Module 2 Chapter 4 and 5

Question 1

Why isn’t the dose the same for each route of administration?

Answer 1

because the body “handles” the drug differently depending on the route of administration

Question 2

Pharmacodynamic effects

Answer 2

“what the drug does to the body”. Ex. does the drug make you sleepy, does it make your lungs dilate, does it treat an infection?

Question 3

Pharmacokinetics

Answer 3

“what the body does to the drug”

the measured response to time and dose (absorption, blood levels, mode of inactivation, etc. )

Question 4

Kinetic terms

The drug Cycle

Answer 4

I .Absorption
II . Distribution (plasma)
III . Metabolism
IV . Excretion
The Drug Cycle deals with the pharmacokinetic variables (absorption, Distribution, Metabolism and Excretion) 

The steps of the Drug Cycle describe how much of administered dose of drug (say, given orally) is absorbed, which body fluids it is distributed to, how long it stays in the blood before being metabolized and when, and where it is excreted.

Question 5

Absorption

Answer 5

***fraction of drug in circulation
involves the movement of a drug from the site of administration through tissues and into the blood. involves three steps:
1. Disintegrate - tablets, capsules, suppositories
2. Dissolve - dissolve by saliva, gastric juice or tissue fluid
3. Absorb - drug passes through the walls of nearby capillaries and is absorbed into the blood

Question 6

distribution

Answer 6

***how the drug partitions in the body

where the drug goes in the body

Question 7

T 1/2 (half life)

Answer 7

the time required for the serum drug level to decrease by 50%

Question 8

Metabolism

Answer 8

the way the drug is broken down

Question 9

Excretion

Answer 9

the way it is cleared from the body

Question 10

Pharmacokinetic factors

Answer 10

Bioavailability
blood level
half life
first pass effect
therapeutic index

Question 11

Albumin

Answer 11

is only one of many proteins that exist in the blood. binder of drugs floating in the plasma. some drug bind to albumin more than others

Question 12

BBB

Answer 12

BLOOD BRAIN BARRIER
exists between the cerebral capillaries and the neurons of the CNS. Some drugs cannot pass through the BBB therefore it can’t treat the disease.
***Ritalis and anesthetic drug can pass through the BBB

Question 13

Metabolism or Biotransformation

Answer 13

drug is transformed from it’s initial, usually active form to a different form (usually, but note always more inactive)

Question 14

the liver

Answer 14

IS the main organ for the metabolism of drugs
drugs that are absorbed in the gut pass through the liver first before they go anywhere else “enterohepatic circulation”
***Liver has importance function to drug metabolism.

Question 15

First Pass Effect

Answer 15

in the liver they are acted on by a series of “microsomal” liver enzymes in a “First Pass Effect”

***initial metabolism by the liver

Question 16

Oral lidocaine

Answer 16

given in huge doses (compared to how much is needed if injected into the site to be numbed) to compensate for the first pass effect.

Question 17

morphine-like opioids, nitroglycerine

Answer 17

metabolized the first time through the liver before they get into the systemic circulation

Question 18

Kidneys

Answer 18

most drugs are excreted from the body by the kidney

Question 19

Name two other ways that drugs are excreted

Answer 19

Bile - from the liver back to the GI tract
The lungs
Mothers’ milk
Saliva, Sweat and Tears

Question 20

the therapeutic effect

Answer 20

***desire clinical effect
is intended to prevent a disease, to diagnose a disease or to treat a disease by controlling, improving or curing the symptoms of the disease

Question 21

topical administration

Answer 21

Absorption
does not need to undergo disintegration, it quickly dissolved in the tissue fluids of the skin.

DO NOT complete the final step of absorption and do not go into into the blood.

Their therapeutic effect is only exerted locally at the site of administration.

Question 22

transdermal administration

Answer 22

patches
the drug in the patch reservoir begins to be released
because the drug is in the liquid form.

DO NOT need to undergo disintegration. it quickly dissolved in the tissue fluids of the skin passes through the walls of near by capillaries and it absorbed into the blood.

Question 23

Oral administration

Answer 23

drug form disintegrates, if necessary. it then dissolved in stomach or intestinal fluids then go through the last step of the absorption.

Question 24

inhalation administration

Answer 24

the vaporized lipid or gas - does not need to undergo disintegration

Question 25

Vaginal or rectal administration

Answer 25

drug form disintegrates and releases the drug topically into the vagina.

Always intended to have only a topical therapeutic effect and there is minimal absorption into the blood.

*** the rate of absorption following rectal administration is rather slow and variable.

Question 26

parenteral administration

Answer 26

following intradermal, subcutaneous, and intramuscular injections, the drug is already in a liquid form and so it quickly dissolved in the tissues fluids of the skin, passes through the walls of nearby capillaries and is absorbed into the blood.

*** IV injections entirely bypass the steps of absorption because the drug is administer directly into a vein and immediately enters the blood.

Question 27

Lidocaine (Xylocaine) -use to treat? administration route?

Answer 27

***given IV/tropical/or transdermal to treat cardiac arrhythmia. Also use for nerve block.

cannot be given orally because no active drug remains after the first pass effect.

Question 28

nitroglycerin

Answer 28

administered orally

Question 29

Elderly persons

Premature babies

Answer 29

declines in liver and kidney functions
***drug doses need to be reduced (prescribed lower doses) to compensate for the prolonged action of un-metabolized drug in the blood and to prevent toxicity from high levels of drug.

Question 30

Excretion

Answer 30

Kidney, saliva, tears, sweat and breast milk
the body get rid off waste products (inactive drug metabolites) and removing active drugs that are not metabolized by the liver.

Question 31

All of these administration routes…except the I.V. parenteral route, I.M parenteral route

Answer 31

must be “absorbed” and pass through some type of membrane or tissue into the blood and then into the target cells.

Question 32

The amount absorbed determines the “bioavailability of the drug

Answer 32

the administered dose of unchanged drug that reaches the systemic circulation

Question 33

sometimes we don’t want the drug absorbed systemically (throughout the body)

Answer 33

Bowel sterilization pre-surgery (neomycin-an antibiotic that is not absorbed-only effects the gut)

Vaginal administration (Premarin-hormone replacement for vaginal tissue, or anti yeast creams)

Rectal route (analgesics for hemorrhoids)

Carafate (anti ulcer drug-binds exposed proteins of ulcer

Question 34

morphine -oral dose vs parenteral dose

Answer 34

must be given in higher doses orally than parenterally because of the first pass metabolism.

Question 35

Chloral-hydrate

Answer 35

does not induce sleep until it is metabolized int he liver to a more active form