exam 1 Flashcards
Refers to movement of a drug across body membranes to reach its target organ (how the body processes it - how it moves to one place to another)
Liver, kidneys and intestines process most of them
Four stages of drug movement:
•1. Absorption
•2. Distribution
•3. Metabolism
•4. Excretion
Pharmacokinetics
time required for a drug’s plasma concentration to decrease by 50% (how long it takes to decrease by 50%)
half life
Refer to drug levels that provide adequate action but minimal adverse effects (how much should we give)
therapeutic drug levels
Refers to unwanted or potentially harmful drug effects
•All drugs have one or more adverse reactions in addition to producing a desired effect
•Can be dose-related or sensitivity-related
adverse reactions
reaction that occurs when drug levels exceed the therapeutic range, possibly causing additional adverse effects.
toxicity
Any environmental substance that can cause birth defect or may halt the pregnancy outright. •Radiation •Maternal infections •Chemicals •Drugs
teratogens
- Developmental disorders
- Structural malformations
- Spontaneous abortions
- Intrauterine growth restriction
- Reversible functional postnatal effects
- Sedation, hypoglycemia, bradycardia and withdrawal
- Central nervous system disorders
- Learning disabilities, immunological and fertility and reproductive disorders
- Effects may manifest at birth but may not appear up to age 5 years of age (esp. developmental)
Teratogenic outcomes
U.S. Food and Drug Administration Medication Categories are based on risk to a fetus:
•Category A: Controlled studies showed no risk to the fetus or there were no studies performed on pregnant women. (safe - Tylenol)
•Category B: Animal studies showed no risk to the fetus or there were no studies performed on pregnant women. (overall safe meds)
•Category C: Either animal studies showed adverse effects to the fetus or no studies in women or animals are available. (iffy but safe - mag sulfate)
pregnancy considerations
- Category D: Adverse effects have been demonstrated on human fetuses based on data from investigational or marketing experience, but use of the medication during pregnancy may be warranted based on potential benefits. (worth the risk if severe - zolfran prevents nausea)
- Category X: Fetal risk has been shown in animals and in women. Drug is contracted in women who are or who may become pregnant because the risks outweigh the potential benefits. (never give due to risk of baby - DES is estrogen to prevent N/V but cause birth defects)
- Category NR: No rating is available.
more pregnancy considerations
- Maternal organs influenced by pregnancy hormones:
- Estrogen - fluid retention so extra blood volume retention
- Progesterone - makes lining thick and luscious
- Human Placental Lactogen - breast feeding - cause insulin resistance
- Human Chorionic Gonadotropin
- Prolactin
more pregnancy considerations (3)
- Physiologic changes during pregnancy caused by:
- Cardiovascular
- 50% increase in volume leads to increased concentration of unbound drug
- Approximately 8 liter increase in total body water
- Kidney
- Increase glomerular filtration leads to greater amount of medication excreted
- Liver
- Increase in hepatic function leads to increased in drug metabolism
- Gastrointestinal tract
- Slowed peristalsis
- Increased water absorption from large intestine
more preg considerations (4)
- Develops during embryonic stage and matures during fetal stage.
- One purpose is to filter i.e. certain bacteria.
- Not an effective filter –smaller particles (herpes), airborne toxins, drugs, medications or other potential teratogens can effect developing baby.
- Rule of Thumb: Any medication administered to a pregnant woman will be administered to the fetus.
placenta
- Less than 1% of maternal dose passes to newborn so few side effects to newborn
- Antimetabolites and therapeutic radiopharmaceuticals are contra-indicated during lactation (cancer therapy)
Lactation
has highest incidence of drug induced developmental defects due to the body forming and growing at a very rapid rate.
first trimester
the largest percentage of drugs goes to the fetus, due to:
•Enhanced blood flow - all organs are created by baby is still receiving too much meds
•Increased surface area
•Thinner membranes separating maternal blood and fetus blood
•Increased amount of free drug in the mother’s circulation
third trimester
