Identifying parents in pharmacy data: a tool for the continuous monitoring of drug exposure to unborn children

Switching pattern and dose adjustment of antidepressants before and during pregnancy

The purpose of the study is to examine the switching pattern and dose adjustment of antidepressants (ADs) prescribed to women from six months before to six months during pregnancy in the Netherlands. The recorded dispenses or refills were collected from the University of Groningen IADB.nl pregnancy subset for all singleton pregnancies in which the mother received ≥ 1 prescription of an AD dispensed before pregnancy and was present in the database at least six months after conception. The rates of continuation, discontinuation, and switching between 2001 and 2020 were assessed for the ADs studied. The mean number of Defined Daily Doses (DDDs) of the most frequently continued ADs used was calculated both before and during pregnancy, and a paired t-test was used to test for significant changes. The continuation rates for AD users, especially for SSRI and SNRI continued users, increased over time from 27% and 19% (2001-2005) to 65% and 65% (2016-2020). The switching rate between ADs remained consistently low from the start of the study (2001-2005) at 2.0% to the end of the study (2016-2020) at 2.3%. Most women who switched between antidepressants during pregnancy received a different SSRI monotherapy (85%), followed by an SNRI (6%), a TCA (4%), and an "other AD" (4%). In most cases observed, the dose adjustment for the mean DDDs during pregnancy compared to the mean DDDs before pregnancy only changed little (less than 10%). Continued use of SSRIs among singleton pregnancies doubled over the study period. The low rate of AD switching and little changes in the DDD adjustment for most AD continuers indicate that pregnant women prefer to continue their prepregnancy medication rather than switch it. Most observed findings cohere with the Dutch national guidelines for antidepressant use during pregnancy.

Exposure to psychotropic drugs before and during pregnancy: what has changed over the last two decades?

Trends in prescribing psychotropic drugs before and during pregnancy may have changed over the years, but actual information is lacking. We therefore compared and assessed the exposure and acceptance rates of classes of antipsychotic (+ lithium), anxiolytic, sedative/hypnotic, antidepressant, and psychostimulant before and during pregnancy in the past two decades. All singleton pregnancies with ≥1 prescription of psychotropic drug from six months before pregnancy until child's birthdate were identified in the pregnancy subset of the IADB.nl prescription database. The prescription patterns of psychotropics were distinguished as continuation rate (CR), initiation rate (IR), discontinuation rate (DR), total exposure rate (TER), and acceptance rate. Singleton pregnancies exposed to psychotropic drugs before and during pregnancy increased from 118.4 to 136.5 (per 1000 singleton pregnancies) between decades. Changing trends were observed in decade 2, including a high increase in the TER of antipsychotic class (3.3 to 6.8) and antidepressant class (23.0 to 40.6). A marked increase for individual drugs was seen for sertraline (TER: 0.6 to 6.6 and PAT: 35.3% to 82.5%), citalopram (TER: 2.3 to 10.0 and PAT: 51.1% to 74.6%), and quetiapine (TER: 0.4 to 3.1 and PAT: 57.1% to 66.0%). Although the total exposure rates of five classes of psychotropics in singleton pregnancies increased in decade 2, only antidepressant class had a higher acceptance rate during pregnancy. Certain SSRI antidepressants and atypical antipsychotics were more frequently prescribed in decade 2 than in decade 1, reflecting that treatment options were preferred for safer treatment choices.

In utero antidepressant exposure not associated with ADHD in the offspring: A case control sibling design

Recent studies have reported an association between antidepressant (AD) use during pregnancy and the risk to develop attention-deficit/hyperactivity disorder (ADHD) in the offspring. However, the association might be confounded by risk factors in the pregnant parent. To control for unmeasured factors between pregnancies carried by the same parent, we set up a case-control sibling study using the University of Groningen prescription database IADB.nl. Children receiving medication for ADHD (cases) before the age of 16 years were matched to siblings not receiving such medication (controls). Exposure was defined as at least two prescriptions for any AD during pregnancy, i.e., the period of 39 weeks before the birth date of the offspring. Secondary analyses were performed to assess the effects of the degree of exposure (the amount of Defined Daily Doses) and the type of AD exposed to. Univariate and multivariate logistic regression was used to estimate odds ratios (ORs) with corresponding 95% confidence intervals (CI). In total, 2,833 children (1,304 cases and 1,529 controls) were included in the analysis. Exposure rate to ADs among cases and controls was 2.2% and 2.4%, respectively. After adjusting for the birth date of the child (as a proxy for the date of pregnancy), age of the pregnant parent at birth, use of psychostimulants, opioids, and antiepileptic drugs by the pregnant parent in the 15 months before birth of the child, an adjusted OR of 1.11 (95% CI 0.67–1.83) was found for the risk of ADHD in the offspring when exposed in utero to ADs. This indicates no increased risk of ADHD in offspring following in utero exposure to ADs. The secondary analyses revealed no statistically significant associations either. The present study provides further evidence that an association between in utero AD exposure and ADHD in offspring might not exist. This perceived association may be caused (at least partially) by confounding by indication. The extent to which depression in the pregnant parent could cause mental disorders such as ADHD in offspring, and the mechanisms involved, should be investigated in further studies.

Antidepressant use during pregnancy and the risk of developing gestational hypertension: a retrospective cohort study

BACKGROUND

Prior studies reported that exposure to antidepressants during pregnancy may be associated with gestational hypertension. The aim of this study is to assess the association between the use of antidepressants during pregnancy and the risk of developing gestational hypertension.

METHODS

A retrospective cohort study using the prescription database IADB.nl was conducted among nulliparous women with singleton pregnancies between 1994 and 2015 in the Netherlands. Logistic regression analysis was used to estimate odds ratios (OR), adjusted OR (aOR) and their corresponding 95% confidence intervals (95% CI). Gestational hypertension as main outcome measure was defined as at least one dispensed record of an antihypertensive drug (methyldopa, nifedipine, labetalol, ketanserin, nicardipine) after 20 weeks of gestation until 14 days after delivery. Sub-analyses were conducted for class of antidepressant, duration and amount of use of antidepressant (≤30, ≥30 Defined Daily Doses or DDDs), and maternal age. Sensitivity analyses to assess uncertainties were conducted.

RESULTS

Twenty-eight thousand twenty women were included, of which 539 (1.92%) used antidepressants. The risk of gestational hypertension was doubled for women using antidepressant (aOR 2.00 95% CI 1.28-3.13). Significant associations were also found for the subgroup selective serotonin reuptake inhibitors (SSRIs) (aOR 2.07 95% CI 1.25-3.44), ≥30 DDDs (aOR 2.50 95% CI 1.55-3.99) and maternal age of 30-34 years (aOR 2.59 95% CI 1.35-4.98). Varying the theoretical gestational age showed comparable results.

CONCLUSION

Prolonged use of antidepressants during the first 20 weeks of gestation appeared to be associated with an increased risk of developing gestational hypertension. When balancing the benefits and risks of using these drugs during pregnancy, this should be taken into account.

The limitations of some European healthcare databases for monitoring the effectiveness of pregnancy prevention programmes as risk minimisation measures

PURPOSE

Pregnancy prevention programmes (PPPs) exist for some medicines known to be highly teratogenic. It is increasingly recognised that the impact of these risk minimisation measures requires periodic evaluation. This study aimed to assess the extent to which some of the data needed to monitor the effectiveness of PPPs may be present in European healthcare databases.

METHODS

An inventory was completed for databases contributing to EUROmediCAT capturing pregnancy and prescription data in Denmark, Norway, the Netherlands, Italy (Tuscany/Emilia Romagna), Wales and the rest of the UK, to determine the extent of data collected that could be used to evaluate the impact of PPPs.

RESULTS

Data availability varied between databases. All databases could be used to identify the frequency and duration of prescriptions to women of childbearing age from primary care, but there were specific issues with availability of data from secondary care and private care. To estimate the frequency of exposed pregnancies, all databases could be linked to pregnancy data, but the accuracy of timing of the start of pregnancy was variable, and data on pregnancies ending in induced abortions were often not available. Data availability on contraception to estimate compliance with contraception requirements was variable and no data were available on pregnancy tests.

CONCLUSION

Current electronic healthcare databases do not contain all the data necessary to fully monitor the effectiveness of PPP implementation, and thus, special data collection measures need to be instituted.

Knowledge and attitude regarding pharmacogenetics among formerly pregnant women in the Netherlands and their interest in pharmacogenetic research

Background

Pharmacogenetics is an emerging field currently being implemented to improve safety when prescribing drugs. While many women who take drugs during pregnancy would likely benefit from such personalized drug therapy, data is lacking on the awareness towards pharmacogenetics among women. We aim to determine the level of knowledge and acceptance of formerly pregnant women in the Netherlands regarding pharmacogenetics and its implementation, and their interest in pharmacogenetic research.

Methods

A population-based survey using postal questionnaires was conducted among formerly pregnant women in the Northern parts of the Netherlands. A total of 986 women were invited to participate.

Results

Of the 219 women who returned completed questionnaires (22.2% response rate), only 22.8% had heard of pharmacogenetics, although the majority understood the concept (64.8%). Women who had experience with drug side-effects were more likely to know about pharmacogenetics [OR = 2.06, 95% CI 1.16, 3.65]. Of the respondents, 53.9% were positive towards implementing pharmacogenetics in their future drug therapy, while 46.6% would be willing to participate in pharmacogenetic research. Among those who were either not willing or undecided in this regard, their concerns were about the consequences of the pharmacogenetic test, including the privacy and anonymity of their genetic information.

Conclusion

The knowledge and attitude regarding the concept of pharmacogenetics among our population of interest is good. Also, their interest in pharmacogenetic research provides opportunities for future research related to drug use during pregnancy and fetal outcome.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-017-1290-z) contains supplementary material, which is available to authorized users.

Maternal use of drug substrates of placental transporters and the effect of transporter-mediated drug interactions on the risk of congenital anomalies

BACKGROUND

A number of transporter proteins are expressed in the placenta, and they facilitate the placental transfer of drugs. The inhibition of P-glycoprotein (P-gp) was previously found to be associated with an increase in the risk of congenital anomalies caused by drug substrates of this transporter. We now explore the role of other placental transporter proteins.

METHODS

A population-based case-referent study was performed using cases with congenital anomalies (N = 5,131) from EUROCAT Northern Netherlands, a registry of congenital anomalies. The referent population (N = 31,055) was selected from the pregnancy IADB.nl, a pharmacy prescription database.

RESULTS

Ten placental transporters known to have comparable expression levels in the placenta to that of P-gp, were selected in this study. In total, 147 drugs were identified to be substrates, inhibitors or inducers, of these transporters. Fifty-eight of these drugs were used by at least one mother in our cases or referent population, and 28 were used in both. The highest user rate was observed for the substrates of multidrug resistance-associated protein 1, mainly folic acid (6% of cases, 8% of referents), and breast cancer resistance protein, mainly nitrofurantoin (2.3% of cases, 2.9% of referents). In contrast to P-gp, drug interactions involving substrates of these transporters did not have a significant effect on the risk of congenital anomalies.

CONCLUSIONS

Some of the drugs which are substrates or inhibitors of placental transporters were commonly used during pregnancy. No significant effect of transporter inhibition was found on fetal drug exposure, possibly due to a limited number of exposures.

Exposure to reactive intermediate-inducing drugs during pregnancy and the incident use of psychotropic medications among children

PURPOSE

Our study aimed to investigate the association between prenatal exposure to reactive intermediate (RI)-inducing drugs and the initiation of psychotropic medications among children.

METHODS

We designed a cohort study using a pharmacy prescription database. Pregnant women were considered exposed when they received a prescription of RI-inducing drugs. These drugs could be either used alone (RI+/FAA-) or combined with drugs exhibiting folic acid antagonism (FAA, RI+/FAA+). The reference group included pregnant women who did not receive any RI-inducing drugs or FAA drugs.

RESULTS

We analyzed 4116 exposed and 30 422 reference pregnancies. The hazard ratio (HR) with 95% confidence interval (CI) was 1.27 (95%CI 1.15-1.41) for pregnancies exposed to RI-inducing drugs as a whole. Considering subgroups of RI-inducing drugs, prenatal exposure to both RI+/FAA+ and RI+/FAA- was associated with the children's initiation of psychotropic medications, HRs being 1.35 (95%CI 1.10-1.66) and 1.26 (1.13-1.41), respectively. The HRs were increased with prolonged exposure to RI-inducing drugs, especially in the first and second trimesters. In a detailed examination of the psychotropics, the incidences of receiving antimigraine preparations and psychostimulants were significantly increased for the exposed children, compared with the reference children. The incidences of receiving antipsychotics and hypnotics were also higher for the exposed children; however, the HRs did not reach significance after adjustment.

CONCLUSIONS

We found a significantly increased incident use of psychotropic medications among children prenatally exposed to RI-inducing drugs, especially during the first and second trimesters. This suggests a detrimental effect during critical periods of brain development. Copyright © 2017 John Wiley & Sons, Ltd.

Impact of Muscarinic M3 Receptor Antagonism on the Risk of Type 2 Diabetes in Antidepressant-Treated Patients: A Case-Controlled Study

BACKGROUND

M₃ muscarinic receptor antagonism has been associated with glucose intolerance and disturbance of insulin secretion.

OBJECTIVE

Our objective was to examine the risk of type 2 diabetes mellitus (T2DM) in patients using antidepressants with and without M₃ muscarinic receptor antagonism (AD_antaM₃ and AD_nonantaM₃, respectively).

METHODS

We designed a case-control study using a pharmacy prescription database. We selected a cohort of patients who initiated antidepressant use between the ages of 20 and 40 years and who did not receive any anti-diabetic prescriptions at baseline. Cases were defined as those who developed T2DM [i.e., receiving oral anti-diabetic medication, Anatomical Therapeutic Chemical (ATC) code A10B] during the follow-up period (1994-2014), and ten random controls were picked for each case from the cohort of patients who did not develop T2DM.

RESULTS

A total of 530 cases with incident T2DM and 5300 controls were included. Compared with no use of antidepressants during the previous 2 years, recent (within the last 6 months) exposure to AD_antaM₃ was associated with a moderately increased risk of T2DM: adjusted odds ratio 1.55 (95% confidence interval 1.18-2.02). In the stratified analyses, this association was dose dependent (>365 defined daily doses) and significant for patients who were in the younger age group (<45 years at the end of follow-up), were female and had no co-morbidity. On the other hand, recent exposure to AD_nonantaM₃ was not associated with a risk for T2DM in any of our analyses.

CONCLUSION

Our results suggest that exposure to AD_antaM₃ was associated with the development of T2DM among antidepressant users.

Association between medication prescription for atopic diseases and attention-deficit/hyperactivity disorder

BACKGROUND

Data on the association between atopic diseases and attention-deficit/hyperactivity disorder (ADHD) have been inconclusive.

OBJECTIVE

To assess whether children with drug-treated ADHD are more likely to receive treatment for asthma, allergic rhinitis, or eczema before the start of ADHD medication use compared with controls and to examine the effect of parents receiving medication for ADHD and atopic diseases on ADHD medication use in their offspring.

METHODS

We conducted a retrospective nested case-control study among children (6-12 years of age) using the Groningen University prescription database. Cases were defined as children with at least 2 prescriptions of methylphenidate within 12 months. For each case, 4 controls were matched on age, sex, and regional area code. Parental prescription data were linked to cases and controls to assess the influence of parents receiving medication for ADHD and atopic diseases on ADHD medication use in their offspring.

RESULTS

We identified 4257 cases and 17,028 matched controls. Drug treatment for asthma, allergic rhinitis, and eczema was more common in cases than controls (adjusted odds ratios [aORs], 1.4 [95% confidence interval (CI), 1.3-1.6], 1.4 [95% CI, 1.1-1.8], and 1.3 [95% CI, 1.1-1.5], respectively). Medication for allergic rhinitis and asthma among parents was associated with ADHD treatment in their children (aORs, 1.3 [95% CI, 1.1-1.5] and 1.2 [95% CI, 1.1-1.3], respectively).

CONCLUSION

This study provides further evidence to support the hypothesis that atopic diseases are associated with ADHD. The parental-offspring association suggests a possible genetic and/or environmental component.

Antibiotic use during pregnancy and asthma in preschool children: the influence of confounding

BACKGROUND

A recent study suggested that early-life intestinal microbiota may play an important role in the development of childhood asthma, indicating that antibiotics taken during early life or in late pregnancy may be associated with childhood asthma.

OBJECTIVE

This study aims to assess the association between prenatal antibiotic use and asthma in preschool children using data from the prescription database IADB.nl. To assess the influence of potential confounding, we conducted both a case-sibling and a case-control study and compared the results.

METHODS

We conducted a case-sibling study in which 1228 children with asthma were compared to 1228 siblings without asthma, using data from the prescription database IADB.nl. In addition, a case-control study was conducted. Asthma in preschool children was defined as ≥ 3 prescriptions for anti-asthma medication within a year before the fifth birthday. Conditional logistic regression was used to estimate crude and adjusted odds ratios (aORs).

RESULTS

In both the case-sibling and case-control analysis, the use of antibiotics in the third trimester of pregnancy was associated with an increased risk of asthma in preschool children (aOR 1.37; 95% CI 1.02-1.83 and aOR 1.40; 95% CI 1.15-1.47). Time-trend analyses showed that results were not influenced by a time trend in antibiotic exposure. A significant association between exposure to antibiotics in any trimester of pregnancy and the development of asthma in preschool children was observed in the case-control analysis only (aOR 1.46; 95% CI 1.34-1.59).

CONCLUSION

Antibiotic use in the third trimester of pregnancy was associated with a small increased risk of asthma in preschool children. This association was robust to time-invariant confounding or exposure time trends, further supporting the important role for early-life intestinal microbiota in the development of childhood asthma.

P-Glycoprotein-Mediated Drug Interactions in Pregnancy and Changes in the Risk of Congenital Anomalies: A Case-Reference Study

Introduction

Drug use in pregnancy is very common but may cause harm to the fetus. The teratogenic effect of a drug is partly dependent on the drug level in the fetal circulation, which is associated with the transport across the placenta. Many drugs are substrates of P-glycoprotein (P-gp), an efflux transporter that acts as a protective barrier for the fetus. We aim to identify whether drug interactions associated with P-gp promote any changes in fetal drug exposure, as measured by the risk of having children with congenital anomalies.

Methods

In this study, cases (N = 4634) were mothers of children with congenital anomalies registered in the EUROCAT Northern Netherlands registry, and the reference population were mothers of children (N = 25,126) from a drug prescription database (IADB.nl).

Results

Drugs that are associated with P-gp transport were commonly used in pregnancy in cases (10 %) and population (12 %). Several drug classes, which are substrates for P-gp, were shown to have a higher user rate in mothers of cases with specific anomalies. The use of this subset of drugs in combination with other P-gp substrates increased the risk for specific anomalies (odds ratio [OR] 4.17, 95 % CI 1.75–9.91), and the addition of inhibitors further increased the risk (OR 13.03, 95 % CI 3.37–50.42). The same pattern of risk increment was observed when the drugs were analyzed separately according to substrate specificity.

Conclusions

The use of drugs associated with P-gp transport was common during pregnancy. For several drug classes associated with specific anomalies, P-gp-mediated drug interactions are associated with an increased risk for those specific anomalies.

Electronic supplementary material

The online version of this article (doi:10.1007/s40264-015-0299-3) contains supplementary material, which is available to authorized users.

Prenatal exposure to acid-suppressive drugs and the risk of allergic diseases in the offspring: a cohort study

BACKGROUND

Recent studies reported increased risks for the development of asthma in children after prenatal exposure to acid-suppressive drugs. As a result of common pathogenesis, associations could also be present for other allergic diseases.

METHODS

Using the prescription database IADB.nl, we conducted a cohort study amongst 33 536 children in the Netherlands, with a maximum follow-up of 8 years. Maternal exposure was defined as ≥1 dispensed prescription for proton pump inhibitors (PPIs) and/or Histamine 2-antagonists (H2As) during pregnancy. Children were considered to have a drug-treated allergic disease if they received either ≥2 prescriptions for dermal (atopic dermatitis), inhaled (asthma) or nasal (allergic rhinitis) steroids within a 12-month period. Clustered Cox proportional hazard regression was used to estimate crude and adjusted hazard ratios (aHR) with 95% confidence intervals (95% CI).

RESULTS

The aHR for the development of any allergic disease was 1.37 (95% CI: 1.14-1.66) for children exposed to PPIs or H2As. Prenatal exposure to PPIs and/or H2As was associated with atopic dermatitis, asthma and allergic rhinitis with aHRs of 1.32 (95% CI 1.06-1.64), 1.57 (95% CI 1.20-2.05) and 2.40 (95% CI 1.42-4.04), respectively. The aHR for the development of two or more (aHR 2.13 95% CI: 1.43-3.19) and three allergic diseases (aHR 5.18 95% CI: 2.16-12.42) were even more elevated after prenatal exposure to PPIs or H2As.

CONCLUSION

Prenatal exposure to PPIs and H2As appeared associated with an increased risk for the development of atopic dermatitis, asthma and allergic rhinitis in the offspring, especially with the development of multiple allergic diseases. Because our study has limitations inherent to observational studies, prospective studies are now warranted to confirm our findings.

Maternal high-dose folic acid during pregnancy and asthma medication in the offspring

PURPOSE

Low-dose folic acid supplementation (0.5 mg) taken during pregnancy has been associated with an increased risk for childhood asthma. The effect of high-dose folic acid (5 mg) advised to women at risk for having a child with neural tube defect has not been assessed so far. Our aim was to investigate the effect of dispensed high-dose folic acid during pregnancy and asthma medication in the offspring.

METHODS

We used data from the pregnancy database IADB.nl, which contains pharmacy-dispensing data of mothers and children from community pharmacies in the Netherlands from 1994 until 2011. The dispension of asthma medication in children exposed in utero to high-dose folic acid was compared with children who were not exposed to this high dose. Incidence rate ratios (IRRs) with 95% confidence intervals (CIs) were calculated.

RESULTS

In 2.9% (N = 913) of the 39,602 pregnancies in the database, the mother was dispensed high-dose folic acid. Maternal high-dose folic acid was associated with an increased rate of asthma medication among children: recurrent asthma medication IRR = 1.14 (95%CI: 1.04-1.30) and recurrent inhaled corticosteroids IRR = 1.26 (95%CI: 1.07-1.47). Associations were clustered on the mother and adjusted for maternal age, maternal asthma medication, and dispension of benzodiazepines during pregnancy.

CONCLUSION

Almost 3% of the children were prenatally exposed to high-dose folic acid. This study suggests that supplementation of high-dose folic acid during pregnancy might increase the risk of childhood asthma.

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.

The population-based prescription database IADB.nl: its development, usefulness in outcomes research and challenges

Research databases with large numbers of prescriptions in observational settings can provide valuable information in addition to the initial randomized controlled trials. This paper reports on the development of prescription database IADB, formerly known as InterAction Database. IADB contains prescriptions from 54 community pharmacies in The Netherlands and covers a population of 500,000 people. Both the age distribution and the prevalence of drugs used are comparable to a large extent with the Dutch population. The representativeness of the population covered is examined by comparing population composition and drug use with data of the whole Dutch population. Enriching IADB with, among others, clinical parameters by linking to other databases is explored. A strong and unique aspect of IADB is the possibility to track patients over time, even when they receive their medication from different pharmacies. The authors conclude IADB is a useful tool for pharmacoepidemiological and pharmacoeconomic outcomes research.

Drugs associated with teratogenic mechanisms. Part I: dispensing rates among pregnant women in the Netherlands, 1998-2009

STUDY QUESTION

What are the dispensing rates of drugs suspected to be associated with teratogenic mechanisms among pregnant Dutch women?

SUMMARY ANSWER

In a substantial proportion of pregnancies in our study population at least one drug associated with a teratogenic mechanism was dispensed in the first trimester of pregnancy.

WHAT IS KNOWN ALREADY

The main teratogenic mechanisms of medical drugs that may affect fetal development in the first trimester of pregnancy have been described previously. However, information on the dispensing rate of such drugs among women at all stages of pregnancy is lacking.

STUDY DESIGN, SIZE, DURATION

To determine how often medications suspected to be associated with a teratogenic mechanism are used by pregnant women, we studied 32 016 pregnancies included in the IADB.nl database between 1998 and 2009.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We estimated dispensing rates of medical drugs suspected to be associated with teratogenic mechanisms in our study population. The IADB.nl database includes all pharmacy dispensings for an estimated population of 220 000 in 1994-1998 and c.500 000 since 1999. In addition, trends in first trimester dispensing rates over time and patterns of receiving multiple drugs associated with teratogenic mechanisms were evaluated. In addition, we determined the number of pregnancies in which multiple prescription drugs from one or more teratogenic categories were dispensed in the first trimester, and we evaluated the numbers of different medications dispensed that could be grouped within a specific teratogenic mechanism.

MAIN RESULTS AND THE ROLE OF CHANCE

In 175 per 1000 pregnancies [95% confidence interval (CI), 171-179] at least one drug associated with a teratogenic mechanism was dispensed in the first trimester. The total dispensing rate was 236 per 1000 pregnancies (95% CI 232-241) in the 3 months before pregnancy and an increasing trend was seen in the second [214 per 1000 (95% CI 209-218)] and third [327 per 1000 (95% CI 322-332)] trimesters. The first trimester dispensing rates increased between 1998 and 2009 for selective serotonin-reuptake inhibitors (P < 0.001) and serotonin receptor agonists/antagonists (P < 0.001). In 71.8% of pregnancies in which drugs associated with teratogenic mechanisms were dispensed in the first trimester, women received drugs related to only one mechanism. Of the pregnancies in which drugs from multiple teratogenic categories were dispensed in the first trimester, 1148 (72.6%) women received drugs from 2 categories, 317 (20.0%) from three categories, 88 (5.6%) from 4 categories, 28 (1.8%) from 5 categories and 1 from 6 categories. Several women received multiple prescription medications grouped within a single teratogenic mechanism in the first trimester, ranging between 13.3% for cyclo-oxygenase inhibitors and 41.8% for serotonin receptor agonists/antagonists.

LIMITATIONS, REASONS FOR CAUTION

We used a dispensing database, therefore actual use of the medication prescribed is unknown and non-compliance could have led to overestimation of exposure prevalences.

WIDER IMPLICATIONS OF THE FINDINGS

Owing to the uncertainties concerning the safety of medication use during pregnancy, the results of this study stress the need for cautious prescription of medication associated with teratogenic mechanisms to women of reproductive age. This is further supported by our finding that women received multiple prescription medications grouped within a single teratogenic mechanism in the first trimester, which would theoretically increase strongly the risk of birth defects.

STUDY FUNDING/COMPETING INTEREST(S)

Marleen van Gelder was supported by the Netherlands Organisation for Scientific Research/NWO (grant no. 021.001.008). No competing interests are declared.

TRIAL REGISTRATION NUMBER

N/A.

Antibiotics prescribed before, during and after pregnancy in the Netherlands: a drug utilization study

PURPOSE

To describe the prescription of antibiotics before, during and after pregnancy, and the trends over a 16-year period in the Netherlands, and to determine whether they were prescribed according to national guidelines.

METHODS

The IADB (http://iadb.nl) contains prescriptions dispensed by community pharmacies in the Netherlands. We extracted information on 18,873 pregnancies for 14,969 women between 1994 and 2009, focusing on antibiotics dispensed in the four trimesters before conception to two trimesters after birth (nine trimesters in total). We calculated trends in prescription rates during pregnancy and over time, and also compared the prescription of antibiotics in the Netherlands with safety category based on the Australian Drug Evaluation Committee.

RESULTS

During pregnancy 20.8% of the women were prescribed at least one antibiotic. The 'beta-lactam antibacterials/penicillins' group and the specific antibiotic amoxicillin were most commonly prescribed in the nine trimesters covered. The prescription rate of the 'other antibacterials' group during pregnancy increased over the years, in contrast to that of the 'sulphonamides/trimethoprim' group, which decreased. In total, 2.0% of pregnancies were exposed to a 'potentially harmful' antibiotic and 0.8% to a 'harmful' antibiotic. Compared with the period before conception, 'safe' antibiotics were prescribed more often during pregnancy than the other groups.

CONCLUSIONS

One in five women was prescribed at least one antibiotic during pregnancy in the Netherlands, which is comparable with rates in other European countries. Our results suggest that antibiotics appear to be prescribed to pregnant women generally in accordance with national recommendations.

A population analysis of prescriptions for asthma medications during pregnancy

BACKGROUND

It is important to control asthma during pregnancy. However, some studies indicate that women stop or change their asthma medications when they become pregnant.

OBJECTIVE

We used a population database to analyze changes in prescriptions for asthma medications to patients before, during, and after pregnancy.

METHODS

We collected information from a pregnancy database that is part of the population-based pharmacy prescription InterAction Database from the northern Netherlands. Our study cohort comprised 25,709 pregnancies for which prescription data were available. We collected data over a study period of 1 year before pregnancy until 6 months after birth and analyzed data from pregnant women who received at least 1 prescription for asthma medication during the study period (n = 2072), identifying all prescriptions for asthma medication and oral corticosteroids.

RESULTS

Prescriptions for asthma medications did not change during pregnancies from 1994-2003. However, during the 2004-2009 period, there was a significant decrease (P = .017) in prescriptions for asthma medications during the first months of pregnancy compared with the months before pregnancy, especially prescriptions of long-acting bronchodilators. Although most asthma prescriptions continued throughout pregnancy, prescriptions for controller therapies were reduced by 30% during the first months of pregnancy.

CONCLUSIONS

Many women stop or reduce their use of asthma medications when they become pregnant. Strategies to safely control asthma during pregnancy are needed.

In utero exposure to antidepressants and the use of drugs for pulmonary diseases in children

Purpose

The use of antidepressants during pregnancy is common. Some studies suggest an association between in utero exposure to antidepressants and the occurrence of pulmonary diseases like asthma later in life. Serotonin reuptake inhibitors (SSRIs) as well tricyclic antidepressants (TCAs) are thought to be involved in the development of the respiratory rhythm generator (RRG) and the maturation of the formation of surfactant. In this study the use of drugs for pulmonary diseases in children who were exposed to antidepressants in utero were compared with non-exposed children.

Methods

The pharmacy prescription database IADB.nl was used for a cohort study in which the use of drugs for pulmonary disease in children after in utero exposure to antidepressants (TCAs, SSRIs) was compared with children with no antidepressant exposure in utero. Drugs for pulmonary diseases were applied as a proxy for disturbed development of the respiratory tract.

Results

A small though significant increase in the incidence risk ratio (IRR) of the use of drugs for pulmonary disease was found after any-time in utero exposure to SSRIs, adjusted for maternal use of antibiotics, of 1.17 (95 % CI 1.16–1.18). An increase was also seen when we looked specifically for the use of SSRIs in at least the first trimester (IRR = 1.18, 95 % CI 1.17–1.20). An increased IRR in the use of drugs for pulmonary disease was also seen when children were exposed to TCAs, but this was not statistically significant. However, in both groups our sample size was rather small. The effect size is modest and may also be confounded by maternal smoking.

Conclusions

In utero exposure to SSRIs leads to a statistically significant increase in the use of drugs for pulmonary diseases, especially when exposure occurred during the first trimester of pregnancy. The increase in the use of drugs for pulmonary disease may also be related to other factors. Therefore, further study is recommended.

Disturbed development of the enteric nervous system after in utero exposure of selective serotonin re-uptake inhibitors and tricyclic antidepressants. Part 2: Testing the hypotheses

AIMS

Antidepressant use has increased in the last decade. Several studies have suggested a possible association between maternal antidepressant use and teratogenic effects.

METHODS

The pharmacy prescription database IADB.nl was used for a cohort study in which laxative and antidiarrhoeal medication use in children after in utero exposure to antidepressants (TCA, SSRI, fluoxetine or paroxetine exposed) was compared with no antidepressant exposure. Laxatives and antidiarrhoeal medication use were applied as a proxy for constipation and diarrhoea respectively, which may be associated with disturbed enteric nervous system (ENS) development.

RESULTS

Children exposed in utero to SSRIs (mainly fluoxetine and paroxetine) in the second and third trimester or to TCAs in the first trimester, more often received laxatives. Combined exposure to TCAs and SSRIs in pregnancy was associated with a 10-fold increase in laxative use. In utero exposure to SSRIs is not associated with antidiarrhoeal medication use compared with non-exposed children. In contrast, antidiarrhoeal medication use was significantly higher in children exposed to TCAs anytime in pregnancy.

CONCLUSIONS

The increased laxative use after second and third trimester exposure to SSRIs might be explained through the inhibitory effect of the serotonin re-uptake transporter (SERT) and because of selectivity for the 5-HT(2B) receptor which affects the ENS. TCA exposure during the first trimester leads to increased laxative use probably through inhibition of the norepinephrine transporter (NET). Exposure of TCAs anytime in pregnancy leads to increase diarrhoeal use possibly through down-regulation of α₂-adrenoceptors or up-regulation of the pore forming α(1c) subunit.

Prescribing of sulfasalazine, azathioprine and methotrexate round pregnancy--a descriptive study

PURPOSE

Continuation or discontinuation of drugs during pregnancy in chronic diseases is an issue of concern. Information on prescribing of disease modifying anti-rheumatic drugs (DMARDs) during pregnancy is scarce. In this study, we report prescribing patterns round pregnancy of sulfasalazine (SSZ), azathioprine (AZA), methotrexate (MTX) and co-medications among women to whom one of these DMARDs were prescribed before pregnancy.

METHODS

The pregnancy-interaction database (IADB.nl, 1994-2004), containing pharmacy dispensing data from Northern- Netherlands, was used. Women to whom SSZ (N = 13), AZA (N = 10) or MTX (N = 6) was prescribed before their first pregnancy were identified and described in detail.

RESULTS

AZA and SSZ are continued during pregnancy by 60% and 38% of the women, respectively, MTX was stopped before pregnancy. Among women receiving SSZ (N = 13) as their initial DMARD, anti-inflammatory and anti-rheumatic drugs (69%) and analgesics (45%) were the most commonly prescribed co-medications. Among women receiving AZA (N = 8) as their initial DMARD, corticosteroids for systemic use (100%) and intestinal anti-inflammatory agents (88%) were the most commonly prescribed co-medications. All women receiving intestinal anti-inflammatory drugs before pregnancy continued this during pregnancy, in contrast to other co-medications which were mainly discontinued.

CONCLUSIONS

Our study showed that DMARDs and co-medication are received before, during and after pregnancy, although no specific prescription patterns were found. Administrative databases, such as the pregnancy-IADB.nl, are useful in describing drug-prescribing patterns for better understanding of drug prescribing around pregnancy in daily practice. Based on these data, we conclude that prescribing of DMARDs and related co-medication is based on the individual patient.

Increase in use of selective serotonin reuptake inhibitors in pregnancy during the last decade, a population-based cohort study from the Netherlands

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

* Recently, the use of selective serotonin reuptake inhibitors (SSRIs), particularly paroxetine, in pregnancy has been associated with an increased risk on specific birth defects or other adverse pregnancy outcomes. * However, the extent of SSRI use in pregnancy is largely unknown.

WHAT THIS STUDY ADDS

* In the last decade the use of SSRIs in the year preceding delivery has increased twofold. * This increase runs parallel with the increase in use of SSRIs among women of fertile age. * Paroxetine is one of the most commonly used SSRIs. * Only recently have sufficient data become available on the use of paroxetine to detect moderate increased risks for specific malformations. * The safety of SSRIs which are less frequently used is not yet established. * Case-control birth defect-monitoring systems may be helpful in providing safety and risk estimates that become more precise as data accumulate for these drugs.

AIMS

Recent case-control studies suggest a relationship between the use of selective serotonin reuptake inhibitors (SSRIs) and the occurrence of birth defects and other adverse pregnancy outcomes. The aim was to determine the extent of the use of SSRIs before and during pregnancy and its trend over the years 1995-2004 in the Netherlands.

METHODS

The study was performed with data from a population-based prescription database. Within this database, women giving birth to a child between 1995 and 2004 were identified. The exposure rate and 95% confidence interval (CI) were calculated as the number of pregnancies per 1000 that were exposed to an SSRI in a defined period (per trimester or in the year preceding delivery). Exposure rates were calculated for 2-year periods: 1995/1996, 1997/1998, 1999/2000, 2001/2002 and 2003/2004. Trends in exposure rates were analysed using the chi(2) test for trend.

RESULTS

Included were 14,902 pregnancies for which complete pharmacy records were available from 3 months before pregnancy until delivery. A total of 310 pregnancies were exposed to an SSRI in the year preceding delivery. The exposure rate increased from 12.2 (95% CI 7.0, 19.8) in 1995/1996 to 28.5 (95% CI 23.0, 34.9) in 2003/2004.

CONCLUSION

There has been a significant increase in the use of SSRIs among pregnant women in the Netherlands over the last 10 years, parallel with the increase in exposure in women of fertile age. In light of the recent warnings about the use of SSRIs in pregnancy, healthcare professionals should be careful in prescribing SSRIs to women planning a pregnancy.

Selection of controls in case-control studies on maternal medication use and risk of birth defects

BACKGROUND

In case-control studies on teratogenic risks of maternal drug use during pregnancy, the use of normal or malformed controls may lead to recall-bias or selection bias. This can be avoided by using controls with a genetic disorder. However, researchers are hesitant to use these as controls because it is unknown whether their selection is independent of exposure status. The aim of this study is to investigate whether first trimester drug use among mothers of children with genetic disorders is representative for the "general pregnant population".

METHODS

From a birth defects registry 565 mothers of infants with a genetic disorder born between 1998-2004 were selected (the "genetic population"). The first trimester exposure rate was calculated for prescription-only drugs as the number of exposed women per 100. By calculating the rate ratio (RR) and 95% CI, the exposure rates in the genetic population were compared with those in the "source population" obtained from a population-based prescription database and consisting of 10,870 mothers who gave birth to a child between 1998-2004.

RESULTS

The mean age at birth was 32.1 for the genetic population and 29.6 for the source population (p = .000). In the genetic population, a higher use was found for antimigraine medication (RR = 2.7, 95% CI = 1.0-7.8) and for ovulation stimulants (RR = 1.6, 95% CI = 1.0-2.6). After adjustment for maternal age, the difference in use of ovulation stimulants disappeared.

CONCLUSIONS

Except for antimigraine medication, first trimester drug use among mothers of infants with genetic disorders is representative for the general pregnant population.

Prevalence and patterns of antidepressant drug use during pregnancy

OBJECTIVE

The aim of this study was to determine the extent and patterns of antidepressant use before, during and after pregnancy in a large population in The Netherlands.

METHODS

Health care records and prescription data from one of the largest Dutch health insurance companies were analysed. The study cohort consisted of 29,005 women who had live births in the period between January 2000 and July 2003. Antidepressant drug use during a specified period was defined as there being a record of a prescription during that period.

RESULTS

During the first trimester of pregnancy 2% of all pregnant women of the study cohort were found to have taken antidepressants; in the second and third trimesters, this figure had dropped to 1.8% of all pregnancies. Antidepressant use before as well as during pregnancy was almost twofold higher in women over 35 years of age than in those under 35 years. Almost 60% of the women who used antidepressants before pregnancy stopped taking them in the first trimester, and a smaller number stopped thereafter. Of all women using antidepressants during pregnancy, one third started this medication during gestation. In the 3 months following delivery, the prevalence of antidepressant use was the same as before pregnancy (2.9%). There was no shift to benzodiazepines in the group of women who stopped taking antidepressants during pregnancy. Although paroxetine and fluoxetine were the most frequently used antidepressants among the study group, all modern antidepressants were used.

CONCLUSION

A considerable number of women are being exposed to antidepressants throughout pregnancy up until delivery. One consequence of this is that their newborns need special care and supervision during the first days of life. However, women who stop taking the medication may risk a relapse of their illness, and this may also have a negative effect on the child.

Drug prescription patterns before, during and after pregnancy for chronic, occasional and pregnancy-related drugs in the Netherlands

OBJECTIVE

To compare the prescription of drugs in women over a period from 2 years before until 3 months after pregnancy, regarding the type of drugs used and the fetal risk.

DESIGN

A cohort study based on pharmacy records of women giving birth to a child between 1994 and 2003.

SETTING

The study was performed with data from the InterAction database, containing prescription-drug-dispensing data from community pharmacies.

POPULATION

The study population included 5412 women for whom complete pharmacy records were available.

METHODS

Drugs were classified into three categories: (1) drugs for chronic conditions, (2) drugs for occasional use and (3) drugs for pregnancy-related symptoms and also classified according to the Australian classification system.

MAIN OUTCOME MEASURES

The prescription rate was calculated as the number of women per 100 women who received one or more prescriptions for a given drug within a specified time period.

RESULTS

About 79.1% of the women received at least one prescription during pregnancy. The prescription rate for most drugs for chronic diseases and for occasional use decreased during pregnancy, whereas, as expected, the prescription rate for pregnancy-related drugs increased. During the first trimester of pregnancy, 1.7% of all drugs prescribed for chronic conditions and 2.3% of the occasional drugs were classified as harmful.

CONCLUSIONS

The increase in prescription rate during pregnancy is caused by an increase in prescription rate of drugs for pregnancy-related symptoms. The prescription of harmful drugs is more commonly associated with drugs for occasional use rather than with drugs for chronic conditions. Therefore, a more cautious prescribing of drugs to healthy women in the fertile age is necessary.

Drug use by pregnant women and comparable non-pregnant women in The Netherlands with reference to the Australian classification system

OBJECTIVE

To describe drug use in pregnancy, and compare drug use of pregnant women with non-pregnant women with respect to possible teratogenicity.

STUDY DESIGN

A cross-sectional study based on pharmacy records from 1997 to 2001 was performed. Pregnant women and matched non-pregnant women (same physician and age) were identified. Prescriptions were set against the Australian risk classification.

RESULTS

Thirty-five percent of all prescriptions for non-pregnant women were safe in pregnancy (Australian classification A), in 14% the risk was unknown (B1, B2), 49% were potentially harmful drugs (B3, C, D, X), and in 3% no classification was available. For pregnant women these figures were 86, 3, 10 and 2%, respectively. In non-pregnant women the highest percentages of prescriptions for unsafe drugs were for psycholeptics (99% not classified as safe), psychoanaleptics (100%), anti-inflammatory/antirheumetic products (100%), antihistamines (94%), antacids/anti-ulcer drugs (81%), antiepileptics (100%), beta-blockers (100%), systemic antimycotics (100%), antiprotozoals (97%), diuretics (100%) and immunosuppressives (100%). In pregnant women this pattern was comparable, except for antihistamines (22%) and antacids/anti-ulcer drugs (3%).

CONCLUSION

We conclude that many drugs used by non-pregnant women should be avoided in pregnancy, and that pregnant women indeed do so. However, for some drug groups the available safe alternatives are limited.