Pharm 1 Flashcards
Pharmacokinetics
movement and alteration of the drug inside the body. absorption, distribution, metabolism, excretion
Pharmacodynamics
action of the drug inside the body
Therapeutics
to care for, tend to, or nurse
ex. Of phototherapy
hyperbiliureinemia in neonates and skin diseases
Chemotheraphy
treat infections, parasitic infestations, and malignancy with specific drugs that have selective toxicity for infecting organsims/malignant cells with not/minimal effects on the host cell
Toxicology
study of poisonous effect of drugs and other chemicals and also includes the study of adverse effects of drugs
clinical pharmacology
study of drugs in human
pharmacogenetics/pharmacogenomics
study of genetic basis for variations in drug response
plant
Plant _ Morphine, Atropine
animal
Animal _ Heparin, Insulin
human
Human _ GH, hCG
mineral
Mineral _ Iron, Al(OH)3
microbes
Microbes - Penicillin
synthetic
Synthetic _Aspirin, Acetaminophen
genetic engineering
Genetic Engineering - Insulin
Ditoxin and digitoxin
from fox clove plant. Woman had edema used plant to decrease edema and doc studied it to from digitoxin
generic name vs brand
acetaminophin vs tylenol
chemical name vs generic name
acetylsalicylic acid vs asprin
proprietary name
brand
Routes of administration (7)
oral, sublingual, parenteral (IV/IM/SC/intraarterial/intraarticular/intrathecal/intraperitoneal/intradermal), rectal, inhalation, topical (vaginal/opthalmic), transdermal
Sublingual
bypass portal system and first pass metabolism eg. Nitroglycerine
parenteral
avoids mouth and intestines
intraarterial
effect in local area
intravenous
go to the whole body, not local actin
intra thecal
injectioninto subarachnoid space in spinal cord. Used for spinal anestesia or brain conditions especially for drugs that don’t cross the blood brain barrier
topical
administere and action on the same site
transdermal
action desiered is systeing–drug is absorbed from the skin
oral pros
most common, convenient, noninvasive, self-medication possible, economical
oral cons
cannot be used for uncooperative/vomiting patiens, certain drugs are not absorbed or destroyed by the gastric juices, cannot be given in emergencies, drugs are more likely to undergo first pass metabolism
sublingual
no first pass metabolism, fast onset of action compared to oral route. Ex GTN (trinitorglycerine used for hypertension, heart failure), nifedipine (ca channel blocker)
parenteral-intravenous pros
immediate action, useful in emergencies, avoids gastric juices/first pass metabolism, can be used in unconcious patients, irritant drugs can be given
intravenous cons
painful, rusk of thrombophlebitis, expertise required, aseptic condition needs to be maintained, costly, attains high concentration in plasma and tissues and can cause toxicity
intramuscular
mild irritant drugs can be given, absorption is quick, volume injected is max 10ml, no first pass metabolism
subcutaneous
absorption is slow and constan, produce sustaned effect, mas 2 ml can be injected, self administration possible (insulin) pellet implantation (drug released over weeks–testosterone), silastic implants (drug released over months–contraception)
intradermal
bcg vaccination, drug sensitivity testing
intraarticular
steroids in rheumatoid arthritis
intrathecal
used where durgs (lipid insoluble/highly polar) do not corss blood brain barrier but require action in brain or spinal space, strict aseptic precautions should be taken, eg. Amphotericin B in cryptococcal meningitis (poor penetration of BBB), spinal anesthesia, opiod analgesics (fentanyl)
rectal
relatively little first pass metabolism, used in patients with vomiting or where drugs induces vomiting, larger amount and drugs with unpleasant taste can be administered, ex. Diazepam, acetaminophen, asprin (not given to children w/ fever bc they can develop reyes)
topical
application of drugs to skin or to the mucus membrane like eye, ear, mouth, airway, rectum and vagina for local actions only, usually no systemic adverse effects
transdermal delivery system
administration of drugs to skin for systemic effects, provides uniform plasma concentration, less inter-indificual variations, no first pass metabolism, convenient–better compliance, eg estradiol, gtn, scopolamine
inhalation
delivery of drug to respiratory tract, alveolar epithelium offers good surface area for lipid soluble drugs, (fastes) very rapid onset of action due to large surface area and more vascualrity, drugs administered in gases or aerosol form, fapid action, no/less systemic toxicity, dose required is less, eg. inhalational anesthetics (nitrous oxide, ether, halothane), albuterol, steroids-beclomethasone in asthma
inhalation cons
training for use (difficult for children and geriatrics), expensive, cannot be given to unconsious patients
dose
amout/quantity ex 5mg (strength of drug)
dosage form
the physical form in shich drug is taken ex. Tablet
dosage form examples
solid, liquid, gaseous, semi-solid
Absorption
passage of drugs from the site of administration to the system circulation/plasma (not seen w/ IV)
process of obsorption
simple/passive diffusion, carrier-mediated facilitated diffusion, active transport, filtration, pinocytosis
simple/passive diffusion
majority of drugs, high conc. To low conc., no energy, not satruable, not inhibited, lipid soluble drugs pass through lipid bilayer by this process, driving force is concentration gradient
carrier-mediated facilitated diffusion
move along conc. Gradient but need carrier, no energy, highly selective, competitive, and sturable, ex. Vit B12, glucose
active transport
against concentration gradient, req both carrier and energy, selective, competitive, and saturable, ex. Iron, levodopa
filtration
passage of some water soluble substanses through aqueous channels in the tight junctions btw adjacent epithelial cells, minor role in drug absorption
pinocytosis
ability of cells to enguf small droplets, important in unicellular organisms like ameba, not in multicellular organsims
c max
maximal drug level obtained with the does
t max
time at chich c max occurs
lag time
time from administration to appearance in the blood
onset of activity
time from administration to blood level reaching minimal effective concentration
duration of action
time plasma concentration remains grater that minimum effective concentration (MEC)
time to peak
time from administration to c max
bioavailability
the proportion of the dose administered that is available at the systemic circulation, rate and extent of drugs reaching the systemic circulation in unchanged form (F)
IV route bioavailability
100%, F = 1
Bioavailability formula
F oral = auc oral / auc iv; change oral to whatever form of administration you want
chemically equivalent
satisfy the chemical and physical standards in parmacopeia; dos not necessary mean biologically equivalent and therapeutically equivalent, differnet brands have different responses
bioavailability - drug related - physical properties of the drug
physical state (liquids better than solids), lipid or water solubility (lipophillic drugs absorbed faster than hydrophillic drugs)
bioavailability - drug related - nature of the dosage form
particle size, disintegration time and dissolution rate, formulation
particle size
small are better absorbed bc inc surface area, inc abs, inc BA
disintegration time
rate of breakup of tablets into particles, higher means lower abs and BA
dissolution rate
rate at which drug goes into solution, higher means inc abs and inc BA
formulation
binding agent/excipient_.incompatible formulation can slow abs and BA ex. Tetracylines w/ ca of mg as excipients slow abs and BA
bioavailability - patient related - physicological factors
pH and ionization constant, gastric emptying, surface area and its vascularity, presence of food, first pass metabolism/pre-systemic elimination
pH and ionization constant
non ionized (lipophillic) efficiently cross membranes
acidic drugs are better absorbed in the
stomach
henderson hasselbalch for acid
ph - pka = log ionized/nonionized
henderson hasselbalch for base
ph - pka = log nonionized/ionized
basic drugs are better absorbed in the
intestine
pka
drug in and eqm of ionized and non ionized (50/50)
ph > pka
good basic abs, more acid ionization (i.e. ph - pka = positive numbers)
ph < pka
good acidic abs, more basic ionization (i.e. ph - pka = negative numbers)
ionized drug - renal clearance, reabsorbtion
more renal clearance, less reabsorbtion
non ionized drug vs renal clearance
inverse relationship
gastric emptying time
lower means more abs more BA (exception - diarrhea)
gastric emptying time accelerated by
metoclopramide
gastric emptying time prolonged by
fatty meal, acid drinks, drugs w/ antimotility effects
surface area and its vascularity
increase means inc abs, inc BA ex. More abs in intestine vs stomach due to inc SA, inc blood flow
presence of food
can facilitate or hamper abs
milk w/ tetracyline
dec abs
food w/ ampicillin
dec abs
fatty diets w/ griseofulvin
inc abs
first pass metabolism
inc means dec BA
Distribution
process by which drug reversibly leaves the blood stream and enters the interstitium represented by Vd
Vd
apparent volume of distribution required to accommodate all the drug if the concentration of the drug throughout the body were the same as that in the plasma
if plasma concentration is less
more drug is distributed to the tissues
Vd formula
Vd = D / C
Vd of Chloroquine
15000L, well distributed throught body
Vd of Warfarin
8L, mostly remains in blood
Vd of 4 L
restricted to vascular compartment
Vd fo 14 L
distrbuted in extracellular fluid but not into cells
Vd of 42
pass most biological barriers distributed in intra and extra cellular fluid
Vd > 42
drugs are extensively stored within specific cells or tissues
Vd vs Plasma concentration
inverse relationship
