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
Pharm - Ch. 04
Pharmacokinetics
| Question | Answer |
|---|---|
| List the four pharmacokinetic processes | Absorption, distribution, metabolism, excretion |
| What factors affect drug absorption? | Rate of dissolution/absorption, surface area, blood flow, lipid solubility, pH partioning |
| What is the most common method drugs use to pass through membranes? | Direct penetration across membrane |
| True or false: to pass channels/pores, drug must go against a concentration gradient, using energy | FALSE. Drugs passed using transport system proteins. With channels, drugs go down a concentration gradient |
| Do charged/ionized molecules directly pass through membranes? | No, because they are hydrophilic |
| What type of drugs can cross membranes easily? | Lipid-soluble drugs |
| How does ionization of drugs help drugs pass between membranes? | By manipulating the pH gradient between two sides of a membrane |
| Acidic drugs will accumulate on ____ side | alkaline |
| Define ion trapping | Weak acid or base moves across membrane due to change in pH, becomes charged, then drug accumulates on one side due to change in charge |
| What does parenteral mean in a pharmacological context? | By injection |
| What are the principal parenteral routes? | Intravenous, subcutaneous, intramuscular |
| Which type of administration results in rapid or slow pattern of absorption? | Intramuscular, subcutaneous |
| What are the barriers for intravenous administration? | None |
| What are the advantages of IV administration? | Rapid onset, precise control over amount, suitability for use with large volumes of fluid and irritant drugs |
| What are the disadvantages of IV administration? | High cost, difficulty, inconvenience, danger because of irreversibility, and potential for fluid overload, infection, embolism |
| What are the advantages of IM/subQ administration? | Suitability for water-soluble drugs and suitability for depot preparations |
| What are the disadvantages of IM/subQ administration? | Inconvenience and potential for discomfort |
| What are the advantages of PO administration? | Ease, convenience, economy, safety |
| What are the disadvantages of PO administration? | High variability, possible inactivation by stomach acid, digestive enzymes, and liver enzymes. |
| True or false: preparations of a drug do not have the same bioavailability if they are absorbed at same rate and same extent | False |
| What are the factors affecting drug distribution? | Blood flow to tissue, capillary beds, blood-brain barrier (lipid-soluble), placental drug transfer, protein binding |
| Is binding to albumin reversible? | Yes |
| P450 proteins do what to drugs? | Metabolize by chemically modifiying. Can result in toxic metabolite buildup if there are toxic levels of drug. |
| Drug metabolism helps with accelerated drug (A), drug (B), increased (C), activation of (D), and (E) variations | (A) excretion, (B) inactivation, (C) therapeutic action, (D) prodrugs, (E) toxicity |
| At what age does the liver fully develop metabolizing capacity? | After 1 year |
| What is the first-pass effect? | Rapid hepatic inactivation of certain PO administered drugs. (Meaning drug never reaches site of action) |
| What are the three renal processes for drug excretion? | Glomerular filtration, passive tubular reabsorption, active tubular secretion |
| What are some examples of nonrenal drug excretion? | Bile, breast milk, lungs, sweat, saliva |
| Why monitor plasma levels to determine therapeutic range? | Plasma levels easiest to accurately measure |
| What is the difference between loading dose and maintenance dose? | Loading dose is a large initial dose of drug used to achieve plateau more quickly. Maintenance dose keeps drug levels at plateau. |
| Define drug half-life | The time for amount of drug in body to decrease by 50% |
| Explain why drug-metabolizing enzymes have therapeutic consequences | A drug can increase rate of its own metabolism, necessitating increase in dosage to maintain therapeutic effects. Drug-metabolizing enzymes can accelerate metabolism of other drugs, which necessitates increase in their dosages too. |
| True or false: enteric-coated oral formulations are designed to release their contents in stomach | False. Designed to release in small intestine |
| True or false: membranes of placenta constitute an absolute barrier to passage of drugs | False. Same factors determine drug movements across all other membranes apply |
| What is the blood-brain barrier describing? | Tight junctions between cells that compose capillary walls of CNS. Drugs must pass through cells of capillary wall to reach CNS instead inbetween. |
| What is enterohepatic recirculation? | Drugs entering intestine in bile can be reabsorbed back into portal blood |
| How many half-lives does it take for a drug to be cleared or reach a plateau? | 4 |
| If plasma drug levels fluctate too much, what three interventions can be used? | 1) give smaller doses at shorter intervals with same total daily dose; 2) use continuous infusion, 3) use a depot preparation |
| True or false: drug A is given at 100x the dose of drug B. Drug A will take more time to reach plateau | False. Time to reach plateau is independent of dosage size |
Created by:
choel
Popular Pharmacology sets