How does pregnancy affect distribution of a drug?
In general, small-molecular-weight and lipophilic drugs readily cross the placenta. The fetus and the amniotic fluid can act as additional compartments, leading to increased drug accumulation and an apparent increase in volume of distribution of certain drugs.
Why does pregnancy increase volume of distribution?
Drug absorption is affected by slower gastric emptying and slower bowel and colonic transit time. The increased plasma volume, change in protein binding, and lower ratio of lean muscle to adipose tissue during pregnancy may result in a greater volume of drug distribution for lipophilic drugs.
What are the main physiological changes in pregnancy?
Introduction. Pregnancy and the associated changes are a normal physiological process in response to the development of the fetus. These changes happen in response to many factors; hormonal changes, increase in the total blood volume, weight gain, and increase in foetus size as the pregnancy progresses.
How mother physiology is affected during gestation period?
Progesterone causes many changes to the genitourinary system. A pregnant woman may experience an increase in the size of the kidneys and ureter due to the increase blood volume and vasculature. Later in pregnancy, the woman might develop physiological hydronephrosis and hydroureter, which are normal.
What affects drug distribution in infants?
The distribution of drugs is dependent upon body composition. Lipophilic drugs have a relatively larger volume of distribution in infants compared with older children owing to their higher comparative levels of fat (22.4% at 12 months vs. 13% at 15 years 32).
What drugs cross the placenta?
Classes of drugs that are known to cross the placenta include opiates, benzodiazepines, ephedrine, local anesthetics, beta blockers, barbiturates, and propofol. Drugs that are known to cross the placenta but are generally considered safe include propofol, ketamine, and fentanyl.
How do the following physiological changes of pregnancy affect pharmacokinetics?
Physiologic changes in pregnancy induce profound alterations to the pharmacokinetic properties of many medications. These changes affect distribution, absorption, metabolism, and excretion of drugs, and thus may impact their pharmacodynamic properties during pregnancy.
When does blood volume increase in pregnancy?
Blood volume increases significantly within the first few weeks of gestation and increases progressively throughout the pregnancy. The total blood volume increase varies from 20% to 100% above prepregnancy levels, usually close to 45%.
What are physiological changes?
Physiological changes occur with aging in all organ systems. The cardiac output decreases, blood pressure increases and arteriosclerosis develops. The lungs show impaired gas exchange, a decrease in vital capacity and slower expiratory flow rates.
Which body system of a pregnant woman shows the greatest physiological changes during pregnancy?
Pregnancy is a dynamic process associated with significant physiological changes in the cardiovascular system. These changes are mechanisms that the body has adapted to meet the increased metabolic demands of the mother and fetus and to ensure adequate uteroplacental circulation for fetal growth and development.
What are the physiological changes during first trimester?
Your body. While your first sign of pregnancy might have been a missed period, you can expect several other physical changes in the coming weeks, including: Tender, swollen breasts. Soon after conception, hormonal changes might make your breasts sensitive or sore.
What are the physiological changes during each stage of labor?
The first stage starts when labor begins and ends with full cervical dilation and effacement. The second stage commences with complete cervical dilation and ends with the delivery of the fetus. The third stage initiates after the fetus is delivered and ends when the placenta is delivered.
Why do infants absorb drugs differently?
Drug actions in infants are variable because of the infant’s physiological attributes: small body mass, high relative body water content, low body fat, greater membrane permeability of the skin, and blood-brain barrier and reduced plasma-binding abilities.
How do proteins affect drug distribution in newborns?
The newborn infant displays a continually changing plasma profile. The presence of fetal proteins and endogenous substrates known to interfere with drug binding can lead to unexpected complications due to a higher than expected ‘free’ drug fraction.
What are the six barriers of placenta?
Components of the placental barrier: In (1) maternal endothelium, (2) maternal connective tissues, (3) uterine epithelium, (4) trophoblasts, (4a) syncytiotrophoblast, (4b) cytotrophoblast, (5) fetal connective tissues, (6) fetal endothelium and (7) trophoblast giant cell.
Which antibody can pass placenta?
IgG is the only antibody class that significantly crosses the human placenta. This crossing is mediated by FcRn expressed on syncytiotrophoblast cells.
What is the volume of distribution of a drug?
Simply defined, the volume of distribution is the volume of plasma that would be necessary to account for the total amount of drug in the patient’s body, if that drug were present throughout the body at the same concentration as found in the plasma.
What are the 3 functions of the placenta?
Functions of the placenta include: Provides your baby with oxygen and nutrients. Removes harmful waste and carbon dioxide from your baby. Produces hormones that help your baby grow.
Why does blood pressure increase during pregnancy?
There are a few possible reasons for this. The amount of blood in a woman’s body increases. According to the journal Circulation , a woman’s blood volume increases by as much as 45 percent during pregnancy. This is extra blood that the heart must pump throughout the body.
What are 3 physiological changes?
Abstract. Physiological changes occur with aging in all organ systems. The cardiac output decreases, blood pressure increases and arteriosclerosis develops. The lungs show impaired gas exchange, a decrease in vital capacity and slower expiratory flow rates.
What are some physiological factors?
The physiological factors include how people feel, their physical health, and their levels of fatigue at the time of learning, the quality of the food and drink they have consumed, their age, etc.
Which hormone is not produced during pregnancy?
So, the correct answer is ‘Estrogen’.
Which physiologic change occurs in the second trimester of pregnancy?
Maternal insulin resistance begins in the second trimester and peaks in the third trimester. This is the result of increasing secretion of diabetogenic hormones such as human placental lactogen, growth hormone, progesterone, cortisol and prolactin.
What are the 3 physiological stages of labor?
Labour has three stages:
- The first stage is when the neck of the womb (cervix) opens to 10cm dilated.
- The second stage is when the baby moves down through the vagina and is born.
- The third stage is when the placenta (afterbirth) is delivered.
What are the 4 P’s of labor?
The ability of the fetus to successfully negotiate the pelvis during labor and delivery depends on the complex interactions of four variables: uterine activity, the fetus, the maternal pelvis and maternal well-being. This is also known as the four Ps: power, passage, passenger and psyche.