General Principles of Pharmacology Flashcards
What are the routes of administration?
Parenteral: Injection
Enteral: oral ingestion
What are the Phases of drug effect?
1) Pharmaceutical phase: how a drug progresses from solid to dissolved. Only applies to oral drugs
2) Pharmacokinetic phase: effect of drug on body. Subphases include absorption, distribution, metabolism, excretion
What is passive and active absorption?
Passive: diffusion. No energy required
Active: involves a carrier such as a protein which will need energy
What is pinocytosis?
When cells engulf a drug to move it across a cell membrane
What factors affect drug absorption?
Drug pH, local blood flow to GI tract, hunger, food content in GI tract
Why are drugs administered intramuscularly take up more readily?
Because of the number of surrounding blood vessels
What affects the process of tissues absorbing the dissolved drug?
The concentration of the drug, the flow of blood to the tissue, percentage of drug bind to the protein
What happens when a drug binds to a protein?
They are inactive in terms of creating a pharmacological response. The drugs bind to the protein at either a high, moderately high, moderate, or low level
What is biotransformation? Where does it occur?
Metabolism. It happens in the liver (mainly) where drugs are inactive due to the enzymes in the liver. This is where it becomes excreted
Note that MOST drugs are inactive in the liver
For the few drugs, CAN drug action happen in the liver? How?
It can but it happens sometimes the enzymatic actions that occur on a drug can produce an active metabolite that makes the drug response more noticeable
What happens to the drug that’s not bound to protein, or active and exerts its effect?
The unbound drug are metabolized in liver and other tissues
What is half life?
Time it takes for 1/2 a drug concentration to be eliminated
Why is it important to know the half life of a drug?
So that we how long it will take for the drug to reach a stable concentration in the blood
You have drugs in your system and they’re bound to be excreted. What factors into the excretion of these drugs?
Bile, feces, saliva, sweat, urine
For any drugs that are in your blood plasma and NOT bound to a protein, where do they go?
To the kidneys to be filtered and excreted
Kidneys are pretty good at filtering but is there anything that can affect the filtration?
Disease or any disorder that affects renal tubular secretion. There are also diseases that decrease blood flow to kidneys. Kidneys need the right amount of blood flow to function well
What are transdermal medications and examples?
Transdermal medications are medications that go on your skin. Example: nicotine patch
How do transdermal medications work?
You put the patch on your skin, you exercise to increase blood flow to the skin, and the drug gets absorbed
Are there any side effects to transdermal medications in conjunction with exercise?
Drug related side effects can increase. Side effects include nausea and palpitations
What is insulin glargine?
Man made insulin
Is having too much insulin bad? Give an example of when it is bad.
Too much insulin causes cells to absorb too much glucose in the body and causes the liver to produce less glucose. (liver can produce and store glucose)
Example: exogenous insulin injected into thigh and then working out increased insulin absorption
What is one downside of exercise while having drugs in your system?
One downside is that exercise can synthesize certain proteins, which means that more drugs can bind to the proteins thus making them inactive. This means you might have to give more of the drug to increase the effectiveness
What is the mechanism of action?
Mechanism of action is when a drug produces an effect or alteration at it’s target cells
How do we know what protein receptor the drug can be received by?
We know as certain drugs have a high affinity for a particular or active part of cell. A receptor is a keyhole and you need a certain drug to fit in to produce a response
What is the agonist? What is an antagonist?
An agonist is a drug that combines w/ the receptor and leads to changes
An antagonist is a drug that interferes or counters the agonist action
What is a competitive antagonist? What’s an example?
Antagonist agent that fights agonist for same receptor it wants to bind with. This prevents mechanism of action from happening
Example: Beta blocker taken in will block beta-1-receptor in cardiac cells. This is to slow down HR and decrease heart contractions
Will agonists and antagonists produce the same effect for every receptor they go into?
No. The effects vary by location of the receptor in the body
Example: cholinergic receptors react with acetylcholine in the salivary gland will produce more saliva but the same reaction somewhere else can slow HR or constrict pupils
How do enzymes affect drug and protein receptor interaction?
Enzymes control biochemical reactions and so it can bind to certain drugs to prevent a reaction from happening
What is the therapeutic index?
It’s a term to describe the relative safety of a drug. It is the ratio b/n toxic dose and effective dose
Represented by TD50 and ED50, the 50 meaning 50% of humans tested and dose of a drug needed to be effective in 50% of like population
In the therapeutic index, what do the numbers mean from 1-50
1-50 is the range of toxicity. The lower the number, the greater the toxicity
How can exercise increase drug side effects?
There are parallel physiological pathways leading to similar outcomes which can cause side effects to worsen
Example: antihypertensive agents to lower blood glucose in diabetes patients. Exercise can lower BP after exercise and lower blood glucose during and after exercise which can lead to negative drug response
What factors affect drug response?
Age: older you get, less the response. May need to give more drugs which in turn can affect drug efficacy or lead to side effects
Body mass: fatter you are, the more you need to up the concentration
Sex: women are smaller. Also includes pregnancy and lactation. Women are also fatter soooo
Other factors: time drug is given, existence of diseases, genetics, mood, mental state, environment, how much food you got in your stomach
What happens if the patient misses a dose? (110)
Don’t take more to “make up” for the last time. Just follow what they were told
