Adverse effects of drugs and chemicals in breast milk on the nursing infant

Effects of silver nanoparticles on maternal mammary glands and offspring development under lactation exposure

The widespread applications of silver nanoparticles (AgNPs) throughout our daily lives have raised concerns regarding their environmental health and safety (EHS). Despite an increasing number of studies focused on the EHS impacts of AgNPs, there remain significant knowledge gaps with respect to their potential health impacts on susceptible populations, such as lactating mothers and infants. Herein, we aimed to investigate the deleterious effects of AgNPs with different sizes (20 and 40 nm) and surface coatings (PVP and BPEI) on maternal mice and their offspring following lactation exposure at doses of 20, 100 and 400 μg/kg body weight. We discovered that AgNPs could accumulate in the maternal mammary glands and disrupt the epithelial barrier in a dose-dependent manner. Notably, BPEI-coated AgNPs caused more damage to the mammary glands than PVP-coated particles. Importantly, we observed that, while AgNPs were distributed throughout the blood and main tissues, they were particularly enriched in the brains of breastfed offspring after maternal exposure during lactation, exhibiting exposure dosage- and particle coating-dependent patterns. Compared to PVP-coated nanoparticles, BPEI-coated AgNPs were more readily transferred to the offspring, possibly due to their enhanced deposition in maternal mammary glands. Moreover, we observed reduced body weight, blood cell toxicity, and tissue injuries in breastfed offspring whose dams received AgNPs. As a whole, these results reveal that maternal exposure to AgNPs results in the translocation of AgNPs into offspring via breastfeeding, inducing developmental impairments in these breastfed offspring. This study provides important new insights into the EHS impacts of AgNP consumption during lactation.

Parkinson's Disease in Pregnancy: A Case Report and Review of the Literature

Background: Pregnancy in Parkinson's disease is a rare occurrence, and to date, clinical experience with its management is rather limited. In clinical practice, doubts concern mainly the impact of PD on gestation, labor, and delivery as well as the safety of dopaminergic drugs. Case and review of the literature: We report the case of a 40-year-old woman with an 8-year history of PD. In the first trimester of her pregnancy, her motor status was similar to the pre-conceptional period. In gestation week 16, her motor status dramatically worsened and she complained of predictable "off" periods in the afternoon. For this reason, her dose of L-DOPA/carbidopa was increased up to 500/125 mg per day. At 39 gestational weeks, she gave birth to a healthy girl with an Apgar score of 9 by an uncomplicated cesarean delivery. The child was not breast fed to avoid exposure to antiparkinsonian drugs. The L-DOPA/carbidopa dosage remained constant during the postpartum period. We performed a systematic review of the literature using Ovid Medline, Scopus, and PubMed (including Cochrane database). We used the search terms "Parkinson disease" AND "pregnancy." We identified 20 studies of PD in pregnancy with a total of 37 pregnant women with PD. The most important available data concern the safety of L-DOPA therapy during pregnancy. There seems to be some risk of worsening of the condition or upcoming of new PD symptoms during or shortly after pregnancy. Conclusion: More data concerning the safety of antiparkinsonian drugs in PD treatment, as well as the effect of pregnancy on parkinsonian symptoms are needed. According to the current state of the art, L-DOPA therapy should be considered preferable to other drugs during pregnancy.

Pamidronate Administration During Pregnancy and Lactation Induces Temporal Preservation of Maternal Bone Mass in a Mouse Model of Osteogenesis Imperfecta

During pregnancy and lactation, the maternal skeleton undergoes significant bone loss through increased resorption to provide the necessary calcium supply to the developing fetus and suckling neonate. This period of skeletal vulnerability has not been clearly associated with increased maternal fracture risk, but these physiological conditions can exacerbate an underlying metabolic bone condition like osteogenesis imperfecta. Although bisphosphonates (BPs) are commonly used in postmenopausal women, there are cases where premenopausal women taking BPs become pregnant. Given BPs' long half-life, there is a need to establish how BPs affect the maternal skeleton during periods of demanding metabolic bone changes that are critical for the skeletal development of their offspring. In the present study, pamidronate- (PAM-) amplified pregnancy-induced bone mass gains and lactation-induced bone loss were prevented. This preservation of bone mass was less robust when PAM was administered at late stages of lactation compared with early pregnancy and first day of lactation. Pregnancy-induced osteocyte osteolysis was also observed and was unaffected with PAM treatment. No negative skeletal effects were observed in offspring from PAM-treated dams despite lactation-induced bone loss prevention. These findings provide important insight into (1) a treatment window for when PAM is most effective in preserving maternal bone mass, and (2) the maternal changes in bone metabolism that maintain calcium homeostasis crucial for fetal and neonatal bone development. © 2019 American Society for Bone and Mineral Research.

Use of Psychotropic Medications in Breastfeeding Women

BACKGROUND

Breastfeeding women who are prescribed with psychotropic medications on a regular basis are often concerned, regarding the possible implications of such treatment on the breastfed infant. A mother's well-being has a direct influence on the well-being of the baby. However, the notorious reputation of psychotropic medications may lead to suboptimal prescribing by the physician and poor adherence by the mother.

METHODS

A PubMed search (from 1976 through February 2017) was conducted for commonly used psychotropic drug classes, as well as individual medications commonly prescribed in these classes, along with the MeSH terms "breastfeeding"/"lactation". In each case, we chose studies that describe the pharmacokinetics of passage into breast milk and/or adverse effects in breastfed infants.

RESULTS

No large-scale controlled studies regarding the safety of psychotropic medications in breastfeeding mothers were reported. Based on case reports and small studies, most psychotropic medications produce low milk levels and low plasma levels in the infant, while serious adverse effects in the breastfed infant are rarely reported. Safety data for some psychotropic medications are still unavailable.

CONCLUSION

According to the data available in the literature to date, most psychotropic medications are expected to produce low levels in breast milk with no clinical importance. Nevertheless, an individual risk-benefit assessment of a proposed treatment should always be performed, as inter-individual differences may have a substantial effect on the breastfeeding infant's response to the treatment. Further studies and additional objective data are needed to consolidate and improve our current knowledge of psychopharmacotherapy in breastfeeding women. Birth Defects Research 109:957-997, 2017. © 2017 Wiley Periodicals, Inc.

New insights into perinatal depression: pathogenesis and treatment during pregnancy and postpartum

Maternal perinatal mental health has enormous consequences for the well-being of the mother, her baby, and the family. Although it is well documented that perinatal depression is both common and morbid, with a prevalence of 10% to 15% in the general population, there remain many critically important unanswered questions about the pathogenesis of perinatal depression and most effective treatment regimens. Current lines of evidence from both human and animal models implicate hormonal dysregulation, abnormalities in hypothalamic-pituitary-adrenal axis activity, and the contributions of genetics and epigenetics as playing key roles in the development of perinatal reproductive mood disorders. Investigations into both human and animal models of perinatal depression offer much promise for the future identification of the underlying pathophysiology and subsequent early identification and/or prevention and appropriate treatment for women at risk for postpartum depression. Lastly, although it is generally accepted that pregnancy is not protective with regard to new onset or relapse of depression, the way to best treat maternal depression during pregnancy and lactation remains hotly debated. Future research in this area will more clearly elucidate the underlying pathogenesis, the potential long-term impact of perinatal depression on the developing fetus, and how best to counsel pregnant women about the risks of untreated major depressive disorder versus the risks of psychopharmacologic treatment during pregnancy and lactation.

Transfer of isoniazid from circulation to breast milk in lactating women on chronic therapy for tuberculosis

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Isoniazid is the most widely used first line antituberculosis drug. It is considered safe during lactation, but limited data are available on the transfer of isoniazid from circulation to milk in lactating women, which can provide an assessment of extent of exposure to the nursling.

WHAT THIS STUDY ADDS

The study documents the transfer pattern and milk to plasma (M : P) ratio of isoniazid at a steady state. Peak plasma and milk concentrations of isoniazid were reached within 1 h and the projected exposure of the drug to the infant is much lower than the prophylactic dose, supporting its safety during breast feeding.

AIM

To determine milk to plasma (M : P) ratios and infant dose (absolute and relative) for isoniazid in lactating women on antituberculosis therapy.

METHODS

Concentrations of isoniazid in plasma and milk were measured in exclusively breast feeding women taking 300 mg day(-1) as treatment for tuberculosis.

RESULTS

Peak plasma and milk concentrations of isoniazid were observed at 1 h. A mean M : P(AUC) value of 0.89 (95% CI 0.7, 1.1) was calculated for isoniazid from seven women over 24 h. The mean absolute infant dose was estimated to be 89.9 mug kg day(-1) (95% CI 65.6, 114) and the relative infant dose was 1.2% of the weight adjusted maternal dose.

CONCLUSIONS

The mean relative dose of isoniazid (1.2%) transmitted to the infant via breast milk is below the 10% notional level of concern. These data suggest that isoniazid therapy is safe during breastfeeding.

Prediction of Milk/Plasma Drug Concentration (M/P) Ratio Using Support Vector Machine (SVM) Method

PURPOSE

Development of reliable computational models to predict/classify milk-to-plasma (M/P) drug concentration ratio remains a challenging object. Support vector machine (SVM) method, as a new algorithm, was constructed to distinguish the potential risk of drugs to nursing infants.

METHODS

Each drug was represented by a large pool of descriptors, of which five were found to be most important for constructing the predictive models. Next, two classification models, linear discriminant analysis (LDA) and SVM, were developed with bootstrapping validation based on the selected molecular descriptors.

RESULTS AND CONCLUSIONS

The classification accuracy of training set and test set for SVM was 90.63 and 90.00%, respectively. The total accuracy for SVM was 90.48%, which was higher than that of LDA (77.78%). Comparison of the two methods shows that the performance of SVM was better than that of LDA, which implies that the SVM method is an effective tool in evaluating the risk of drugs when experimental M/P ratios have not been investigated.

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.

Movement disorders in pregnancy

Movement disorders are not particularly common during pregnancy, with a few exceptions. RLS occurs most commonly followed by CG. Currently, with the incidence of rheumatic fever lower than previously, any woman who develops CG should be checked for illness other than rheumatic heart disease. The differential includes systemic lupus erythromatosis and antiphospholipid antibody syndrome. Regarding the use of dopaminergic agents, the dopamine agonist, pergolide, can be maintained during pregnancy for the treatment of PD, Segawa disease, and RLS. The use of levodopa and ropinirole should be limited during pregnancy because of the possible teratogenic effects. Amantadine is contraindicated during pregnancy. The data on selegiline are controversial; animal studies show possible serotonergic effects and teratogenic effects. If treatment is indicated in patients who have Tourette syndrome, the high potency neuroleptics drugs (haloperidol) are preferred to treat associated symptoms. Depression is a common comorbidity in patients who have PD, HD,Tourette syndrome, or other chronic neurologic diseases. Depression treatment during pregnancy is covered by Levy et al elsewhere in this issue. As discussed previously, most of the data on the use of drugs during pregnancy, especially the dopaminergic agents, are limited to animal studies and case reports. Therefore, it is in part left to the neurologist to decide on treatment based on the individual patient, clinical judgment, and inferences from animal studies and limited case reports.

Environmental chemicals in human milk: a review of levels, infant exposures and health, and guidance for future research

The aim of this review is to introduce the reader to various science and policy aspects of the topic of environmental chemicals in human milk. Although information on environmental chemicals in human milk has been available since the 1950s, it is only relatively recently that public awareness of the issue has grown. This review on environmental chemicals in human milk provides a resource summarizing what is currently known about levels and trends of environmental chemicals in human milk, potential infant exposures, and benefits of breast-feeding relative to the risks of exposures to environmental chemicals. The term "environmental chemicals," as it pertains to human milk, refers to many classes of exogenous chemicals that may be detected in human milk. For example, pharmaceutical agents and alcohol are environmental chemicals that have been found in human milk. Other chemicals, such as heavy metals and volatile organic compounds, have also been detected in human milk. Most research on environmental chemicals in human milk has concentrated on persistent, bioaccumulative, and toxic (PBT) chemicals. In this review, a description of human milk is provided, including a brief review of endogenous substances in human milk. Determinants of levels of PBTs are discussed, as are models that have been developed to predict levels of PBTs in human milk and associated body burdens in breast-feeding infants. Methodologies for human milk sampling and analysis, and concepts for consideration in interpretation and communication of study results, as developed by the Technical Workshop on Human Milk Surveillance and Research for Environmental Chemicals in the United States are described. Studies which have compared the health risks and benefits associated with breast-feeding and formula-feeding are discussed.

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.

Common breastfeeding problems

Breastfeeding is a learned art. It also is a physiological, psychological, and social event involving two individuals. Many factors impact the breastfeeding experience. This article outlines proper management, good counseling skills, anticipatory guidance, and ongoing support, which can facilitate positive outcomes in breastfeeding.

Pregnancy after liver transplantation

The first known posttransplantation pregnancy was in 1958 in a renal transplant recipient who had received a kidney from her identical twin sister. The first known posttransplantation pregnancy in a liver transplant recipient was in 1978. Information available from female kidney transplant recipients helped in the decision making involved in the management of this case, as well as those that followed. Over the last 20 years, issues specific to liver transplantation and pregnancy have been identified. Similar to the kidney transplant recipient population, when prepregnancy recipient graft function is stable and adequate, pregnancy appears to be well tolerated. Also similar to kidney transplant recipients, there has been no evidence of a specific malformation pattern among the children, and although prematurity and low birth weight occur, overall newborn outcomes have been favorable. Pregnancy in the setting of recurrent liver disease, such as recurrent hepatitis C, poses a potential problem among liver transplant recipients, as well as the possible adverse effects of immunosuppression on maternal kidney function. Also of significance, peripartum graft deterioration has more severe consequences in this transplant recipient population. Therefore, pregnancy must be considered carefully in this transplant recipient group. Since 1991, the National Transplantation Pregnancy Registry (NTPR) has studied the safety of pregnancy outcomes in solid-organ transplant recipients. The purpose of this review is to catalog studies in the literature, as well as to present current data from the registry with management guidelines.

Topical metronidazole. A review of its use in rosacea

Topical application of the antibacterial agent metronidazole is effective in the treatment of moderate to severe rosacea, although its mechanism of action has yet to be clearly established. Metronidazole preparations (0.75 and 1% cream, 0.75% gel and 0.75% lotion) were significantly more effective than placebo in patients with moderate to severe rosacea when administered to the affected area once or twice daily for 7 to 12 weeks. The mean number of papules and pustules decreased by between 48 and 65.1% during the treatment period. Reductions were fairly consistent regardless of formulation, strength or application frequency and were significant compared with placebo (p < 0.05). In 1 study, most of the overall effects of metronidazole were observed within the first 3 weeks. Although data are limited, topical metronidazole appears to improve inflammatory lesions and erythema as effectively as oral tetracyclines. Like tetracyclines, however, metronidazole has no effect on telangiectasia. Metronidazole 0.75% gel seems to be effective in maintaining remission of rosacea symptoms in patients successfully treated with both oral tetracycline and topical metronidazole. In the only study, 77% of patients treated with metronidazole gel compared with 58% of placebo recipients (p < 0.05) remained in remission 6 months after the tetracycline was stopped. The effects of topical metronidazole preparations on rosacea symptoms are palliative, not curative, but preliminary data suggest that relapse rates after cessation of therapy are no worse than those after cessation of oral oxytetracycline. Topical metronidazole formulations are generally well tolerated locally, with stinging, dryness, burning and itching reported in < or = 2% of patients. Because minimal concentrations of metronidazole are absorbed after topical administration, systemic adverse events and drug interactions seen with oral or intravenous metronidazole are unlikely.

CONCLUSIONS

Topical metronidazole formulations are significantly more effective than placebo when used in the initial treatment of patients with moderate to severe rosacea. Furthermore, limited evidence suggests that the use of topical metronidazole alone may be as effective as oral tetracyclines against the disorder's inflammatory component. Therefore, for those patients with a preference for topical rather than oral therapy, the use of a topical metronidazole formulation must be a consideration.

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.

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.

Rapid disappearance of zaleplon from breast milk after oral administration to lactating women

Five lactating mothers were administered the therapeutic dose of zaleplon (10 mg) orally in an open-label, single-dose, pharmacokinetic study. Plasma and breast milk were sampled through 8 hours after dose administration for subsequent determinations of zaleplon and its major, though inactive, plasma metabolite 5-oxo-zaleplon. Zaleplon concentrations peaked in plasma and milk approximately 1 hour after dosing and then disappeared rapidly. The mean terminal half-life was slightly greater than 1 hour. Milk concentrations "mirrored" plasma concentrations closely with no discernible delay between peak times. The average milk-to-plasma (M/P) concentration ratio for zaleplon was approximately 0.50 over the time course. 5-oxo-zaleplon was undetectable in all but one milk sample. The maximum exposure of an infant to zaleplon during a feeding at peak milk concentrations was estimated to range from 1.28 micrograms to 1.66 micrograms, corresponding to 0.013% to 0.017% of the maternal dose or 0.320 microgram/kg to 0.415 microgram/kg for a 4 kg infant. The results indicate that zaleplon taken by a nursing mother is transferred through breast milk to her infant in very small quantities that are unlikely to be clinically important.

Pregnancy in Parkinson's disease: a review of the literature and a case report

Pregnancy is rare in Parkinson's disease (PD). In the literature on studies of antiparkinsonian drugs in animals during pregnancy, there are reports on malformations of the skeletal and circulatory system. However, the majority of studies in animals have not shown any teratogenicity. Amantadine has been teratogenic in rats and selegiline has caused neurochemical and behavioral alterations in rats when coadministered with clorgyline. The published experience with humans consists of 35 pregnancies among 26 women suffering from PD, including this report, and a number of cases treated with antiparkinsonian agents for other reasons. With the exception of the majority of the cases where amantadine was used, complications have been rare. However, there are indications that suggest a possible risk of a woman's parkinsonism worsening in connection with pregnancy. We also report the case of a woman with PD who was treated with L-dopa-benserazide during an uncomplicated pregnancy and gave birth to a healthy boy without experiencing any worsening of her PD.

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).

Drug use during lactation

Breast-feeding is an essential physiologic process that provides ideal nutrition to the infant as well as protection against disease. All drugs are excreted into breast milk and are bioavailable to the infant. However, most medications do not pose significant risk to the nursing infant, and breast-feeding should be continued despite medication use in most cases. These decisions should be made using a stepwise approach Pharmacists should be aware of which drugs are contraindicated and which drugs should be used cautiously, in addition to which drugs should be recommended if necessary during lactation information on use of specific drugs is presented in this article. With knowledge of the principles of drug passage into breast milk, the goal of the pharmacist should be to minimize the infant's exposure to drugs while supporting the mother's desire to continue breast-feeding.

Variables affecting nicotine metabolism

Nicotine metabolism is exceedingly sensitive to perturbation by numerous host factors. To reduce the large variations and discrepancies in the literature pertaining to nicotine metabolism, investigators in future studies need to recognize and better control these host factors. Recent advances in the understanding of nicotine metabolism have suggested new approaches to elucidating underlying mechanisms of certain toxic effects associated with cigarette smoking.