Pharmacokinetics A and D

Question 1

Quantitative description of the time course of drug distribution in the body

Answer 1

Absorption
o Distribution
o Biotransformation [metabolism]
o Excretion

Question 2

Ethyl alcohol absorption

Answer 2

Small intenstine most 75-80%
stomach 20-25%
colon negibile

Question 3

How is ethyl alcohol absorbed

Answer 3

through mucosal surfaces of the GI tract
-simple difussion

Question 4

Ficks Law

Answer 4

Rate is proportional to the concentration gradient of alcohol across a membrane and to a diffusion coefficient that is constant for ethyl alcohol and specific membrane

Question 5

Factors Affecting absorption

Answer 5

Food, concentration and dose, physiology and drugs

Question 6

How does food affect absoprtio

Answer 6

reduced efficiency of absorption due to prolonged gastric emptying time
Reduces and shifts the right
Isn’t released into small intestine since small intestine is closed to absorbed food

Question 7

Time to peak Alcohol concetration

Answer 7

Fasting .5-2 hours
nonfasting 1-3 hrs

Question 8

What has impact with food on alcohol

Answer 8

Directly proportional to size of meal
Indirectly proportion to elapsed time from food intake and alcohol consumption
reduction in Cpmax 9-23%

Question 9

Time to peak alcohol concetration

Answer 9

Peak generally occurring in less than 30 minutes
Winek et al

Question 10

Variation in BAC after last drink

Answer 10

Gullberg and Predmore
Mean time to reach peak BAC, with and without food was 19 minutes
Breen et al (1998)
Avg time to peak after one for the road: 16 – 20 minutes

Question 11

Concentration and dose

Answer 11

Alcohol is most rapidly absorbed when the concentration is between 10 – 30%

Question 12

Concentration dilute solutions

Answer 12

Result in a lower concertation gradient across the absorbing membrane
Larger volume may delay gastric emptying

Question 13

concentration solution grater

Answer 13

irritating to the gastric mucosa and pyloric sphincter
Causing increased secretion of mucosa and delayed gastric emptying
Tripling the dose from 0.4 to 1.2 g/kg of alcohol, produces a 79% increase in time required to achieve peak BAC in fasting subjects and a 61% increase in non-fasting subjects

Question 14

Physiology and drug

Answer 14

Changes in motility, blood supply, or morphology of the GI tract
Whether induced by internal or external factors, may result in a significant change in the rate of absorption of ethyl alcohol

Question 15

Physiologoy increasing abosrption

Answer 15

Increased GI motility
Chronic gastritis or ulcers
Cholinergic
Increase GI blood flow
Chronic gastritis
Ingestion of warm liquids/food
Accelerated emptying
Ingestion of carbonated liquids
Chronic alcoholism
Gastrectomy (gastric by-pass)

Question 16

Physiology decreasing absorption

Answer 16

Decreased GI motility
Nausea (exclusive of vomiting)
Shock
Anticholinergics
Decreased GI blood flow
Fear, pain
Sympathomimetics
Delayed gastric emptying
Gastric fibrosis
Carcinomatosis
Smoking cigarettes

Question 17

Bariatric Surghery-gastric by pass

Answer 17

Most efficient method to tx morbid obesity
Complaints of increased sensitivity of reduced tolerance to EtOH as compared to pre-surgical state
Reduction in body weight [20 – 40% within 1-2 years]
Increased dose per Kg of body weight
Rapid absorption of EtOH
Higher Cmax
Earlier Tmax

Question 18

Is alcohol hydrophilic or hydrophobic

Answer 18

hydrophilic–

Question 19

Volume of Distribution

Answer 19

Volume of distribution is and expression of the total body water
Variability due to adiposity
Vd of alcohol decreases with age
Volume of Distribution
Males: 0.7 L/kg avg. 0.62-0.70 (.59-.9)
Females: 0.6 L/kg avg. .55-.66(.46-.86)

Question 20

Blood-tissue ratio

Answer 20

Whole blood consists mainly of water with red/white cells, proteins, lipids
DUI-whole blood
Hospital test on serum/plasma which runs higher