Pharm Exam 1

What is a drug?

anything that prevents, cures, or treats a medical condition

what is an example of something that we can ingest that helps alleviate symptoms?

caffeine

how to drugs affect people?

drugs affect men, women, adults, and children very differently

what are the two most important properties of a drug?

safety and efficacy

what happens when both safety and efficacy are high?

the drug will be prescribed more often

does a perfect drug exist?

no

what are other things we want in a drug?

• convenient administration

• inexpensive

• once a day

• few drug-drug interactions

• rapid, predictable response

what does it mean when a drug has a rapid, predictable response?

• we know how long it takes to be effective

• we can predict potential negative responses

what are the classifications of drugs?

• therapeutic

• pharmacologic

• prototype

characteristics of a therapeutic drug class?

• umbrella term

• usually contains a prefix

• what is it designed to do?

  ex: Anti-hypertensive

what is the exception to the therapeutic drug class?

analgesics (pain medications)

characteristics of a pharmacologic drug classification

• how long does the drug work?

• mechanism of action

• how does the drug do what its supposed to do?

  • ex: beta blockers, ACE inhibitors

characteristics of a prototype drug

• reference drug

• safest and most effective drug in that class

• typically the most commonly prescribed

• all drugs in the class are structurally similar

what are the ways to name a drug?

• chemical

• generic

• trade

characteristics of generic name

• cheaper

• in parentheses

• always lowercase

• different from the brand drug in terms of inactive ingredients

characteristics of trade name

• brand name

• always capitalized

• $ (bc company owns rights to this drug)

who regulates drugs?

FDA (food drug aministration)

what does the FDA regulate?

anything that claims to prevent, cure, or treat a medical condition

ex: food, medication, and cosmetics

what is unique about the FDA regulations with supplements and cosmetics?

it is regulated by the FDA but there is no testing involved

characteristics of pre-clinical research

• usually tested on animals

• occur in test tubes and petri dishes

characteristics of Phase 1 Drug Development

• is this drug safe in humans?

• healthy volunteers (do not have disease)

• 20-80 people

• white males, so data is skewed

• placebos were used, but not anymore

characteristics of Phase 2 Drug Development

• does the treatment really work?

• 500 people with disease in testing

• ideal dose

• signs and symptoms

characteristics of Phase 3 Drug Development

• is it better than the standard of care (what we’re already using)

• looking for variability

• 500 to several thousand with the disease

• more representative picture of the country

characteristics of surveillance period

• where most of the info about a drug is revealed

• not just young, white men

• pregnant women, children, and people with different ethnicities

are OTC drugs dangerous

yes, they can be just as dangerous as prescription drugs

what are the 4 phases of pharmacokinetics?

1. absorption

2. distribution

3. metabolism

4. excretion

what are the phases of pharmacodynamics for the oral route of administration?

• absorption

• metabolism

• distribution

• metabolism

• excretion

what is absoroption?

site of administration to the blood stream

what is absorption affected by?

GI Tract

what happens to absorption when the stomach is empty?

it increases

when is the stomach considered empty?

1 hour before and two hours after eating

what decreases absorption?

fatty foods (drugs are lipid soluble)

what are the routes of administration?

• oral

• IV

• topical

• respiratory

• oral

examples of oral administration

• sublingual

• buccal

examples of IV administration

• IM

• ID

• SQ

what method of oral administration is fastest

liquid

characteristics of IV drug administration

• not absorbed

• goes directly into the bloodstream

• 100% bioavailability

what do you need to be prepared for with IV drug administration?

• be prepared for immediate responses and reactions

  ex: anaphylaxis

what is the first pass effect

• loss of some drug to metabolism through hepatic portal system (system of veins that transports blood from digestive tract to liver)

• only drugs you swallow

• greatly reduces drug’s bioavailability

what drugs are susceptible to the first pass effect?

oral pills and liquid medications

what are extended release capsules?

drugs intended to be released over a long period of time

what are enteric coated medications?

drugs that have a coating making them easier to be digested

what does it mean to have lower bioavailability?

losing some of the drug before it reaches circulation

what are the factors that influence a drug’s ability too pass through the barriers?

• size

• ionization

• lipid solubility

what makes it easier for a drug to pass through the barrier?

• smaller drugs

• nonionized (drugs that are not charged)

• fat soluble/lipophilic

why do fat soluble/ lipophilic drugs cross barriers more easily

it makes it easier to cross the lipid bilayer of the cell membrane

what is distribution?

movement of drugs throughout the body after absoption

what is distribution affected by?

• perfusion

• protein/ drug binding

what happens when there is more perfusion?

there is more distribution of drugs

what is the protein in the blood that helps with drug distribution?

albumin

what does it mean when a drug is bound to a protein?

it is bound, inactive, and has no effect

what happens when a drug makes it to the target site?

it is free, active, and can cause a response

what population is more susceptible to toxicities?

older adults

why are older adults more susceptible to toxicities?

bc they have lower albumin levels so it can not be distributed effectively

what is an active drug

a drug that is working and can elicit a response

what are free drugs?

drugs that are not bound to a protein and can now cause an effect

what happens when there is too much of a “free” drug?

toxicities can occur

what is an inactive drug?

a drug that is not working and cannot elicit a response

what is metabolism?

changing a drug to be easier to excrete

where does metabolism primarily occur?

liver

what is the cytochrome P450 system?

enzymes that sit on hepatocytes and alter drugs

what are hepatocytes?

liver cells

what is true about the enzymes of the cytochrome P450 system?

they are responsible for metabolizing drugs

what are metabolites?

altered form of a drug after metabolism

what are the roles of drugs in the P450 system?

• drugs as a substrate

• drugs as an inducer

• drugs as an inhibitor

what is a substrate?

things that are metabolized by enzymes

characteristics of drugs that act as inducers

• encourages drug metabolism

• drugs wear off faster

• shorter therapeutic effect

characteristics of drugs that act as inhibitors

• blocks metabolism of other drugs

• more free drug buildup in the body

what drugs does the P450 system affect?

drugs that are being metabolized at the same time

what is excretion?

how drugs leave the body

what is the primary system in excretion?

the renal system

what are the systems involved in excretion?

• renal

• biliary

• pulmonary

• glandular

how does the pulmonary system excrete drugs?

exhalation

how does the glandular system excrete drugs?

• through ducts

  ex. sweat, saliva, and milk

why are we worried about excretion through milk ducts?

bc of breastmilk and its teratogenic effects

how does kidney function impact how long a drug stays in the body?

• impaired kidney function makes drug excretion take longer

• potentially administer a lower dose

• buildup can lead to toxicities

what are the benefits of oral drug administration?

• safer

• cheaper

• more convenient

what other things affect drug absorption besides the GI tract?

• acidic foods and drinks

• PPI/H2 antagonists

what are the risks associated with IV administration?

• bypass barriers w needle

• potentially introduce infection into bloodstream

• proper disposal

• sharps care and safety

what should you assess before oral administration?

mucous membranes

what can you do for a drug in toxic concentrations?

• hold drug for a period of time

• reduce the dose or frequency

what can you do for a drug in sub-therapeutic range?

increase the dose or frequency

how do you measure what therapeutic range a drug is in?

through serum drug trough levels

what is a trough level?

lowest serum concentration before the next scheduled dose

what is a loading dose?

initial large dose of a drug to get you to therapeutic range

what do you to after a loading dose is given?

give continuous maintenance doses

when are loading doses used?

• used in situations where you need a fast effect

  ex: emergency

characteristics of regular, repeated dosing

it takes longer for the drug to have an effect

what is a half life?

the amount of time it takes for ½ of the original amount of drug in the body to be removed

what is the ideal half life?

4-4.5 hours

how many half lives until the drug is effectively eliminated from the body?

4.5

what do you assess during drug metabolism?

• liver function tests

  ex: AST/ALT, bilirubin, AP

what do you assess during drug distribution?

• serum protein levels

  ex: albumin and total protein

what do you assess during drug excretion?

• kidney function tests

  BUN, Creatinine, GFR

how is the duration of a drug affected by protein binding?

it is much longer

how is a drug dose affected by protein binding?

potentially larger dose for therapeutic effect

why do drug interactions increase with highly bound protein drugs?

• bc there is competition for limited binding sites

• risk for other free drug effects and toxicity

how does age affect drug protein binding?

age REDUCES albumin levels

characteristics of agonists

• mimics endogenous substances

• increased responses

characteristic of partial agonists

mimics endogenous substances to a lesser degree