Test 3 Flashcards
What is pharmacology?
Pharmacology is the study of how drugs interact with the body to produce therapeutic effects.
What is pharmacy?
Pharmacy is the practice of compounding and dispensing medicines
What are pharmacotherapeutics?
Pharmacotherapeutics are the EDUCATED applications of drugs for the treatment of diseases as associated with patient care.
IE - Appropriate drug, appropriate dose, for the appropriate disease, for the appropriate patient.
What are pharmacodynamics?
Pharmacodynamics are the effects of a drug on a physiologic or biochemical function of the body: “What a drug does to the body”
REMEMBER - drug has effect on body at the SAME time the body has an effect on the drug.
pharmaco Dynamics = what the Drug does to the body
What are pharmacokinetics?
- Effects of the body on a drug (What the body does to a drug)
- Fate of a drug during its course in the body: absorption, distribution, metabolism, and elimination/excretion.
“Kinetics makes me think of motion, and our bodies are constantly in motion, thus kinetics = body in motion = what the body in motion does to the drug”
An example being: Drug concentrations in body fluids and tissues and how they vary with time due to what the body is doing to the drug through absorption, distribution, metabolism, excretion, etc.
Name the listed drug components that are active ingredients (5)
- Alkaloids (atropine)
- Glycosides (digitalis)
- Polypeptides (insulin) (long chain of amino acids)
- Salts (morphine, potassium chloride)
- Steroids (cortisone, estrogen, progesterone, testosterone, aldosterone)
Name the listed drug components that are additives (inactive) -
Blinders Diluents Disintegrators dyes flavorings fillers lubricants vehicles
True or False - A drug additive should NOT effect the active ingredient within the drug.
True
True or False - Drug companies must always use the same ADDITIVES for a drug when making a generic version of the drug.
False - Different companies may use different additives for drugs, so a drug from one company to another may not be equivalent to a trade name or to another generic form from a different company.
Also, the desired effects can be changed, IE - blood levels of a drug and the side effects can both be effected.
Ex: Cyclosporine - one formulated by one company can have a different interactions than from another company. They MUST NOT switch companies of a medication… must ALWAYS get the same medication from the same company.
Routes of drug administration
Enteral (by mouth through the GI tract) Subligual (under the tongue) Buccal (in gums and cheeks) Rectal (in the bum) Parenteral (IV, IM, SQ) Inhalation (respiratory system) Topical (on the skin or eyes) Intrathecal (Subarachnoid space in brain) Epidural (Epidural space in spinal cord) Intranasal (Nasal mucosa) Transdermal (SLOW specific administration through the skin.
Enteral administration
Most common form of administration
ORAL - through the GI tract.
- passes from mouth to stomach. Some drugs absorbed here, most drugs are absorbed in the SMALL INTESTINE (duodenum)
- drugs must be able to permeate the gut lining.
- drugs hit portal circulation first (hepatic first pass metabolism)
- after the liver, drugs enter systemic circulation.
Include Feeding/Gastric tubes.
Sublingual administration (SL)
Absorbed through capillary bed under the tongue to systemic circulation.
NO HEPATIC FIRST PASS - (but will hit liver later on)
Buccal administration
Absorbed through capillary bed of buccal mucosa (between gums and cheeks) into systemic circulation.
NO HEPATIC FIRST PASS
Rectal administration (PR “per rectum”)
absorbed from rectal capillaries into BOTH SYSTEMIC AND PORTAL CIRCULATIONS.
-Degree of intestinal metabolism and/or Hepatic first pass effect varies depending on how far the medication is inserted into the rectum.
Rate of absorption is inconsistent “because everyone’s ‘finger of administration’ is a different length”
What is parenteral administration?
IV, IM, SQ.
Bypass the GI tract straight into systemic circulation, so NO hepatic first pass effect.
IV drugs are injected directly….
into the blood or systemic circulation. Rapid onset of action. 100% bioavailability
IM injections are injected…
directly into muscular tissue from where it is absorbed into capillaries and systemic circulation.
Rate of absorption depends on whether drug is aqueous (water) based and rapidly absorbed OR oil-based and slowly absorbed.
Also depends on rate of blood flow to site of injection.
HIGHER BLOOD FLOW = HIGH RATE OF ABSORPTON
Subcutaneous injections are injected where?
Subcutaneous tissue from where it is absorbed into capillaries and systemic circulation.
Rate is affected by same factors as IM, oil/water base, rate of blood flow to injection site.
Inhalation
- Drug absorbed from mucosa of respiratory system where it may have local effect and/or be absorbed into capillaries and systemic circulation.
- No hepatic first-pass effect.
- Often delivered in metered-dose devices or by aerosolization.
Topical Administration
(THINK LOCAL)
Drug usually in cream, ointment, or liquid form, applied to skin or eyes for local effect.
-Usually LITTLE systemic absorption, but can be increased by using on extensive parts of the skin, long term use, skin excoriation (torn or worn skin), and the individual pharmacology of the drug.
Intrathecal
- Drug administered into subarachnoid space surrounding spinal cord and brain.
- Used for drugs that cannot cross the blood-brain barrier when given systemically and that are required to treat conditions of the central nervous system.
Epidural
- Drug administered into epidural space surrounding the spinal cord (between the dura mater and the ligamenta flava [the ligaments that join adjacent vertebral laminae]).
- Used for administration of analgesics and anesthetics.
Intranasal
- Drug, usually in liquid or powder form, applied to nasal mucosa from where it has local effects and/or absorbed into capillaries and systemic circulation for systemic effects.
- No hepatic first-pass effect.
Transdermal
- Patch containing a special formulation of a drug is applied to the skin.
- The drug is slowly absorbed through the skin into the capillaries and systemic circulation.
- No hepatic first-pass effect.
- Requires adequate amount of adipose tissue for adequate absorption.
- Much more absorption into systemic circulation than from a simple topical drug application.
Drugs that are NOT administered via the GI tract / absorbed into portal circulation / transported to the liver where hepatic first-pass effect metabolism occurs will AT SOME POINT be transported to the liver via the hepatic __; then these drugs will be metabolized in the liver (but this is not hepatic first-pass effect/metabolism).
hepatic artery
- Most drugs exert their actions on cells by first binding with cell receptors – either body cell receptors or microorganism cell receptors.
- The receptors are proteins that may be membrane-bound (part of the cell membrane) or intracellular (in the cytoplasm or in the nucleus).
- Each cell has only a certain number of receptors; therefore, they can become __.
saturated
-When a drug binds with a cell receptor, several outcomes are possible:
1- Opening or closing of ion channels in the cell membrane, which alters the membrane potential and the cell’s activities; leads to rapid target cell response.
2- Activation or inhibition of intracellular enzymes, G-proteins, second messengers (e.g., cAMP, cGMP, calcium-calmodulin, inositol phosphate, many others). The second messenger then activates or inhibits intracellular protein kinases (enzymes) or various chemical reactions to bring about the cell response to the drug.
3- Increased nuclear DNA transcription to mRNA, and increased ribosomal protein synthesis, which then brings about a cell response; target cell response takes hours to days to weeks.
4- Inhibition of DNA synthesis, ribosomal protein synthesis, and/or bacterial cell wall production.
1- ion channels (rapid)
2- secondary messengers and kinases
3- increase DNA transcription (hours to weeks)
4- inhibit DNA, protein, or cell wall synthesis
Inhalation administration
Drug absorbed from mucosa of respiratory system where it may have local effect and/or be absorbed into capillaries and systemic circulation.
NO HEPATIC FIRST-PASS EFFECT
Ex: nebulizers
Often delivered in metered-dose devices or by aerosolization
Each cell has only a certain # of receptors which means…
it can become SATURATED.
- maximal effect is reached when receptors are saturated.
Intrathecal (Brain/Spinal cord) administration
Drug administered into the subarachnoid space surrounding the spinal cord and brain.
-used for drugs that CANNOT cross the blood-brain barrier when given systemically and that are required to treat conditions of the CNS.
Where are enteral drugs primarily absorbed?
The small intestine, the duodenum particularly. The duodenum has a large surface area is why the most absorption of oral meds occurs here.
Epidural
Drug administered into epidural space surrounding spinal cord (between the dura mater and the ligamenta flava (the ligaments that join adjacent vertebral laminae)).
-used for admin of analgesics and anesthetics
Getting excess amounts of any kind of agent can lead to what?
receptor DOWN-regulation (a protective mechanism to protect cells from excess stimulation by an agent)
Ex: too much chronic oxycodone creates “tolerance”(down-regulation)
Transdermal
(THINK SYSTEMIC)
DIFFERENT THAN TOPICAL - is specifically formulated to SLOWLY absorb into the SYSTEMIC circulation.
- requires adequate amount of adipose tissue contact for adequate absorption.
- NO hepatic first effect.
- Number of receptors on target cells may increase in number (up-regulate) over time and thus become more responsive to endogenous or exogenous agents OR
- May decrease in number (down-regulate) over time and thus become less responsive to endogenous or exogenous agents.
- Binding of an endogenous or exogenous agent with receptors often causes receptor __-regulation to protect target cells from excess stimulation by the agent.
- Deficiency of an endogenous agent may cause receptor __-regulation to increase target cells’ responsiveness to the agent.
down-regulation
up-regulation
Affinity is the strength of binding/affinity between a drug and its receptor.
-The __ the affinity of a drug and its receptors, the __ the target cell response.
greater the affinity the greater the response
What about this whole hepatic first - pass thing? What if drugs DON’T have it?
Drugs that are not administered via the GI tract and then absorbed into portal circulation to be transported to the liver where hepatic first-pass effect/metabolism occurs
- WILL at some point be transported to the liver via the hepatic artery; then these drugs will be metabolized in the liver (but this is NOT HEPATIC FIRST-PASS EFFECT/metabolism)
An agonist is a drug that binds to the same cell receptor as an endogenous agent and brings about the __ change in the function of the cell as the endogenous agent.
same
the LOADING DOSE is an __ dose of a drug, higher than subsequent doses, to achieve a rapid therapeutic plasma concentration.
first or initial
a PARTIAL AGONIST does not produce maximal effects even when bound with __ cell receptors.
-EXAMPLE: Buprenorphine (used to treat opioid addiction and to treat acute and chronic pain) is a partial agonist for µ-opioid receptors.
all
an ANTAGONIST is a drug that__ the effects of an endogenous agent on the function of a cell; also blocks effects of an agonist drug on a cell.
inhibits or blocks
with a Competitive antagonist, the degree of inhibition produced depends on the __ of antagonist: as the __ of the antagonist increases the degree of inhibition increases.
- In addition, clinical response depends on the concentration of an agonist that is competing for binding to receptors. As the concentration of agonist increases, the concentration of antagonist needed for inhibition also increases.
- EXAMPLE: The beta receptor antagonists such as propranolol, metoprolol, and atenolol
concentration
concentration
An Irreversible antagonist is an antagonist that binds __ and tightly with receptors so that the receptors are completely unavailable for binding of agonist.
- EXAMPLE: Phenoxybenzamine (used to treat pheochromocytoma [excess norepinephrine and epinephrine produced by a adrenal medulla tumor])
irreversibly
What is an Antagonist?
A drug that inhibits (blocks) effects of an endogenous agent on the function of a cell; also blocking effects of an agonist drug on a cell.
the DOSE is the __ of drug administered at one time (e.g., 500 mg; 40 Units; 5 mcg/kg
amount
the DOSAGE is the overall drug regimen, including the amount per dose, the frequency of dosing, and the total length of the drug regimen (e.g., 500 mg four times a day for 10 days).
dosage = amount, frequency, and length (or “age”) of regimen
the dose”age”
the LOADING DOSE is an __ dose of a drug, higher than subsequent doses, to achieve a rapid therapeutic plasma concentration.
first or initial
the MAINTENANCE DOSES are the doses of a drug, following a loading dose, to maintain a steady-state therapeutic plasma concentration. To maintain a steady-state plasma concentration, the maintenance dosage regimen must equal the rate of drug metabolism and elimination from the body.
-Dosing Rate = Clearance (i.e., rate of elimination from the body) X Desired Plasma Concentration of the Drug
clearance x desired plasma concentration = dosing rate
the ONSET OF ACTION is the Time it takes for a drug dose to begin to have a therapeutic __.
effect
the HALF-LIFE is the amount of time for the plasma concentration of a drug to decrease by __% after discontinuation of the drug; related to volume of distribution (see below) and clearance/elimination rate of the drug (see below).
50%
Maintenance dose
Doses of a drug following a loading dose, to maintain a STEADY state therapeutic plasma concentration.
To maintain a steady-state plasma concentration, the maintenance dose must EQUAL the rate of drug metabolism and elimination from the body!!!
What is the dosing rate?
Should equal the clearance rate from the body times the desired plasma concentration of the drug.
DR = CxPc (don’t need to compute)
the THERAPEUTIC INDEX is a measure of drug safety.
the Formula is: __50/__50
LD50/ED50
think “LED”, not “EDLD”
the MARGIN OF SAFETY is based on the therapeutic index.
- The __ the therapeutic index, the __ the margin of safety and the safer the drug is to administer without causing side effects.
- a Therapeutic Index less than or equal to 2.0 is difficult to use without the patient developing toxicity (e.g., digoxin, TI = 2.0).
higher
higher
STEADY-STATE CONCENTRATION is the time the (therapeutic) plasma concentration of a drug remains relatively __ (i.e., remains at a plateau).
constant
the PEAK is when drugs are administered (other than by continuous IV infusion), the plasma concentration of the drug increases immediately after the drug is administered and then decreases several hours after the drug is administered.
- The PEAK is the high point of fluctuation of a plasma drug concentration.
- Toxic effects are __ likely during the peak.
most
the TROUGH is the low point of fluctuation of a plasma drug concentration.
-Drug effects are __ during the trough.
unlikely
the HALF-LIFE is the amount of time for the plasma concentration of a drug to decrease by __% after discontinuation of the drug; related to volume of distribution (see below) and clearance/elimination rate of the drug (see below).
50%
What are drug receptors?
Proteins that may be membrane-bound (part of cell membrane) or intracellular (in the cytoplasm or nucleus).
with a CONTINUOUS IV INFUSION, plasma drug concentration rises rapidly.
- Steady state plasma drug concentration reached after __ to __ half-lives; INCREASING rate of infusion increases the plasma drug concentration AFTER steady state is reached, but does not DECREASE the time to reach steady state.
- Also requires same amount of time (4-5 half-lives) for clearance/elimination of 90-95% of the drug from the body.
4 to 5
Each cell has only a certain # of receptors which means…
it can become SATURATED.
When a drug binds with a cell receptor, what outcomes are possible? (4)
- Opening/closing of ion channels in cell membrane. Alters membrane potential and the cell’s activities; leads to RAPID TARGET CELL RESPONSE!!!
- Activate or inhibit intracellular enzymes, G-proteins, second messengers. The second messenger then activates or inhibits intracellular PROTEIN KINASES (enzymes) or various chemical reactions to bring about cell response.
- Increased nuclear DNA transcription to mRNA and increase ribosomal protein synthesis, which then brings about a cell response. THIS CAN TAKE A VERY LONG TIME, hours all the way even to weeks!
- Inhibition of DNA synthesis, ribosomal protein synthesis, and/or bacterial cell wall production.
What is receptor up-regulation?
Number of receptors on target cells increase in number (over time) and thus become MORE responsive to endogenous (made inside the body) or exogenous (made outside the body) agents.
What is receptor down-regulation?
Number of receptors on target cells decrease (over time) and thus become LESS responsive to agents.
Getting excess amounts of any kind of agent can lead to what?
receptor DOWN-regulation (a protective mechanism to protect cells from excess stimulation by an agent)
Too much chronic oxycodone creates “tolerance”(down-regulation)
PROTEIN BINDING COMPETITION- when one or more drugs __ for binding sites on plasma proteins.
- Thus, one drug is unable to bind with its protein binding site, which may increase the concentration of that drug (at least transiently).
- However, if the displaced drug is eliminated by the kidneys while in “limbo”, the concentration of the displaced drug will soon decrease, perhaps even to subtherapeutic levels.
compete
What is the affinity of drug receptors?
Is the strength of binding/affinity between a drug and its receptor.
The GREATER the affinity of a drug and its receptors, the GREATER the target cell RESPONSE.
A drug Agonist is what?
A drug that binds to the SAME cell receptor as an endogenous agent and brings about the SAME change in the function of the cell as the endogenous agent.
What is a STRONG (or full) Agonist drug?
A drug that produces maximal effects when bound with only a few receptors.
Ex - morphine, isoproterenol
What is a PARTIAL Agonist drug?
A drug that does NOT produce maximal effects even when bound with ALL cell receptors. (It produces a sub-maximal response)
Ex: - Buprenorphine - used to treat opioid addiction, is a partial agonist for u-opioid receptors.
ANTAGONISM is when one drug __ the effect of another drug (chemical antagonism) (1 + 1 = 0).
- The antagonist may or may not have pharmacologic activity by itself.
- E.G., naloxone antagonizes opioid analgesics.
- E.G., protamine antagonizes heparin.
- NOTE that both naloxone and protamine have pharmacologic effects of their own in addition to being antagonists for other drugs.
inhibits or stops
Only what form of a drug may leave the vasculature and hit the target cells?
Free form (when this happens, more of the BOUND form a drug is released into the blood)
Tissue reservoirs
Bones, adipose tissue.
Some drugs bind with the metals in bones - calcium
sometimes drug level in blood decreases, and then subsequently some of the drug is release from the reservoir. (depends on the nature of the drug and the receptor)
What is a major site of biotransformation of drugs?
Hepatic enzymes in Liver. - metabolites go back to the blood..
Excretion - what is major organ?
Kidneys -
Some of free form of drug and some metabolites (broken down parts of a drug) are excreted.
during the DISTRIBUTION PHASE of half life(t1/2 alpha) a RAPID decrease in the plasma drug concentration as a drug dose is __ throughout the body.
distributed
during the ELIMINATION PHASE of half life (t1/2 beta) a SLOW decrease in the plasma concentration of a drug because of its metabolism and __ from the body.
clearance/elimination
Rule of Thumb: It takes __ to __ half lives after starting a drug-dosing regimen for full effects to be seen.
4 to 5
It takes __ to __ half lives after stopping a drug for 90-95% of the drug to be cleared/eliminated and most of the drug effects to stop.
4 to 5
If the routes of drug clearance/elimination are altered, then it takes longer for a drug to be cleared/eliminated and its half-life is __. NOTE: This does NOT mean an increase in the NUMBER of half-lives, but an increase in the LENGTH or TIME of each half-life
lengthened or increased
the DRUG DOSE - TIME - RESPONSE CURVE is an individual’s response to __ doses of a given drug over time.
-Shown as a graph that compares the magnitude of drug actions with the concentration of the drug required to cause those actions, which are affected by everything you can imagine.
increasing
RED-MAN (RED-NECK) SYNDROME is related to __ IV infusion of vancomycin.
- Characterized by fever, chills, paresthesias, vasodilatation, hypotension, and erythema at the base of the neck and upper back.
- Usually resolves 15-20 minutes after infusion stopped.
- After symptoms subside, restart the infusion at a SLOW rate.
rapid
a SINGLE DOSE exhibits __ plasma drug concentration rise and peak as the drug enters the bloodstream, and then fall rapidly as the drug is distributed from the blood to tissues, and then is biotransformed and eliminated/cleared.
one
INTERMITTENT DOSING leads to __ peaks and troughs of plasma drug concentration.
- Drug must be administered for 4 – 5 half-lives of the drug before steady state is reached.
- Also requires same amount of time (4-5 half-lives) for clearance/elimination of 90-95% of the drug from the body.
multiple
with a CONTINUOUS IV INFUSION, plasma drug concentration rises rapidly.
- Steady state plasma drug concentration reached after __ to __ half-lives; INCREASING rate of infusion increases the plasma drug concentration AFTER steady state is reached, but does not DECREASE the time to reach steady state.
- Also requires same amount of time (4-5 half-lives) for clearance/elimination of 90-95% of the drug from the body.
4 to 5
What is an Antagonist?
A drug that inhibits
EFFICACY is the degree to which a drug causes maximal effects, or the __ of a drug for treatment of a specific condition.
effectiveness