Pharmacology CH2 SG

agonist

binds to receptor to make it do something

antagonist

binds to receptor to block it from doing something

bioavailability

amount of the drug that actually enters the system’s circulation

enternal

Most common type of administration phase’s route of administration that absorbs anywhere throughout the GI tract that can either be systemic or local.

first-pass effect

Some of the drug may get into the blood and out the colon while some of it will get into the liver where metabolism blocks the drug from reaching systemic circulation. This is why pills need to have a higher concentration.

hypersensitivity

Sensitivity to a drug can be influenced by allergies or immune-mediated and can require airway and/or ventilatory assistance.

idiosyncratic effect

abnormal reaction that occurs instead of what was predicted. EXCLUDES allergies

inhalation

type of enternal route of administration that can be both local and systemic

local effect

treatment is within the area it was placed in/goes to

lung availability/total systemic availability ratio (L/T ratio)

The amount of the drug specific to the lung versus the body is only 10% of what actually makes it through when using the inhalation method

parenteral

Type of route of administration in the administration phase that does not utilize the UI tract but instead the bloodstream (e.g., IVs, IMS, subcutaneous/injections)

pharmacodynamics

Third phase in drug action that is relative to what the drug does to the body including the interaction it has with the cell, the body’s response to drug concentration (drug response), and the action of the drug

pharmacokinetics

Second phase in drug action that is relative to what the body does to the drug to make it available.

receptor

In relation to drugs, it has a direct relationship with both agonist and antagonist drugs that either enhances the function of the cell or halts its process.

synergism

1 + 1 = 3: one drug in addition to another one makes their shared effect better.

systemic effect

affects the whole body through blood circulation which allows for more side effects.

tachyphylaxis

rapidly developing tolerance = rapid decrease in response to the drug

tolerance

the more tolerant the body is the worse the intensity of the drug is over time as it is PROGRESSIVE

topical

Type of route of administration in the administration phase that is only local due to it being directly placed in skin or mucous membranes.

transdermal

Type of route of administration in the administration phase that is systemic but can TARGET locally and supplies long-term circulation.

Best systemic drug distribution

Enteral route

Best local drug distribution

parenteral route

Aqueous diffusion

Part of the pharmacokinetic phase’s absorption phase that happens within the aqueous compartments of the body and follows normal diffusion’s concentration gradient.

lipid diffusion

Part of the pharmacokinetic phase’s absorption phase and based on the properties of the drug, can be easily absorbed into the bloodstream. Drugs that are soluble are nonionized and nonpolar, and thus a weak acid or base are more easier absorbed than those that are ionized and polar. However, a weak acid is more easily absorbed due to its stronger bond. The weaker the bond is, the easier it is to break the strong bond.

carrier-mediated transport

Part of the pharmacokinetic phase’s absorption phase that is helpful for drugs that are formed to imitate natural substances that the lipid membrane naturally transports (e.g. amino acids, sugars, peptides).

pinocytosis

Part of the pharmacokinetic phase’s absorption phase that allows the drug to be engulfed into and transport through the membrane with the help of being incorporated within a cell.

What influences drug distribution

Drug distribution is the second phase of the pharmacokinetic phase and is influenced by the rate and extent of absorption versus the rate of elimination per dose, as well as how much was distributed.

What is the primary site of drug metabolism?

Liver

Describe the “first pass” effect?

First past effect only refers to enteric methods of administration as when drugs enter the GI tract, blood is drained into the liver which is the main hub for metabolizing. This causes most of the drug dose to have no effect on the body . To bypass this effect, two options include increasing the dosage or by switching routes of administration (e.g. injection).

What is the primary site of drug elimination

Kidney

Explain plasma “half life”.

How long it takes for the plasma concentration within a drug to decrease by ½ which determines how long the drug is eliminated from the body. Plasma concentration within a drug is directly proportionate to the drug’s concentration in the tissue.

What percentage of an inhaled drug goes to the stomach vs. the lungs

90%:10%

Are inhaled drugs designed for “systemic” or “local” effects?

They are intended to local effects; however, parts of it becomes systemic with the smaller percentage that makes it to the stomach.

Protein binding and cell receptors

In the pharmacodynamic phase, drugs will initially bind to a specific protein to either promote the protein’s initial function or to halt it. Drugs are built to accurately replicate what normal cell receptors bind to: only specific shaped drug-protein can fit and function within a receptor. The more accurately the drug-protein fits into the receptor, the less side effects there are, as the shape replication is NOT perfect.

Cell receptors

Potency

ED50: the concentration of given drug producing 50% of drugs maximum effect.
Example given:
fentanyl - 1mg = ED50
tylenol - 100mg = ED50
fentanyl > tylenol potency

Maximal effect

Greatest response that a drug can produce where more dosage does not promote a better response.

agonist

promotes initial function

antagonists

stops/obstructs/lessens initial function

synergism

1 + 1 = 3
One drug taken with another drug to INCREASE the effects of their shared effect. They both function fine alone.

additivity

1 + 1 = 2
One drug taken with another drug that give two different effects

Potentiation

1 + 1 = 1
One drug taken with another drug to get one effect. Both drugs need each other to build the effect.

Given solution %

mg/1mg = x mg/1mL (move decimal over once to the right)
answer in mg/mL

Given dilution in ratio (1:x)

(1g of drug * 1000mg/g)/x mL solution = z mg/mL
x = 1:x
answer in mg/mL

Given on hand x% solution and ordered y mg. find volume z.

DH/VH = DD/VD
x% mg/1mL = y mg/z VD mL
% is found in solution formula
answer % solution in mg/mL
answer volume desired in mL

Given on hand x% solution and ordered y mL. find dose z.

DH/VH = DD/VD
x% mg/1mL = z mg/y VD mL
% is found in solution formula
answer % solution in mg/mL
answer volume desired in mL

Given drug dilution solution ratio x and ordered y mg. find volume z.

(1g drug * 1000mg/g)/x mL = on hand mg/mL
on hand mgmL/1 = y mg/z
answer on hand in mg/mL
answer volume in mL

Given drug dilution solution ratio x and ordered y mL. find dose z.

(1g drug * 1000mg/g)/x mL = on hand mg/mL
on hand mg/mL/1 = z/y mL
answer on hand in mg/mL
answer dose in mg