Distribution and excretion of sertraline and N-desmethylsertraline in human milk

Sertraline, citalopram and paroxetine in lactation: passage into breastmilk and infant exposure

Objectives

This study aimed to investigate the plasma and breastmilk concentrations for sertraline, citalopram and paroxetine for assessment of the Milk/Plasma (M/P) ratio and Absolute Infant Dose (AID), and to determine actual infant drug exposure through breastfeeding. Subsequently, informed recommendations will be formulated regarding the advisability of breastfeeding in women undergoing treatment with the three most widely used antidepressants.

Methods

A pharmacokinetic study in lactating women and their infants using sertraline, citalopram or paroxetine was performed. Paired breastmilk and plasma samples and single point infant plasma samples were collected to determine antidepressant concentrations. An Area Under the Curve (AUC) based approach with the trapezoidal rule was used to calculate M/P ratios and AID for all three antidepressants by combining all measured concentrations for the same dose.

Results

Thirty-seven lactating women and their infants participated in this study. 111 paired breastmilk and plasma samples and 37 single point infant plasma samples were collected. Detectable concentrations of sertraline, citalopram and paroxetine were present in all breastmilk samples. For sertraline and citalopram M/P ratio is above one, indicating higher breastmilk than plasma concentrations, however, drug exposure by breastmilk did not lead to detectable plasma drug levels in any of the 15 infants for sertraline, for nine (out of 13) infants for citalopram and for eight (out of nine) infants for paroxetine.

Conclusion

Given the well-known benefits of breastfeeding, our findings support breastfeeding of infants by mothers who are taking sertraline, citalopram or paroxetine is safe. Sertraline and paroxetine are the preferred antidepressants during breastfeeding, reaching mostly undetectable infant drug levels.

Consensus Panel Recommendations for the Pharmacological Management of Breastfeeding Women with Postpartum Depression

INTRODUCTION

Our consensus statement aims to clarify the use of antidepressants and anxiolytics during breastfeeding amidst clinical uncertainty. Despite recent studies, potential harm to breastfed newborns from these medications remains a concern, leading to abrupt discontinuation of necessary treatments or exclusive formula feeding, depriving newborns of benefits from mother's milk.

METHODS

A panel of 16 experts, representing eight scientific societies with a keen interest in postpartum depression, was convened. Utilizing the Nominal Group Technique and following a comprehensive literature review, a consensus statement on the pharmacological treatment of breastfeeding women with depressive disorders was achieved.

RESULTS

Four key research areas were delineated: (1) The imperative to address depressive and anxiety disorders during lactation, pinpointing the risks linked to untreated maternal depression during this period. (2) The evaluation of the cumulative risk of unfavorable infant outcomes associated with exposure to antidepressants or anxiolytics. (3) The long-term impact on infants' cognitive development or behavior due to exposure to these medications during breastfeeding. (4) The assessment of pharmacological interventions for opioid abuse in lactating women diagnosed with depressive disorders.

CONCLUSIONS

The ensuing recommendations were as follows: Recommendation 1: Depressive and anxiety disorders, as well as their pharmacological treatment, are not contraindications for breastfeeding. Recommendation 2: The Panel advocates for the continuation of medication that has demonstrated efficacy during pregnancy. If initiating an antidepressant during breastfeeding is necessary, drugs with a superior safety profile and substantial epidemiological data, such as SSRIs, should be favored and prescribed at the lowest effective dose. Recommendation 3: For the short-term alleviation of anxiety symptoms and sleep disturbances, the Panel determined that benzodiazepines can be administered during breastfeeding. Recommendation 4: The Panel advises against discontinuing opioid abuse treatment during breastfeeding. Recommendation 5: The Panel endorses collaboration among specialists (e.g., psychiatrists, pediatricians, toxicologists), promoting multidisciplinary care whenever feasible. Coordination with the general practitioner is also recommended.

Generic Workflow to Predict Medicine Concentrations in Human Milk Using Physiologically-Based Pharmacokinetic (PBPK) Modelling-A Contribution from the ConcePTION Project

Women commonly take medication during lactation. Currently, there is little information about the exposure-related safety of maternal medicines for breastfed infants. The aim was to explore the performance of a generic physiologically-based pharmacokinetic (PBPK) model to predict concentrations in human milk for ten physiochemically diverse medicines. First, PBPK models were developed for "non-lactating" adult individuals in PK-Sim/MoBi v9.1 (Open Systems Pharmacology). The PBPK models predicted the area-under-the-curve (AUC) and maximum concentrations (C_max) in plasma within a two-fold error. Next, the PBPK models were extended to include lactation physiology. Plasma and human milk concentrations were simulated for a three-months postpartum population, and the corresponding AUC-based milk-to-plasma (M/P) ratios and relative infant doses were calculated. The lactation PBPK models resulted in reasonable predictions for eight medicines, while an overprediction of human milk concentrations and M/P ratios (>2-fold) was observed for two medicines. From a safety perspective, none of the models resulted in underpredictions of observed human milk concentrations. The present effort resulted in a generic workflow to predict medicine concentrations in human milk. This generic PBPK model represents an important step towards an evidence-based safety assessment of maternal medication during lactation, applicable in an early drug development stage.

Antidepressant transfer into amniotic fluid, umbilical cord blood & breast milk: A systematic review & combined analysis

OBJECTIVE

Data regarding the ability of antidepressants to enter fetal, newborn and infant fluids have become gradually available, but mechanisms of antidepressant transfer remain poorly understood. Here we calculated penetration ratios in an array of matrices from combined samples of pregnant/breastfeeding women taking antidepressants.

METHOD

We performed a systematic literature search of PubMed and EMBASE to identify studies with concentrations of antidepressants from maternal blood, amniotic fluid, umbilical cord blood and/or breast milk. Penetration ratios were calculated by dividing the concentrations in amniotic fluid, umbilical cord plasma or breast milk by the maternal plasma concentration. When data from multiple studies were available, we calculated combined penetration ratios, weighting the study mean by study size.

RESULTS

Eighty-five eligible studies were identified. For amniotic fluid, the highest penetration ratios were estimated for venlafaxine (mean 2.77, range 0.43-4.70 for the active moiety) and citalopram (mean 2.03, range 0.35-6.97), while the lowest ratios were for fluvoxamine (mean 0.10) and fluoxetine (mean 0.11, range 0.02-0.20 for the active moiety). For umbilical cord plasma, nortriptyline had the highest ratio (mean 2.97, range 0.25-26.43) followed by bupropion (mean 1.14, range 0.3-5.08). For breast milk, the highest ratios were observed for venlafaxine (mean 2.59, range 0.85-4.85), mianserin (mean 2.22, range 0.80-3.64) and escitalopram (mean 2.19, range 1.68-3.00).

CONCLUSION

We observed considerable variability across antidepressants regarding their ability to enter fetal, newborn and infant fluids. Measuring antidepressant concentrations in a maternal blood sample can provide a reliable estimate of fetal/infant exposure, although further evidence for concentration-dependent effects is required.

Antidepressants in breast milk; comparative analysis of excretion ratios

Despite increasing prescription rates of antidepressants in pregnant and breastfeeding women over the past decades, evidence of drug exposure for neonates through lactation is very sparse. Concentrations of three antidepressants citalopram, sertraline, and venlafaxine were measured in maternal blood and breast milk in 17 women receiving antidepressant therapy during breastfeeding period. We also computed concentration-by-dose-ratios (C/D) and milk to serum (plasma) penetration ratios (M/P). Non-parametric tests were applied. Serum concentration of citalopram and daily dosage correlated positively while daily dosage and mother milk concentration did not (rho = 0.939, p = 0.005, and rho = 0.772, p > 0.05 respectively). A significant correlation was also found between serum and milk concentrations (rho = 0.812, p = 0.05). Venlafaxine daily dosage correlated positively with the active moiety milk concentration (rho = 0.949, p = 0.014). No significant correlations were reported for sertraline. The amount of antidepressant concentrations to which neonates may be exposed, assessed as absolute infant dose (AID), was particularly low with the highest median AID being 0.16 mg/kg/day for venlafaxine. No significant difference was detected for the M/P ratios between different drugs (p > 0.05), whereas the comparison of C/D ratios revealed lower values in the sertraline group, with the highest values reported for citalopram group (p = 0.007 for serum concentrations and p = 0.008 for mother milk). Findings suggest that breastfeeding under antidepressant treatment constantly exposes children with measurable drug concentrations. As daily dosage and serum concentration of the antidepressants did not predict drug concentrations in mother milk, measuring of drug concentrations in milk helps to quantify drug exposure during breastfeeding. More data-even data of drug concentrations in breastfed children-are needed to better assess the effects of drug exposure on children's development.

Quality of Lactation Studies Investigating Antidepressants

Introduction: The aim of this study was to determine the quality of lactation studies investigating antidepressants in breast milk according to the Food and Drug Administration (FDA) draft guidelines and the article by Begg et al., 2002, published in the official journal of the International Lactation Consultant Association (ILCA). Materials and Methods: We used PubMed and LactMed^® for the literature search. Furthermore, cross references were searched for additional studies. Results: A total number of 60 articles were included for review. For selective serotonin reuptake inhibitors and venlafaxine, only two studies correctly assessed the absolute infant dose and milk to plasma ratio; one sertraline and one fluoxetine study. Of all tricyclic antidepressants, one study for amitriptyline and one for nortriptyline assessed these endpoints correctly. We found a lack of information on breast milk sampling methods in many studies. Concentrations needed for the calculations were based on single measurements instead of at least five measurements during one dose interval, and the relative infant dose was not normalized by maternal weight, or an average maternal weight of 70 kg was used as a standard. Discussion: We conclude that the quality of the current literature on this topic does not meet the standards of the FDA. Studies of higher quality are needed to determine the extent of drug transfer to breast milk for antidepressants, so an adequate recommendation about use of these drugs during lactation can be given.

Medications and Breast-Feeding: A Guide for Pharmacists, Pharmacy Technicians, and other Healthcare Professionals Part III

Objective:

To provide a guide for practicing pharmacists, pharmacy technicians, and other healthcare professionals so that they are able to counsel and advise breast-feeding mothers and fellow healthcare professionals on the safety and use of antiinfectives, vaccines, antiepileptics, benzodiazepines, psychotherapeutic drugs, and radiopharmaceuticals during breast-feeding.

Data Sources:

Primary texts used by the breast-feeding community ( Medications and Mothers' Milk, Drugs in Pregnancy and Lactation, Drugs and Human Lactation) were searched, as well as Micromedex, MEDLINE, PubMed, EMBASE, and EMBASE2 (1984–February 2004).

Study Selection/Data Extraction:

Multiple sources were used wherever available to validate the data, and primary articles were used to verify all tertiary source information. Search terms included breast-feeding, lactation, nursing, and medications, as well as specific drug names.

Data Synthesis:

Concerns regarding medication use during breast-feeding have caused mothers to either discontinue nursing or not take necessary medications. Complete avoidance of medications or cessation of breast-feeding is often unnecessary. Although there are drugs that can be harmful to nursing infants, breast-milk concentrations of most drugs are insufficient to cause any harm.

Conclusions:

Having objective and reliable information on medications enables pharmacists, pharmacy technicians, other healthcare providers, and mothers to make educated decisions regarding drug therapy and breast-feeding.

The pharmacokinetics of sertraline in overdose and the effect of activated charcoal

AIMS

To investigate the pharmacokinetics (PK) of sertraline in overdose and the effect of single dose activated charcoal (SDAC).

METHODS

Patients presenting to a toxicology unit with sertraline overdoses had demographic and clinical information recorded, and serial serum collected for measurement of sertraline concentrations. Monolix® version 4.2 was used to develop a population PK model of sertraline overdose and the effect of SDAC. Uncertainty in dose time was accounted for by shifting dose time using lag time with between subject variability (BSV). BSV on relative fraction absorbed was used to model uncertainty in dose.

RESULTS

There were 77 timed sertraline concentrations measured in 28 patients with sertraline overdoses with a median dose of 1550 mg (250-5000 mg). SDAC was given to seven patients between 1.5 and 4 h post-overdose. A one compartment model with lag time of 1 h and first order input and elimination adequately described the data. Including BSV on both lag time and relative fraction absorbed improved the model. The population PK parameter estimates for absorption rate constant, volume of distribution and clearance were 0.895 h(-1) , 5340 l and 130 l h(-1) , respectively. The calculated half-life of sertraline following overdose was 28 h (IQR 19.4-30.6h). When given up to 4 h post-overdose, SDAC significantly increased the clearance of sertraline by a factor of 1.9, decreased the area under the curve and decreased the maximum plasma concentration (Cmax ).

CONCLUSIONS

Sertraline had linear kinetics in overdose with parameter values similar to those in therapeutic use. SDAC is effective in increasing clearance when given 1.5 to 4 h post-overdose.

Antidepressants, anxiolytics, and hypnotics in pregnancy and lactation

AIMS

Untreated perinatal depression and anxiety disorders are known to have significant negative impact on both maternal and fetal health. Dilemmas still remain regarding the use and safety of psychotropics in pregnant and lactating women suffering from perinatal depression and anxiety disorders. The aim of the current paper was to review the existing evidence base on the exposure and consequences of antidepressants, anxiolytics, and hypnotics in women during pregnancy and lactation and to make recommendations for clinical decision making in management of these cases.

MATERIALS AND METHODS

We undertook a bibliographic search of Medline/PubMed (1972 through 2014), Science Direct (1972 through 2014), Archives of Indian Journal of Psychiatry databases was done. References of retrieved articles, reference books, and dedicated websites were also checked.

RESULTS AND CONCLUSIONS

The existing evidence base is extensive in studying multiple outcomes of the antidepressant or anxiolytic exposure in neonates, and some of the findings appear conflicting. Selective serotonin reuptake inhibitors are the most researched antidepressants in pregnancy and lactation. The available literature is criticized mostly on the lack of rigorous well designed controlled studies as well as lacunae in the methodologies, interpretation of statistical information, knowledge transfer, and translation of information. Research in this area in the Indian context is strikingly scarce. Appropriate risk-benefit analysis of untreated mental illness versus medication exposure, tailor-made to each patient's past response and preference within in the context of the available evidence should guide clinical decision making.

Sertraline and breastfeeding: review and meta-analysis

We examined the risk-benefit profile of sertraline treatment during breastfeeding, summarized the available literature on sertraline use, presented previously unpublished data, and performed a correlation-based meta-analysis of sertraline serum levels in mother-infant pairs. We conducted a search of PubMed and the National Library of Medicine LactMed database. We performed a meta-analysis to examine correlations between maternal and infant serum sertraline levels in the existing literature and in previously unpublished data. Of 167 available infant sertraline levels, 146 (87.4 %) were below the limit of detection, and the meta-analysis found no significant relationship between maternal and infant sertraline concentrations. Of 150 infant desmethylsertraline levels, 105 (70.0 %) were below the limit of detection. The correlation analysis revealed a significant relationship between maternal and infant desmethylsertraline concentrations, but this metabolite has only a fraction of the activity of sertraline. A significant relationship was also found for the sum of sertraline and desmethylsertraline, which stems primarily from the contribution of desmethylsertraline. Sertraline is a first-line drug for breastfeeding women due to documented low levels of exposure in breastfeeding infants and very few adverse events described in case reports. Based on the current literature, neither routine serum sampling nor genotyping is warranted for breastfeeding mothers taking sertraline and/or their infants. Routine pediatric care is appropriate monitoring for breastfed infants of women who take sertraline monotherapy.

Time-dependent inhibition of CYP3A4 by sertraline, a selective serotonin reuptake inhibitor

Drug-drug interactions associated with selective serotonin reuptake inhibitors (SSRIs) are widely known. A major interaction by SSRIs is the inhibition of cytochrome P450 (P450)-mediated hepatic drug metabolism. The SSRI, sertraline, is also reported to increase the blood concentration of co-administered drugs. The potency of sertraline directly to inhibit hepatic drug metabolism is relatively weak compared with the other SSRIs, implying that additional mechanisms are involved in the interactions. The study examined whether sertraline produces time-dependent inhibition of CYP3A4 and/or other P450 enzymes. Incubation of human liver microsomes with sertraline in the presence of NADPH resulted in marked decreases in testosterone 6β-hydroxylation activities, indicating that sertraline metabolism leads to CYP3A4 inactivation. This inactivation required NADPH and was not protected by glutathione. No significant inactivation was observed for other P450 enzymes. Spectroscopic evaluation revealed that microsomes with and without sertraline in the presence of NADPH gave a Soret peak at 455 nm, suggesting the formation of metabolic intermediate (MI) complexes of sertraline metabolite(s) with the reduced form of P450. This is the first report indicating that sertraline produced time-dependent inhibition of CYP3A4, which may be associated with MI complex formation.

Antidepressants in pregnancy: a review of commonly prescribed medications

Perinatal depression is an increasingly common comorbidity of pregnancy and is associated with adverse birth outcomes. Newer classes of antidepressants have been developed with a variety of mechanisms and improved side effect profiles. There is increasing use of these medications in reproductive-aged women. Medical providers have to balance the need to prevent relapse of maternal depressive symptoms with the need to minimize fetal exposure to medications. We review the literature on 10 of the most commonly used antidepressant medications: citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, venlafaxine, duloxetine, bupropion, and mirtazapine. The pharmacokinetic properties of the medications are detailed, as well as practical considerations for their use in pregnant and lactating women. Guidance on counseling and management of pregnancies complicated by perinatal depression is discussed.

TARGET AUDIENCE

Obstetricians & Gynecologists and Family Physicians.

LEARNING OBJECTIVES

After completing this CME activity, physicians should be better able to differentiate the current classes of medications utilized commonly for perinatal depression, evaluate the reported adverse effects of antidepressant medications on the patient and developing fetus and choose the appropriate antidepressant medications for a depressed patient who is breast-feeding.

Estimated infant exposure to enantiomer-specific methadone levels in breastmilk

BACKGROUND AND OBJECTIVES

Breastfeeding, a public health priority, improves outcomes for infants. Methadone is dispensed as a racemic mixture; R-methadone is the active enantiomer. Pharmacologic data for R-methadone in breastmilk could improve risk-benefit decision-making for treatment of lactating women. This study estimated infant exposure to R- and S-methadone via breastmilk by theoretic infant dose (TID) and relative infant dose (RID) and reported the milk-to-maternal plasma (M/P) ratio.

METHODS

Women treated with methadone doses of 40-200 mg/day (mean, 102 mg/day) provided concomitantly collected plasma and breastmilk samples 1-6 days after delivery. Most (16 of 20) samples were taken at the time of peak maternal plasma levels; thus infant exposure estimates are for maximum possible exposure. Concentrations of R- and S-methadone were measured in maternal plasma and breastmilk; M/P ratio, TID, and RID were calculated for each enantiomer and total methadone.

RESULTS

The 20 participants were 18-38 years old and publicly insured; a quarter did not complete high school, and only one was not white. R-Methadone concentration was 1.3-3.0 times that of S-methadone in all breastmilk samples. The mean (SD) R-, S-, and total methadone M/P ratios were 0.52 (0.28), 0.28 (0.15), and 0.40 (0.21), respectively. Mean (range) R-, S-, and total methadone TID were 0.02 mg/kg/day (0.004-0.099), 0.013 mg/kg/day (0.002-0.071), and 0.033 mg/kg/day (0.006-0.170), respectively. Mean (range) RID of R-, S-, and total methadone were 2.7% (0.7-10.1%), 1.6% (0.3-7.2%), and 2.1% (0.52-8.8%), respectively.

CONCLUSIONS

R-Methadone is found in higher concentrations than S-methadone in breastmilk. Even at high methadone doses, breastmilk methadone concentrations were relatively low and support American Academy of Pediatrics recommendations that dose should not be a factor in determining whether women on methadone breastfeed.

Antidepressant drugs and breastfeeding: a review of the literature

The use of antidepressants in breastfeeding mothers is controversial: Manufacters often routinely discourage breastfeeding for the nursing mother despite the well-known positive impact that breastfeeding carries on the health of the nursing infant and on his or her family and society. We conducted a systematic review of drugs commonly used in the treatment of postpartum depression. For every single drug two sets of data were provided: (1) selected pharmacokinetic characteristics such as half-life, milk-to-plasma ratio, protein binding, and oral bioavailability and (2) information about lactational risk, according to some authoritative sources of the literature: Drugs in Pregnancy and Lactation edited by Briggs et al. (Lippincott Williams, Philadelphia, 2008), Medications and Mothers' Milk by Hale (Hale Publishing, Amarillo, TX, 2010), and the LactMed database of TOXNET ( www.pubmed.gov ; accessed June 2010). Notwithstanding a certain variability of advice, we found that (1) knowledge of pharmacokinetic characteristics are scarcely useful to assess safety and (2) the majority of antidepressants are not usually contraindicated: (a) Selective serotinin reuptake inhibitors and nortryptiline have a better safety profile during lactation, (b) fluoxetine must be used carefully, (c) the tricyclic doxepine and the atypical nefazodone should better be avoided, and (d) lithium, usually considered as contraindicated, has been recently rehabilitated.

The use of antidepressants in pregnant and breastfeeding women: a review of recent studies

Antidepressants are one of the most commonly prescribed medications for pregnant and lactating women. However, there have been some recent concerns about their safety. This article summarizes recent research on the impact of untreated depression on the baby, the effects of antidepressants on the baby when prescribed during pregnancy, the short- and longer-term effects of prenatal exposure on infants and children, and the passage of medications into breast milk. Recommendations are made on providing mothers and their health care providers with information so they can make accurate risk/benefit analyses about using these medications while pregnant or breastfeeding.

Pharmacokinetics of sertraline across pregnancy and postpartum

Insufficient data inform dosing of antidepressants and clinical monitoring for major depressive disorder (MDD) during the perinatal period. The objectives were to assess the pharmacokinetics of sertraline (SER) across pregnancy and postpartum. Participants treated with SER for MDD underwent serial sampling to measure steady-state concentrations of SER and norsertraline during the second and third trimesters and postpartum (total of 3 assessments). Blood was drawn before observed SER administration and 0.5, 1, 2, 4, 6, 8, 10, 12, and 24 hours after administration. A sensitive high-performance liquid chromatography/mass spectrometric method for simultaneous determination of serum concentrations of SER and norsertraline was developed and validated. For each sampling period for SER, area under the serum concentration versus time curve, maximal serum concentration (Cmax), and the time at which Cmax occurred (Tmax) were determined. Of 11 women initially enrolled, 6 completed second- and third-trimester assessments, and 3 completed all 3 assessments (including the postpartum assessment). Mean changes on all pharmacokinetic parameters were nonsignificant between assessments, although there was a marked heterogeneity among individuals. Results were not significantly altered by incorporation of body weights into the analyses. The range of pharmacokinetic changes between individuals was broad, indicating heterogeneity regarding the impact of pregnancy on SER metabolism. Overall, lowest observed SER area under the curve and Cmax occurred in the third trimester (observed in 5 of 6 participants). Despite nonsignificant mean pharmacokinetic changes, the range of pharmacokinetic changes across pregnancy warrants careful monitoring of depressive symptoms in women with MDD in late pregnancy and further study.

SSRIs during breastfeeding: spotlight on milk-to-plasma ratio

OBJECTIVE

To investigate the usefulness of the milk-to-plasma (M/P) ratio for assessing the risks for the breastfed infant associated with the maternal use of SSRIs.

DATA SOURCES

Medline, Toxnet, Embase, Current Contents, and PsycInfo indexed articles from 1980 to September 2006.

STUDY SELECTION AND DATA EXTRACTION

All studies reporting the M/P ratio in mothers taking SSRIs while breastfeeding or studies which such an information could be calculated from data reported in the article.

DATA SYNTHESIS

Higher M/P ratios were rarely associated with a clinically significant impact on the babies during the early phases of breastfeeding.

CONCLUSIONS

So far no evidence-based information seems to support the hypothesis that SSRIs characterized by a M/P ratio <1.0 should be preferred. Hence, physicians should consider different parameters when attempting to choose the safest SSRI for the breastfeeding woman. These parameters might be represented by the number of well-documented published adverse event reports and the tendency of each SSRI of inducing in the infants serum concentrations that are elevated above 10% of average maternal serum levels. In any case, if the mother wishes to breastfeed her infant while taking a SSRI, the baby should be closely monitored in order to promptly detect any iatrogenic event.

Use of contemporary antidepressants during breastfeeding: a proposal for a specific safety index

Despite the well known severe repercussions of maternal depression on infants' well being, women are often reluctant to seek pharmacological treatment for postnatal depression. The fear of adverse events for the suckling infant plays an important role in such maternal considerations. However, the pharmacological approach to mood disorders at postpartum onset often represents one of the most realistic options in a number of clinical conditions. Therefore, the necessity exists to establish the safety of antidepressant treatment in the breastfed infant. For this reason, the aim of this article is to propose a specific safety index that assesses the frequency and degree of severity of adverse events in infants associated with maternal treatment with second-generation antidepressants during puerperium. The index is derived from a simple formula that uses the number of reports of adverse events in infants exposed to antidepressants as the numerator and the combined total of reports of healthy outcomes and reports of adverse events as the denominator. The sum is then multiplied by 100. A value of < or =2 indicates that the drug should be relatively safe for use during breastfeeding, a value of 2.1-10 indicates that the drug should be used with great caution and a value >10 indicates that the drug should be contraindicated in breastfeeding mothers. In addition to the figure created by this calculation, each drug will also be assigned a letter or the combination of a letter and a subscripted number to symbolise, respectively, the type and clinical management of the most serious recorded event. At this early developmental stage of the index, a complete classification of contemporary antidepressants regarding their safety in infants nursed to the breast is unfeasible. Indeed, because of the lack of suitable published data, so far the index has been limited to the evaluation of four antidepressants. In accordance with the index classification for these four antidepressants, sertraline and paroxetine should be considered as first-line medications in women who need to start antidepressant treatment during the postpartum period and wish to continue breastfeeding. The utilisation of fluoxetine and citalopram seems conversely to be associated with a relatively higher risk of adverse events (with a low degree of severity, however). For the other newer antidepressant drugs, the index is still of no assistance to the patient or physician in deciding on the safety of their use in lactation.

Use of psychotropic medications in treating mood disorders during lactation : practical recommendations

Many new mothers who need antidepressant or mood-stabilising drug treatment may wish to breastfeed their infants, but are hesitant to do so because of possible harmful effects of the medication on the infant. This article reviews current data on drug excretion into breast milk and the effects on the breast-fed child, and provides recommendations for the use of the different psychotropic drugs in lactating women. Relevant literature was identified through systematic searches of MEDLINE, EMBASE and the Science Citation Index Expanded (ISI) from 1966 to February 2005. The present knowledge is based on the accumulation of case studies. No randomised controlled trials in breast-fed infants have been performed and there is a lack of long-term follow-up studies. Use of SSRIs and TCAs (except doxepin) is compatible with breastfeeding. However, if treatment with an SSRI is started in the postpartum period, fluoxetine and citalopram may not be drugs of first choice. With regard to other antidepressants, such as venlafaxine, trazodone, mirtazapine, reboxetine, moclobemide and other MAOIs, very little knowledge exists. Breastfeeding should be avoided while using lithium. Carbamazepine and sodium valproate (valproic acid) are generally better tolerated by the breast-fed infant than lithium. Data on lamotrigine are still sparse. Knowledge is also scarce on the novel antipsychotics and thus recommendations in lactating women cannot be made for these agents. It is unwise to expose infants unnecessarily to drugs that may have severe adverse effects. As such, clozapine should probably be avoided because of the risk of agranulocytosis. Our knowledge of the impact of drug exposure through breast milk is still limited. Infant drug exposure is, however, generally higher during pregnancy through placental passage than through breast milk. Despite the low dosage transferred to the infant through breast milk, premature infants and infants with neonatal diseases or inherited disturbances in metabolism may be vulnerable to such exposure.

Transfer of reboxetine into breastmilk, its plasma concentrations and lack of adverse effects in the breastfed infant

OBJECTIVE

To investigate the transfer of reboxetine into milk, the absolute and relative infant doses via milk and to assess plasma concentrations and adverse unwanted effects in the breastfed infant.

METHODS

Multiple samples of blood and milk were obtained over a dose interval at steady-state from four women who were taking reboxetine for postnatal depression. Drug concentrations in plasma and milk were measured by high performance liquid chromatography and milk/plasma ratio (M/P), absolute infant dose and relative infant dose were estimated by standard methods. Their four, breastfed, infants were also examined clinically, and a blood sample was taken for drug analysis.

RESULTS

The median (range) dose taken by the women was 6 (4-10) mg/day. There was no significant difference in reboxetine concentration between paired fore-and hind-milk samples. The mean (95% CI) M/P was 0.06 (0.03, 0.09). Absolute infant dose was 1.7 (0.7, 2.4) microg/kg/day for reboxetine while the relative infant dose was 2.0% (1.3, 2.7%). Three of the infants met normal developmental milestones and no adverse effects were seen in any infant. The fourth infant had developmental problems that were not associated with the maternal reboxetine therapy. The concentrations of reboxetine in plasma from the four infants were <4 microg/l, 2.6 microg/l, 2.3 microg/l and 5 microg/l, respectively.

CONCLUSION

The study suggests that reboxetine use by lactating women is safe for the breastfed infant. Nevertheless, our study had only four mother/baby pairs, and each decision to breastfeed should always be made on the basis of an individual risk/benefit analysis.

Drug use and breastfeeding

Section 1 describes the benefits of breastfeeding to both mother and infant as well as the potential risks to the infant from maternal drug use. The extent of adverse drug-related events and the need for quality information on drug transfer is stated. Section 2 describes the physiology of lactation and the effects of drugs that stimulate or decrease milk production. Section 3 deals with transport mechanisms for drug passage into milk and factors that may modify the infant's exposure to drugs. The critical descriptors of 'absolute' and 'relative' infant dose are defined to give an objective measure of infant exposure to drugs in milk. Section 4 reviews new or commonly used drugs under the headings of analgesics and anti-inflammatory agents, neurological, endocrine, psychotropic and antihypertensive drugs. Section 5 concludes with an expert opinion of the drug industry and drug use in lactation, herbal preparations, the process of 'risk-benefit' analysis, minimising infant exposure, understanding drug-related adverse events and fostering good experimental design for drugs in lactation studies.

The Use of Tricyclic Antidepressants and Selective Serotonin Reuptake Inhibitors in Women Who Are Breastfeeding

Postpartum depression is a well-recognized psychiatric condition that has gained increased attention over the past decade due to several nationally publicized tragedies. Medical management of this condition in women who are breastfeeding provides a unique challenge to health care professionals who may seek to maintain a fine balance between limiting the infant's exposure to hormone-altering drugs and maintaining the benefits of breastfeeding. No controlled trials have examined antidepressant therapy in nursing women; however, numerous case reports and case series have been published. Relatively few serious adverse effects have been reported. Although tricyclic antidepressants have been the treatment of choice in the past, selective serotonin reuptake inhibitors are gaining popularity due to their superior safety profiles. Of all the agents reviewed in the literature, sertraline was the most prescribed, and no adverse effects were reported. Therefore, this agent would be a good first choice for treatment-naive women. For treatment of postpartum depression in women with a history of successfully treated depression, the most practical approach may be to continue therapy with the previously effective agent. Treatment should be maintained at the lowest effective dosage to minimize infant exposure. Both mother and child should be closely monitored; in addition, collaboration between the prescribing physician and the child's pediatrician is essential.

The use of selective serotonin reuptake inhibitors during pregnancy and breast-feeding: a review and clinical aspects

Mood and anxiety disorders are common in women during their childbearing years. The prevalence of depression has been reported to be between 10% and 16% during pregnancy. The use of selective serotonin reuptake inhibitors during pregnancy or lactation is, to date, not promoted because of lack of safety documentation. However, the off-label use of these drugs has been common for several years. In the treatment of mood and anxiety disorders during pregnancy, the serotonin reuptake inhibitors are often preferred over tricyclic antidepressants because of their relatively few adverse effects and safety in overdose. This has created concern among women planning pregnancies and pregnant women, as well as among their families and physicians. Several studies and reports of the use of serotonin reuptake inhibitors during both pregnancy and lactation have been published and advanced our knowledge. We here review and discuss those studies which have been published so far on this subject.

The Safety of Newer Antidepressants in Pregnancy and Breastfeeding

The pregnancy and postpartum periods are considered to be relatively high risk times for depressive episodes in women, particularly for those with pre-existing psychiatric illnesses. Therefore, it may be necessary to start or continue the pharmacological treatment of depression during these two timeframes. Hence, the aim of this review is to examine the effects on the fetus and infant of exposure, through the placenta and maternal milk, to the following drugs: fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, escitalopram, mirtazapine, venlafaxine, reboxetine and bupropion. The teratogenic risks, perinatal toxicity and effects on the neurobehavioural development of newborns associated with exposure through the placenta or maternal milk to these medications need to be carefully assessed before starting psychopharmacological treatment in pregnant or lactating women. In spite of the limitations of some of the studies reviewed, the older selective serotonin-reuptake inhibitors (SSRIs) [as we await further data regarding escitalopram] and venlafaxine seem to be devoid of teratogenic risks. By contrast, the data concerning possible consequences related to exposure to SSRIs via the placenta and breastmilk on neonatal adaptation and long-term neurocognitive infant's development are still controversial. Nevertheless, a number of reports have shown that an association between placental exposure to SSRIs and adverse but self-limiting effects on neonatal adaptation may exist. In addition, the information on both teratogenic and functional teratogenic risks associated with exposure to bupropion, mirtazapine and reboxetine is incomplete or absent; at present, these compounds should not be used as first-line agents in the pharmacological treatment of depression in pregnancy and breastfeeding. Untreated depression is not without its own risks since mothers affected by depression have a negative impact on the emotional development of their children and major depression, especially when complicated by a delusional component, may lead to the mother attempting suicide and infanticide. Consequently, clinicians need to help mothers weigh the risks of prenatal exposure to drugs for their babies against the potential risks of untreated depression and abrupt discontinuation of pharmacological treatment. Given these situations, we suggest that choosing to administer psychopharmacological treatment in pregnant or breastfeeding women with depression will result primarily from a careful evaluation of their psychopathological condition; currently, the degree of severity of maternal disease appears to represent the most relevant parameter to take this clinical decision.

Fluoxetine during pregnancy: impact on fetal development

Women are at greatest risk of suffering from depression during the childbearing years and thus may either become pregnant while taking an antidepressant or may require a prescription for one during pregnancy. The antidepressant fluoxetine (FX) is a selective serotonin reuptake inhibitor (SSRI), which increases serotonin neurotransmission. Serotonin is involved in the regulation of a variety of physiological systems, including the sleep–wake cycle, circadian rhythms and the hypothalamic–pituitary–adrenal axis. Each of these systems also plays an important role in fetal development. Compared with other antidepressant drugs, the SSRIs, such as FX, have fewer side effects. Because of this, they are now frequently prescribed, especially during pregnancy. Clinical studies suggest poor neonatal outcome after exposure to FX in utero. Recent studies in the sheep fetus describe the physiological effects of in utero exposure to FX with an 8 day infusion during late gestation in the sheep. This is a useful model for determining the effects of FX on fetal physiology. The fetus can be studied for weeks in its normal intrauterine environment with serial sampling of blood, thus permitting detailed studies of drug disposition in both mother and fetus combined with monitoring of fetal behavioural state and cardiovascular function. Fluoxetine causes an acute increase in plasma serotonin levels, leading to a transient reduction in uterine blood flow. This, in turn, reduces the delivery of oxygen and nutrients to the fetus, thereby presenting a mechanism for reducing growth and/or eliciting preterm delivery. Moreover, because FX crosses the placenta, the fetus is exposed directly to FX, as well as to the effects of the drug on the mother. Fluoxetine increases high-voltage/non-rapid eye movement behavioural state in the fetus after both acute and chronic exposure and, thus, may interfere with normal fetal neurodevelopment. Fluoxetine also alters hypothalamic function in the adult and increases the magnitude of the prepartum rise in fetal cortisol concentrations in sheep. Fetal FX exposure does not alter fetal circadian rhythms in melatonin or prolactin. Studies of the effects of FX exposure on fetal development in the sheep are important in defining possible physiological mechanisms that explain human clinical studies of birth outcomes after FX exposure. To date, there have been insufficient longer-term follow-up studies in any precocial species of offspring exposed to SSRIs in utero. Thus, further investigation of the long-term consequences of in utero exposure to FX and other SSRIs, as well as the mechanisms involved, are required for a complete understanding of the impact of these agents on development. This should involve studies in both humans and appropriate animal models.

Neonatal exposure to drugs in breast milk

There are many benefits of breast-feeding both for the infant and for the mother. Nursing mothers who are also taking medications or exposed to environmental hazards may be confronted with a difficult choice to discontinue nursing or maternal medication or risk potential harm to the infant. Frequently, these decisions are made without sufficient information or understanding of the factors influencing exposure. The current review explores two indices of exposure, together with their pharmacokinetic determinants. Both of the indices include the milk to serum (M/S) concentration ratio for a given drug and the volume of milk consumed. The first exposure term, EI(Dose), expresses neonatal dose as a percentage of maternal dose and is inversely related to the maternal systemic clearance. By contrast, the second exposure term, EI(Conc), expresses infant concentration as a percentage of maternal concentration and is inversely related to the infant systemic clearance. Issues related to intersubject variation in M/S (e.g., colostrum vs. mature milk, fore vs. hind milk) and infant clearance (e.g., ontogeny of elimination pathways, pharmacogenetics) and their role in modulating exposure are also discussed.

A novel system for the determination of antidepressant concentrations in human breast milk

The high incidence of psychiatric illness in the postpartum period and the increasing percentage of women who breastfeed has focused attention on the treatment of breastfeeding women with psychotropic medications and, additionally, the exposure of nursing infants to these medications. Consequently, there has been an increased effort to develop standardized methods for quantifying psychotropic medications in breast milk. This paper details a novel method for quantifying the concentrations of multiple selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs) in breast milk. The method consists of a common liquid/liquid and solid-phase extraction followed by HPLC separation on a common column and UV detection. Assay system 1 measures fluoxetine, norfluoxetine, fluvoxamine, and paroxetine; assay 2 measures sertraline and desmethylsertraline; and assay 3 measures the TCAs including doxepin, nordoxepin, desipramine, imipramine, nortriptyline, and amitriptyline. The method is shown to be a highly accurate and precise technique for measuring 12 different antidepressants in human breast milk and to be free of the matrix effects often encountered in breast milk drug analyses.

Frequency of infant adverse events that are associated with citalopram use during breast-feeding

OBJECTIVE

The purpose of this study was to determine the frequency of infantile adverse events from exposure through breast-feeding to maternal citalopram therapy.

STUDY DESIGN

This was a prospective, observational cohort study. Women who were breast-feeding were placed in three groups on the basis of citalopram use: group 1 consisted of 31 women who were depressed and were undergoing citalopram therapy, group 2 consisted of 12 women who were depressed but were not undergoing citalopram therapy, and group 3 consisted of 31 healthy women who were matched to group 1 by maternal age and parity. Data collection included infant feeding method, medication use, and adverse events.

RESULTS

There was no statistically significant difference in the rate of adverse events in the three groups (3/31 events, 0/12 events, and 1/31 events in groups 1, 2, and 3, respectively). The average dose of citalopram that was used in group 1 was 25.3+/-11.4 mg per day (range, 10-60 mg/d).

CONCLUSION

To our knowledge, this is the first prospective, controlled study to examine the safety of citalopram during breast-feeding, which should be continued during maternal citalopram therapy.

Clinical pharmacokinetics of sertraline

Sertraline is a naphthalenamine derivative with the predominant pharmacological action of inhibiting presynaptic reuptake of serotonin from the synaptic cleft. It was initially marketed for the treatment of major depressive disorder and is now approved for the management of panic disorder, obsessive-compulsive disorder and post-traumatic stress disorder. Sertraline is slowly absorbed following oral administration and undergoes extensive first-pass oxidation to form N-desmethyl-sertraline, a weakly active metabolite that accumulates to a greater concentration in plasma than the parent drug at steady state. Sertraline is eliminated from the body by other metabolic pathways to form a ketone and an alcohol, which are largely excreted renally as conjugates. The elimination half-life of sertraline ranges from 22-36 hours, and once-daily administration is therapeutically effective. Steady-state plasma concentrations vary widely, up to 15-fold, in patients receiving usual antidepressant dosages between 50 and 150 mg/day. However, only sparse data have been published that support useful correlations between sertraline plasma concentrations and therapeutic or adverse effects to justify therapeutic drug monitoring. Sertraline has minimal inhibitory effects on the major cytochrome P450 enzymes, and few drug-drug interactions of clinical significance have been documented. Like other selective serotonin reuptake inhibitors, sertraline is well tolerated in therapeutic dosages and relatively safe in overdosage.

Studying drugs in human milk: time to unify the approach

The trend globally for mothers to breastfeed has highlighted the need for information on drug transfer into breast milk and the extent to which the suckling neonate may be exposed and affected. This review discusses robust study methodologies that will yield high-quality information on all aspects of this process. Methods for assessing drug transfer into breast milk are examined. The place of the milk/plasma ratio, the amount of drug in breast milk, and the volume of milk produced are discussed in the context of their utility in estimating both absolute and relative infant dose. The measurement of plasma drug concentrations and pharmacodynamic effects in the breastfed infant exposed to drugs are identified as important factors that can assist in deciding whether drug present in breast milk is a significant risk for the nursing infant.

Estimates of nursing infant daily dose of fluoxetine through breast milk

BACKGROUND

This study compared three methods of estimating the daily dose of fluoxetine to nursing infants and the relationship between these estimates and infant serum concentrations.

METHODS

Breast milk and infant serum concentrations of fluoxetine and norfluoxetine were obtained from 10 nursing mother-infant pairs. Quantification of daily infant dose was determined by three methods: 1) collection of the total volume of breast milk over 24 hours and determination of the average breast milk concentration (Baby's Total Daily Dose); 2) determination of the maximum and minimum breast milk concentrations during 24 hours and an estimated milk consumption of 150 mL/kg/day (Atkinson Model); and 3) determination of the gradient of excretion of medication into breast milk at a specified time after the maternal dose, applying this gradient to each nursing collection and summing the values for 24 hours (Mathematical Model). The relationship between the 24-hour medication dose, obtained from each method, and the infant serum concentrations was examined.

RESULTS

A total of 177 breast milk and 10 infant serum samples were collected. An estimate of the infant daily medication dose obtained by the Mathematical Model was the best predictor of total infant serum concentration.

CONCLUSIONS

Breast milk analysis may allow one to determine whether medication concentrations will be detectable in an infant, eliminating the need for an infant serum concentration. Although the Mathematical Model seems to reflect infant serum concentration most accurately, all three methods suggest that the maximum dose that a nursing child receives over the course of a year equals as much as 120 mg, or 160 +/- 47% of the maternal daily dose.

Molecular descriptors that influence the amount of drugs transfer into human breast milk

Most drugs are excreted into breast milk to some extent and are bioavailable to the infant. The ability to predict the approximate amount of drug that might be present in milk from the drug structure would be very useful in the clinical setting. The aim of this research was to simplify and upgrade the previously developed model for prediction of the milk to plasma (M/P) concentration ratio, given only the molecular structure of the drug. The set of 123 drug compounds, with experimentally derived M/P values taken from the literature, was used to develop, test and validate a predictive model. Each compound was encoded with 71 calculated molecular structure descriptors, including constitutional descriptors, topological descriptors, molecular connectivity, geometrical descriptors, quantum chemical descriptors, physicochemical descriptors and liquid properties. Genetic algorithm was used to select a subset of the descriptors that best describe the drug transfer into breast milk and artificial neural network (ANN) to correlate selected descriptors with the M/P ratio and develop a QSAR. The averaged literature M/P values were used as the ANN's output and calculated molecular descriptors as the inputs. A nine-descriptor nonlinear computational neural network model has been developed for the estimation of M/P ratio values for a data set of 123 drugs. The model included the percent of oxygen, parachor, density, highest occupied molecular orbital energy (HOMO), topological indices (chiV2, chi2 and chi1) and shape indices (kappa3, kappa2), as the inputs had four hidden neurons and one output neuron. The QSPR that was developed indicates that molecular size (parachor, density) shape (topological shape indices, molecular connectivity indices) and electronic properties (HOMO) are the most important for drug transfer into breast milk. Unlike previously reported models, the QSPR model described here does not require experimentally derived parameters and could potentially provide a useful prediction of M/P ratio of new drugs only from a sketch of their structure and this approach might also be useful for drug information service. Regardless of the model or method used to estimate drug transfer into breast milk, these predictions should only be used to assist in the evaluation of risk, in conjunction with assessment of the infant's response.

Fluoxetine and norfluoxetine concentrations in nursing infants and breast milk

BACKGROUND

This study's goal was to characterize nursing infants' exposure to fluoxetine through breast milk and to identify variables for minimizing such exposure.

METHODS

Nursing women on stable daily doses of fluoxetine were recruited into the study. Breast milk, maternal and infant serum concentrations of fluoxetine and norfluoxetine were determined with high-performance liquid chromatography.

RESULTS

Nineteen nursing women one with a pair of dizygotic twins participated in the study. The women were on stable daily doses of fluoxetine (10-60 mg/day) and all but two took the medication during the last trimester of pregnancy. Fluoxetine was detectable in 30% (n = 6) of the nursing infant sera (< 1-84 ng/mL), whereas norfluoxetine was found in 85% (N = 17) (< 1-265 ng/mL). Peak breast milk concentrations occurred approximately 8 hours after maternal dosing and predicted norfluoxetine concentrations in infant serum. Maternal serum fluoxetine and norfluoxetine concentrations correlated highly with infant norfluoxetine concentrations. A daily maternal fluoxetine dosage of 20 mg or lower was significantly less likely to produce detectable concentrations of either fluoxetine or norfluoxetine in infants compared to higher daily dosages. No adverse effects were reported in any infant.

CONCLUSIONS

Our findings demonstrate that maternal serum and peak breast milk concentrations of fluoxetine and norfluoxetine predict nursing infant serum norfluoxetine concentrations. In nursing women taking 20 mg/day or less of fluoxetine, infant serum concentrations were typically low.

The selective serotonin reuptake inhibitor sertraline: its profile and use in psychiatric disorders

The naphthylamine derivative sertraline is a potent and selective inhibitor of serotonin reuptake into presynaptic terminals. Sertraline has a linear pharmacokinetic profile and a half-life of about 26 h. Its major metabolite, desmethylsertraline does not appear to inhibit serotonin reuptake. Sertraline mildly inhibits the CYP2D6 isoform of the cytochrome P450 system but has little effect on CYP1A2, CYP3A3/4, CYP2C9, or CYP2C19. It is, however, highly protein bound and may alter blood levels of other highly protein bound agents. Sertraline is a widely used serotonin reuptake inhibitor that has been shown to have both antidepressant and antianxiety effects. Many clinical trials have demonstrated its efficacy in depression compared with both placebo and other antidepressant drugs. Its efficacy has also been demonstrated in randomized, controlled trials of patients with obsessive-compulsive disorder, panic disorder, social phobia, and premenstrual dysphoric disorder. In short-term, open-label studies it has appeared efficacious and tolerable in children and adolescents and in the elderly, and data are positive for its use in pregnant or lactating women. Typical side effects include gastrointestinal and central nervous system effects as well as treatment-emergent sexual dysfunction; withdrawal reactions may be associated with abrupt discontinuation of the agent. The safety profile of sertraline in overdose is very favorable. Sertraline's efficacy for both mood and anxiety disorders, relatively weak effect on the cytochrome P450 system, and tolerability profile and safety in overdose are factors that contribute to make it a first-line agent for treatment in both primary and tertiary care settings.

Citalopram and demethylcitalopram in human milk; distribution, excretion and effects in breast fed infants

AIMS

To characterize milk/plasma (M/P) ratio and infant dose, for citalopram and demethylcitalopram, in breast-feeding women taking citalopram for the treatment of depression, and to determine the plasma concentration and effects of these drugs in their infants.

METHODS

Seven women (mean age 30.6 years) taking citalopram (median dose 0.36 mg kg(-1) day(-1)) and their infants (mean age 4.1 months) were studied. Citalopram and demethylcitalopram in plasma and milk were measured by high-performance liquid chromatography over a 24 h dose interval. Infant exposure was estimated (two separate methods) as the product of milk production rate and drug concentration in milk, normalized to body weight and expressed as a percentage of the weight-adjusted maternal dose.

RESULTS

Mean M/PAUC values of 1.8 (range 1.2-3) and 1.8 (range 1.0-2.5) were calculated for citalopram and demethylcitalopram, respectively. The mean maximum concentrations of citalopram and demethylcitalopram in milk were 154 (95% CI, 102-207) microg l(-1) and 50 (23-77) microg l(-1). Depending on the method of calculation, mean infant exposure was 3.2 or 3.7% for citalopram and 1.2 or 1.4% for demethylcitalopram. Citalopram (2.0, 2.3 and 2.3 microg l(-1)) was detected in three of the seven infants. Demethylcitalopram (2.2 and 2.2 microg l(-1) was detected in plasma from two of the same infants. No adverse effects were seen in the infants, all were within appropriate percentile limits for weight and all had normal Denver developmental quotients.

CONCLUSIONS

The mean combined dose of citalopram and demethylcitalopram (4.4-5.1% as citalopram equivalents) transmitted to infants via breast milk is below the 10% notional level of concern. Plasma concentrations of these drugs in the infants were very low or absent and there were no adverse effects. These data support the safety of the use of citalopram in breast feeding women. Nevertheless, each decision to breast feed should always be made as an individual risk:benefit analysis.

Sertraline in paired blood plasma and breast-milk samples from nursing mothers

Paired blood and breast-milk samples were collected from 10 nursing mothers receiving sertraline. Samples were collected at steady state when the patients had been taking stable doses of 50-150 mg/day over several weeks. Sertraline concentrations in both fluids were determined using a specific, validated HPLC method. Plasma and milk concentrations showed a wide inter-individual variability for the same dose. Mean plasma concentrations were linearly related to dose, but this was not the case for breast-milk concentrations. An overall milk to plasma ratio of 1.76+/-1.72 was recorded. The average dose to the infants ranged from 1.1 to 31.1 &mgr;g/kg, which is less than 2 per cent of the maternal dose per day. Further studies are necessary to determine if these doses are detrimental to the development of the infant. Copyright 2000 John Wiley & Sons, Ltd.

Antidepressants and breast-feeding: a review of the literature

For every antidepressant so far investigated in the breast milk of mothers prescribed these medications, findings indicate that some amount of drug will be excreted into the breast milk. Nursing infants will be exposed to some, usually a very low, amount of drug and drug metabolites. Levels of drug exposure to infants for the many antidepressants available are examined, discussing milk to plasma drug concentration ratios and the infant dose as a percentage of the maternal dose. Drug concentrations in infant plasma and adverse effects of drug exposures to infants are reviewed. Factors influencing the decision on whether to breast or bottle feed an infant nursed by a mother taking antidepressants are discussed, concluding that the decision needs to be made on an individual basis. The lactating mother, in consultation with her doctor, should be in a position to make an informed decision on whether or not to breast feed. Under certain circumstances the decision to bottle feed may be wise, but more commonly the advantages of breast-feeding will outweigh the very low risk of an adverse event from drug exposure to the infant.

Breastfeeding and maternal medication use

Drug therapy during lactation requires recognition of several elements, including drug properties, the status of the infant, the mother's milk production, and what is known about particular drugs. It is important to consider the various properties of a drug when evaluating its possible effects in the breastfeeding infant. In addition, the volume of milk the infant receives and its composition can influence exposure levels. Other factors of importance include the infant's age, frequency of feedings, recommended drug dosage, and whether the drug is short- or long-acting. Suggestions are offered for appropriate drug therapy when the mother is breastfeeding, including the safety of drugs commonly administered during lactation and questions to ask when a mother seeks assistance about suggested medication use.