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Biomedical subjects

Thomas W Hale

Publications and source records attributed to Thomas W Hale.

8 recordsLinked to original sources
PubMed2004

Transfer of celecoxib into human milk.

The aim of this study was to investigate the transfer of celecoxib into human milk. In one group of 3 breastfeeding patients on celecoxib at steady state, milk levels were determined at set intervals over 24 hours. Plasma levels were determined in 2 of their infants, age 17 and 22 months. In a second group of 2 subjects, intravenous lines were placed and a single 200-mg dose of celecoxib was followed by multiple paired plasma and milk samples over 8 hours. The mean milk-to-plasma ratio for celecoxib was 0.23 (95% confidence interval [CI]: 0.15-0.31). The average concentration of celecoxib in milk during the 8-hour dosing interval was 66 microg/L (95% CI: 41-89). The absolute infant dose averaged 9.8 microg/kg/d (95% CI: 6.2-13.4); the mean relative infant dose was 0.30%. Therefore, the average clinical dose transferred to the infant daily would be approximately 0.3% of the weight-adjusted maternal dose. The authors suggest that the use of celecoxib in breastfeeding mothers at these doses is very unlikely to cause untoward effects in breastfed infants.

Adult↗
PubMed2003

Measurement of nicotine and cotinine in human milk by high-performance liquid chromatography with ultraviolet absorbance detection.

A high-performance liquid chromatographic (HPLC) assay for the determination of nicotine and cotinine in human milk was developed using an extraction by liquid-liquid partition combined with back extraction into acid, and followed by reverse-phase chromatography with UV detection of analytes. The assay was linear up to 500 microg/l for both nicotine and cotinine. Intra- and inter-day relative standard deviations (R.S.D.) were <10% (25-500 microg/l) for both nicotine and cotinine. Limits of quantitation (LOQ) were 10 and 12 microg/l for nicotine and cotinine, respectively, while the limits of detection (LOD) were 8 and 10 microg/l for nicotine and cotinine, respectively. The mean recoveries were 79-93% (range 25-500 microg/l) for nicotine and 78-89% (range 25-500 microg/l) for cotinine. The amount of fat in the milk did not affect the recovery. We found that this method was sensitive and reliable in measuring nicotine and cotinine concentrations in milk from a nursing mother who participated in a trial of the nicotine patch for smoking cessation.

Chromatography, High Pressure Liquid↗
PubMed2003

Use of nicotine patches in breast-feeding mothers: transfer of nicotine and cotinine into human milk.

OBJECTIVE: Our objective was to assess the extent of exposure to nicotine and cotinine in breast-fed infants during maternal smoking and later during maternal use of the nicotine transdermal patch to achieve smoking cessation. METHODS: Fifteen lactating women (mean age, 32 years; mean weight, 72 kg) who were smokers (mean of 17 cigarettes per day) participated in a trial of the nicotine patch to assist in smoking cessation. Serial milk samples were collected from the women over sequential 24-hour periods when they were smoking and when they were stabilized on the 21-mg/d, 14-mg/d, and 7-mg/d nicotine patches. Nicotine and cotinine in milk were quantified by HPLC, and infant dose was calculated. Plasma concentrations of nicotine in the breast-fed infants were assessed, and the infants were also clinically assessed. RESULTS: Nicotine and cotinine concentrations in milk were not significantly different between smoking (mean of 17 cigarettes per day) and the 21-mg/d patch, but concentrations were significantly lower (P <.05) when patients were using the 14-mg/d and 7-mg/d patches than when smoking. There was also a downward trend in absolute infant dose (nicotine equivalents) from smoking or the 21-mg patch through to the 14-mg and 7-mg patches (P <.05 at both 14-mg and 7-mg doses, compared with smoking). Milk intake (shown as median and 25th to 75th percentile) by the breast-fed infants was similar while their mothers were smoking (585 mL/d [507-755 mL/d]) and subsequently when their mothers were using the 21-mg (717 mL/d [504-776 mL/d]), 14-mg (731 mL/d [535-864 mL/d]), and 7-mg (619 mL/d [520-706 mL/d]) patches (chi(2) = 3.19, P =.364). CONCLUSIONS: We conclude that the absolute infant dose of nicotine and its metabolite cotinine decreases by about 70% from when subjects were smoking or using the 21-mg patch to when they were using the 7-mg patch. In addition, use of the nicotine patch had no significant influence on the milk intake by the breast-fed infant. Undertaking maternal smoking cessation with the nicotine patch is, therefore, a safer option than continued smoking.

Administration, Cutaneous↗
PubMed2003

Pseudoephedrine: effects on milk production in women and estimation of infant exposure via breastmilk.

AIMS: To assess the effects of pseudoephedrine on breast blood flow, temperature and milk production, and to estimate the likely infant dose during breastfeeding. METHODS: Eight lactating women (mean age 35 years and weight 69 kg) participated in a single-blind randomized crossover study of 60 mg pseudoephedrine hydrochloride vs placebo. Breast blood flow and surface temperature were measured from 0 to 4 h following the dose, and change in plasma prolactin was measured as the difference between predose and 1 h postdose concentrations. Milk production was measured for 24 h following placebo and pseudoephedrine. Infant dose of pseudoephedrine for a 60-mg dose administered four times daily to the mother was quantified as the product of average steady-state drug concentration in milk and an estimated milk production rate of 0.15 l x kg(-1) x day(-1) and expressed relative to the maternal weight-adjusted dose. RESULTS: There were no physiologically significant changes in breast blood flow or temperature between the placebo and pseudoephedrine periods. The mean change in plasma prolactin was slightly (13.5%), but not significantly lower (t = 1.245, P = 0.253) after pseudoephedrine (1775 mU x l(-1)) compared with placebo (2014 mU x l(-1)). However, the mean milk volume was reduced by 24% from 784 ml x day(-1) in the placebo period to 623 ml x day(-1) in the pseudoephedrine period (difference between means 161 ml x day(-1) (95% CI: 63, 259 ml x day(-1)); t = 3.9, P = 0.006). Assuming maternal intake of 60 mg pseudoephedrine hydrochloride four times daily, the estimated infant dose of pseudoephedrine was 4.3% (95% CI, 3.2, 5.4%) of the weight-adjusted maternal dose. CONCLUSIONS: A single dose of pseudoephedrine significantly reduced milk production. This effect was not attributable to changes in blood flow, but depression of prolactin secretion may be a contributing factor. At the maximum recommended pseudoephedrine doses, the calculated infant dose delivered via milk was < 10% of the maternal dose, and is unlikely to affect the infant adversely. The ability of pseudoephedrine to suppress lactation suggests a novel use for the drug.

Adrenergic alpha-Agonists↗