Verapamil and norverapamil in plasma and breast milk during breast feeding

2023 HRS expert consensus statement on the management of arrhythmias during pregnancy

This international multidisciplinary expert consensus statement is intended to provide comprehensive guidance that can be referenced at the point of care to cardiac electrophysiologists, cardiologists, and other health care professionals, on the management of cardiac arrhythmias in pregnant patients and in fetuses. This document covers general concepts related to arrhythmias, including both brady- and tachyarrhythmias, in both the patient and the fetus during pregnancy. Recommendations are provided for optimal approaches to diagnosis and evaluation of arrhythmias; selection of invasive and noninvasive options for treatment of arrhythmias; and disease- and patient-specific considerations when risk stratifying, diagnosing, and treating arrhythmias in pregnant patients and fetuses. Gaps in knowledge and new directions for future research are also identified.

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

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 common cardiology and general medications 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, healthcare providers, and mothers to make educated decisions regarding drug therapy and breast-feeding.

Cluster Headache: Special Considerations for Treatment of Female Patients of Reproductive Age and Pediatric Patients

Cluster headache is a rare disorder that is more common in adult male patients. It has a unique phenotype of unilateral, severe, to very severe headaches lasting 15 to 180 min with ipsilateral autonomic symptoms. Time to correct diagnosis can be protracted. A number of treatment options exist for the standard cluster headache patient, but special considerations must be made for female patients of reproductive age and pediatric patients. The objective of this article is to explore the current literature pertaining to special considerations in cluster headache management, including treatment of pregnant or breastfeeding patients and pediatric patients.

Maternal medication, drug use, and breastfeeding

This article reviews the necessary skills required for clinicians to make informed decisions about the use of medications in breastfeeding women. Even without specific data on certain medications, this review of kinetic principles, mechanisms of medication entry into breast milk, and important infant factors can aid in clinical decision making. In addition, the article reviews common medical conditions (eg, depression, hypertension, infections) in breastfeeding women and their appropriate treatment.

Breastfeeding and migraine drugs

PURPOSE

Breastfeeding women may suffer from migraine. While we have many drugs for its treatment and prophylaxis, the majority are poorly studied in breastfeeding women. We conducted a review of the most common anti-migraine drugs (AMDs) and we determined their lactation risk.

METHODS

For each AMD, we collected all retrievable data from Hale's Medications and Mother Milk (2012), from the LactMed database (2014) of the National Library of Medicine, and from a MedLine Search of relevant studies published in the last 10 years.

RESULTS

According to our review, AMDs safe during breastfeeding are as follows: low-dose acetylsalicylic acid (ASA), ibuprofen, sumatriptan, metoprolol, propranolol, verapamil, amitriptyline, escitalopram, paroxetine, sertraline, acetaminophen, caffeine, and metoclopramide. AMDs compatible with breastfeeding but warranting caution are as follows: diclofenac, ketoprofen, naproxen, most new triptans, topiramate, valproate, venlafaxine, and cyproheptadine. Finally, high-dose ASA, atenolol, nadolol, cinnarizine, flunarizine, ergotamine, methysergide, and pizotifen are contraindicated.

CONCLUSIONS

According to our review, the majority of the revised AMDs were assessed to be compatible with breastfeeding.

Maternal medication, drug use, and breastfeeding

This article reviews the necessary skills required for clinicians to make informed decisions about the use of medications in women who are breastfeeding. Even without specific data on certain medications, this review of kinetic principles, mechanisms of medication entry into breast milk, and important infant factors can aid in clinical decision making. In addition, common medical conditions and suitable treatments of depression, hypertension, infections and so forth for women who are breastfeeding are also reviewed.

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.

Prediction of milk/plasma concentration ratio of drugs

OBJECTIVE

The milk to plasma (m/p) concentration ratio of drugs is used to estimate the amount of drug offered to the suckling infant. Published literature was reviewed to identify drugs for which sufficient data exist for calculation of m/p ratio and to examine whether the existing empiric data agree with the published method of Atkinson for mathematical prediction of m/p ratios based on physiochemical characteristics.

METHODS

Using a comprehensive reference text, we identified studies reporting sufficient data to calculate m/p ratio based on the AUC for milk and plasma. Subsequently, we calculated the m/p ratio with Atkinson's formula based on pKa, lipophilicity, and protein binding. We then correlated the empiric versus predicted (calculated) m/p ratios.

RESULTS

Of 192 drugs of which at least some data on milk accumulation have been published, there were sufficient data to quantify m/p ratios for only 69 medications (78 studies). There was no significant correlation between the empiric m/p ratios and the predicted values using the Atkinson's model.

CONCLUSIONS

Reliable data on m/p concentration ratios exist for few medications. Presently, there is no appropriate model to predict milk concentrations of drugs in humans.

Excretion of antihypertensive medication into human breast milk: a systematic review

OBJECTIVE

To establish which antihypertensive medications are safe for use while breastfeeding, by reviewing the available evidence.

METHODS

Reports of studies examining the transfer of antihypertensive medications to breastmilk were identified from multiple MEDLINE and EMBASE searches, manual review of bibliographies of articles and textbooks on drug use during lactation. The reports were reviewed and the results were compiled.

RESULTS

Prospective cohort studies and case reports constituted the only available evidence. Compilation of these results found that the milk to plasma (M/P) ratios varied widely across the beta-blocker family, the beta-blockers with low protein binding having the highest M/P ratios. The angiotensin-converting enzyme (ACE) inhibitors, methyldopa, and some calcium channel blockers had low M/P ratios.

CONCLUSION

The available data to date indicate that ACE inhibitors, methyldopa, beta-blockers with high protein binding, and some calcium channel blockers all appear to be safe treatments of hypertension in a nursing mother. The data suggest that drugs to be avoided are beta-blockers with low protein binding. However, the available evidence is limited and further studies are needed to confirm these findings.

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.

Pharmacokinetics of verapamil in lactating rabbits. Prediction of verapamil distribution into rabbit milk

In this work, we have studied the pharmacokinetics and milk penetration of verapamil following intravenous administration in lactating rabbits. Milk-to-serum drug concentration ratios (M/B(obs)) have been determined using area under the milk and serum concentration-time profiles, and the resulting values have then been compared with those obtained by theoretical classical diffusion milk transfer models that were described by Fleishaker et al. [J. Pharm. Sci. 76 (1987) 189.], Atkinson and Begg [Br. J. Clin. Pharmacol. 25 (1990) 495.], and Stebler and Guentert [Pharm. Res. 9 (1992) 1299.]. The pharmacokinetic profile of verapamil in lactating rabbits following endovenous administration is described in the form of a two-compartment model. Moreover, we detected an important milk transfer after endovenous administration of verapamil in lactating rabbits. M/B(obs) was near 15. The classical diffusional models mentioned were not able to predict this extensive transfer of verapamil into rabbit milk. However, when the classical Fleishaker equation was modified and a stepwise regression was carried out, we found that the M/B(obs) value could be predicted using the plasma and milk protein binding.

Calcium channel antagonists and lactation: an update

Approximately 14% of women of age 20-54 years old have hypertension. For those women who are on medication for hypertension and are pregnant, this poses potential problems. In many cases, antihypertensive agents may be continued in women with chronic hypertension if taken prior to pregnancy. This article discusses the antihypertensive class, calcium channel antagonists, with regard to their physiochemical properties and lactation.

Prediction of drug distribution into human milk from physicochemical characteristics

Decisions about the safety of breast feeding during maternal ingestion of drugs require knowledge of the amount of drug which might be present in the milk. For many drugs this has not been studied, and mothers are usually advised against breast feeding. In many cases this is undoubtedly unnecessary, as the total dose to which the baby is exposed is often negligible. It would be very helpful, therefore, to be able to predict the approximate amount of drug which might be present in milk. Existing theory of pH partitioning enables estimation of the distribution of unbound drug, i.e. milk: plasma unbound ratios. However, these ratios are poor estimates of the concentration ratios for whole milk, because whole milk contains proteins and lipid in which drugs will distribute in amounts which depend on their particular physicochemical properties. To predict the milk: plasma concentration ratios for whole milk the amount of drug present in the protein and lipid phases must be considered along with the unbound drug distribution. A 'phase distribution model' has therefore been developed which permits estimation of whole milk: plasma concentration ratios. The model requires a knowledge of the unbound drug concentration ratio, the plasma and milk unbound fractions and the milk lipid: ultrafiltrate partition coefficient. Evaluation of the model by comparison of predicted whole milk ratio values with literature milk: plasma area under the curve (AUC) ratios indicated a trend to overprediction for acidic and neutral drugs and underprediction for basic drugs. Transformation of the phase distribution equation by taking logarithms results in a relationship which can be analysed by multiple linear regression to derive predictive equations for acidic and basic drugs which take into account the relative contributions of each component of the model. Regression of the logarithms of the literature milk: plasma AUC values against the independent variables resulted in good correlations for acidic and basic drugs. The independent variables explained 93.1% and 82.9% of the variance in the values for acidic and basic drugs, respectively, with random scatter of residuals. The equations, together with those to predict unbound fractions of drug in milk and milk lipid: ultrafiltrate partition coefficients, enable the ratio of the milk: plasma AUCs to be estimated for any acidic or basic drug for which the distribution into human milk is not known, using the pKa, octanol: water partition coefficient and plasma protein binding values of the drug. The data set for neutral drugs (n = 3) was too small to develop a correlation equation.(ABSTRACT TRUNCATED AT 400 WORDS)

Excretion of tiapamil in breast milk

The excretion of tiapamil in breast milk was studied in six lactating mothers (3-7 days post partum) following a single oral 600 mg dose of the drug. The milk/plasma ratio of tiapamil derived from the areas under the plasma and milk concentration-time curves was 0.44 +/- 0.10 mean +/- s.d.). Assuming an intake of 350 ml of milk during a dosing interval of 12 h, the newborn would be exposed at the maximum to 0.053 mg tiapamil. This small amount does not represent a risk for the baby.

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.