Module 5 Excretion Flashcards
1
Q
Excretion Sites
A
- Kidney
- Bile
- Lung
- Breast milk
2
Q
Renal Excretion
A
- Majority of drug excretion
- Limit duration & intensity of effects (healthy kidneys)
3
Q
Nephron Regulated Substances
A
- Water
- Electrolyte
- Drug
4
Q
Nephron Regulated Processes
A
- Blood volume
- Blood pressure
- pH
- Solute (drug) excretion
5
Q
Affecting Factors of Renal Excretion
A
- Glomerular filtration
- Tubular secretion
- Tubular reabsorption
6
Q
Glomerular Filtration
A
- Enter through renal artery
- Low molecular drugs into renal tubules (hydrostatic pressure)
- Lipid solubility & pH have no effect
- Non-protein bound drugs ONLY
7
Q
Glomerular Filtration Rate
A
- 120mL/min/1.73m2
- 20% total plasma flow
8
Q
Tubular Secretion
A
- Unfiltered drugs leave via efferent arteriole
- Form capillaries around proximal tubule
- Drugs secrete from blood into tubules
- Systems for weak acid & base
9
Q
Tubular Reabsorption
A
- Drug concentration increases towards distal tubule
- Loop of Henle concentrates tubular substances
- Drug conc > blood conc (distal tubule)
- Uncharged/lipid soluble reabsorbed into blood
10
Q
Effects of Aging (Infants)
A
- Low kidney function
- GFR of infants 40/mL/min/1.73m2
- Kidney function reaches normal adult at 2 yrs
11
Q
Effects of Aging (Elderly)
A
- Decreased renal function
- Decreased drug excretion
12
Q
Billary Drug Excretion
A
- Bile, feces excretion
- Molecular weight greater than 300 Da
- Polar & lipophilic
- Glucuronidated
13
Q
Billary Transport
A
- Transporters on canalicular membrane of hepatocytes
- Move drugs/metabolites from liver into bile
14
Q
P-GP Role in Excretion
A
- Transports amphipathic drugs into bile
15
Q
MRP2 Role in Excretion
A
- Transports glucuronidated metabolites into bile
16
Q
Drugs Released in Bile
A
- Released into intestine
- During digestion
17
Q
Drugs Released in Intestine
A
- Excreted into feces
- Enterohepatic recycling
18
Q
Enterohepatic Recycling
A
- Drugs & conjugates excreted in bile
- Enter intestinal lumen
- Intestinal bacteria CAN conjugate or leave drug
- Original drug may be reabsorbed intestinally
- Drugs persist in body longer
19
Q
Pulmonary Drug Excretion
A
- Gaseous/volatile drugs
- Not reliant on drug metabolism
20
Q
Affecting Factors of Pulmonary Excretion
A
- Respiration rate
- Cardiac output
- Solubility of drug in blood (high solubility = low excretion)
21
Q
Breast Milk Excretion
A
- Prevents infant exposure
- Breast cancer resistance protein transports drugs
22
Q
Breast Excreted Drug Composition
A
- Low protein binding
- Low molecular weight
- High lipophilicity
23
Q
Breast Milk Composition
A
- Lower pH
- High lipid concentration
24
Q
Hair Excretion
A
- Hair follicles
- Determine drug exposure time based on hair length
- Hair grows 1cm/month
25
Q
Saliva Excretion
A
- Swallowed
- Intestinal absorption/fecal excretion
26
Q
Sweat Excretion
A
- Washed away
- Dermal reabsorption (minimal)
