Cardiovascular Pharmacotherapeutic Considerations During Pregnancy and Lactation

Optimising Fluvoxamine Maternal/Fetal Exposure during Gestation: A Pharmacokinetic Virtual Clinical Trials Study

Fluvoxamine plasma concentrations have been shown to decrease throughout pregnancy. CYP2D6 polymorphisms significantly influence these changes. However, knowledge of an optimum dose adjustment according to the CYP2D6 phenotype is still limited. This study implemented a physiologically based pharmacokinetic modelling approach to assess the gestational changes in fluvoxamine maternal and umbilical cord concentrations. The optimal dosing strategies during pregnancy were simulated, and the impact of CYP2D6 phenotypes on fluvoxamine maternal and fetal concentrations was considered. A significant decrease in fluvoxamine maternal plasma concentrations was noted during gestation. As for the fetal concentration, a substantial increase was noted for the poor metabolisers (PM), with a constant level in the ultrarapid (UM) and extensive (EM) metabolisers commencing from gestation week 20 to term. The optimum dosing regimen suggested for UM and EM reached a maximum dose of 300 mg daily at gestational weeks (GW) 15 and 35, respectively. In contrast, a stable dose of 100 mg daily throughout gestation for the PM is sufficient to maintain the fluvoxamine plasma concentration within the therapeutic window (60-230 ng/mL). Dose adjustment during pregnancy is required for fluvoxamine, particularly for UM and EM, to maintain efficacy throughout the gestational period.

Pregnancy affects the pharmacokinetics of sildenafil and its metabolite in the rabbit

1. There is growing interest in the use of sildenafil during pregnancy for various maternal and fetal conditions. This study aims to investigate the effect of pregnancy on the maternal pharmacokinetics (PK) of sildenafil and its main metabolite desmethylsildenafil in rabbits. Using NONMEM, population PK modeling was performed based on plasma samples from 31 rabbits of whom 15 were pregnant and 16 were not. All received a single subcutaneous sildenafil dose of 10 mg/kg. One sample was obtained per rabbit at either 30, 60, 120, 360, 720 or 1320 min after sildenafil administration. 2. A two- and one-compartment PK-model best described the data for sildenafil and desmethylsildenafil, respectively. Compared to non-pregnant rabbits, the central and peripheral volume of distribution and inter-compartmental clearance of sildenafil were lower in pregnant rabbits [32.1 versus 12.2 L, 110 versus 44.4 L and 25.5 versus 12.1 L/h; all p < 0.05]. The formation clearance from sildenafil to desmethylsildenafil was also reduced during pregnancy [13.3 versus 7.8 L/h; p < 0.05]. 3. In contrast, the elimination clearance of desmethylsildenafil, was higher in pregnancy [73.5 versus 116. 9; p < 0.05]. In rabbits, pregnancy impacts PK parameters of sildenafil and its metabolite, leading to an increased peak concentration and 24 h exposure for sildenafil and a decreased 24 h exposure for desmethylsildenafil.

Acute myocardial infarction in pregnancy following unlicensed use of methylenedioxymethamphetamine (‘ecstasy’)

Acute myocardial infarction is rare in pregnancy; however, the emerging trend towards advanced maternal age and the rising prevalence of obesity and diabetes suggest that more cases of myocardial infarction are likely to be encountered in pregnancy. However, there is scanty evidence on the risk of myocardial infarction with regard to socially misused substances in pregnancy. We describe the management of a case of acute myocardial infarction following unlicensed use of 3,4-methylenedioxymethamphetamine (‘Ecstasy’) in pregnancy. The case highlights a rare but serious risk associated with substance misuse in pregnancy.

Beneficial effects of combinatorial micronutrition on body fat and atherosclerosis in mice

AIMS

More than two billion people worldwide are deficient in key micronutrients. Single micronutrients have been used at high doses to prevent and treat dietary insufficiencies. Yet the impact of combinations of micronutrients in small doses aiming to improve lipid disorders and the corresponding metabolic pathways remains incompletely understood. Thus, we investigated whether a combination of micronutrients would reduce fat accumulation and atherosclerosis in mice.

METHODS AND RESULTS

Lipoprotein receptor-null mice fed with an original combination of micronutrients incorporated into the daily chow showed reduced weight gain, body fat, plasma triglycerides, and increased oxygen consumption. These effects were achieved through enhanced lipid utilization and reduced lipid accumulation in metabolic organs and were mediated, in part, by the nuclear receptor PPARα. Moreover, the micronutrients partially prevented atherogenesis when administered early in life to apolipoprotein E-null mice. When the micronutrient treatment was started before conception, the anti-atherosclerotic effect was stronger in the progeny. This finding correlated with decreased post-prandial triglyceridaemia and vascular inflammation, two major atherogenic factors.

CONCLUSION

Our data indicate beneficial effects of a combination of micronutritients on body weight gain, hypertriglyceridaemia, liver steatosis, and atherosclerosis in mice, and thus our findings suggest a novel cost-effective combinatorial micronutrient-based strategy worthy of being tested in humans.

Risks of congenital malformations and perinatal events among infants exposed to calcium channel and beta-blockers during pregnancy

PURPOSE

Calcium channel blockers and beta-blockers (BBs) are widely used during pregnancy, but data on their safety for the developing infant are scarce. We used population-based data from 5 HMOs to study risks for perinatal complications and congenital defects among infants exposed in-utero.

METHODS

We studied women older than 15 years delivering an infant between 1/1/96 and 12/31/00, who had been continuously enrolled with prescription drug coverage for ≥ 1 year prior to delivery. Information on prescription drug dispensings, inpatient, and outpatient diagnoses and procedures was obtained from automated databases at each HMO.

RESULTS

There were 584 full-term infants exposed during pregnancy to BBs and 804 full-term infants exposed to calcium-channel blockers, and over 75,000 unexposed mother-infant pairs with ≥ 30 days follow-up. Infants exposed to BBs in the third trimester of pregnancy had over threefold increased risk for hypoglycemia (RR 3.1; 95% CI 2.2, 4.2) and an approximately twofold increased risk for feeding problems (RR 1.8; 95% CI 1.3, 2.5). Infants exposed to calcium-channel blockers in the third trimester had an increased risk for seizures (RR 3.6 95% CI 1.3, 10.4). Chart review confirmed the majority of the exposed seizure and hypoglycemia cases. There were no increased risks for congenital anomalies among either group of infants, except for the category of upper alimentary tract anomalies; this increased risk was based on only two exposed cases.

CONCLUSIONS

Infants whose mothers receive BBs are at increased risk for neonatal hypoglycemia, while those whose mothers take calcium-channel blockers are at increased risk for neonatal seizures.

Acute Myocardial Infarction in Pregnant Women

Acute myocardial infarction (AMI) in pregnant women is a rare but potentially lethal occurrence that should be carefully managed, especially in consideration of cardiac conditions being a rising cause of maternal deaths. Risk factors for AMI occurrence, in addition to typical cardiac-related risk factors, include medical conditions such as (pre) eclampsia, blood transfusions, thrombophilia and postpartum infections. Being older, multigravida or in the third trimester of pregnancy is also associated with an increased risk. The pathophysiological causes underlying AMI in pregnancy are diverse but generally associated with the coagulative and physiological changes related to the pregnancy. The selection of diagnostic modality and treatment options require careful consideration for pregnancy-related changes as well as risk of harm to the patient and fetus. This paper serves to review available literature regarding an extensive range of management issues that directly impact on maternal and fetal outcomes. Key words: Myocardial infarction, Pregnancy complications, Obstetric labour complications

Acute coronary syndrome in pregnancy

Acute coronary syndrome (ACS) in pregnancy has traditionally been considered to be a rare event, but the combination of normal physiological changes of pregnancy and more prevalent cardiovascular risk factors are increasing its incidence in this population. The present report describes a 39 year-old woman that is seven weeks pregnant presenting with a non ST elevation myocardial infarction. The incidence, risk factors, pathophysiology and management of ACS in pregnancy are discussed.

Acute myocardial infarction associated with pregnancy

Acute myocardial infarction (AMI) during pregnancy or the early post-partum period is rare but has been shown to be associated with poor maternal as well as fetal outcome. Major changes in both diagnosis and treatment of AMI in the nonpregnant patient have lead to improved outcome which may also affect pregnant patients. The purpose of this paper is to review available information related to the pathophysiology and clinical profile and provide recommendations for the diagnosis and management of AMI occuring during pregnancy and the early post-partum period.

Congenital heart disease in pregnancy

INTRODUCTION

Pregnancy, birth, and the puerperium are associated with significant physiological changes and adaptations in the cardiovascular system, which pose a significant risk to pregnant women with congenital heart disease (CHD). Thanks to advances in pediatric cardiac surgery and cardiology the majority of children with CHD survive to adulthood, and an increasing number eventually become pregnant. In fact, cardiac disease - mostly congenital - is now a leading cause of maternal death in western industrialized countries.

METHODS

Selective literature review.

RESULTS AND DISCUSSION

Optimal care of women with CHD before, during, and after pregnancy requires a multidisciplinary team including obstetricians, cardiologists, and anaesthetists. Successful pregnancy at a minimum risk is feasible for most women with CHD when appropriate counseling and optimal care are provided.

Pathophysiology and medical management of systemic hypertension in preeclampsia

Hypertension that complicates preeclampsia in pregnancy is a disorder that requires special consideration in both prevention and pharmacologic treatment. In recent years, few advances have been made regarding the pathophysiology and prevention of preeclampsia; however, there have been some promising results from studies on possible modes of screening women for preeclampsia before clinical signs and symptoms are apparent. The recommendations for first-line drug therapy for the hypertensive complications of preeclampsia have changed little, primarily because first-line medications have had the advantage of extensive research experience. Recent clinical trials have demonstrated the efficacy and safety of various second-line drugs for the hypertensive complications of preeclampsia; whether these therapies can eventually replace the standard recommended first-line medications will require more extensive long-term investigation.

Pregnancy in women with valvular heart disease

Patients with valvular disease who desire pregnancy or are already pregnant require specialised care. Ideally, women undergo preconceptual counselling that addresses any procedures needed to decrease the risks of pregnancy, including valve replacement, if the patient has symptoms at baseline. Management during pregnancy includes replacing any contraindicated medications with safer alternatives, optimising loading conditions, careful monitoring and aggressive treatment of any exacerbating factors. Rarely, percutaneous or surgical intervention is required during pregnancy. Labour and delivery often require invasive haemodynamic monitoring and a multi-disciplinary team for optimal maternal and fetal outcomes.

Pathophysiology and Medical Management of Systemic Hypertension in Pregnancy

Hypertension in pregnancy includes a group of distinct disorders that require special consideration in both prevention and pharmacologic treatment. In recent years, there have been few advances regarding the pathophysiology and prevention of preeclampsia or in the recommendations for first-line drug therapy for its hypertensive complications. Similarly, the recommendations for pharmacologic treatment of women with chronic hypertension antedating pregnancy have changed little primarily because first-line medications have the advantage of having had more extensive research experience. Recent clinical trials have demonstrated the efficacy and safety of various second-line drugs for the hypertensive disorders of pregnancy; whether these therapies can eventually replace the standard recommended medications will require more extensive long-term investigation.

Valvular Heart Disease and Pregnancy

A large number of prosthetic heart valves (PHV) are being implanted in patients with both congenital and acquired valvular disease. Many of the recipients of such valves are women of childbearing age who desire to have children. The main issues involved with pregnancy in a patient with PHV include the selection of PHV in women during their childbearing age, risks to both the mother and the fetus associated with pregnancy and the management of the patients with PHV during gestation.