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What is Drug action?
The physicochemical interaction between the drug molecule and molecures in the body that alters a physiolocial process in the body by one of three methods
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What are the three methods for Drug action
- Replacement
- Interruption
- Potentiation
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Replacement
Exogenous drug replacement and endogenous substance
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Interuption
Drug Process that interfers with a physiological process
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Potentiation
Drug enchnaces a physiological process
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Three Phases of drug activity
- Pharmacutical phase
- Pharmacokinetic Phase
- Pharmacodynamic Phase
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Pharmaceutical phase
- Occurs after drug is given
- involving disintegration-dissolution of dosage form
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Pharmacokinetic Phase
Absorbtion, metabolism, distribution and elmination of a drug
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Pharmacodynamic Phase
Effect of drug on body
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What % of drugs are administered Orally
80%
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Where are the oral drugs absorbed into blood stream
small intestine
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Rate Limiting Time
- Lipid soluble > water soluble > suspension solution >
- Powder > capsules > tablets > coated tablets > enteric-coated tablets
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Pharmacokinetics
- ADME
- Absorption
- Distribution
- Metablolism
- Elimination
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Pharmacokinetics 3 ways the drug can enter the cells
- Passive diffusion
- Active (carrier-mediated) diffusion
- Pinovytosis
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Passive diffustion
- No energy required
- Most drugs
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Active Diffustion
- Carrier molecule and energy required
- Drugs: Glucose, amino acids, 5-fluorouralcil
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Pinocytosis
- Process of engulfing drug and pulling it across the membrabce which fuses with lysosymes in cell that hydrolze or break down contecnt of vessicle
- Drugs Vitamins A D E and K
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Factors affecting Absorption
- PH
- Soluibility
- Routes of adminstration
- Circulation
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What is Drug action
- Physiological interaction between the drug molecule and molecules in the body that alters a physiological process of the body in one of three ways:
- Replacement
- Interruption
- Potentation
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Replacement
:the drug replaces an existing physiological process such as estrogen replacement
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Interruption
The drug interferes with a physiological process. This occurs when an antihypertensive (high blood pressure) drug interferes with the process that constricts blood vessels and may cause blood pressure to rise.
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Potentiation
The drug stimulates a physiological process as in the case of furosemide (Lasix) which is a diuretic and stimulates the kidneys to excrete urine
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Explain how drug action works in the body
- Drug action begins when the drug enters the body and
- is absorbed into the blood stream where the drug is transported to receptor sites throughout the body. Once the drug hooks onto a receptor site, the drugs pharmacological response initiates.
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Endogenous
Endogenous means produced or grown from within an organism i.e. Epinephrine
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Exogenous
Exogenous means originating from outside an organism i.e albuterol
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