Term
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Definition
Pharmacokinetics is the study of drug movement throughout the body.
pharmaco: medicine
kinetics: movement or motion |
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Term
| Name the 4 pharmacokinetic processes (how the drug is handled by the body) |
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Definition
1. absorption
2. distribution
3. metabolism
4. excretion |
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Term
| Drugs use two processes to cross membranes. Name and describe them. |
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Definition
1. Active transport: movement of a chemical against a concentration gradient.
Cotransport: movement of 2 or more chemicals against a gradient.
2. Passive transport (diffusion): movement of a chemical from a high to low concentration. |
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Term
| Describe absorption (one of the 4 pharmacokinetic processes): |
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Definition
| Absorption is a process involving the movement of a substance from its administration site across body membranes to circulating fluids. |
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Term
| What is the primary pharmacokinetic factor (process) determinng the length of time it takes for a drug to produce its effects? |
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Definition
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Term
| Name a few factors that affect absorption. |
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Definition
*The drug dose (drugs administered in higher doses are absorbed more quickly)
*The speed of digestive motility
*Exposure to enzymes in the GI tract
*Blood flow to the site of administration
*degree of ionization (ability of a drug to become ionized depends on the surrounding pH.)
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Term
Something to remember about absorption:
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Definition
Acids are absorbed in acids and
bases are absorbed in bases. |
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Term
Define distribution (the 2nd pharmacokinetic process): |
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Definition
transport of drugs/chemicals throughout the body |
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Term
| What is the most basic factor determining the distribution of a drug? |
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Definition
The amount of blood flow to body tissues.
Heat, lungs, brain and kidneys have the most blood flow.
Skin, bone and adipose tissue have the least blood flow. |
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Term
The physical properties of the drug greatly influence how it moves throughout the body.
Lipid-solubility is an important characteristic because it determins how quickly a drug is absorbed, mixes within the bloodstream crosses membranes and ends up in body tissues. |
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Definition
| Lipid-soluble agents are not limited by the barriers that normally stop water-soluble drugs thus they are more completely distributed to body tissues. |
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Term
| A ______-_______ ________ is when a drug binds, reversibly, to plasma proteins making them too large to cross capillary membranes thus the drug is not distributed to body tissues. |
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Definition
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Term
| Name two organs that possess special anatomic barriers that prevent many chemicals from entering. What are those barriers called? |
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Definition
Brain and placenta
Blood-brain barrier and
fetal-placental barrier
*There are still some medications/chemicals that can cross these barriers such as anticonvulsants to act on the CNS in the brain and alcohol can cross the fetal placental barrier |
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Term
| The process of chemically converting a drug to a form that is more easily removed from the body is referred to as: |
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Definition
Metabolism
(also called biotransformation) |
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Term
| The primary site of drug metabolism takes place in the __________? |
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Definition
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Term
| During metabolism in the liver, the addition of side chains, called __________ make drugs more water soluble a more easily excreted by the kidneys. |
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Definition
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Term
| The hepatic microsomal enzyme system is responsible for what? |
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Definition
| The hepatic microsomal enzymes inactivate drugs and accelerate their excretion. |
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Term
| Drugs that have no pharmacologic activity unless they are first metabolized to their active form are called __________. |
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Definition
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Term
| Some drugs produce enzyme induction in the liver which does what? |
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Definition
Enzyme induction increases metabolic activity in the liver causing drugs to be metabolised faster.
In these cases a higher does of the medication may be needed to produce a therapeutic effect |
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Term
| Drugs given orally are subjected to the hepatic portal circulation which carries blood to the liver before other body tissues. Some drugs can be completely metabolized to an inactive form before they ever reach circulation. What is the called? |
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Definition
First-pass effect
Sublingual, buccal, rectal and parenteral routes all bypass the first-pass effect. |
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Term
| The primary site of excretion is the __________. |
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Definition
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Term
| The rate of excretion determins the drugs concentration in the bloodstream and concentration determins the drugs duration of action. The duration of action is described by the drugs ________________? |
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Definition
Plasma half-life (t1/2) :
The length of time required for the plasma concentration to decrease by 1/2 after administration.
The greater the half-life, the longer it takes for a drug to be excreted. |
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Term
| define minimum effective concentration, toxic concentration, and therapeutic range. |
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Definition
Minimum effective range: amount of drug required to produce a therapeutic effect.
Toxic concentration: amount of drug that will result in serious adverse effects.
Therapeutic range: plasma concentration between the minimum and toxic concentration range. |
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Term
| A higher ammount of a drug given once or twice to "prime" the blood stream with a sufficient level of durg is called: |
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Definition
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Term
| Before plasma levels drop back to zero drug concentration, intermittent __________ doses are given to keep the drug concentration within a therapeutic range. |
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Definition
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Term
| What is Enterohapatic Recirulation? |
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Definition
| It is the recycling of drugs and other substances by the circulation of bile through the intestines and liver. |
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Term
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Definition
| It is the chemical attraction that impels certain molecules to unite with others to form complexes, |
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