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31 Cards in this Set
- Front
- Back
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What does ADME stand for? |
Absorption Distribution Metabolism Excretion |
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Define Absorption |
Process of transfer of drug from site of administration into the general/systemic circulation |
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What are the three categories of Factors influencing Absorption |
Pharmaceutical properties Physiochemical properties Physiological variables |
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What are the Pharmaceutical properties? (3) |
Pharmaceutical form Disintegration Dissolution |
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What are the Physiochemical properties? (3) |
Solubility pH of drug Molecular Weight |
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What are the Physiological properties (6) |
Surface area Contact time Conc. Of drug at absorption site Absorption site Interactions Transport systems |
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What factors may play a role in the oral route? (5) |
Drug stability in digestive tract Gastric emptying rate Presence of food/other drugs Alteration in intestinal motility Resistance of drug to bio transformation system |
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What is Bioavailability? |
The fraction of administered drug which reaches the systemic circulation of the patient as the parent drug |
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What is First Pass Metabolism? |
Phenomenon of drug metabolism, whereby the concentration of a drug is greatly reduced before it reaches the systemic circulation. |
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What are the routes of administration? |
Enteral (Oral) Parental (IV, IM, Subcut) Mucous membranes (inhalers, sublingual) Transdermal |
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Enteral - Advantages |
+ Convenient + Painless + No infection + Inexpensive |
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Enteral - Disadvantages |
- 1st pass effect - Requires GI absorption - Slow delivery - Harsh GI environment |
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Parental - Advantages |
+ Rapid delivery + High bioavailability + No 1st pass GI |
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Parental - Disadvantages |
- Irreversible - Infection - Pain - Fear - Trained personnel |
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Mucous membranes - Advantages |
+ Rapid delivery + Direct delivery + No 1st pass/GI + Convenient/Painless + Low infection |
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Transdermal - Advantages |
+ Simple/Convenient/Painless + Excellent for longterm use + No 1st pass or GI |
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Transdermal - Disadvantages |
Requires highly lipophilic drug Slow delivery |
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Define Distribution |
Process by which a compound is transferred from the general circulation to other parts of the body and into the tissues. |
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What factors influence Distribution? |
Lipid solubility and Volume of distribution (Vd) Lipid/water solubility Plasma protein/tissue binding |
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What factors increase the fraction of an unbound drug? |
Saturability Displacement Late pregnancy Renal impairment Low plasma albumin |
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Define Metabolism |
The processes by which a drug is chemically altered in a way that facilitates it's action OR enhances it's elimination from the body. |
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What are the sites of drug metabolism? |
Liver Kidney GI tract Lungs Skin |
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What factors influence Metabolism? |
Race and Ethnicity Functional capacity Genetics Environment Interactions |
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Excretion - Definition |
The processes by which drugs or their metabolites are removed from the body. |
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What routes are drugs or metabolites excreted via? |
Renal Biliary Respiratory Dermal |
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What factors influence renal excretion? |
Renal blood flow Renal function Glomerular filtration rate Urine flow rate and pH Conc. of blood in plasma Protein binding Size of drug complex Age |
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What is the clinical significance of altered renal function? |
Caution drugs with renal excretion Caution drugs with active metabolites Caution drugs with narrow window Caution drugs with renal side effects |
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Define Half Life |
Time required to reduce plasma conc. to 1/2 of it's original value. |
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Define Steady State |
Rate of administration = Rate of elimination |
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Define Therapeutic Window |
The range of drug concentrations within which the drug exhibits maximum efficacy and minimum toxicity in majority of patients. |
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Define Therapeutic Drug Monitoring |
Individualisation of drug dosage by maintaining plasma or blood drug conc. within a targeted therapeutic window. |
