Module 1

Question 1

What is pharmacokinetics?

Answer 1

the study of how drugs move in the body

Question 2

What are the 4 components pharmacokinetics?

Answer 2

1. Absorption
2. distribution
3. metabolism
4. excretion

Question 3

What is passive transport?

Answer 3

moving form high to low concentration -> drugs are small, non-ionized and lipid soluble

Question 4

What is active transport?

Answer 4

moving from against concentration gradient, required energy ATP -> drugs are larger ionized and non-lipid soluble

Question 5

What is fast onset (IV) in absorption?

Answer 5

fast absorption

Question 6

What is slow onset (IM) in absorption?

Answer 6

slow absorption

Question 7

What are the three routes of administration in absorption?

Answer 7

1. Enteral route = delievered to GI tract throught -> PO. cheek, SL, NG, rectal
2. Topical route = delivered to mucous membranes = slower absorption
3. Parental route = anything other than enteral/topical -> IV, IM, SC, IP, bone, spinal cord

Question 8

What does drug ionization in absorption mean?

Answer 8

• ionized = positive/negative charge

- non-ionized = no charge

Question 9

What are two types of drug interactions in absorption?

Answer 9

1. drug-drug interaction = tetracycline capsule + carbonate (CaCO3) > delays absorption
2. drug-food interaction = high fat meal + carbamazepine > higher rate of absorption

Question 10

What does bioavailabilty mean in absorption?

Answer 10

The fraction of an administered dose of an unchanged drug that reaches the site of action (F)

Question 11

What is drug distribution?

Answer 11

describes how are transported throughout the body

Question 12

What is drug solubility in distribution?

Answer 12

drug solubility is the ability for a drug to cross the plasma membrane.

• lipid soluble = easier to cross plasma membrane
• water soluble = has more barriers

Question 13

What are blood brain barriers in distribution?

Answer 13

protect the brain from toxic substances/pathogens, levodopa used in place of dopamine = pro drug.

Question 14

What is the fecal placental barrier in distribution?

Answer 14

protects the baby from harmful substances/pathogens but not as efficient as the blood brain barrier.

Question 15

What is metabolism?

Answer 15

the process of changing the activity of a drug and make it more likely to be excreted

Question 16

What is a prodrug in metabolism?

Answer 16

it is a metabolite that is more active than the original molecule

Question 17

What is a hepatic enzyme in metabolism?

Answer 17

cytochrome P450 system (CYP450) -> responsible for most metabolism of drugsm nutrients and endogenous susbtances. Changes in enzyme activity after drug actions. the result of the change depends on whether the drug is a substrate, an inducer or an inhibitor of the CYP450 system.

Question 18

6 parts of the CYP450 system in metabolism?

Answer 18

1. Substrate = substance on which an enzyme acts when a drug is metabolized by CYP450 enzyme
2. Enzyme inducer = drug speeds up the metabolic activity
3. Enzyme inhibitor = drug that has the ability to decrease metabolic activity. End result = less active property and more inactive property
4. Drug = metabolized by enzymes = inactive metabolite
5. Prodrug = metabolized by enzymes = active metabolite
6. First-past effect = important mechanism of metabolism

Question 19

What is patient variation in metabolism?

Answer 19

• Patients with liver disease have lower hepatic enzyme
• smoking and chronic alcohol consumption can induce hepatic enzyme = may require higher doses
• Genetic variations cause “slow metabolizers” and “fast metabolizers”
• Pharmacogenomics = customize therapy to DNA

Question 20

What is excretion?

Answer 20

The process of removing drugs from the body through; renal, pulmonary or glandular excretion.

Question 21

What are time-response relationships in excretion?

Answer 21

the therapeutic response most drugs depend on their concentration in the plasma

Question 22

What is plasma half-life (t 1/2) in excretion?

Answer 22

• the length of time required for a drugs concentration to decrease by 1/2 (1-2 minutes to months). Drugs with longer half-lives are better for chronic conditions
• it takes approximately 4/-5 t1/2 before the drug is considered eliminated (94% gone)

Question 23

What is maintaining therapeutic range in excretion?

Answer 23

• most conditions required repeated dosing in order to keep drug plasma within the therapeutic range
• we reach plateau in approximately 4 t1/2 of the drug if we give equal dose

Question 24

What are loading and maintenance doses in excretion?

Answer 24

• loading dose = allows us to reach plateau levels faster with larger dose
• maintenance dose = allows us to maintain a certain level of dose