NSG 511 Exam 1 Questions With Correct
Answers
Pharmacokinetics
The |movement |of |a |drug |in |the |body
How |to |get |into |(absorption |and |distribution), |through |(metabolism) |and |out |(excretion) |of |the
|body.
Absorption
The |movement |of |a |drug |from |its |site |of |administration |into |the |blood.
Ex: |from |GI |tract |through |membrane |to |blood
Distribution
The |movement |of |the |drug |from |bloodstream |to |interstitium |to |cells
1. |Need |adequate |blood |flow
2. |Has |to |exit |the |vasculature
3. |Blood |brain |barrier |(hard |to |get |into |brain)
4. |Placenta |(if |lipid |soluble |drug, |it |will |cross |membrane |and |enter |fetal |circulation)
,Metabolism
The |chemical |alteration |of |the |drug, |usually |by |the |liver, |in |preparation |for |excretion
1. |metabolizing |enzymes |(cytochrome |P450) |chemically |alter |the |drug
2. |hepatic |enzymes |convert |drug |from |lipid |to |polar/water |form |in |preparation |for |renal |
excretion
Excretion
The |removal |of |drugs |from |the |body, |typically |by |the |kidneys.
What |is |the |structure |of |the |membrane |that |the |drug |must |cross |at |every |step |of |
pharmacokinetics?
Lipid |bilayer |(separates |one |tissue |from |another)
How |does |a |drug |cross |a |membrane?
1. |Channels |and |pores |(holes |in |the |membrane)
2. |Transport |systems |to |move |drugs |across |membranes |into |and |out |of |the |body |(ⓣ |= |into |
body, |or |P-glycoprotein |transporters |= |out |of |body)
3. |Direct |membrane |penetration |(drug |must |be |lipid |soluble)
,What |are |the |barriers |to |a |drug |crossing |a |membrane?
1. |Polar |state |(molecule |with |an |uneven |distribution |of |charges |but |no |net |charge |[like |
dissolves |like])
2. |Ionization |(molecules |with |a |net |charge; |drugs |in |an |ionic |form |will |not |cross |a |lipid |
membrane |easily |
Polar |state
Molecules |with |an |uneven |distribution |of |charges |but |no |net |charge. |
Ex: |water |(polar) |will |not |dissolve |in |oil |(like |dissolves |like)
Polar |molecules |with |not |cross |the |lipid |membrane.
Ionization
Ions |are |molecules |with |a |net |charge. |Drugs |in |an |ionic |form |will |not |cross |a |lipid |membrane |
easily. |
Most |drugs |are |in |a |weak |acid |or |weak |base |form |and |ionize |easily |when |in |an |environment |
opposite |the |pH |of |the |drug.
, Acids |ionize |in |bases |and |bases |ionize |in |acids.
Which |drugs |will |cross |a |membrane |easily?
Non-ionized |drugs |and |non-polar |drugs
Acid |drug |in |an |acid |environment |(since |it |doesn't |ionize |-- |an |acid |drug |in |a |basic |
environment |will |ionize |and |cannot |cross |the |GI |membrane |to |get |into |the |blood |stream)
Aspirin |re |acidity
Aspirin |is |an |acid |drug, |which |is |irritating |to |the |GI |mucosa |and |causes |gastritis |and |ulceration.
|Patients |who |take |aspirin |are |advised |to |take |it |with |food |(increases |the |pH |of |the |stomach) |
and |with |a |full |glass |of |water |(speeds |it |to |the |small |intestine)
The |stomach |lining |is |protected |but |less |drug |is |absorbed |which |isn't |a |problem |because |the |
surface |area |of |the |small |intestine |is |really |large |compared |to |the |stomach |and |some |drug |will
|be |absorbed.
Factors |affecting |absorption |across |a |membrane
Liquids |increase |absorption |since |they |are |not |broken |down, |solids |decrease |absorption |
because |they |have |to |be |broken |down
Large |surface |area |increases |absorption
Answers
Pharmacokinetics
The |movement |of |a |drug |in |the |body
How |to |get |into |(absorption |and |distribution), |through |(metabolism) |and |out |(excretion) |of |the
|body.
Absorption
The |movement |of |a |drug |from |its |site |of |administration |into |the |blood.
Ex: |from |GI |tract |through |membrane |to |blood
Distribution
The |movement |of |the |drug |from |bloodstream |to |interstitium |to |cells
1. |Need |adequate |blood |flow
2. |Has |to |exit |the |vasculature
3. |Blood |brain |barrier |(hard |to |get |into |brain)
4. |Placenta |(if |lipid |soluble |drug, |it |will |cross |membrane |and |enter |fetal |circulation)
,Metabolism
The |chemical |alteration |of |the |drug, |usually |by |the |liver, |in |preparation |for |excretion
1. |metabolizing |enzymes |(cytochrome |P450) |chemically |alter |the |drug
2. |hepatic |enzymes |convert |drug |from |lipid |to |polar/water |form |in |preparation |for |renal |
excretion
Excretion
The |removal |of |drugs |from |the |body, |typically |by |the |kidneys.
What |is |the |structure |of |the |membrane |that |the |drug |must |cross |at |every |step |of |
pharmacokinetics?
Lipid |bilayer |(separates |one |tissue |from |another)
How |does |a |drug |cross |a |membrane?
1. |Channels |and |pores |(holes |in |the |membrane)
2. |Transport |systems |to |move |drugs |across |membranes |into |and |out |of |the |body |(ⓣ |= |into |
body, |or |P-glycoprotein |transporters |= |out |of |body)
3. |Direct |membrane |penetration |(drug |must |be |lipid |soluble)
,What |are |the |barriers |to |a |drug |crossing |a |membrane?
1. |Polar |state |(molecule |with |an |uneven |distribution |of |charges |but |no |net |charge |[like |
dissolves |like])
2. |Ionization |(molecules |with |a |net |charge; |drugs |in |an |ionic |form |will |not |cross |a |lipid |
membrane |easily |
Polar |state
Molecules |with |an |uneven |distribution |of |charges |but |no |net |charge. |
Ex: |water |(polar) |will |not |dissolve |in |oil |(like |dissolves |like)
Polar |molecules |with |not |cross |the |lipid |membrane.
Ionization
Ions |are |molecules |with |a |net |charge. |Drugs |in |an |ionic |form |will |not |cross |a |lipid |membrane |
easily. |
Most |drugs |are |in |a |weak |acid |or |weak |base |form |and |ionize |easily |when |in |an |environment |
opposite |the |pH |of |the |drug.
, Acids |ionize |in |bases |and |bases |ionize |in |acids.
Which |drugs |will |cross |a |membrane |easily?
Non-ionized |drugs |and |non-polar |drugs
Acid |drug |in |an |acid |environment |(since |it |doesn't |ionize |-- |an |acid |drug |in |a |basic |
environment |will |ionize |and |cannot |cross |the |GI |membrane |to |get |into |the |blood |stream)
Aspirin |re |acidity
Aspirin |is |an |acid |drug, |which |is |irritating |to |the |GI |mucosa |and |causes |gastritis |and |ulceration.
|Patients |who |take |aspirin |are |advised |to |take |it |with |food |(increases |the |pH |of |the |stomach) |
and |with |a |full |glass |of |water |(speeds |it |to |the |small |intestine)
The |stomach |lining |is |protected |but |less |drug |is |absorbed |which |isn't |a |problem |because |the |
surface |area |of |the |small |intestine |is |really |large |compared |to |the |stomach |and |some |drug |will
|be |absorbed.
Factors |affecting |absorption |across |a |membrane
Liquids |increase |absorption |since |they |are |not |broken |down, |solids |decrease |absorption |
because |they |have |to |be |broken |down
Large |surface |area |increases |absorption
