Pharm 2.

Question 1

Which types of drug pass through membranes most easily?

Answer 1

small, non charged

Question 2

Why do most drugs need to be water soluble?

Answer 2

to be dissolved int eh gastrointestinal fluid or carried by plasma

Question 3

What happens with protein bound drugs?

Answer 3

unable to cross capillary membrane

Question 4

What helps decided the portion of ionized/non-ionized drugs?

Answer 4

pH

Question 5

What type of drugs cannot diffuse across membranes?

Answer 5

ionized (charged)

Question 6

Henderson-Hasselbach Equation

Answer 6

pH = pKa + log A-/HA

Question 7

Weak acid drug

Answer 7

easily absorbed by GI tract - can be given as a pill to be swallowed

Question 8

Weak base drug

Answer 8

weak absorption in GI tract, pill form not good (because charged in acid environment)

Question 9

enteral

Answer 9

drug administration that uses a portion of GI tract

Question 10

parenteral

Answer 10

drug administration that does not use the GI tract

Question 11

enteral routes

Answer 11

oral, rectal, sublingual

Question 12

parenteral routes

Answer 12

intravenous, intraarterial, intramuscular, subcutaneous, intrathecal, topical, inhalation

Question 13

oral advantages

Answer 13

ease, safety, self-administration, cheap, prolonged absorption causing prolonged effect

Question 14

oral disadvantages

Answer 14

absorption may be too slow, absorption often variable and unpredictable, drug may be too irritating, destroyed by gastric acid/enzymes, completely metabolized on first pass through liver - not available for comatose, vomiting patients

Question 15

rectal advantages

Answer 15

useful for infants, comatose, vomiting patients; useful for foul-smelling distasteful drugs; useful for drugs destroyed in upper GI, avoids immediate metabolism by liver!, for local action in rectum

Question 16

rectal disadvantages

Answer 16

nuisance, poor compliance, absorption may be erratic, incomplete, possibility of rectal irritation

Question 17

sublingual advantages

Answer 17

by-passes liver when first absorbed, rapid absorption

Question 18

sublingual disadvantages

Answer 18

drugs must be soluble in saliva, not too distasteful, have appropriate pKa for rapid absorption, tablets must be small

Question 19

intravenous advantages

Answer 19

rapid effect, can watch response and titrate drugs!, all dose enters circulation, when oral route not available, for drugs given in large volume, for drugs too irritating when given IM or SC, for infusion and continuous monitoring, parenteral administration of hypertonic solutions possible

Question 20

intravenous disadvantages

Answer 20

cost, skill, danger of infection, possible anaphylactic reaction, danger of embolus formation, danger of adverse cardiovascular effects if administration too rapid, pain

Question 21

intraarterial advantages

Answer 21

administration of radiopaque material for visualization of circulatory tree, high concentration of drug going to local area when available

Question 22

intraarterial disadvantages

Answer 22

same as IV: cost, skill, danger of infection, possible anaphylactic reaction, danger of embolus formation, danger of adverse cardiovascular effects if administration too rapid, pain

Question 23

intramuscular advantages

Answer 23

when oral route not available, absorption less variable than oral, may be less painful than SC, absorption more rapid than SC, possibility of slowing absorption to prolong effect

Question 24

intramuscular disadvantages

Answer 24

pain, sterile technique, possible local necrosis, lag period before effect onset, accident IV injection possible, not to be used after anticoagulant

Question 25

subcutaneous advantages

Answer 25

absorption usually slower than after IM and effect more prolonged, same as IM: when oral route not available, absorption less variable than oral, may be less painful than SC, absorption more rapid than SC, possibility of slowing absorption to prolong effect

Question 26

subcutaneous disadvantages

Answer 26

same as IM: pain, sterile technique, possible local necrosis, lag period before effect onset, accident IV injection possible, not to be used after anticoagulant

Question 27

intrathecal advantages

Answer 27

(introduction of drug into cerebral spinal space): when local effect on CNS required

Question 28

intrathecal disadvantages

Answer 28

skill, danger of spinal cord injury

Question 29

topical advantages

Answer 29

for local action on or under skin/membrane, non invasive

Question 30

topical disadvantages

Answer 30

difficulty of absorption through skin, danger of excessive absorption through membranes and systemic toxicity

Question 31

inhalation advantages

Answer 31

rapid absorption for systemic action(lots of surface area in lung), high concentration attainable for local effect, self administration possible

Question 32

inhalation disadvantages

Answer 32

possible excessive absorption and systemic toxicity, poor regulation of dosage, irritation of pulmonary

Question 33

which administration of drugs has most free drug molecules in plasma?

Answer 33

IV

Question 34

which administration of drugs has the most sustained plasma level?

Answer 34

oral

Question 35

bioavailability

Answer 35

fraction of dose available for biologic action (oral drug administration has “first pass” effects - how much of drug actually reaches circulation)

Question 36

how is bioavailability measured?

Answer 36

area under the curved for the oral dose form vs the intravenous dose form (AUC oral / AUC iv)

Question 37

What can be a problem with generic drugs?

Answer 37

chemical equivalence does not necessarily equal biological equivalence!! (the generic might not have as much bioavailability)

Question 38

What is the equation to predict plasma concentration of a drug?

Answer 38

Cp = Dose/Vd (volume of distribution)

Question 39

How does the plasma concentration equation change if there are significant limitation in bioavailability?

Answer 39

Cp = (F x Dose) / Vd F = fraction absorbed

Question 40

What is often the limiting step of for achieve a desired plasma level of a drug given orally?

Answer 40

dissolution

Question 41

When is it esp. important to predict plasma concentration of a drug?

Answer 41

1. drugs that are potent in small doses 2. drugs given for serious illnesses 3. changes in drug manufacturer

Question 42

What factors affect absorption of enteral drugs?

Answer 42

form of drug, food in stomach, illness, blood flow to GI

Question 43

What is the order of fastest absorbed enteral drugs?

Answer 43

solution > suspension > capsule > tablet > timed release

Question 44

Why is blood flow important to consider in speed of absorption of enteral drugs?

Answer 44

if someone is in shock, they won’t have blood flow to GI tract thus no absorption. you want to avoid orally given pills when someone is in shock

Question 45

What factors affect absorption of parenteral drugs?

Answer 45

blood flow (need blood flow to area of administration), heat, cold, illness, form of drug

Question 46

What is the predominant influence of the absorption of parenteral drugs?

Answer 46

blood flow

Question 47

How does heat/cold affect absorption of parenteral drugs?

Answer 47

cold slows absorption of toxins/drugs while heat increases absorption and muscle activity