Medications in pregnancy and lactation: Part 2. Drugs with minimal or unknown human teratogenic effect

Antihistamine use during breastfeeding with focus on breast milk transfer and safety in humans: A systematic literature review

Current data on use of antihistamines during breastfeeding and risks to the breastfed infant are insufficient. The aim of this systematic review was to provide an overview of studies measuring the levels of antihistamines in human breast milk, estimating the exposure for breastfed infants and/or reporting possible adverse effects on the breastfed infant. An additional aim was to review the antihistamine product labels available in the European Union (EU) and the United States. We searched seven online databases and identified seven human lactation studies that included 25 mother-infant pairs covering cetirizine, clemastine, ebastine, epinastine, loratadine, terfenadine and triprolidine. In addition, one study investigated the impact of chlorpheniramine or promethazine on prolactin levels among 17 women, and one study investigated possible adverse drug reactions in 85 breastfed infants exposed to various antihistamines. The relative infant dose was below 5% for all antihistamines, ranging from 0.3% for terfenadine to 4.5% for clemastine. Most product labels of the 10 antihistamines with available information in both the EU and the United States reported lack of evidence and recommended to avoid use during breastfeeding. The knowledge gap on antihistamines and lactation is extensive, and further human studies are warranted to ensure optimal treatment of breastfeeding women with allergy.

Association Between Fexofenadine Use During Pregnancy and Fetal Outcomes

IMPORTANCE

Fexofenadine hydrochloride is a frequently used drug for treatment of allergic conditions during pregnancy, but the fetal safety of fexofenadine use has not been well studied.

OBJECTIVE

To investigate the risk of adverse fetal outcomes associated with fexofenadine use during pregnancy.

DESIGN, SETTING, AND PARTICIPANTS

A nationwide registry-based cohort study was conducted on pregnancies in Denmark from January 1, 2001, to December 31, 2016. Data analysis was performed from March 21, 2019, to January 29, 2020. From a cohort of 1 287 668 pregnancies, fexofenadine use was compared with cetirizine hydrochloride use during pregnancy, matched in a 1:1 ratio on propensity scores. Distinct study cohorts and exposure time periods were applied according to each outcome analysis. Sensitivity analyses included comparing pregnancies with vs without fexofenadine exposure during pregnancy but with previous use before pregnancy and with loratadine use during pregnancy as additional comparator groups.

EXPOSURE

Filled prescription for fexofenadine.

MAIN OUTCOMES AND MEASURES

Major birth defects and spontaneous abortion. Secondary outcomes were preterm birth, small size for gestational age (SGA), and stillbirth. Logistic regression was used to estimate prevalence odds ratios (ORs) of major birth defects, preterm birth, and SGA, and Cox proportional hazards regression was used to estimate hazard ratios (HRs) of spontaneous abortion and stillbirth.

RESULTS

For the analyses of major birth defects and spontaneous abortion, a total of 2962 and 4901 pregnancies with fexofenadine use were included, respectively, matched in a 1:1 ratio with pregnancies with cetirizine use. Mean (SD) age of the fexofenadine cohort for analyses of major birth defects was 30.6 (4.8) years and, for analysis of spontaneous abortion, 30.4 (5.5) years. Infants born with major birth defects occurred in 118 pregnancies (4.0%) with fexofenadine use compared with 112 pregnancies (3.8%) with cetirizine use. Spontaneous abortion occurred in 413 pregnancies (8.4%) with fexofenadine use compared with 439 pregnancies (9.0%) with cetirizine use. Fexofenadine use during pregnancy was not associated with an increased risk of major birth defects (prevalence OR, 1.06; 95% CI, 0.81-1.37) or spontaneous abortion (HR, 0.93; 95% CI, 0.82-1.07) compared with cetirizine use during pregnancy. Preterm birth occurred in 370 pregnancies (7.5%) with fexofenadine use compared with 382 pregnancies (7.7%) with cetirizine use (prevalence OR, 0.97; 95% CI, 0.83-1.12), SGA occurred in 515 pregnancies (10.1%) with fexofenadine use compared with 523 pregnancies (10.2%) with cetirizine use (prevalence OR, 0.98; 95% CI, 0.87-1.12), and a total of 16 pregnancies (0.3%) with fexofenadine use ended in stillbirth compared with 24 pregnancies (0.4%) with cetirizine use (HR, 0.67; 95% CI, 0.36-1.27). Sensitivity analyses of the primary outcomes, including the comparisons of pregnancies with loratadine use and pregnancies unexposed to fexofenadine during pregnancy but with prior use of fexofenadine, showed similar results.

CONCLUSIONS AND RELEVANCE

Use of fexofenadine during pregnancy does not appear to be associated with an increased risk of adverse fetal outcomes.

Medication Use among Pregnant Women from the 2015 Pelotas (Brazil) Birth Cohort Study

Background: Medication use during pregnancy is a common practice that has been increasing in recent years. The aim of this study is to describe medication use among pregnant women from the 2015 Pelotas (Brazil) Birth Cohort Study. Methods: This paper relies on a population-based cohort study including 4270 women. Participants completed a questionnaire about the antenatal period, including information about medication use. We performed descriptive analyses of the sample and the medications used and adjusted analyses for the use of medications and self-medication. Results: The prevalence of medication use was 92.5% (95% CI 91.7-93.3), excluding iron salts, folic acid, vitamins, and other minerals. The prevalence of self-medication was 27.7% (95% CI 26.3-29.1). In the adjusted analysis, women who had three or more health problems during pregnancy demonstrated higher use of medicines. Self-medication was higher in lower income groups and among smokers and multiparous women (three pregnancies or more). Acetaminophen, scopolamine, and dimenhydrinate were the medications most commonly used. Conclusions: This study describes the pattern of drug use among pregnant women in a population-based cohort study, with a high prevalence of self-medication. Greater awareness of the risks of self-medication during pregnancy is required, focusing on groups more prone to this practice, as well as ensuring qualified multidisciplinary prenatal care.

A Meta-Analysis of the Relationship Between Maternal Folic Acid Supplementation and the Risk of Congenital Heart Defects

Controversial opinions exist with respect to the relationship between maternal folic acid (FA) supplementation and birth prevalence of congenital heart defects (CHDs).Eligible articles were retrieved by searching databases, including PubMed, Cochrane library, EMBASE, CNKI, and WanFang up to September 2015. A meta-analysis was performed to evaluate the effects of FA on CHDs. Odds ratios (ORs) and 95% confidence interval (CIs) were merged using STATA 12.0. Meta-regression analysis was used to explore the possible sources of heterogeneity. Subgroup analysis according to the selected sources was also performed. Publication bias was assessed by Egger's test.Twenty studies were included in the meta-analysis. The overall analysis showed that FA supplementation was significantly associated with decreased risk of CHDs. The meta-regression analysis showed that geographical area could be an important source of heterogeneity. The subgroup analysis based on the geographical area revealed that FA supplementation during pregnancy was a protective factor against CHDs in Chinese and European patients, but not in American patients. Subgroup analysis according to literature quality also displayed positive associations between FA supplementation and the decreased risk of CHDs of China.FA supplementation during pregnancy significantly decreases the risk of CHDs in newborns in China and Europe.

[Specific features of emergency dental care in pregnant women]

The aim of the study was to evaluate the algorithm of safe emergency dental care in pregnant patients. Eighty-five pregnant women aged 20-35 were included in the study. The paper presents elaborated state-of-the-art guidelines for emergency dental care in pregnant patients. Articaine 4% with epinephrine 1:200,000 is recommended as a choice agent for local anesthesia in these patients.

Medicine use and safety while breastfeeding: investigating the perspectives of community pharmacists in Australia

Consumers and health professionals rely on community pharmacists for accurate information about the safety of medicines. Many breastfeeding women require medications, yet we know little about the advice provided to them by pharmacists in Australia. The aim of this study therefore was to investigate the perspectives of community pharmacists in Australia on medication use and safety in breastfeeding using a postal survey of a national random sample of 1166 community pharmacies in 2011. One hundred and seventy-six pharmacists responded (51% female). Of the 52% of participants with children, many (70%) had a total breastfeeding duration (self or partner) of 27 weeks or more. The majority (92%) were confident about supplying or counselling on medication during breastfeeding. The most commonly used resources were drug company information, Australian Medicines Handbook and the Royal Women's Pregnancy and Breastfeeding Medicine Guide. Most (80%) believed the available information to be adequate and 86% thought it accessible. Over one-third were unaware that ibuprofen and metronidazole are compatible with breastfeeding. Most (80%) were able to name at least one medicine that may decrease milk supply. We found that community pharmacists discuss medicine use in lactation and are confident of their ability to do so; however, their knowledge may be variable.

Identifying associations between maternal medication use and birth defects using a case-population approach: an exploratory study on signal detection

BACKGROUND

The effects of many drugs on the unborn child are unknown. In a case-population design, drug exposure of cases is compared with that of a source population; this kind of study can be useful for generating signals.

OBJECTIVE

To see whether a comparison of drug use rates from the birth defect registry EUROCAT NNL (cases) with prescription rates from a population-based prescription database, the IADB (population), could be used to detect signals of teratogenic risk of drugs.

METHODS

We defined 3,212 cases from the EUROCAT NNL database, a population-based birth defect registry in the Northern Netherlands and 29,223 population controls from the IADB, a prescription database with data from community pharmacies in the same geographical area, born between 1998 and 2008. We classified the malformations of the 3,212 cases into several malformation groups according to organ system (based on the International Classification of Diseases codes and the EUROCAT guidelines). If a child had multiple malformations in several organ systems (n = 253, 7.9 %), he/she was counted in all the categories represented. For several groups of malformations we calculated rate ratios (RR) and 95 % confidence intervals for drugs acting on the central nervous system and for drugs considered to be safe for use in pregnancy. The RRs were based on first-trimester drug use rates from the cases in the EUROCAT NNL database and prescription rates from the population controls in the IADB.

RESULTS

For drugs acting on the central nervous system we found significantly increased RRs for the anti-epileptic drug valproic acid and for some selective serotonin reuptake inhibitors. For drugs considered to be safe only the anti-hypertensive methyldopa showed significantly increased RRs.

CONCLUSION

We show that a case-population study is a suitable method for detecting signals of possible teratogenicity, provided that the teratogenic effects and the drugs under study are as specific as possible and the drugs are widely used.

A review of antihistamines used during pregnancy

Antihistamines are one of the most common drugs that are used extensively in various dermatological and nondermatological conditions. The use of H-1-antihistamines during pregnancy has been very controversial due to possible teratogenic effects of these drugs. None of the antihistamines available today have been categorized as safe during pregnancy. Control studies are available for certain first generation drugs regarding their safety in pregnancy, but the newer agents require further studies to be declared safer in pregnancy. A few drugs are comparatively safer to use in pregnancy than others. Every drug used in pregnancy carries a risk for teratogenicity and careful risk/benefit assessment should be done before prescribing them.

General maternal medication use, folic acid, the MDR1 C3435T polymorphism, and the risk of a child with a congenital heart defect

OBJECTIVE

We sought to investigate maternal and child functional MDR1 C3435T polymorphism, periconception medication, folic acid use, and the risk of a congenital heart defect (CHD) in the offspring.

STUDY DESIGN

MDR1 3435C>T genotyping was performed in 283 case triads (mother, father, child) and 308 control triads. Information on periconception medication and folic acid use was obtained through questionnaires.

RESULTS

Mothers with MDR1 3435CT/TT genotype and using medication showed a significant association with the risk of a child with CHD (odds ratio [OR], 2.4; 95% confidence interval [CI], 1.3-4.3) compared to mothers with MDR1 3435CC genotype not using medication. This risk increased without folic acid use (OR, 2.8; 95% CI, 1.2-6.4), and decreased in folic acid users (OR, 1.7; 95% CI, 0.8-3.7). Children carrying the MDR1 3435CT/TT genotype and periconceptionally exposed to medication without folic acid did not show significant risks.

CONCLUSION

Mothers carrying the MDR1 3435T allele, using medication without folic acid, are at nearly 3-fold increased risk for CHD in the offspring.

Comparison of recorded medication use in the Medical Birth Registry of Norway with prescribed medicines registered in the Norwegian Prescription Database

PURPOSE

Maternal medication use during pregnancy is explored extensively, as it may cause birth defects. This study aimed to evaluate the validity of recorded medication use in the Medical Birth Registry of Norway (MBRN).

METHODS

This study was based on the nationwide population-based registries, the MBRN and the Norwegian Prescription Database (NorPD). These registries were linked using a unique 11-digit identification number. The sensitivity, specificity and positive predictive value (PPV) of recorded medication use in MBRN were computed using data from NorPD as the reference.

RESULTS

Among the 163,678 pregnancies included in our study, the sensitivity for total drug use during pregnancy was calculated to be 32% and PPV was 82%. When we looked at the use of medication during the whole pregnancy, the sensitivities of drug registration for the main groups in the Anatomical Therapeutic Chemical (ATC)-classification varied from 50% (ATC group H) to 2% (ATC group S).

CONCLUSION

The medication use recorded in MBRN is poor compared with prescribed medicines registered in NorPD. There was a substantial difference between the different ATC codes regarding the sensitivity of MBRN in the registration of medication use during pregnancy.

Successful drug development despite adverse preclinical findings part 2: examples

To illustrate the process of addressing adverse preclinical findings (APFs) as outlined in the first part of this review, a number of cases with unexpected APF in toxicity studies with drug candidates is discussed in this second part. The emphasis is on risk characterization, especially regarding the mode of action (MoA), and risk evaluation regarding relevance for man. While severe APFs such as retinal toxicity may turn out to be of little human relevance, minor findings particularly in early toxicity studies, such as vasculitis, may later pose a real problem. Rodents are imperfect models for endocrine APFs, non-rodents for human cardiac effects. Liver and kidney toxicities are frequent, but they can often be monitored in man and do not necessarily result in early termination of drug candidates. Novel findings such as the unusual lesions in the gastrointestinal tract and the bones presented in this review can be difficult to explain. It will be shown that well known issues such as phospholipidosis and carcinogenicity by agonists of peroxisome proliferator-activated receptors (PPAR) need to be evaluated on a case-by-case basis. The latter is of particular interest because the new PPAR α and dual α/γ agonists resulted in a change of the safety paradigm established with the older PPAR α agonists. General toxicologists and pathologists need some understanding of the principles of genotoxicity and reproductive toxicity testing. Both types of preclinical toxicities are major APF and clinical monitoring is difficult, generally leading to permanent use restrictions.

Providing contraception for women taking potentially teratogenic medications: a survey of internal medicine physicians' knowledge, attitudes and barriers

BACKGROUND

The majority of women prescribed category D or X medications may not receive adequate contraceptive counseling or a reliable contraceptive method. Physicians who prescribe potentially teratogenic medications have a responsibility to provide women with contraceptive counseling, a method of highly-effective contraception, or both.

OBJECTIVE

Investigate the knowledge, beliefs and barriers of primary care physicians toward providing adequate contraception to women taking potential teratogens.

DESIGN & PARTICIPANTS

Self-administered confidential survey of primary care internal medicine physicians at an urban, academic medical center.

MEASUREMENTS

Knowledge of potential teratogenic medications and contraceptive failure rates was assessed. Participants' beliefs about adequacy of their medical education, practice limitations and attitudes toward improving provision of contraception to women on potential teratogens were assessed.

RESULTS

One hundred and ten physicians responded (57.3%). Nearly two-thirds (62.3%) of participants had cared for reproductive aged women taking category D or X medications in the past year. The mean percent of correctly identified category D or X medications was 58.4% (SD 22.1%). The mean percent correct for knowledge of published contraceptive failure rates was 64.6% (SD 23.1%). Most respondents (87.6%) felt it is the responsibility of primary care physicians to provide contraception. Time constraints were reported to be somewhat or very limiting by 61.3% and over half felt medical school (63.2%) or residency (58.1%) inadequately prepared them to prescribe or counsel about contraceptives.

CONCLUSIONS

Primary care physicians commonly encounter reproductive age women taking category D or X medications, but may lack sufficient knowledge and time to counsel about potential teratogens and contraception to prevent fetal exposure to these drugs.