Term
| What are the mechanisms of drug transport? |
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Definition
| passive diffusion, filtration/bulk flow, carrier-mediated transport, endocytosis, (ion-pair transport) |
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Term
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Definition
| the mechanism for transfer of drugs across capillary membranes |
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Term
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Definition
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Term
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Definition
| pH at which the product equals the reactant |
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Term
| How is a drug ultimately unbound to its receptor in receptor mediated endocytosis? |
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Definition
| acidification of the vesicle from 7 to 5 |
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Term
| Name examples of parenteral administration. |
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Definition
| IV, IM, subq, inhalation, through skin |
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Term
| Irritating solutions are best given by what route? |
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Definition
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Term
| What affects the rate of absorption of an IM injection? |
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Definition
| surface area of capillaries and solubility of the drug in the interstitial fluid |
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Term
| How can you slow down absorption rate of IM injection? |
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Definition
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Term
| How are subq injections abosorped? |
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Definition
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Term
| Which has a faster abosrption IM or subq? |
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Definition
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Term
| How can you decrease the absorption of Subq drug? |
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Definition
| suspend in oil or implant a solid pellet |
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Term
| What are the advantages of enteral administration? |
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Definition
| safe, covenient, economical |
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Term
| How are drugs absorbed in the mouth? |
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Definition
| mouth has a small surface area and a pH of 6. Can diffuse passively: sublingual (NTG) or buccal (chewing tobacco) |
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Term
| How can the stomach absorb drugs? |
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Definition
| passive diffusion; pH of 1-2, more rapid transfer of acid than base (ion trapping) |
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Term
| What is the primary site for absorption of most orally administered drugs? |
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Definition
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Term
| How does the small intestine abosrb drugs? |
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Definition
| pH of 5-8; large surface area. usually by passive diffusion also facilitated diffusion, active transport, endocytosis and filtration |
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Term
| Why does the large intestine absorb less than the small intestine? |
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Definition
| smaller surface area and solid nature of contents |
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Term
| What are the advantages of rectal administration/ |
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Definition
| drugs that cause gastric irritation, after GI surgery, uncooperative patients, 50% avoids first pass effect |
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Term
| What else is in a tablet besides the drug? |
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Definition
| fillers, disintegraters, binders, lubricants |
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Term
| What are the pros and cons of administering a drug through the lung? |
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Definition
| large surface area and lots of blood flow but cumbersome administration b/c particles need to be the right size |
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Term
| By what method does the lung absorb drugs? |
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Definition
| passive diffusion mostly but some active transport |
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Term
| Why do you cover nicotine patches in saran wrap? |
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Definition
| induce moisture to get drug in acqueous solution to enhance absorption |
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Term
| What factors influence drug distribution? |
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Definition
| regional blood flow, capillary permeability, rate of transfer into tissues, binding to plasma proteins, accumulation into tissues |
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Term
| WHy should digoxin not be taken with a drug that affects intestinal motility? |
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Definition
| because it is absorbed very slowly |
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Term
| What tissues will see IV administered drugs first? |
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Definition
| highly vascularized ones like the brain and the liver (esp seen if the drug is lipid soluble and transfered rapidly |
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Term
| How is thiopental so fast acting and breif? |
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Definition
| because inital high concentrations are lipid soluble and diffuse into the brain and other highly perfused areas. As the drug diffuses it reaches lower concentrations in teh brain and no longer has an affect |
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Term
| Where in the body is capillary permeability increased? |
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Definition
| glomerulus and liver sinusoids |
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Term
| What accounts for the delayed onset and prolonged effects of warfarin? |
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Definition
| binding to plasma proteins |
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Term
| What are the three types of plasma proteins? |
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Definition
| albumin, lipoproteins, and alpha1-acid glycoprotein |
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Term
| How does albumin bind drugs? |
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Definition
| has one to 2 high affinity sites for acids. weaker binding of lipid soluble drugs and weak bases |
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Term
| How do lipoproteins bind drugs? |
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Definition
| bind lipid soluble drugs and amoutn of drug absorption depends on lipid content of lipoproteins |
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Term
| What kinds of drugs does alpha1-acid glycoprotein bind? |
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Definition
| basic drugs; levels are inducible by trauma, injury or stress; 1/2 life of 5.5 days |
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Term
| What causes a drug to accumulate in tissues? |
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Definition
| ion trapping, binding to intracellular components (e.g. iodine in thyroid), partitioning into lipid |
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Term
| How does the blood brain barrier prevent substances from entering the CNS? |
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Definition
| glial cells and endothelial cells form tight jxns. Stops only drugs that are water soluble, NOT lipid soluble. Altered by inflammation |
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Term
| How does placental barrier prevent substances from crossing the placenta? |
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Definition
| smaller fenestra but still allows diffusion of very small particles |
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Term
| Where else in the body is a barrier similar to the BBB? |
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Definition
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