Week 2 Flashcards
Onset of action
The first sign of therapeutic effect on the drug concentration curve.
The first sign of therapeutic effect on the drug concentration curve.
Onset of action
Peak level
Highest concentration of a drug in the system. Make sure the therapeutic level is reached without being toxic.
Highest concentration of a drug in the system. Make sure the therapeutic level is reached without being toxic.
Peak level
Has a protective function. Made up of a single layer of epithelial cells, tight junction if epithelial cells. Astrocytes surround capillaries to prevent unwanted molecules from getting from the capillaries into the CSF. to enter the CSF, molecules have to be small, lipid-soluble, lower iconic charge, same pH as CSF.
Blood-brain barrier
Has a protective function. Made up of a single layer of epithelial cells, tight junction if epithelial cells. Astrocytes surround capillaries to prevent unwanted molecules from getting from the capillaries into the CSF. to enter the CSF, molecules have to be small, lipid-soluble, lower iconic charge, same pH as CSF.
Blood-brain barrier
Barrier between maternal and fetal blood flow.
Delivers nutrients but protects from pathogens, drugs, and the mother’s immune system. Has few intercellular bridges (cell junctions) which prevents things from passing the barrier.
Sugars, fats, I2, antibodies, and CO2 can still pass the barrier.
Fetal placental barrier
Can cause a buildup of renally-excreted drugs.
Renal insufficiency
Use of FDA-approved drug in a dose or route for which it was not approved or for a clinical condition other than the FDA-approved use.
Off-label prescribing
Gastric ph does not reach adult level until 1. If an acidic environment is needed for absorption, less will be absorbed by infants.
Greater BSA. Greater absorption of topical meds
Infant skin more permeable. More absorption of topical meds.
Immature peripheral circulation. Prevents absorption of IM or SQ meds.
Pediatric absorption
CYP3A7:
cytochrome P450. The earliest isoenzyme to show activity. Present in utero and rapidly decreases after birth. Then CYP3A4 and 5 increase after 6 mo.
Phase 1 Metabolism in pediatrics
Neonate or preterm infant has immature kidneys. Reduced GFR and decreased tubular secretion and reabsorption during the first 6 months leads to extended 1/2 life.
3 months: kidneys concentrate urine at the adult level, but urinary excretion is low until approximately 30 mo.
Monitor drug doses and therapeutic blood levels to prevent toxicity.
Pediatric excretion
A: controlled studies in prefers and no risk.
B: animal studies show no risk. No pregnant human studies.
C: animal studies show no risk. No human studies. Benefits might outweigh risks.
D: risk; benefit might outweigh risk in serious situation.
X: demonstrated fetal abnormalities; risk outweighs benefit; should not be used.
FDA pregnancy categories
Progesterone decreases gastric tone and mobility. Prolonged stomach emptying time. Alters pharmacokinetics of oral meds.
Progesterone promotes respiratory changes. Increased tidal volumes, increased pulm vasodilation, inhaled drug absorption increased.
Absorption in pregnancy
HR increases 10-15 bpm
50% inc in blood vol causes hemodilution of albumin to potentiate drug distribution.
Plasma lipid levels increase altering drug transport and distribution.
Drugs compete for receptor sites occupied by hormones resulting in more unbound free drug.
Drugs that are not lipophilic enter fetal circulation
Drug metabolism is not affected by pregnancy or lactation.
Distribution and metabolism in pregnancy
Drugs with increased lipid solubility and low protein binding such as CNS agents pass easily into breast milk.
Drugs of low molecular weight pass into milk
Low pH produce high concentrations
Distribution during lactation
Polypharmacy: taking multiple meds with multiple interaction and ADRs at the same time.
Multiple prescribers= multiple drugs
Physical body changes: inc proportion of body fat, inc cardiovascular effects, reduces renal function, inc effect of drugs on the CNS.
Drug therapy and the geriatric patient
Overall slowed drug absorption related to decreases gastric acidity, GI motility, and reduced blood flow.
Decrease gastric acid: drugs requiring an acidic environment to dissolve with take longer to be absorbed. Decreases systemic availability
Reduced blood flow to organs decreasing drug absorption
Decreases blood flow, so dec absorption at IM or SQ site.n
Absorption in the geriatric populatio
Decreases drug distribution: decreased body mass, reduced albumin, less effective blood-brain barrier, dec cardiac output, changes in body weight, poor nutrition, dehydration, inactivity, bedrest
Drug distribution in the elderly
Liver size declines and there is a decrease in hepatocytes.
The liver’s capacity to remove metabolic byproducts is reduced.
Aging effects the efficacy of Phase 1 end phase metabolism. Slowed metabolism, reduced oxidation, increased drug blood levels, extended 1/2 lives.
Drug metabolism in the elderly
Phenobarbital
Phenytoin
Methylxanthines
Drugs requiring oxidation for metabolism
Can have decreases renal function, GFR, and renal tubular excretion.
Creatine levels may remain normal despite decreased GFR levels.
Less Creatine levels in general because of less body mass.
Drug excretion in geriatric patients
High doses may interfere with cardiac, antidiabetic, or anticoagulant therapy.
Ginger
Increase effect of MAO inhibitors, antihypertensives, and hypoglycemics.
Interferes with action of steroids.
Red ginseng may increase CNS stimulant effects of coffee or tea.
Ginseng
Interferes with hypoglycemic therapy
May potentiate antithrombotic therapy
May increase bleeding and clotting times with antiplatelet or anticoagulant therapy
Garlic
Hypersensitivity responses.
Small drugs are not immunogens.
Drugs act as happens (bind covalently with a protein to trigger an immune response)
Four types of hypersensitivity responses.
Allergic reactions
Results from production of IgE after exposure to an antigen.
Urticaria, wheezing, rhinitis, anaphylaxis.
Type 1 hypersensitivity response
Occurs when drug binds to cells (RBCs) and is recognized by an antibody, usually IgG.
Complement and cytotoxic T cells are activated
This response is rare
Type II hypersensitivity response
