Haloperidol excretion in human milk

Balancing the Use of Medications While Maintaining Breastfeeding

Breast milk is the most beneficial nutrition a mother can give her infant. Fortunately, the dose of most drugs transferred into milk is small and does not lead to clinically significant effects on the infant. In almost all instances, the mother should be advised to continue breastfeeding. Certain medications are absolutely contraindicated, including anticancer agents, radioactive drugs, and those that inhibit milk production. However, most medications can be used safely. An improved understanding of the relationship between maternal and infant exposure to medications would provide a more enlightened understanding of the risk and benefit analysis for individual drugs.

The quality of lactation studies including antipsychotics

THE AIM OF THE STUDY

The aim of this study is to determine the quality of lactation studies that investigated antipsychotics in breast milk according to the Food and Drug Administration (FDA) and International Lactation Consultant Association (ILCA) draft guidelines.

MATERIALS AND METHODS

We used the draft FDA and ILCA guidelines to review the quality of articles including antipsychotic use during breastfeeding. We used PubMed and Lactmed for the literature search. Furthermore, cross references were searched for additional studies.

RESULTS

Of the 51 studies, only one olanzapine and one quetiapine study calculated the milk to plasma ratio (M:P ratio), the Absolute Infant Dose (AID), and the Relative Infant Dose (RID) correctly. In the remaining studies, at least one of the three endpoints was not determined properly. No correct endpoints were calculated in studies containing chlorpromazine, chlorprothixene, clozapine, haloperidol, sulpiride, trifluoperazine, ziprasidone, zonisamide, and zuclopenthixol. This review investigated that there was a lack of information on the sampling methods of breast milk. Furthermore, the concentrations needed for the calculations of the three endpoints were mainly based on single measurements instead of at least five measurements during one dose interval. In many studies, the RID was not calculated correctly due to the fact that the RID was not normalized by the maternal weight or an average maternal weight of 70 kg was used as a standard.

CONCLUSION

Except for two studies, most studies about the safety of antipsychotic use during lactation did not meet the criteria of the draft FDA and ILCA guidelines. Further research is mandatory to assess the safety of using antipsychotics while breastfeeding.

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.

Pharmacology and pharmacokinetics of sedatives and analgesics

The agents used for sedation and analgesia during endoscopy have complex pharmacokinetic and pharmacodynamic properties. Knowledge of these characteristics is necessary for determining the proper agent and dose for specific patient needs. Short-acting agents, such as fentanyl, midazolam, and propofol, provide rapid sedation with a short duration of action that allows patients to return to normal functioning rapidly. When designing a dosing regimen with these agents, age and organ (liver, kidney) function of patients and concomitant medications that may interfere with metabolic and elimination pathways must be considered.

Antipsychotic medication during pregnancy and lactation in women with schizophrenia: evaluating the risk

OBJECTIVE

To review studies investigating the following: whether exposing developing infants to antipsychotic medication during pregnancy and lactation is associated with increased risks of teratogenic, neonatal, and long-term neurobehavioural sequelae; whether schizophrenia itself affects pregnancy outcome; and whether the course of schizophrenia symptoms is altered by pregnancy and lactation.

METHOD

We summarize the results from articles identified via a MedLine search for the period January 1, 1966, to December 1, 2001.

RESULTS

Women with schizophrenia are at increased risk for poor obstetrical outcomes, including preterm delivery, low birth weight, and neonates who are small for their gestational age. A lack of information in the literature makes it difficult to comment on the relative risk of exposing developing infants to atypical antipsychotics. However, typical antipsychotics appear to carry an increased risk of congenital malformations when the fetus is exposed to phenothiazines during weeks 4 to 10 of gestation. Lack of information also precludes an understanding of whether changes associated with pregnancy and lactation significantly alter the course of schizophrenia symptoms.

CONCLUSION

Research is needed so that physicians may more accurately inform women about the relative risks of using antipsychotic medications during pregnancy and lactation. Increased knowledge about the risks of medication exposure will allow clinicians to limit treatment to situations in which the risk of untreated maternal illness outweighs the risk of exposing a developing infant to medications.

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.

Transfer of drugs and other chemicals into human milk

The American Academy of Pediatrics places emphasis on increasing breastfeeding in the United States. A common reason for the cessation of breastfeeding is the use of medication by the nursing mother and advice by her physician to stop nursing. Such advice may not be warranted. This statement is intended to supply the pediatrician, obstetrician, and family physician with data, if known, concerning the excretion of drugs into human milk. Most drugs likely to be prescribed to the nursing mother should have no effect on milk supply or on infant well-being. This information is important not only to protect nursing infants from untoward effects of maternal medication but also to allow effective pharmacologic treatment of breastfeeding mothers. Nicotine, psychotropic drugs, and silicone implants are 3 important topics reviewed in this statement.

Antipsychotics and breast-feeding: a review of the literature

Many women with mental illnesses would like to breast feed their infants. In light of the limited but rapidly growing data, it seems that in some cases the possible physiological and psychological benefits may outweigh putative risks. All antipsychotics are secreted into breast milk but the concentrations and effects vary. There is a subgroup of mothers with mental illnesses who want to breast feed their infants and who are receiving a single established antipsychotic drug (principally, haloperidol or chlorpromazine) at the lowest possible clinically effective dose. As a tentative conclusion, this group could experience benefits from being able to nurse which would outweigh the risk of exposing their babies to very small amounts of antipsychotic drugs. However, larger study groups with longer follow-up periods would be required to confirm this tentative conclusion. Those mothers who require 2 or more antipsychotic drugs simultaneously and those taking one drug, but at the upper end of the recommended dose range, should not be advised to breast feed. Safety considerations suggest that women taking atypical antipsychotics would be advised not to breast feed because of the limited experience with these agents. When mothers taking antipsychotic drugs do nurse, it is desirable to monitor drug concentrations in breast milk and in the infants themselves. Close monitoring of the infant is essential.

Psychotropic drugs in mothers' milk: a comprehensive review of assay methods, pharmacokinetics and of safety of breast-feeding

Many mentally ill women want to breast-feed their babies but, if they are taking psychotropic drugs, there is very little systematic data upon which to base decisions about whether or not it is safe to do so. We therefore attempt to provide a comprehensive and critical summary of existing case reports and of studies of breast-feeding in relation to commonly used psychotropic drugs. The literature review focuses on the following drugs: antidepressants: tricyclics and serotonin selective reuptake inhibitors (SSRIs); antipsychotic drugs: chlorpromazine, perphenazine, haloperidol and clozapine; mood stabilizers: lithium and carbamazepine; and benzodiazepines. The research literature consists mainly of single case reports and there have been very few attempts at controlled, longitudinal investigations. Findings are often difficult to compare because of differences in methods or because of lack of key information. Most data are available about the tricyclic antidepressants but even here we have found that the reports cover only a grand total of 66 mother-infant pairs. Dilemmas about whether or not to contraindicate breast-feeding arise most commonly in relation to postnatal depression. The findings to date suggest that provided that infants are healthy at the outset it is likely that the benefits of breast-feeding will outweigh potential hazards if their mothers are taking established tricyclic drugs at recommended dose levels. Much less is known about risks associated with SSRI antidepressants or about antipsychotic drugs such as phenothiazines and butyrophenones or mood stabilizers such as carbamazepine, all of which enter breast-milk. Safeguards are suggested for future single case studies, which, as they accumulate, will provide a platform for mounting controlled prospective studies properly to test for any acute toxic effects and for possible long-term adverse effects of such drugs on infants' development. Appendix 1 is a review of assay methods. Appendix 2 examines pharmacokinetic factors in newborn preterm and sick infants with special reference to contraindications to breast-feeding. Appendix 3 is a review of methods for assessing infant health and development.

A guide to the safety of CNS-active agents during breastfeeding

For most agents with CNS activity, there are limited data regarding their safety in breastfeeding. Any decision to institute treatment for a neurological or psychiatric disorder must weigh the benefits of maternal treatment against the potential harm to the breastfeeding mother of withholding medication which may improve her illness. For the neonate, one must balance the risk of medication exposure against the benefit of receiving breast milk. Most tricyclic antidepressants can be used in lactating women. Because of the limited data, selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitors should only be used with due consideration of the potential adverse effects. Breastfeeding is best avoided by women who require lithium therapy, because of both the immature excretory systems in the infant and relatively high doses received by the infant. There is little information about the safety of antipsychotic medications in breastfeeding. Concerns include toxicity and abnormal neurological development in the infant. These agents may be used with caution. Most agents which cause depression of the CNS, including opiates and sedatives, can be used in small doses and for short courses in breastfeeding mothers. Most anticonvulsants can be used in lactating women. Reference texts and consultation with experts are useful adjuncts to discussion of the risks and benefits of therapy with the patient. The scope of this review is limited to drugs with therapeutic uses, thus drugs of abuse are not discussed, nor are caffeine and alcohol (ethanol).

Breast feeding and anaesthesia

Anaesthetists require a good knowledge of the excretion of drugs in breast milk and the potential hazards to suckling infants of drug ingestion via breast milk. A brief account of the physiology of lactation is given. The mechanisms of drug passage into breast milk are discussed followed by a review of the excretion in breast milk of drugs used in anaesthetic practice. Suggestions for the management of anaesthesia in breast feeding mothers are offered.

Breastfeeding and the use of psychotropic medication: a review

The advisability of continuing breastfeeding is an important issue for women with postpartum depression or psychosis. A review of the literature on psychotropic drugs in breast milk is presented. All of the major classes of psychotropic drugs (antidepressants, antipsychotics, antianxiety agents, lithium, hypnotics) have been shown to pass into breast milk following maternal ingestion. Generally, the doses to which children are exposed from breast milk, calculated from measured milk/plasma ratios, are small. Nevertheless most authors err on the side of caution and suggest that breastfeeding be avoided. There is inadequate research on the excretion of drugs into breast milk and the effects on the infant.

An overview of somatic treatment of psychosis during pregnancy and postpartum

Treatment and management of the psychotic pregnant patient is insufficiently covered by most standard texts and the current literature. To date, there are no controlled studies on the efficacy of different therapeutic modalities during pregnancy. Medications that have proved effective in the treatment of the various psychoses are not without added risk for the pregnant patient. However, there is no effective medical treatment without attendant risk. Although the psychotic pregnant patient presents a therapeutic dilemma, these patients can be effectively treated by a program that allows for flexibility and innovation within the framework of sound conservative medical practice. Professional territorial difficulties can be avoided by a unified effort.

Drugs in human milk. Clinical pharmacokinetic considerations

Drugs ingested by a lactating mother would be expected to appear in human milk to some extent and be ingested by a breast-feeding infant. Drugs pass from maternal plasma into milk by passive diffusion and are distributed within the aqueous, protein and lipid phases of milk. Distribution into milk will be affected by physiochemical characteristics of the drug: acid-base characteristics, relative protein binding in plasma and milk, and lipid solubility, as well as milk composition. The milk-to-plasma concentration ratio is the most commonly quoted index of drug distribution into human milk. However, calculation of the daily infant dose of drug ingested in milk, and from this the dose in milk relative to the maternal dose on a weight-adjusted basis, is a more relevant indicator of infant exposure to a drug. This is particularly true for drugs with a high volume of distribution, for which only a small proportion of the mother's dose is contained within the plasma and available for distribution into milk. A better indication of infant exposure to a drug is the steady-state plasma drug concentration in a breast-feeding infant, the major determinants of which are the dose rate (via milk) and the oral availability and clearance in the infant. Although in neonates the rate of absorption may be different from adults, there is little evidence that its extent is significantly different. Clearance, however, is impaired in very young infants, particularly if premature. The decreased clearance would result in a proportional increase in steady-state plasma concentrations in the breast-feeding infant. Consideration of the dose ingested in milk and the approximate clearance in infants of different ages allows estimation of likely steady-state plasma concentrations in breast-feeding infants. From these considerations, recommendations regarding the safety of drugs during breast-feeding can be made. Drugs which are very toxic or have dose-independent toxicity should be considered separately. Recommendations regarding 'social' drugs such as nicotine, alcohol, caffeine and theobromine are particularly difficult, as doses are uncontrolled and vary variable.

Principles of drug biodisposition in the neonate. A critical evaluation of the pharmacokinetic-pharmacodynamic interface (Part I)

Rational pharmacotherapy is dependent upon an understanding of the clinical pharmacokinetic and pharmacodynamic properties of the drugs employed. Although the available data on drug biodisposition and action in the neonate have increased considerably in the last few years, pharmacokinetic-pharmacodynamic interactions for many drugs remain poorly understood. The ontogeny of drug absorption, distribution, metabolism, and elimination are addressed in this review. Drug absorption from any site depends upon both the physicochemical properties of the drug and a variety of patient factors. Absorption of orally administered drugs may be affected by changes in gastric acidity and emptying time as well as by bile salt pool size, bacterial colonisation, and extraintestinal disease states such as congestive heart failure. Factors affecting drug absorption following intramuscular, percutaneous, and rectal administration are also discussed. Drug distribution in the neonate is influenced by a variety of important and predictable age-dependent factors. The developmental aspects of protein binding and body water compartments are described. Additionally, hepatic drug metabolism assumes an important role in understanding the pharmacokinetic and pharmacodynamic properties of many compounds. Certain biotransformation pathways, including hydroxylation by the P450 mono-oxygenase system and glucuronidation, demonstrate only limited activity at birth, while other pathways, such as sulphate or glycine conjugation, appear very efficient at birth. Elimination of drugs excreted unchanged in the urine is dramatically reduced in the newborn, compared with older infants and children, due to immaturity of both glomerular filtration and tubular secretory processes. The glomerular filtration rate remains markedly reduced prior to 34 weeks gestational age, increasing as a function of post-conceptual age until adult values are achieved by approximately 2.5 to 5 months of age. Tubular secretory capacity is also limited at birth, approaching adult values by approximately 7 months of age. Published reports describing the pharmacokinetics and pharmacodynamics of commonly used drugs in the neonatal period, as well as differences in drug biodisposition among premature infants, full term neonates, and older infants and children, are reviewed. Our recommendations for neonatal drug therapy are based upon a critical interpretation of these data, an understanding of fetal development and maturational processes, and an understanding of how disease states may affect drug biodisposition in the neonate.

Haloperidol secreted in breast milk

A nursing mother was given haloperidol 5 mg twice daily for puerperal psychosis and continued to breast feed under hospital supervision. Despite considerable amounts of haloperidol being secreted in the breast milk (up to 23.5 micrograms/l), the infant was apparently not sedated, fed well, and continued to thrive. The findings suggest that maternal ingestion of haloperidol for short periods has no deleterious effect on the infant's development.