Free and total plasma levels of lopinavir during pregnancy, at delivery and postpartum: implications for dosage adjustments in pregnant women

BACKGROUND

Physiological changes associated with pregnancy may alter antiretroviral plasma concentrations and might jeopardize prevention of mother-to-child HIV transmission. Lopinavir is one of the protease inhibitors more frequently prescribed during pregnancy in Europe. We described the free and total pharmacokinetics of lopinavir in HIV-infected pregnant and non-pregnant women, and evaluated whether significant alterations in its disposition and protein binding warrant systematic dosage adjustment.

METHODS

Plasma samples were collected at first, second and third trimester of pregnancy, at delivery, in umbilical cord and postpartum. Lopinavir free and total plasma concentrations were measured by HPLC-MS/MS. Bayesian calculations were used to extrapolate total concentrations to trough (Cmin).

RESULTS

A total of 42 HIV-positive pregnant women and 37 non-pregnant women on lopinavir/ritonavir were included in the study. Compared to postpartum and control values, total lopinavir Cmin was decreased moderately (31-39%) during pregnancy, and free Cmin minimally, showing significant alteration only at delivery (-35%). However, total and free Cmin remained in all patients above the target concentrations for wild-type virus of 1,000 ng/ml, and above the unbound IC50(WT) of 0.64-0.77 ng/ml of lopinavir, respectively. Lopinavir free fractions remained higher during pregnancy compared to postpartum and controls, and were influenced by α-1-acid-glycoprotein and albumin decrease. Free cord-to-mother ratio (0.43) was 2.7-fold higher than total cord-to-mother ratio (0.16), suggesting higher fetal exposure.

CONCLUSIONS

The moderate decrease of total lopinavir concentrations during pregnancy is not associated with proportional decrease in free concentrations. Both reach a nadir at delivery, albeit not to an extent that would put treatment-naive women at risk of insufficient exposure to the free, pharmacologically active concentrations of lopinavir. No dosage adjustment is therefore needed during pregnancy as it is unlikely to further enhance treatment efficacy but could potentially increase the risk of maternal and fetal toxicity. Nonetheless, in case of viral resistance in treatment-experienced pregnant women, loss of virological control or questionable adherence, it is justified to consider lopinavir dosage adjustment based on total plasma concentration measurement.

Pregnant women's perception of cesarean section on demand

AIMS

To assess pregnant women's awareness of and attitudes towards cesarean section (CS) on demand, as well as to identify specific target groups by focusing on differences dependant on the participants' background, parity and intended mode of delivery.

METHODS

The study was conducted at two centers during three months. German-speaking pregnant women were invited to answer an anonymous, structured questionnaire. We compared urban vs. rural, nulliparous vs. parous and women opting for a CS vs. denying this wish, with regard to awareness and attitudes towards CS on demand.

RESULTS

Ninety-two percent of the 201 participants were aware of the possibility to deliver by CS on demand. Their sources of information were mostly print media reports, television, or friends. Pain avoidance and missing the birth experience were the main reasons for and against CS on demand, respectively. For women opting for CS on demand, traumatically-experienced previous birth and the child's well-being were other important reasons for a CS.

CONCLUSIONS

Because negative birth experience appears to be decisive for pregnant women's attitude towards CS on demand and their perception of CS seems to be partly based on misconceptions, antenatal counseling should focus on these aspects.

Previous birth experience and birth anxiety: predictors of caesarean section on demand?

OBJECTIVE

The purpose of this study was to investigate pregnant women's intentions for opting for caesarean section (CS), their experiences regarding previous births and their expectations for subsequent delivery. Our objectives were to identify medical and psychological predictors pertaining to the decision for CS on demand.

DESIGN

The cross-sectional survey was conducted at two study centres over a three-month period including German speaking women at any time of pregnancy and consisted of an anonymous structured questionnaire. Logistic regression was computed to investigate the predictive value of medical variables, birth experience and birth anxiety on the demand for CS.

RESULTS

Nineteen of 201 participants preferred to deliver by CS on demand and 15 felt uncertain about their decision. How the preceding delivery had been experienced was significantly better in the vaginal delivery (VD)-group (women not considering CS on demand) than in the CS-group (good experience in 81.7% and 52.0% respectively, p = 0.007). A negative previous birth experience and a preceding CS were predictors for the wish to deliver by CS.

CONCLUSIONS

As negative birth experience predicts the wish for a CS, specific supportive care during first pregnancy could play a pivotal role in making this decision.

Effects of chronic nicotine administration on insulin, glucose, epinephrine, and norepinephrine

There is an inverse relationship between nicotine administration and body weight. Previous research indicates that this relationship results partially from effects of nicotine on energy intake. The present research includes two animal studies designed to investigate the effects of chronic nicotine administration on biochemical responses that affect energy utilization. The results indicate that chronic nicotine administration is accompanied by significant decreases in circulating insulin levels. Nicotine increases levels of catecholamines, but this effect is short-lived. The effects of nicotine on insulin are consistent with the conclusion that nicotine administration increases energy utilization.

Effects of nicotine on body weight in rats with access to "junk" foods

The present experiment examined effects of nicotine on body weight of male and female rats when Oreo cookies, potato chips, laboratory chow, and water were available. Body weight and eating behavior were measured for 17-day periods before, during, and after nicotine or saline administration. There was an inverse relationship between nicotine and body weight. These effects were paralleled by changes in consumption of sweet foods. There were no effects of nicotine on salty or bland food consumption. Excessive gains in body weight after cessation of nicotine administration were greater for females than for males.

Sex differences in nicotine's effects on consummatory behavior and body weight in rats

Nicotine administration and cessation have greater effects on body weight and eating behavior in female than in male rats. These generalizations are based on studies of body weight and eating behavior for 2-3 week periods before, during, and after nicotine administration. Therefore, the sex differences may reflect differences in sensitivity to nicotine or simply differences in the time course of nicotine's effects. The present research was designed to replicate these previous studies and to examine long-term effects of nicotine cessation on body weight. Nicotine or saline was administered SC to female and male Sprague-Dawley rats for 16 days. Body weight, food consumption, and water consumption were measured before, during, and after nicotine administration. In addition, body weight was measured for 4 months after cessation of nicotine. There was an inverse relationship between nicotine and body weight. Also, there was an inverse relationship between nicotine and general consummatory behavior for females but not for males. The body weight of females that had received nicotine were indistinguishable from controls up to 4 months after cessation of nicotine. The body weight of males that had received 12 mg nicotine per kg per day remained lower than controls.