Module 1B - Pharmacologic Principles

Pharmacology

adverse effect

• undesirable, inadvertent, unexpected, and potentially dangerous responses to medication

• not the same as side effects

Indication

intended use - what the pt is getting it for - either to prevent, treat, or diagnose a given condition

Contraindicated

HARD STOP - do not give, not safe to give

caution

use caution if giving and monitor closely

therapeutic effectiveness

• intended goal of the medication being given

• lets us know it is working how it’s supposed to

hepatoxicity

causes severe liver damage

nephrotoxicity

causes severe kidney damage

toxicity

either taking too much medication or taking for too long

allergic reaction

immune system reacts resulting in rash, hives, itching

Anaphylaxis

• most severe form of allergic reaction

• life threatening!!

• can present as hypotension, swelling, obstruction of the airway

• treated with IM epinephrine

pharmacokinetics

how medicine moves through the body and what the body does to the medication

absorption

transmission of medication from the location of administration to the blood stream

bioavailability

amount of medication that enters into circulation to have an effect on the body

IV administration

medication directly enters bloodstream resulting in complete and immediate absorption with no limitations. 100% bioavailability

distribution

the transportation of medication to sites of action by bodily fluids

poor blood flow

delays/limits medication distribution

metabolism

• changes medication into less active or inactive forms by the action of enzymes

• liver is the primary location of this

• also known as biotransformation

first pass effect

• what happens when medications go through the liver

• results in reduced amount of medication available

• IV and sublingual bypass this

clinical s/s of impaired liver function

yellow sclera, clay colored stools, jaundice, elevated AST/ALT, ascites, nausea, vomiting, anorexia

excretion

elimination of medication from the body primarily though the kidneys

clinical s/s of impaired kidney function

elevated creatinine/BUN, decreased urine output (less than 30ml/hr), rapid weight gain (fluid retention), dark/cloudy urine, imbalanced I/O, peripheral edema, increased RR, imbalanced electrolytes

considerations for older adults

increased occurrence of kidney and liver damage leading to impaired metabolism and excretion → may need smaller doses due to increased risk of toxicity

polypharmacy

taking 5 or more medications a day → increases risk of interactions and side effects

considerations for pediatrics

immature blood brain barrier → medications often have greater CNS effect

immature kidney/liver → slower metabolism/excretion

decreased first pass metabolism → more active medication in circulation

high/wide therapeutic index/window

wide safety margin, blood levels do not need to be monitored

ex: OTC medications

low/narrow therapeutic index/window

narrow safety margin, blood levels need to be monitored due to high risk for toxicity, require a prescription.

ex: warfarin, digoxin

peak

• highest concentration of medication in an individual

• timing of measurement depends on route of admin and medication

peak of IV meds

15-30 min

peak of IM meds

30-60 min

peak of PO meds

about 60 min

Trough

• lowest concentration of medication in an individual

• measured immediately before the next dose

half-life

the time it takes for the medication in the body to drop by 50%

short half-life

medications leave the body more quickly → short dosing interval

long half-life

medications leave the body slower → longer dosing interval

• increased risk for toxicity

pharmacodynamics

how the medication acts on the body

agonist

mimics receptor activity → turns switch completely on

agonist/antagonist

some activation/deactivation of site → less effective than full agonist/antagonist

antagonist

blocks receptor activity → turns switch completely off

pharmaceutics

the study of medication properties in different routes, study the safety and efficacy of meds

enteric coating

• should always be taken whole

• med may be either irritating to stomach lining or destroyed by stomach acid

sustained release/extended release

designed to be released over a longer period of time

PO meds - pay attention

to crushing, cutting, and diluting instructions, you should only ever cut scored tablets

verbal/phone orders

listen carefully, write them down, MUST READ BACK

10 rights of medication administration

client, medication, dose, time, route, documentation, education, to refuse, assessment, evaluation