PharmacoDYNAMICS
(how a medicine changes the body) - it's the mechanism of drug action and its relationship between drug concentration and responses of the body
PharmacoDYNAMICS
1.Used to help predict if the medication will assist the client or will produce a significant change in the client
2.Replaces a missing substance
3.Destroys or inhibits a pathogen
4.Stimulates, suppresses, or disrupts a process
PharmacoKINETICS
Consists of four processes: absorption, distribution, biotransformation (metabolism) and excretion
PharmacoKINETICS (absorption)
movement of the drug through blood circulation from the site of administration to target tissue
i. onset of action: the time between the administration of a medication and the beginning of its effects
ii. duration: amount of time that a medication exerts
PharmacoKINETICS (distribution)
i. process by which the drug diffuses or is transferred from the intravascular space (blood stream) to extravascular space (body tissues)
ii. factors affecting distribution
***blood flow to the tissue, e.g., vasoconstriction reduces drug distribution and
PharmacoKINETICS (biotransformation [metabolism])
chemical conversion or transformation of drugs into compounds that are easier to eliminate
i. phase I: oxidation, reduction, or hydrolysis by the cytochrome P-450 enzyme system
ii. phase II: conjugation of substance, improves renal excretion
iii. half-lif
PharmacoKINETICS (excretion)
elimination of unchanged drug or metabolite from the body, through renal, biliary, or pulmonary processes
i. route of excretion depends on the drugs chemical properties
ii. kidneys are responsible for excreting most drugs
Therapeutic range
a. range of concentrations at which a drug or other therapeutic agent is effective with minimal toxicity to most people
b. common drug examples: acetaminophen, aminophylline, digoxin, lithium, phenytoin, propranolol, theophylline
Peak
point in time after the administration when a medication exerts its strongest therapeutic and adverse effects; a serum blood sample is drawn (about 1 hour) after the drug is administered
Trough
the lowest drug level that is needed to reach therapeutic range; a serum blood is drawn (about 30 minutes) before medication administration
Technique for MDI
without spacer
**shake canister for 2 to 5 seconds
**hold MDI with thumb under the mouthpiece and the index and middle fingers on top of the canister
positioning mouthpiece -
client has two options:
i. place mouthpiece of MDI in mouth with opening pointing toward the ba
Technique for MDI *
with spacer
*
***breathe normally through spacer
depress canister, spraying one puff into spacer
***inhale slowly and fully for 5 seconds
hold breath for 10 seconds
**always rinse mouth after
****wait 20 to 30 seconds between puffs before administering second puff or a
nasal spray administration
**gently blow nose before administration
**shake container
**tilt head slightly back
**occlude one nostril, insert spray tip into the other nostril
**activate spray and gently inhale
Rectal Suppository
*if used for systemic indication, have client defecate if possible to allow facilitation of medication
position client on left lateral position and insert just beyond internal sphincter
*instruct client to retain the medication for 20 to 30 minutes for st
Vaginal Suppository
*position client supine with knees bent, feet flat on bed and close to hips (a modified lithotomy position)
*use application device to insert suppository
SubQ injection Needle
*5/8 inch needle, greater than 21 gauge
*insulin syringes come in many smaller sizes: 5/16 inch or 8 mm and the pen needles are 1/2 inch (12.7 mm), 5/16 inch (8 mm) and 3/16 inch (5 mm) lengths
SubQ facts
i. inject medication into subcutaneous tissue to avoid muscle
iii. use 45-degree or 90-degree angle
iv. aspiration not required
v. do not massage injection site
vi. rotate injection sites
CONTRAINDICATED IN: SHOCK, CARDIAC ARREST, DEC. PERFUSION TO TISSUE
suitable medications for subcutaneous administration
i. isotonic
ii. nonviscous
iii. non-irritating
iv. water-soluble
v. small volumes of medication (0.5 to 1 mL)
Intramuscular (IM)
90-degree angle
a. four common sites: ventrogluteal, dorsogluteal, vastus lateralis, and deltoid
b. absorption affected by the muscle's perfusion, fat content, and degree of vasoconstriction
c. administration
IM administration
verify need to aspirate
ii. four common sites: ventrogluteal, dorsogluteal, vastus lateralis, and deltoid
iii. inject medication into large muscle; avoid soft tissue other than muscle, especially nerves and vessels
iv. needle angle: perpendicular (90 degr
IM injection in children
*younger than 18 months: use vastus lateralis muscle
*older than 18 months: use vastus lateralis, ventrogluteal, deltoid
*inject up to 2 mL for children (deltoid should be limited to 0.5-1 mL)
IM injection in Adults 18 yrs and older
*injection sites: vastus lateralis, ventrogluteal, and deltoid muscles
*inject up to 3-5 mL for adults (deltoid should be limited to 0.5-1 mL)
PICC LINE
*smaller, longer (40 to 65 cm catheters) and more flexible than other central line
--procedure:
*sterile procedure performed at bedside
inserted through a peripheral vein in the upper arm, usually either the basilica, cephalic or brachial vein; catheter e
isotonic crystalloid solutions
osmotic pressure similar to plasma; expands extracellular fluid WITHOUT CHANGING OSMORLARITY
hypotonic crystalloid solution -
exerts less osmotic pressure than plasma; fluids shift into interstitial spaces and cells, causing cells to SWELL
hypertonic crystalloid solution
exerts more osmotic pressure than plasma; osmosis pulls fluids out of the cells, causing them to SHRINK
hypertonic colloid solutions -
also expand intravascular volume plasma but colloids contain molecules too large to pass through semipermeable membranes
INSTILLING EYEDROPS TECNIQUE
1. Wash hands and apply gloves; rinse powdery residue from gloves
2. Instruct client to recline or tilt head back
3. Instruct client to look up
4. Pull lower lid down and to the side
5. Apply drop at lower, outer aspect of eye (lower conjunctival sac)
6.
technique - eye ointment
1 WASH HANDS. 2 INSTRUCT CLIENT TO TILD HEAD BACK OR RECLINE 3. LOOK UP
i.apply a thin line of ointment along the edge of the lower lid moving from**
inner canthus to outer canthus
**
ii. instruct the client to gently close the eye and move the eye around
OTIC Ear Drop PREP
ii. position client on unaffected side with affected ear facing up
iii. remove ear drainage or cerumen with cotton-tip applicator; avoid pushing cerumen into ear canal
iv. open ear canal
**********In a child younger than age 3, pull the lobe down and back
OTIC , instillation of ear drops
i. fill dropper with medication
ii. hold dropper about 1/2 inch above ear canal
iii. gently squeeze bulb on dropper to instill prescribed number of ear drops
iv. instruct client to remain in place for 5 to 10 minutes
v. repeat in other ear if necessary af
WARNING WHEN CUTTING PILLS
do not cut ***
capsules, enteric-coated, sustained-release, or extended-release tablets or capsules
**
medication PREGNANCY RISK categories
A: no risk to fetus in the first trimester
B: may or may not show risk in animals, no risk shown in human studies
C: risk shown in animals, insufficient data in pregnant women
D: demonstration of human risk in selected clinical studies
X: clear demonstrat
refeeding syndrome
(first 24 to 48 hours of therapy): bradypnea, lethargy, confusion, weakness
Prevent Complications in Medicine administration
a. rebound hypoglycemia: withdraw TPN slowly
b. microemboli: use 0.2 �m-filter (except with lipid emulsion)
c. administer solution at a constant rate and do not flush or irrigate the system
d. injury: check expiration date of solution, verify TPN order
e.