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22 Cards in this Set
- Front
- Back
What are the 4 stages of pharmacokinetics? |
Absorption Distribution Metabolism Elimination |
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What is the therapeutic range of a drug? |
The range between the minimum effective concentration and the maximum effective concentration before toxicity |
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Name some routes of administration |
Enteral e.g oral, stomach tube, rectal Parenteral e.g IV, IM, SC, intra-cardiac Topical e.g Skin, eye, ear Other e.g inhalation |
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If 100% of a drug reaches circulation, what would its bio-availability be? Give an example of how this can occur |
1 Drugs given IV |
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What does bioavailability mean? |
The amount of drug that reaches the circulation |
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Describe the pharmacokinetics of a drug given orally |
Pass into GIT absorbed in SI enter hepatic circulation where liver detoxified substances before they reach systemic circulation |
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What is the first pass effect? |
A drug may be partially or completely broken down - greatly reducing the concentration before it reaches the systemic circulation |
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Is a drug given orally likely to have a high or low bioavailability? |
Low, but varies |
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What will hydrophilic and lipophilic drugs do? |
Hydrophilic- dissolve easily in water Lipophilic (hydrophobic) - dissolve easily in fats |
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What route of administration will hydrophilic drugs be absorbed quickest? |
IV/ IM |
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What route of administration will lipophilic drugs be absorbed quickest? |
Orally/SC |
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What does drug distribution mean? |
the movement of the drug from circulation to body tissues |
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Name a plasma protein that transports drugs through the circulation |
Albumin |
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If a drug has a higher affinity for albumin, how would this affect the dosage? |
Higher dosage required |
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Where does drug metabolism mostly occur? |
Liver |
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Give an example of a drug that becomes more active once metabolised |
Prednisolone |
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What happens during the 2 phases of metabolism, after the drug is metabolized into metabolites? |
1 - transformed by various enzymes 2- Metabolite joined with a molecule to make it hydrophilic |
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What must a drug need to be, in order to be excreted in bodily fluids? |
Hydrophilic |
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Which are the main 2 routes of excretion? |
Urine, via kidney Faeces, via liver (in bile) |
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Why is the elimination half life important? |
Tells us when a drug needs to be administered Insufficient dosing - lack of therapeutic effect Over dosing - toxicity |
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What may renal elimination be affected by? |
Glomerular elimination rate affected by hypotension/hypertension, hypovolaemia, CRF |
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What may hepatic elimination be affected by? |
Liver disease GIT disease |