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43 Cards in this Set
- Front
- Back
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1. What factors determine the amount of drug present at its active site at any one time?
Five things... |
1. Route of drug administered
2. Absorption 3. Distribution 4. Biotransformation (metabolism) 5. Excretion |
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2. What are the two types of pharmocological responses to a drug?
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1. Therapeutic
2. Adverse reactions |
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3. What are six adverse reactions to drugs?
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1. Side effects
(any effect other than therapeutic 2. Toxic (tissue pathology) 3. Idiosyncratic (unusual affect of drug) 4. Hypersensitivity (i.e. penicillin) 5. Lethal 6. Placebo |
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4. What is pharmacokinetics?
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How the body handles a drug or movement of drug through body
**what body does to drug **absorption, distribution, biotransformation, excretion |
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5. What is pharmacodynamics?
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Interactions between drug and biological system leading to a series of events resulting in a pharmacological response
**What drug does to body |
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6. What are the three main routes of adminstration for a drug?
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1. Enteral (i.e. oral)
*involves GI tract 2. Enteral-Related 3. Parenteral *routes not using GI tract |
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7. What is the most common enteral route of adminstration?
What are two types of enteral-related routes of adminstration? What are five types of parenteral routes of adminstration? |
Oral
*only true enteral route 1. Sublingual 2. Rectal 1. Respiratory 2. Subcutaneous 3. Intramuscular 4. Intravenous 5. Skin |
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8. When given orally where is a drug mostly absorbed?
Where is the major site of metabolism for orally given drugs? What type of metabolism is there? Are orally given drugs good for emergency situations? |
Upper part of small intestine (duodenum)
Liver is major site of metabolism First pass metabolism so limited amount of drug gets into circulation Not good for emergency situations even though usually very safe b/c takes time |
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9. What are the common side effects of orally administered drugs?
What destroys orally administered drugs? |
GI irritation
*nausea, vomiting GI acids and enzymes *many oral drugs are coated with enteric coating that dissolves in pH of small intestine |
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10. Where does a sublingual administered drug dissolve?
How is a sublingually administered drug absorbed? What is an example of a sublingually administered drug? |
Under the tongue in saliva
Absorb directly into the blood system b/c have lots of blood vessels under the tongue **eliminate first pass biotransformation Nitroglycerine tablet **relieve chest pain in 30-60 secs |
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11. What are rectally administered drugs useful for?
In what patient are they used more common in? What percent of rectally administered drugs bypass the liver? |
Useful for localized effect for inflammation (upper GI)
Used in newborns 50% bypasses the liver |
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12. What is the respiratory route for drug administration?
What path do these drugs take? What type of drugs are administered through the respiratory route? |
Inhalation for local or systemic effect
Drug goes through lungs, picked up by blood, goes back to heart and into circulation Drugs to brain (NO, pot) and to lungs (for asthma) |
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13. How are subcutaneously administered drugs given?
What is an example? |
Given under the skin
Insulin **constant steady absorption |
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14. What is the intramuscular route of administration used for?
What does this mean? What type of drugs are given intramuscular? Who cannot be given intramuscular drugs and why? |
Can be used for depot effect
Slowly leaches out of muscle so have prolonged level over period of time Vaccines and some drugs *can be painful Children b/c don't have enough muscle |
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15. How are intravenous drugs given?
Are IV drugs good in an emergency situation? Can they be dangerous? |
Directly into bloodstream
Excellent in emergency b/c have rapid onset Can be dangerous esp if eject too much |
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16. What are two ways in which drugs are administered through the skin?
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1. Topical
-local effect 2. Transdermal -place patch and drug is slowly absorbed into blood |
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17. What are the three dosage forms of drugs?
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1. Solids
-tablets, capsules, caplets 2. Liquid (aqueous( -solutions, suspensions, syrups, elixirs *useful for pediatrics 3. Gaseous |
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18. What is drug absorption?
How does drug absorption occur for most drugs? What is this? |
Movement of drug from site of administration, through membranes and into general circulation
Through passive diffusion Drug moves across membranes based on its lipid/water partition coefficient |
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19. How can drugs move via passive diffusion?
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Water-soluble drug through an aqueous channel or pore
Lipid-soluble drug dissolved in a membrane |
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20. What is meant by active transport processes?
Three characteristics... |
1. Involves carrier protein
*drug must fit into carrier (sensitivity of fit) 2. Carriers are saturable 3. Requires energy (ATP) |
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21. What is facilitated diffusion?
What is filtration? |
Carrier mediated with concentration gradient
Passive through membrane pores |
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22. What are factors influencing passive absorption?
Faster the rate of absorption when... Five things... |
1. The higher the concentration of drug
2. The more lipid soluble 3. The lower the molecular weight 4. The larger the surface area 5. The greater the regional blood flow |
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23. Why does the stomach have less absorption than the small intestine?
Three things... |
1. Has thicker membrane
2. Transient time in the stomach 3. Smaller surface area |
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24. Why are local anesthetics given with a vasoconstrictor?
What does a higher partition coefficient mean? |
Want to decrease the regional blood flow or else drug will be carrier away
More lipid soluble so greater rate of absorption |
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25. Which form of a drug is more lipid soluble?
What does this mean in terms of drug absorption? What is the degree of ionization based upon? (two things) |
Non-ionized (uncharged) form is more lipid soluble
Better crosses membranes 1. pH of physiological compartment 2. pKa of drug |
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26. What is the Henderson-Hasselbach equation?
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pKa -pH = log(assoc. form)/(non-assoc. form)
For weak acids: non-ionized/ionized For weak bases: ionized/non-ionized |
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27. Where is the major site of absorption?
How is the pH here? |
Small intestine
Begins as pH 5.5 but has microvilli that are acidic Becomes more alkaline as move through small intestine |
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28. What are the general rules of absorption for weak acids?
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1. Initial absorption may be in stomach
**transient time here though and thick membrane of stomach and smaller SA prevent much absorption 2. Major portion in upper part of small intestine |
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29. Where are weak bases absorbed when given orally?
How are charged molecules absorbed? How are neutral molecules absorbed? |
Upper portion of small intestine
Poorly absorbed Readily absorbed |
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30. What is bioavailability?
What are some factors that affect bioavailability? (three things) |
Amount of drug administered that enters the blood stream
1. First pass metabolism 2. Solubility of drug 3. Chemical stability in GI tract |
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31. What is distribution?
What does the initial distribution and extent of distribution depend upon? (six things) |
Movement of drug from general circulation to site of action and other tissues of the body
1. Physiochemical characteristics 2. Cardiac output 3. Regional blood flow 4. Degree of plasma protein binding 5. Degree of tissue protein binding 6. CNS and placenta |
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32. What are the physiochemical properties of the drug?
What determines this for a drug? (four things) |
Ability of the drug to pass biological membranes
1. Lipid solubility 2. pKa 3. Molecular weight 4. Presence of appropriate carrier system in membrane |
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33. What happens if a person has reduced CHF and thus cardiac output?
What happens if a tissue has high perfusion rate? What tissues have a high perfusion rate? (three) |
Reduce distribution of drugs to body
Drugs get to these parts quickly Lungs, kidneys, brain |
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34. How can the degree of plasma binding protein binding affect absorption?
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May facilitate the absorption into the blood
It will reduce the ability of the drug to enter other tissues since only free molecules readily leave the capillaries |
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35. What happens if the dose is less than available binding sites?
What happens if the does is greater than available binding sites? |
Most drug molecules are bound to albumin and concentration of free drug is low
Most albumin molecules contain a bound drug and the concentration of free drug is significant |
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36. What happens if warfarin is displaced?
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Have free warfarin and excessive bleeding occurs
**drugs may displace each other from binding sites causing adverse reactions |
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37. Where do drugs with sufficient lipid solubility first distribute?
Where do they accumulate less rapidly? |
Distribute to those areas with high regional blood flow (liver, heart, CNS)
Accumulate less rapidly in skeletal muscle and even more slowly into adipose tissue |
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38. Why is entrance into the CNS restricted?
How long does it take for some drugs to cross the placental barrier? How is the distribution of drugs highly bound to plasma proteins? Which form of the drug can reach its site of action? |
Blood brain barrier - need to be highly lipid soluble
**prevents water soluble drugs from crossing Takes 20 minutes to get into fetal blood Have slower rate of distribution Only unbound (free) |
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39. What are the physiological volumes of...
1. Plasma 2. Interstitial fluid volume 3. Intracellular fluid volume 4. TBW What weight does a usual dose refer to? |
Plasma = 4 L
Interstitial fluid volume = 10L Intracellular fluid volume = 28L TBW = 42L 70kg (150 lb) adult |
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40. What are the processes to terminate the action of drugs?
Three... |
1. Redistribution
2. Biotransformation (metabolism) 3. Excretion |
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41. What is elimination?
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Metabolism + Excretion
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42. What is redistribution?
What are two factors that alter redistribution? |
Movement of drug away from its active site to other tissues where it can be stored
1. Physiochemical properities 2. Blood flow |
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43. How can a highly lipid soluble drug redistribute?
What is an example of this? |
Redistribute away from its active site and be stored in adipose tissue
Thiopental (very lipid soluble) **Given IV and distributes rapidly to profuse areas (brain, kidney, liver) & action is terminated by redistribution to adipose tissues away from brain |
