Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
pharmacology 2
| Term | Definition |
|---|---|
| •Onset of action | It's the time it takes a drug to reach the concentration needed to produce a therapeutic effect. |
| •Peak effect | It's the maximum drug effect produced by a drug once it has reached its highest concentration in the body. |
| Duration of action | It is the time between the onset of action and the discontinuation of drug action. |
| 4 phases of pharmokinetics | absorption, distribution, metabolism, elimination |
| absorption | It involves the movement of drug molecules from the site of administration, across cell membranes, into the circulatory system of the body (blood or lymphatic system). |
| The amount of absorption is influenced by? | route of administration |
| Ease of absorption is influenced by | how easily drugs move across cell membranes |
| drugs can move across the cell membrane only if: | -drugs can pass through lipid layers of the cell membrane - drug is small enough to pass through |
| passive transport | Move from a region of greater concentration to a region of lesser concentration. |
| active transport | Drugs can move across cell membranes regardless of concentration. They can travel from an area where the drug concentration is low to one where it’s high. This process requires energy and special carrier proteins or pumps. |
| Ionized (charged) | Less likely to cross cell membranes |
| Non-ionized (uncharged) | More likely to diffuse across membranes (passive diffusion) |
| Whether a drug is ionized or non-ionized depends on: | The chemical properties of the drug (is it a weak acid or base?) The pH of the surrounding fluid |
| Weak acids (like aspirin) absorb better in: | acidic environments (like the stomach) |
| Weak bases (like codeine) absorb better in: | basic environments (like the small intestine) |
| where is absorption the greatest? | areas of the body that have a good blood supply, such as under the tongue and the small intestine greater across single cell membranes than multiple cell layers. |
| Microvilli | increase the surface area of the small intestine, making it the largest absorbing surface in the body. |
| Contact time | Drug absorption increases the longer the drug is in contact with the absorbing surface |
| Distribution | The process of movement of the drug from the circulatory system, across barrier membranes, to the site of drug action. |
| • Drug properties • Extent of drug binding to blood proteins or tissue • Blood supply to the region • Ability of the drug to cross natural body barriers | Factors Influencing Distribution |
| Hydrophobic OR lipophilic • Nonionized • Or small enough to pass through slit junctions in the capillary wall | Properties of drug and distribution |
| Plasma proteins | drug is unable to move out of the blood vessel to get to the site of drug action. • act like a drug reservoir for bound drug trapped within the blood vessels. • Warfarin, phenytoin are highly protein bound |
| bound drug | a medication molecule that is reversibly attached to a large macromolecule, such as a plasma protein (like albumin) |
| Metabolism | a biochemical process involving transformation of active drugs to a compound that can be easily eliminated or prodrugs (enalapril) to active drugs (enalaprilat). |
| prodrug | A drug that requires activation, generally by enzymatic and/or chemical biotransformation, to have its therapeutic effect |
| metabolite(s) | Most drugs are transformed by enzymes to a ________ that is more active or less active than the original drug. |
| CYP450s | most important metabolic enzymes are found in the liver |
| First-Pass Effect | describes a process whereby the liver metabolizes nearly all of a drug to an inactive metabolite, before it passes into the general circulation. |
| 3 major routes of elimination: | Kidney Lung Bowel (feces) |
| Elimination half-life | is the time it takes for 50% of the drug to be cleared from the bloodstream. It takes approximately eight _____ to entirely eliminate a drug from the body |
| Bioavailability | describes the extent to which an administered amount of drug reaches the site of action and is available to produce drug effect(s) |
| bioavailability is influenced by: | • Drug absorption • Distribution to the site of action |
| Bioequivalence | two drug products are the same in terms of the rate and extent to which their active ingredient becomes available at the site of action The bioavailability of generic drugs is compared with the innovator product to determine if the generic is __ |
| Pharmaceutical equivalents | - same active ingredients/ Different inactive ingredients • Different dosage form • Exhibit different rates of absorption than the brand name |
| Therapeutic alternative | Different active ingredients, yet produce the same desired therapeutic outcome |
| Pharmaceutical alternatives | Same active ingredient as the brand-name product • Strength and dosage form may be different |
Created by:
user-1991937