 0.92) than magnesium sulphate. Stillbirths and neonatal deaths were not reported.There are insufficient data for reliable conclusions about the comparative effects of any other drugs.

AUTHORS' CONCLUSIONS

Until better evidence is available the choice of antihypertensive should depend on the clinician's experience and familiarity with a particular drug; on what is known about adverse effects; and on women's preferences. Exceptions are nimodipine, magnesium sulphate (although this is indicated for women who require an anticonvulsant for prevention or treatment of eclampsia), diazoxide and ketanserin, which are probably best avoided.

Hypertension in pregnancy: a review of therapeutic options

Hypertensive disorders in pregnancy are common and can occur as a result of pre-existing hypertension or as new onset hypertension usually in the second half of pregnancy. In either situation there is potential for considerable perinatal and maternal morbidity and mortality. This review article aims to compare therapeutic options outlined in a selection of national guidelines and to look in more detail at the most commonly prescribed drugs - labetalol, methyldopa and nifedipine - with respect to their pharmacology and the evidence for their use in pregnancy. We will also consider the rationale for identifying and treating hypertension in pregnancy and the effect this can have on short- and long-term maternal and neonatal outcomes.

A comprehensive review of hypertension in pregnancy

Hypertension is the most common medical disorder encountered during pregnancy. Hypertensive disorders are one of the major causes of pregnancy-related maternal deaths in the United States. We will present a comprehensive update of the literature pertinent to hypertension in pregnancy. The paper begins by defining and classifying hypertensive disorders in pregnancy. The normal vascular and renal physiological changes which occur during pregnancy are detailed. We will summarize the intriguing aspects of pathophysiology of preeclampsia, emphasizing on recent advances in this field. The existing diagnostic tools and the tests which have been proposed for screening preeclampsia are comprehensively described. We also highlight the short- and long-term implications of preeclampsia. Finally, we review the current management guidelines, goals of treatment and describe the potential risks and benefits associated with various antihypertensive drug classes. Preeclampsia still remains an enigma, and the present management focuses on monitoring and treatment of its manifestations. We are hopeful that this in depth critique will stimulate the blossoming research in the field and assist practitioners to identify women at risk and more effectively treat affected individuals.

How to manage hypertension in pregnancy effectively

The hypertensive disorders of pregnancy (HDP) are a leading cause of maternal mortality and morbidity in both well and under-resourced settings. Maternal, fetal, and neonatal complications of the HDP are concentrated among, but not limited to, women with pre-eclampsia. Pre-eclampsia is a systemic disorder of endothelial cell dysfunction and as such, blood pressure (BP) treatment is but one aspect of its management. The most appropriate BP threshold and goal of antihypertensive treatment are controversial. Variation between international guidelines has more to do with differences in opinion rather than differences in published data. For women with severe hypertension [defined as a sustained systolic BP (sBP) of ≥160 mmHg and/or a diastolic BP (dBP) of ≥110 mmHg], there is consensus that antihypertensive therapy should be given to lower the maternal risk of central nervous system complications. The bulk of the evidence relates to parenteral hydralazine and labetalol, or to oral calcium channel blockers such as nifedipine capsules. There is, however, no consensus regarding management of non-severe hypertension (defined as a sBP of 140-159 mmHg or a dBP of 90-109 mmHg), because the relevant randomized trials have been underpowered to define the maternal and perinatal benefits and risks. Although antihypertensive therapy may decrease the occurrence of BP values of 160-170/100-110 mmHg, therapy may also impair fetal growth. The potential benefits and risks do not seem to be associated with any particular drug or drug class. Oral labetalol and methyldopa are used most commonly, but many different β-adrenoceptor blockers and calcium channel blockers have been studied in clinical trials.

Antihypertensive drugs in pregnancy

Blood pressure targets and medications that are safe differ in pregnant women compared with nonpregnant individuals. The principles of treatment for mild, moderate, and severe hypertension in pregnancy, chronic versus gestational versus preeclampsia, and women hypertensive at term versus remote from term are reviewed. The choice of antihypertensive drugs also is discussed; methyldopa, labetalol, and nifedipine, among others, appear safe for use in pregnancy, whereas angiotensin converting enzyme inhibitors and angiotensin receptor blockers should be avoided. The management of increased blood pressure in the postpartum period, and agents to use in lactation, are also discussed.

Therapeutics and anaesthesia

Many aspects of hypertension care outside pregnancy may be applied in pregnancy, but little information is available on which to base decision-making. It would seem reasonable to continue previous dietary salt restriction and physical activity in women with pre-existing (and controlled) hypertension, encourage a heart-healthy diet in all women with a hypertension disorder of pregnancy, and take patient preference into account when deciding on place of care. Although bed rest has become a key part of obstetric practice and for care of women with a hypertension disorder of pregnancy, in particular, the evidence is lacking to support this practice. This may also increase thromboembolic risk. Antihypertensive treatment is strongly advised for women with severe hypertension. The most common agents are parenteral labetalol, hydralazine, or oral nifedipine capsules. Clinicians should familiarise themselves with multiple agents. Until the role of antihypertensive treatment for non-severe hypertension in pregnancy is clarified by ongoing research, clinicians should explicitly state an individual patient's blood pressure goal, which could reasonably be anywhere between 130/80 and 155/105 mmHg. Labetalol and methyldopa are used most commonly. Breastfeeding should be encouraged. Many risk factors for hypertension (e.g. obesity), as well as hospitalisation and pre-eclampsia, all increase the thromboembolic risk for pregnant women, and care providers should consider thromboprophylaxis in the appropriate setting. Finally, anaesthetists play a critical role in the management of women with a hypertension disorder of pregnancy, and should be involved earlier rather than later in the course of their care.

Control of hypertension in pregnancy

The hypertensive disorders of pregnancy are a leading cause of maternal mortality and morbidity. Complications are not limited to preeclampsia but also complicate both preexisting hypertension and isolated gestational hypertension. Blood pressure (BP) management is important but is only one aspect of management of the hypertensive disorders of pregnancy, which may be caused or exacerbated by underlying uteroplacental mismatch between maternal supply and fetal demand. BP treatment thresholds and goals vary in international guidelines, largely reflecting differences in opinion rather than differences in published data. Because of short-term maternal risks, there is consensus that BP should be treated when sustained at greater than or equal to 160 to 170 mm Hg systolic and/or 110 mm Hg diastolic. There is no consensus regarding management of nonsevere hypertension, and randomized controlled trials involving just over 3000 women have not clarified the relative maternal and perinatal risks and benefits. Although antihypertensive therapy may decrease transient severe maternal hypertension, therapy may also impair fetal growth and perinatal health and outcomes. The CHIPS Trial (Control of Hypertension In Pregnancy Study) is recruiting to answer this question.

Vascular and cellular calcium in normal and hypertensive pregnancy

Normal pregnancy is associated with significant hemodynamic changes in the cardiovascular system in order to meet the metabolic demands of mother and fetus. These changes include increased cardiac output, decreased vascular resistance, and vascular remodeling in the uterine and systemic circulation. Preeclampsia (PE) is a major complication of pregnancy characterized by proteinuria and hypertension. Several risk factors have been implicated in the pathogenesis of PE including genetic and dietary factors. Ca2+ is an essential dietary element and an important regulator of many cellular processes including vascular function. The importance of adequate dietary Ca2+ intake during pregnancy is supported by many studies. Pregnancy-associated changes in Ca2+ metabolism and plasma Ca2+ have been observed. During pregnancy, changes in intracellular free Ca2+ concentration ([Ca2+](i)) have been described in red blood cells, platelets and immune cells. Also, during pregnancy, an increase in [Ca2+](i) in endothelial cells (EC) stimulates the production of vasodilator substances such as nitric oxide and prostacyclin. Normal pregnancy is also associated with decreased vascular smooth muscle (VSM) [Ca2+](i) and possibly the Ca2+-sensitization pathways of VSM contraction including protein kinase C, Rho-kinase, and mitogen-activated protein kinase. Ca2+-dependent matrix metalloproteinases could also promote extracellular matrix degradation and vascular remodeling during pregnancy. Disruption in the balance between dietary, plasma and vascular cell Ca2+ may be responsible for some of the manifestation of PE including procoagulation, decreased vasodilation, and increased vasoconstriction and vascular resistance. The potential benefits of Ca2+ supplements during pregnancy, and the use of modulators of vascular Ca2+ to reduce the manifestations of PE in susceptible women remain an important area for experimental and clinical research.

The management of severe hypertension

Although definitions of severe hypertension vary, thresholds of >or=160-170 mm Hg systolic and/or >or=110 mm Hg diastolic are in most common usage. A recent focus has been placed on systolic hypertension given the increased pulse pressure in these women. In pregnancy, there is a general consensus that severe hypertension should be treated. Among woman with pre-eclampsia, attention must be paid to other end organ dysfunction, as blood pressure (BP) management is but one aspect of care. The urgency of antihypertensive therapy will depend primarily on the absolute level of BP. However, most clinicians will also consider both the rate of BP rise and the presence of maternal symptoms. Most commonly, severe hypertension is treated with parenteral labetalol or hydralazine, or oral nifedipine (capsules or PA tablet). Other options will depend on local availability. MgSO(4) should not be relied on as an antihypertensive.

Pharmacotherapeutic options for the treatment of preeclampsia

PURPOSE

Pharmacotherapeutic options for the treatment of preeclampsia are reviewed.

SUMMARY

Risk factors for the development of preeclampsia include microvascular diseases, such as diabetes mellitus; vascular and connective tissue disorders; hypertension; antiphospholipid antibody syndrome; and nephropathy. Several pathophysiological factors contribute to the development of the preeclamptic state, including vasospasm onset, coagulation system activation, increased inflammatory response, and ischemia. The specific agents used for the treatment of preeclampsia are dependent on a number of factors including symptom severity, maternal or fetal compromise, the progression to eclampsia, gestational period, and cervical status. The diagnosis of preeclampsia beyond the gestation period of 38 weeks requires delivery. The presence of maternal compromise or eclampsia at gestation greater than 20 weeks also necessitates delivery. In cases of chronic or mild hypertension, oral methyldopa may be administered on an outpatient basis. Intravenous hydralazine is a commonly administered arteriolar vasodilator that is effective for hypertensive emergencies associated with pregnancies. The most common adverse effect of hydralazine administration is unpredictable hypotension. Labetalol decreases heart rate and may be preferred because of a lack of reflex tachycardia, hypotension, or increased intracranial pressure. However, the drug of choice for the prevention and control of maternal seizures in patients with severe preeclampsia or eclampsia during the peripartum period is i.v. magnesium sulfate. Therapeutic serum magnesium levels cause cerebral vasodilation, thereby reversing the ischemia produced by cerebral vasospasm during an eclamptic episode. The results of one study indicated that women receiving magnesium sulfate therapy had a 58% lower risk of eclampsia than placebo.

CONCLUSION

Magnesium sulfate remains the drug of choice for the prevention and treatment of preeclampsia. Alternative antihypertensive agents may provide additional benefit in the management of hypertension for preeclamptic patients.

Identification of Photoproducts of Hexahydroquinoline Derivatives by GC-EI-MS and HPLC-ESI-MS

Photoproducts of hexahydroquinoline derivatives have been analyzed with gas chromatography electro ionization-mass spectrometry (GC-EI-MS) and high performance chromatography electrospray ionization-mass spectrometry (HPLC-ESI-MS). The study was performed on four HHQ derivatives: 2,6,6-trimethyl-3-carbomethoxy-5-oxo-4-(R-phenyl)-1,4,5,6,7,8-hexahydroquinoline; R=2'-Me, 3'-Me, 2'-MeO, and 3'-MeO. The photochemical degradation of each of the HHQ derivatives led to the appearance of one product. The photoproducts were identified as the corresponding tetrahydroquinoline analogues, which were formed by dehydrogenation of dihydropyridine moiety. In GC-mass spectra, the most frequent way of fragmentation was elimination of CH3* or CH3O* radical of the ester group. In the photoproducts substituted at 2'-position of the phenyl ring, elimination of isobutene (C4H8) was observed. In the photoproducts with 3'-position substituents, elimination of COOCH3* radical was noted.

Drugs for treatment of very high blood pressure during pregnancy

BACKGROUND

Very high blood pressure during pregnancy poses a serious threat to women and their babies. Antihypertensive drugs lower blood pressure. Their comparative effects on other substantive outcomes, however, is uncertain.

OBJECTIVES

To compare different antihypertensive drugs for very high blood pressure during pregnancy.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (28 February 2006) and CENTRAL (The Cochrane Library 2006, Issue 2).

SELECTION CRITERIA

Studies were randomised trials. Participants were women with severe hypertension during pregnancy. Interventions were comparisons of one antihypertensive drug with another.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data.

MAIN RESULTS

Twenty-four trials (2949 women) with 12 comparisons were included. Women allocated calcium channel blockers rather than hydralazine were less likely to have persistent high blood (five trials, 263 women; 6% versus 18%; relative risk (RR) 0.33, 95% confidence interval (CI) 0.15 to 0.70). Ketanserin was associated with more persistent high blood pressure than hydralazine (four trials, 200 women; 27% versus 6%; RR 4.79, 95% CI 1.95 to 11.73), but fewer side-effects (three trials, 120 women; RR 0.32, 95% CI 0.19 to 0.53) and a lower risk of HELLP (Haemolysis, Elevated Liver enzymes and Lowered Platelets) syndrome (one trial, 44 women, RR 0.20, 95% CI 0.05 to 0.81). Labetalol was associated with a higher risk of hypotension (one trial 90 women; RR 0.06, 95% CI 0.00 to 0.99) and caesarean section (RR 0.43, 95% CI 0.18 to 1.02) than diazoxide. Data were insufficient for reliable conclusions about other outcomes. The risk of persistent high blood pressure was greater for nimodipine compared to magnesium sulphate (two trials 1683 women; 47% versus 65%; RR 0.84, 95% CI 0.76 to 0.93). Nimodipine was also associated with a higher risk of eclampsia (RR 2.24, 95% CI 1.06 to 4.73) and respiratory difficulties (RR 0.28, 95% CI 0.08 to 0.99), but fewer side-effects (RR 0.68, 95% CI 0.54 to 0.86) and less postpartum haemorrhage (RR 0.41, 95% CI 0.18 to 0.92) than magnesium sulphate. Stillbirths and neonatal deaths were not reported. There are insufficient data for reliable conclusions about the comparative effects of any other drugs.

AUTHORS' CONCLUSIONS

Until better evidence is available, the choice of antihypertensive should depend on the clinician's experience and familiarity with a particular drug, and on what is known about adverse effects. Exceptions are diazoxide, ketanserin, nimodipine and magnesium sulphate, which are probably best avoided.

Acute hypertensive emergencies in pregnancy

OBJECTIVE

Obstetrical hypertensive emergencies are life-threatening conditions involving significant risk to both the mother and fetus. Aggressive treatment of the maternal hypertensive state requires an initial consideration of the effect of treatment on the fetus, via changes to the uteroplacental circulation with treatment. The challenge then is to correct blood pressure using appropriate, safe pharmacologic agents to prevent catastrophic maternal consequences, while minimizing acute changes to placental perfusion and any corresponding fetal ill effects. Hypertension in pregnancy may be one manifestation of a multiple-system pathologic process, as is the case in preeclampsia. Blood pressure control, along with delivery, will be the first step in treating the renal, hematologic, hepatic, and cardiac dysfunction that can be seen in preeclampsia.

DESIGN

A review of medications most commonly used for hypertensive emergencies in pregnancy.

CONCLUSIONS

Hypertensive emergencies in pregnancy require prompt evaluation and treatment in an intensive care setting to prevent untoward effects to both the fetus and mother.

Nifedipine for Severe Hypertension in Pregnancy: Emotion or Evidence?

A meta-analysis of randomized controlled trials suggests that nifedipine appears to be a reasonable agent for treatment of acute severe hypertension in pregnancy. However, in a 1999 survey of Canadian practitioners, most stated that they rarely or never use nifedipine capsules for treatment of acute severe pregnancy hypertension. Also, there are case reports of adverse outcomes following use of nifedipine capsules in pregnancy, although the risks appear to have been overplayed. We suggest that a reasonable approach is ongoing use of nifedipine capsules, with perhaps an initial dosage of 5 mg rather than 10 mg. Having women swallow the capsule without first biting it may also be a prudent approach, because there is insufficient information from most of the published clinical trials to say exactly how the nifedipine capsules were administered. Further, use of the 10 mg nifedipine prolonged action tablet may also be a reasonable approach for treatment of severe hypertension in pregnancy, although more data are needed. Such research would be particularly relevant given that nifedipine appears to be a promising treatment for spontaneous preterm labour. We must resist the temptation to throw out of our limited therapeutic armamentarium an effective oral preparation before adequately considering the evidence.

Drugs used in hypertensive diseases in pregnancy

PURPOSE OF REVIEW

This review will summarize results derived from the most recent publications on the use of drugs in women with hypertensive diseases in pregnancy.

RECENT FINDINGS

There is consensus that severe hypertension should be treated without delay to reduce maternal risks of acute cerebrovascular complications. There is no consensus that antihypertensive drugs improve maternal or fetal outcome in mild to moderate hypertension. Evidence exists that antihypertensive drugs may halve the risk of severe hypertension in pregnancy. No proof exists that antihypertensive drugs reduce perinatal mortality or development of preeclampsia, and such drugs have not been associated with improved fetal growth. Clinical trials indicate non-consistent data concerning antihypertensive treatment on antenatal rate of hospitalization, proteinuria at delivery and neonatal respiratory distress syndrome. Hydralazine has for many years been regarded as the first drug of choice for treatment of severe hypertension in pregnancy. Recent findings indicate that the calcium antagonist nifedipine might be a better alternative. Angiotensin converting enzyme inhibitors and angiotensin II receptor antagonists should be discontinued due to fetotoxicity. The beta1-selective adrenoceptor blocker atenolol in the first trimester is associated with low birth weight.

SUMMARY

Large randomized controlled trials are urgently needed to determine whether antihypertensive therapy in pregnancy results in greater benefit than risks for mother and fetus.

Pharmacologic treatment of hypertensive disorders during pregnancy

Pregnancy complicated by hypertension is a common problem faced by clinicians. It can lead to substantial maternal and/or fetal/neonatal morbidity and mortality. There are a variety of medications that can be used during pregnancy either for treatment of significant chronic hypertension or in cases of acute severe hypertension. Most antihypertensive drugs have been shown to be safe for use in pregnancy. A variety of medications are available to treat more severe hypertension, although the use of pharmacologic therapy to treat mild chronic hypertension during pregnancy has not been supported in the literature. The data are more limited concerning drugs that would be used in the event of hypertensive emergencies or in an intensive care setting; however, in such a situation, maternal health and life become paramount and, despite lack of good studies, appropriate treatment should be rendered.