Penetration of fleroxacin into breast milk and pharmacokinetics in lactating women

Antibiotics and lactation: An overview of relative infant doses and a systematic assessment of clinical studies

Breastfeeding is important for the development of the child. Many antibiotics are considered safe during breastfeeding. The aim of the study was to assess the quality of lactation studies with antibiotics using the FDA and International Lactation Consultant Association quality guidelines for lactation studies. The secondary goal was to determine the exposure of the breastfed infant to antibiotics in relation to bacterial resistance and the developing microbiome. A literature search was performed and the included studies were scored on methodology, parameters concerning maternal exposure to antibiotics, maternal plasma and milk sampling. The infant exposure has been calculated and expressed as a percentage of a normal infant therapeutic dose. Sixty-six studies were included in five antibiotic groups (broad-spectrum penicillin, cephalosporins, macrolides and lincosamides, quinolones and sulphonamides). Cephalosporins were the most studied group of antibiotics (n = 21). Fifteen studies met all the criteria of "mother exposure to antibiotic". Six studies met every criterion related to "plasma sampling". Only one case report met all listed criteria for lactation studies. The correct calculation of infant exposure to antibiotics via the milk:plasma ratio (AUC) varies between 13% for macrolides and 38% for broad-spectrum penicillin. The highest assessed exposure as a percentage of infant therapeutic dose was for metronidazole (11%). The studies meet to a limited extent with the quality standards for lactation research. The breastfed infants are exposed to a subtherapeutic concentration of antibiotics.

Effects of breast pumping on the pharmacokinetics and pharmacodynamics of ethanol during lactation

This study tested two hypotheses. First, that breast pumping contributes to the previously observed decrease in ethanol bioavailability in lactating women. Second, that the effects of breast pumping are more pronounced when ethanol is consumed after a meal. The within-subject factor was test condition (fed or fasted) and the between-subject factor was experimental group (pumped before, PB; pumped after, PA). Those randomly assigned to the PB group (N = 8) breast pumped 1 h before drinking, whereas those assigned to the PA group (N = 8) breast pumped 0.6 h after drinking. Pumping before drinking significantly decreased blood ethanol concentration (P < 0.05) and ethanol bioavailability (P = 0.05). Pumping after drinking sped up elimination (P = 0.008), attenuated ethanol-induced hypothermia (P = 0.002), and increased feelings of stimulation (P = 0.03). The effects were more pronounced when ethanol was consumed after a meal. Common neural/hormonal responses to food and suckling may contribute additive effects in altering the pharmacokinetics/pharmacodynamics of ethanol, and perhaps of other drugs, during lactation.

Lactational state modifies alcohol pharmacokinetics in women

BACKGROUND

Given the physiological adaptations of the digestive system during lactation, the present study tested the hypothesis that lactation alters alcohol pharmacokinetics.

METHODS

Lactating women who were exclusively breastfeeding a 2- to 5-month-old infant and 2 control groups of nonlactating women were studied. The first control group consisted of women who were exclusively formula-feeding similarly aged infants, whereas the other consisted of women who had never given birth. A within-subjects design study was conducted such that women drank a 0.4 g/kg dose of alcohol following a 12-hour overnight fast during one test session (fasted condition) or 60 minutes after consuming a standard breakfast during the other (fed condition). Blood alcohol concentration (BAC) levels and mood states were obtained at fixed intervals before and after alcohol consumption.

RESULTS

Under both conditions, the resultant BAC levels at each time point were significantly lower and the area under the blood alcohol time curve were significantly smaller in lactating women when compared with the 2 groups of nonlactating women. That such changes were due to lactation per se and not due to recent parturient events was suggested by the finding that alcohol pharmacokinetics of nonlactating mothers, who were tested at a similar time postpartum, were no different from women who had never given birth. Despite lower BAC levels in lactating mothers, there were no significant differences among the 3 groups of women in the stimulant effects of alcohol. However, lactating women did differ in the sedative effects of alcohol when compared with nulliparous but not formula-feeding mothers. That is, both groups of parous women felt sedated for shorter periods of time when compared with nulliparous women.

CONCLUSIONS

The systemic availability of alcohol was diminished during lactation. However, the reduced availability of alcohol in lactating women did not result in corresponding changes in the subjective effects of alcohol.

Breast cancer resistance protein (BCRP/ABCG2) transports fluoroquinolone antibiotics and affects their oral availability, pharmacokinetics, and milk secretion

The breast cancer resistance protein (BCRP/ABCG2) is an ATP-binding cassette drug efflux transporter that extrudes xenotoxins from cells in intestine, liver, mammary gland, and other organs, affecting the pharmacological and toxicological behavior of many compounds, including their secretion into the milk. The purpose of this study was to determine whether three widely used fluoroquinolone antibiotics (ciprofloxacin, ofloxacin, and norfloxacin) are substrates of Bcrp1/BCRP and to investigate the possible role of this transporter in the in vivo pharmacokinetic profile of these compounds and their secretion into the milk. Using polarized cell lines, we found that ciprofloxacin, ofloxacin, and norfloxacin are transported by mouse Bcrp1 and human BCRP. In vivo pharmacokinetic studies showed that the ciprofloxacin plasma concentration was more than 2-fold increased in Bcrp1(-/-) compared with wild-type mice (1.77 +/- 0.73 versus 0.85 +/- 0.39 microg/ml, p < 0.01) after oral administration of ciprofloxacin (10 mg/kg). The area under the plasma concentration-time curve in Bcrp1(-/-) mice was 1.5-fold higher than that in wild-type mice (48.63 +/- 5.66 versus 33.10 +/- 4.68 min x microg/ml, p < 0.05) after i.v. administration (10 mg/kg). The milk concentration and milk/plasma ratio of ciprofloxacin were 2-fold higher in wild-type than in Bcrp1(-/-) lactating mice. We conclude that Bcrp1 is one of the determinants for the bioavailability of fluoroquinolones and their secretion into the milk.

Drugs that affect the fetus and newborn infant via the placenta or breast milk

In general, drugs that are taken by a mother during pregnancy or after birth may be transferred to the fetus or the infant (through breast milk). Many factors are involved that determine the amount of drugs that are transferred and their potential effects on the fetus or infant. A careful assessment of the risk versus benefit is necessary and should be individualized. In the breastfed infant, many measures can be undertaken further so that the amount of drug transferred to the infant is minimized.

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.

Use of anti-infective agents during lactation: Part 2--Aminoglycosides, macrolides, quinolones, sulfonamides, trimethoprim, tetracyclines, chloramphenicol, clindamycin, and metronidazole

Because many antibiotics are excreted into breast milk, it can be difficult for a practitioner to choose an antibiotic for a lactating patient that will have minimal risks to her nursing infant. This article is the second of a three-part series discussing the use of anti-infective agents during lactation. The authors review general information regarding use and common side effects for several classes of antibiotics. They also summarize information, including documented milk concentrations, milk-to-plasma ratios, and other pharmacokinetic properties, in a table that can help practitioners choose antibiotics that may be considered safe to use in the lactating mother.

Fleroxacin. A review of its pharmacology and therapeutic efficacy in various infections

The fluoroquinolone antibacterial agent fleroxacin has a broad spectrum of in vitro activity which encompasses most Gram-negative species (particularly Enterobacteriaceae) and a number of Gram-positive organisms, including methicillin-sensitive staphylococci. It is available as oral and intravenous formulations. In clinical trials, fleroxacin has been evaluated in the treatment of uncomplicated urinary tract infections (single or multiple once-daily oral doses of 200 or 400mg), gonorrhoea and chancroid (single oral doses of 200 or 400mg), complicated urinary tract, nonpneumococcal lower respiratory tract and skin and soft tissue infections and typhoid fever (multiple once-daily oral or intravenous regimens, usually 400 mg/day), bacterial enteritis, and traveller's diarrhoea (single or multiple once-daily oral doses of 400mg). Bacteriological cure rates were generally around 90% or higher in complicated and uncomplicated urinary tract infections, uncomplicated gonorrhoea (approximately 100%), pyelonephritis, bacterial enteritis and typhoid fever, and exceeded 80% in lower respiratory tract, and skin and soft tissue infections and chancroid. These cure rates were similar to, or better than, those achieved with standard comparator antibacterial agents such as penicillins, cephalosporins, cotrimoxazole, or other quinolones. Fleroxacin 400mg once daily also achieved bacteriological cure in approximately 80% of patients with bone and joint infections in preliminary studies. In Japanese studies using a lower dosage of 200 or 300 mg/day, fleroxacin was reported to be bacteriologically effective in a range of infections, including urinary tract and upper and lower respiratory tract infections. Fleroxacin has a relatively long elimination half-life, which allows once-daily administration, and it appears to have less propensity for interactions with other medications in comparison to many other fluoroquinolones. Its tolerability profile is typical of this class of compound, with adverse events mostly relating to the gastrointestinal tract, CNS, and skin and appendages (including phototoxicity). Recent pooled tolerability data from worldwide clinical trials indicate that adverse events are reported by approximately 27% of patients receiving 200 mg/day orally or 400 mg/day orally or intravenously, and 17% of those receiving a single oral dose of 400mg. These exceed incidences reported for established fluoroquinolones, possibly indicating recent trends towards increased rates of reported adverse effects with these agents. However, in direct comparative studies with twice-daily fluoroquinolones, fleroxacin 400mg once daily produced a similar incidence of adverse effects to ofloxacin 800 mg/day and a slightly higher incidence than ciprofloxacin 1000 mg/day, while fleroxacin 200mg once daily produced a similar incidence to norfloxacin 800 mg/day.(ABSTRACT TRUNCATED AT 400 WORDS)