INTRO

therapeutic index

ratio between drugs therapeutic effect and toxic effect

how to calculate therapeutic index

toxic (td50)/beneficial (ed50)

low therapeutic index vs high

higher = safer

tolerance

decreasing response to repetitive drug doses

dependence

physiologic/psychological need for drug

adverse drug event

all preventable, med error

adverse drug reaction

inherent. not preventable. undesirable, normal dose

iatrogenic response

treatment induced but unintentional

teratogenic

disrupts fetal development

mutagenic

alters dna, mutation

carcinogenic

promotes development of cancer

pharmacokinetics

how its absorbed, distrubted to body, excreted, etc.

factors of drug absorption

has to cross cell membrane: solubility in water/fat, molecule shape/size

iv injection

straight to bloodstream, rapid action

other routes of drug administration

needs to be absorbed from site of administration. depends on absorption rate (ka)

factors affecting ka

route of administration, blood supply, pH, solubility, gut

central compartment of drug absorption

organs, blood vessel. low volume distribution. hydrophilic (low lipid solubility)

peripheral compartment of drug absorption

skin/fat store. high volume distribution. lipophilic (high lipid solubility)

volume of distribution

drug (mg) in body/plasma concentration. tendency to remain/distribute in blood plasma

high distribution

leaves extravascular. = higher dose

plasma protein binding

only free fractions move to target site. most are bound to protein (free fraction:plasma protein bound)

major organ of metabolism

liver. drug becomes either unchanged or a metabolite (inactive/active)

active metabolites

clinical

n.b.

nota bene. take notice/note well

drugs affecting metabolism

genetic, other drugs, age, disease

first pass effect

metabolism of drug and entry into circulation. oral = metabolized by liver before circulation. iv = prevents first pass effect bc alr injected to circulation

first pass metabolism mechanic

gut ➡️ liver (portal vein) ➡️ body

prodrug

metabolites that enter liver but not metabolized by liver. inactive medication that converts into an active, therapeutic drug once it enters the body and undergoes metabolic processing

presystemic metabolism

single entry to gut e.g. propanolol

excretion of drugs

urine, gut, sweat, saliva, breath (lungs)

bioavailability

extent that active ingredients are absorbed and transported to site of action

od

once a day

bid

12 hourly

tid

8 hourly

qid

6 hourly

prn

as required

depot

weekly/monthly/quarterly

stat

immediately

plasma levels are only consistent with

iv infusion

short half life requires

more frequent dosing

long half life requires

less frequent dosing

steady state concentation

plateau concentration,

therapeutic index ratio

maximum tolerated dose/minimum curative dose. indication of safety. antibiotic

sublingual route

abundant blood supply, quick effect, no first pass metabolism, no degredation by digestive juices

rectal route

rich blood supply, no irritation of git

significance of protein binding on drugs

prolongs action of drug by acting as reservoir (delays metabolic degredation/excretion)

drugs that are free, unbound example

albumin

enteric coating

pills w coating that resists stomach acid but disintegrates in intestines

sr preparations

sustained/time release. specialized medication preparations to release drug gradually into your body over an extended period

pharmacotheraputics

use of drugs to treat, cure disease

site of drug excretion

kidneys

site of drug metabolism

liver

enteral drug administration types (3)

oral, sublingual, rectal (enteral: intestines/gi tract)

4 kinds of parenteral drug administration

intravenous, intramuscular, subcutaneous, intradermal (parenteral: bypasses/avoids gi tract)

topical vs. transdermal administration

topical: applied directly to skin, localized. transdermal: applied to skin via patch/ointment, but absorbed into bloodstream via skin

alkaloid plant drugs

morphine, atrophine, quinine, reserphine. ephedrine

glycoside plant drugs

digoxin. digitoxin

animal derived drugs

insulin, heparin

mineral derived drugs

ends in ate

microorganisms derived drugs

ends in in

semisynthetic derived drugs

ends in one. hydromorphone. hydrocordone. or in/e. amoxicillin, ampicillin, doxycycline

synthetic drugs examples

aspirin, paracetamol

inorganic drugs

metals

synthetic source

sulphonamide, procraine

biosynthetic source

recombinant human erythropiotin. recombinant bovine somattotropine

caustics

silver nitrate

demulcents

zinc oxide, tannic acid

filtration

only small water soluble molecules cross hydrophilic pores

after meals

p.c.

as directed by doctor

ut dict

as needed

p.r.n.

at night

noct

bedtime

h.s.

before meals

a.c.

by mouth

p.o.

capsule

cap

daily

qd

day

d

dispense as written (no substituting generic or brand name drugs)

daw

drop

gtt

every 3 hours

q 3 h

every hour

qh

every morning

qAM

every other day

q.o.d.

four times a day

q.i.d.

in each eye

O.U.

into the muscle

I.M.

into the vein

I.V.

left eye

O.S.

milligram

mg

milliliter

ml

pill

pil

right eye

O.D.

tablespoon

tbsp

tablet

tab

teaspoon

tsp

three times a day

t.i.d.

twice a day

b.i.d.

twice a night

b.i.n.

under the tongue (sublingual)

s.l.