PTCB PREP: SECTION 1 - MEDICATIONS

what is pharmacodynamics?

• study of how drugs cause their effects to happen

• usually by interacting w/ specific receptors found in cell membranes or intracellular fluid

what is an agonist?

the drug

what is an antagonist?

other drugs competing to bind at the same receptor as a drug (agonist)

what is pharmacokinetics?

study of body processes that interact w/ drugs: absorption, distribution, metabolism, and excretion (ADME)

what do the ADME processes involve the movement of drugs across within the body?

cellular membranes

what is absorption?

drug’s movement from site of administration into the bloodstream

what 3 factors influence the rate of absorption?

• molecule size

• lipophilicity (lipid/fat-loving)

• pH environment

what is distribution?

drug’s movement throughout body to reach their target sites

what is 1 factor that influences distribution?

tissue perfusion rates (rate of blood flow to tissues)

ex: highly perfused tissues → receive higher proportion of drug

what is metabolism/biotransformation?

• body transforms drugs into hydrophilic forms/water-soluble metabolites to eliminate them

• drug is transformed bcuz its considered a foreign substance (xenobiotics) → cannot be eliminated in this form

what is phase 1 metabolism?

drugs transformed into hydrophilic metabolites/forms thru oxidation, reduction, and hydrolysis

what is phase 2 metabolism?

combining hydrophilic metabolites w/ polar groups for excretion

what is excretion?

elimination of drug from body:

• hydrophilic metabolites exit thru urine/bile

• tears

• sweat

• breath

• saliva

which organ plays a primary role in drug metabolism?

the liver bcuz it has many different enzymes

what is metabolism that happens in the liver called?

hepatic metabolism

which organ plays a primary role in drug excretion?

kidney

what is excretion that happens in the kidney called?

renal excretion

what is a generic name of a drug?

its approved name

what is a brand name of a drug?

its name made by its manufacturing company

what is an over-the-counter (OTC) drug?

• nonprescription drug (doesnt need a prescription)

• for relief of common symptoms

what are 2 categories of supplement drugs?

• water-soluble vitamins

• fat-soluble vitamins

what are water-soluble vitamins?

• vitamins that dissolve in water & arent retained in the body

• needs:

  • energy production

  • nerve function

  • strong immune system

• vitamin B, C

what are fat-soluble vitamins?

• vitamins that accumulate/build-up in fat tissues & liver

• for:

  • vision

  • bone health

  • antioxidant protection

  • blood clotting

• vitamins A, D, E, K

what are the requirements for a drug to be pharmaceutically equivalent?

• same active ingredient

• same dosage form

• same route of administration

• same strength/concentration

what are the requirements for a drug to be bioequivalent?

• no known/potential bioequivalence issues

• follows in vitro standard/bioequivalence standard

what are the requirements for a drug to be therapeutically equivalent?

• pharmaceutical equivalent - same active ingredient, strength, dosage form, route of administration

• bioequivalent - same action

what is bioavailability?

fraction of a drug that enters the bloodstream &is available for action @ its target site

what should be regularly monitored if a patient is taking warfarin?

international normalized ratio (INR) - how long it takes for blood to clot. makes sure blood isnt too thin or thick (either is dangerous)

what is First Pass Effect?

• common for oral route

• when med is first absorbed by liver (doesnt bypass GI tract) → affects systemic effects

how are IM injections delivered?

into muscle tissue @ 90 degree angle

how are SC injections delivered?

into tissue layer between skin & muscle @ 45 degree angle

how are IV injections delivered?

straight into vein @ 25 degrees

how are ID injections delivered?

under skin @ 10-15 degrees

what are 4 common allergenic meds (meds that are more likely to cause drug allergies)?

• antibiotics:

  • penicillins

  • cephalosporins

  • sulfonamides

• NSAIDs:

  • aspirin

  • ibuprofen

  • naproxen

• chemotherapy drugs:

  • taxanes

  • monoclonal antibodies

• contrast agents

what is drug stability?

drug’s ability to maintain its efficacy and safety by remaining stable (unchanged) during its time of use and storage

what is Current Good Manufacturing Practices (CGMPs)?

• enforced by FDA

• requires drug manufacturers to do stability testing to assess effectiveness of their drugs

what is chemical stability?

drug’s ability to maintain its chemical properties when exposed to various environmental conditions that could cause degradation

what is the most common type of chemical degradation?

hydrolysis - drug reacts w/ water

what is physical stability?

drug’s ability to maintain its physical properties overtime

what is microbiological stability?

• prevention of microbial contamination during the storage & transportation of drugs

what is an oral suspension?

• solid particles suspended/dispersed in a liquid

• excessive settling of particles is bad

what is a reconstitutable?

powdered drugs mixed w/ a liquid solvent by the patient

what is Narrow Therapeutic Index (NTI) meds?

• drugs that have a small difference between therapeutic dose (the dose that provides desired effect) & toxic dose (the dose that can cause harmful/toxic effects)\

• narrow margin of safety - a small change in dose or blood concentration → significant therapeutic responses or adverse effects

what are 4 examples of NTI meds?

• warfarin - anticoagulant

• digoxin - for heart failure & arrhythmias

• levothyroxine - thyroid hormone

• phenytoin - antiepileptic (for seizures in those w/ epilepsy)

what does monitoring INR for warfarin help healthcare providers determine?

appropriate dosage adjustments to maintain its therapeutic effects within a safe range

what is drug compounding?

preparing customized meds for patients w/ specific needs

what is sterile compounding?

preparing customized meds in a sterile environment to reduce risk of contamination & ensure patient safety

what is Personal Protective Equipment (PPE)?

for reducing risk of introducing contaminants

what are 4 examples of PPE?

• gloves

• masks

• gowns

• head coverings

what 3 things should the sterile compounding area have?

• controlled airflow

• HEPA (high-efficiency particulate air) filtration systems

• surfaces that are easy to clean & disinfect

what are 3 examples of aseptic technique?

• proper hand hygiene

• disinfection of work surfaces

• use of sterile tools & equipment

what is non-sterile compounding?

preparing customized meds that dont require sterile environment

what are standard operating procedures (SOPs) for?

• minimizing errors

• maintaining quality control

which type of compounding is USP 795 for?

non-sterile compounding

what are the steps for non-sterile compounding?

1. creating a formula:

   • create a formula using the compounding formula for specific product

   • make calculations to determine specific amounts of ingredients needed

2. preparing:

   • wash hands

   • wear PPE

3. obtaining equipment:

   • obtain tools to weigh or measure ingredients

4. mixing & blending:

   • combine ingredients in correct ratios & proper order by using the compounding formula instructions

   • make sure to thoroughly and uniformly mix ingredients

5. documentation & labeling:

   • record exact amounts of each ingredient used during compounding

   • label final product (ex: strength of ingredients)

whats the difference between ointments & creams?

• ointments: oil-based, water in oil

• creams: water based, oil in water

what is spatulation?

• for making ointments

• equal amounts of each ingredient are geometrically mixed on an oil slab until create uniform mixture (ointment)

what is geometric mixing?

mixing small amount of active ingredient w/ large amount of diluent continuously

what are emulsions?

2 immiscible/unmixable liquids (water and oil)

what are techniques for making suppositories?

• hand rolling

• fusion molding

• compression molding

what is hand rolling for suppositories?

mixing suppository base w/ med to form a cone-shaped mold

what is fusion molding for suppositories?

• suppository base is melted

• active ingredient is suspended/dispersed in melted base

• liquid mixture is poured into molds to cool & solidly

what is compression molding?

• suppository base isnt melted

• powder is used to mix base & active ingredient

• mixture is compressed into molds using pressure

what are suppositories commonly administered thru?

• rectally

• sometimes vaginally

what are enemas?

• liquid solutions administered rectally to treat constipation or ulcerative colitis

• absorbed by colon lining for local effects

what does USP <795> include?

non-sterile compounding

what does USP <797> include?

sterile compounding

what are 4 types of inactive ingredients?

• additives

• diluents

• excipients

• preservatives

what are additives?

for preparing dosage form

what are diluents?

for increasing bulk weight or volume

what are excipients?

to help deliver active ingredient in body

what are preservatives?

to slow, minimize, or prevent bacterial growth

what are the 6 types of solid dosage forms?

• capsules

• lozenges

• powders

• tablets

• suppositories

• granules

which has a quicker onset of action: solid or liquid dosage forms?

liquid dosage forms bcuz they dont need to be dissolved

what are 6 types of liquid dosage forms?

• solutions

• syrups

• suspensions

• elixirs

• emulsions

• tinctures

what are lozenges?

hard circular/oval, sugar flavored solid dosage form surrounding a drug

ex: cough drops

what is a solution?

• liquid dosage form

• homogenous (evenly distributed) mixture of 1/more dissolved drugs (solute) in a liquid vehicle (solvent)

• no drug particles can be seen when held up to light

what is a suspension?

• liquid dosage form

• mixture of very small particles (insoluble drug) in a liquid that settle → must shake well to get correct dose

• small particles (insoluble drug) can be seen when held up to light

what are suppositories?

solid dosage form inserted into rectum, vagina, or urethra

what kind of solutions are elixirs and tinctures?

nonaqeous hydro-alcoholic solutions (water and alcohol)

what is the caution of elixirs and tinctures?

• can interact w/ other meds patients are taking

• not for babies

what are elixirs?

• liquid dosage form

• drug in sweetened water w/ alcohol (3-25%)

what are tinctures?

• liquid dosage form

• drug in a higher concentration alcohol than elixirs

what are semisolid dosage forms?

• too thick to be considered a liquid; too soft to be considered a solid

• for topical route

what are 4 types of semisolid dosage forms?

• ointments

• creams

• pastes

• gels

what are ointments?

• oily semisolid dosage form

• mostly for local effect not systemic effect

what is the ointment that provides systemic, not local effect?

nitroglycerin ointment

what are pastes?

• semisolid dosage form

• stiffer and less greasy than ointments

• for oozing lesions bcuz they can absorb water

what are creams?

• semisolid dosage form

• contain water and oil

• for larger areas

what are gels?

• sicky and transparent semisolid dosage forms

• solid diffused throughout a viscous liquid

• quickly absorbed by skin

which dosage form has the label: “For External Use Only”?

semisolid dosage forms

which dosage form has the label: “Do Not Crush or Chew”?

extended release tablet

which dosage form has the label: “Shake Well”?

suspensions

which dosage form has the label: “Caution: Contains Alcohol”?

elixirs/tinctures

what are pharmacodynamic drug interactions?

happens when the effect of a drug is changed by the presence of another substance acting at the same place

what are the 3 types of effects for pharmacodynamic interactions?

• additive effects - total effect is same as sum of each drug

• synergistic effects - total effect is greater than sum of each drug

• antagonistic effects - action of drug is diminished

what are pharmacokinetic drugs interactions?

happen when the concentration of a drug is changed in the body due to change in clearance, peak levels, etc.

warfarin + aspirin

• drug-drug interaction

• increases bleeding risk

ACE inhibitors + spironolactone

• drug-drug interaction

• causes hyperkalemia (high potassium blood levels)

digoxin + amiodarone or verapamil

• drug-drug interaction

• increases digoxin levels