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79 Cards in this Set
- Front
- Back
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What are the Different Drug classifications |
Therapeutic and Pharmacologic |
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Therapeutic Classification |
- Describes what is being treated by the drug - State what condition is being treated by the body ex: ANTICOAGULANTS= influence blood clotting ex: ANTIHYPERTENSIVE= lowers blood pressure |
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Pharmacologic Classification |
-Describes how the drug reacts BY THE BODY ex: DIURETIC= lowers blood plasma ex: CALCIUM CHANNEL BLOCKER=blocks heart calcium channels |
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What are the 3 routes of administration |
- Enteral Route: delivered to GI - Topical:Meds applied to skin or mucous membranes - Parenteral: Delivered INTO skin layers, subcutaneous tissue, muscle or veins |
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Enteral Route: Delivery |
-Orally -NG or gastronomy tubes -Tablets or capsules -Sublingual or Buccal Routes |
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Enteral Route: Tablets or Caspules |
-SAFEST SKIN BARRIER NOT COMPROMISED -Slow Onset -Enteric: coated -Extended Release(long acting, sustained release) * The following should not be chewed, crushed or opened: Extended release, enteric coated drugs, oral cavity drugs -first pass effect |
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Enteral Route:Sublingual and Buccal Routes |
-external routes meds not swallowed but kept i mouth to be absorbed -are not subjective to stomach acid or first pass affect -meds kept in mouth -if multiple meds ordered, admin oral and them sublingual -buccal-in cheeks |
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Enteral Route: NG and Gastrostomy Tubes |
-Liquid form -Should not deliver sustained released meds -exposed to same processes as PO |
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What is the First pass effect |
Drugs absorbed in stomach and small intestine 1st travel to the liver where they may be INACTIVATED before the reach their target organs |
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Topical Route |
-meds applied to skin or mucous membranes - most commonly used - Given for local and systemic effects - absorbed slowly if membrane is thick, and fast if it is thin - |
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Topical Route: Administration |
- skin-transdermal (contain specific dose of med) - ophthalmic=eye: absorbed into systemic circulation via drainage of the drug into the nasolacrimal ducts and then to the nasopharynx - Otic= ear: brought to room temp, systemic adverse effects not observed unless applied to open abrasions - Intranasal= nose: rapid onset of action, avoids first pass effect,mucous secretion unpredictable -respiratory tract -urinary tract -vagina-local conditions or birth control -Rectum-local or synthetic, comatose pt safe, suppository or edema, avoid 1st pass effect |
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Parenteral Route |
Delivered into skin layers, subcutaneous tissue, muscles or veins - less common routes: arteries (intrarterial) bone(intraosseous, body cavities (intrathecal) and organs ( intracardiac) - Intradermal- into dermis layer, small vol of meds - Subcutaneous- delivers to deepest layer of skin-->insulin, vitmains, vaccines -Intramuscular- directly into large muscles, tissue can recieve larger volume of drug, more rapid onset of action -Intravenous- directly into blood stream, most dangerous route: 3 types--> Large volume infusion, Intermediate infusion, IV bolus (push) admin |
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Drug Prototypes |
is the agent to which all other drugs in a class are compared |
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Bioavailability |
the rate and extent to which the active ingredients are absorbed from a drug product and then available at the site of action |
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nurse responsibilities to meds |
-what drug is ordered:name, use, effects, precautions, considerations, effects - why prescribed for specific patient - how supplied from pharmacy - |
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Pharmacokinetics |
focuses on what the body does to drugs after they are administered |
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Process of pharmacokinetics |
Absorption Distribution Metabolism Excretion |
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Pharmacokinetics: Diffusion |
- Use diffusion and active transport to cross plasma membranes to reach their target cells * small, nonionized, lipid soluble Diffusion: simple diffusion or passive transport -movement of a chemical from an area of higher to lower concentration |
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Factors affecting movement across plasma membranes |
- size of drug molecule -ionization of molecule -lipid solubility |
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Facilitated Diffusion |
-utilizes carrier proteins to cross membranes - Does not require energy from cell -Active transport pumps require cell energy * goes against gradient from low concentration to high |
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Absorption |
process of moving a drug from site of admin to the bloodstream -primary factor for determining onset of drug action ***Route of Admin- one of the most important variables affecting absorption -absorb faster from areas of body where blood flow is high -manipulation of blood flow to slow ab. = vasoconstrictors, ice packs -small intestine=most absorption |
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Drug Ionization |
-Depending on pH of surrounding fluid, most drugs are in either charged or uncharged state - acids are absorbed in acids=nonionized -bases absorbed in bases=nonionized -carry positive or a negative charge depending on pH -ionization affects ability to cross membrane and be excreted into the body |
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Distribution |
How drugs are transported throughout the body |
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Factors affecting distribution |
-blood flow to tissues: heart, liver, kidneys high blood flow % so these organs receive highest exposure to absorbed drugs -drug solubility:determines how quickly a drug is absorbed,mixes within the bloodstream,crosses membranes and becomes localized in body tissues *lipid soluble not limited by barriers more distributed to body tissues -tissue storage- bone marrow, teeth,eyes and adipose tissue high affinity(attraction to certain meds), may remain in body for many months and released slowly - drug-protein binding |
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Drug protein binding |
-drug protein complexes cant cross capillary membranes * complexes too large to cross membrane, continue circulating in bloodstream and unavilable for distrubution to site of action -only free, unbound drugs reach target tissues and be excreted by kidneys -competition of protein binding sites -Each drug has protein binding % |
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Special barriers to drug distribution |
*blood brain barrier - does not contain pores -protects from pathogens and toxins -lipid soluble drugs able to cross -Inflammation increase permeability (meningitis) -not fully developed in neonates -brain cancer and infections in brain difficult to treat *fetal placental barrier- prevents harmful substances from entering the fetus--inefficient alcohol, prescription drugs, caffeine can cross |
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Metabolism |
changes the activity of a drug and makes it more likely to be excreted -alters structure and function of drugs allowing excretion -primary site is the liver -changes lipid soluble( easily absorbed and distributed) to water soluble( easily excreted by kidneys) - functional changes alter pharmacologic activity--> less pharmacologic activity and greater therapeutic activity * metabolites may be more toxic ex tylenol |
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Prodrugs |
meds that require metabolism to produce their therapeutic actions -have no pharmacological activity |
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Hepatic Microsomal enzymes |
-How most metabolism is accomplished in the liver -enzyme cytochrome P450(CYP)- an enzyme that metabolizes many drugs - many different isoenzymes that perform different metabolic functions *determine the speed a drug is metabolized * contribute largely to drug-drug interactions |
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CYP Systems |
-Drugs as substrates( drugs metabolized by a CYP enzyme) - Drugs as enzyme inhibitors ( drug inhibits action of CYP isoenzymes and can contribute to toxic drug levels, effect amount of drug available) - Drugs as enzyme inducers( accelerate metabolism of specific isoenzymes and the metabolic activity in the liver, drug level may decrease more rapidly higher doses may be required could take days to weeks of pharmacotherapy |
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Patient variation in Metabolism |
- infants lacking mature microsomal enzyme systems until 1yrs old - enzyme activity often reduced in older adults- require lower doses -decreased metabolism with liver impairment- decrease drug dosage - Genetic variations of CYP enzymes- may cause people to metabolize at different rates |
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Excretion |
processes removal of drugs from the body - rate of excretion determines drug blood level -kidney primary spot |
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Renal excretion |
-some drugs go through reabsorption after renal filtration -excretion dependent on urine pH--> manipulation of pH for kidney filtrate to speed up excretion |
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Pulmonary excretion |
- gases and volatile liquids -most excreted un-metabolized -RR and blood flow affect excretion the faster the rate the faster the excretion |
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glandular secretion |
-Saliva, sweat, breast milk -taste and smell some drugs -breast milk secretion (water soluble drugs) |
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Fecal and Biliary excretion |
-feces, bile - enterhepatic recirculation- prolong action increase half life |
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Time response Relationship |
Therapeutic response directly related to their concentration in blood plasma |
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Half Life |
estimates the duration of action for most meds -plasma half time t1/2 - length of time required for plasma concentration decreases by half - short half-life: drug given MORE frequently(short duration), given every few hrs - long half life: drug given LESS frequently(beneficial for treating preventive conditions like pregnancy seizures) chronic conditions ex; heart failure, hypertension), given once a day * appprox 4 half -lives until excretion ex- drugs half life 8 mins- 32 mins to be eliminated--not applied w/renal impairment |
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pharmacodynamics |
What the drug does to the body -involves drug mechanism of action - involves effect of drug concentration |
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Interpatient Variability:Frequency distribution curve |
# of pts responding with a particular drug action at different doses -peak of curve represents the largest number of pts responding to drug, does not show magnitude of response |
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Median Effective Dose ED50 |
The dose required to produce a specific therapeutic response in 50% of a group of pts -usually the average or standard dose for a drug |
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Therapeutic Index(TI) |
describes the drugs margin of safety = median lethal dose(LD 50)/ median effective dose (ED50) the larger difference between two doses the greater the TI -the higher the value the safer the drug |
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Median lethal Dose |
the dose of drug that will kill 50% of tested lab animals |
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Median Toxicity Dose (TD50) |
Dose that will be given and cause toxicity in 50% of pts |
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Margin of Safety(MOS) |
amount of drug that is lethal to 1% of animals(LD1)/ amount of drug that produces a therapeutic effect in 99% of animals (ED99) * the higher the MOS value the safer the drug |
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Dose Response Relationship |
how the actions of a drug change with increasing dose -drug dose correlates to degree of response three phases: 1. lowest doses 2. most desirable range 3. plateau reached- increasing dose will not increase therapeautic effect, increasing could cause toxicity **Adjust dose in small increments |
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Potency |
the amount of drug needed to produce a specified effect - more potent drug produces therapeutic effect at lower doses -compares doses of two different drugs |
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Efficacy |
maximum response that can be produced from a particular drug -always more important that potency |
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Receptor theory |
most drugs produce their actions by activations or inhibiting specific cellular response - a cellular molecule to which a medication binds to produce its effects -drugs specific target -meds bind to receptors, like "lock and key" -intrinsic activity- bind to recepetor and produce strong action( correlate with efficacy if high activity= high efficacy) - can be molecules or majority proteins -once occupied,triggers 2nd messenger-biochemical events- drug stim or inhib activity |
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Agonist |
mimic the action of endogenous substances or molecule -response may be greater than endogenous activity *partial agonist- produce weaker action than endogenous substances |
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Antagonist |
prevent action of endogenous substances -may compete with agonist - useful in blocking excess endogenous activity -may reverse adverse effects of overdoses ** DO NOT have intrinsic activity -functional antagonist- inhibit the effects of an agonists not by competing for a receptor but by changing pharmacokinetic factors |
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Adverse effects |
-Undesirable effects -can be harmful |
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Adverse effects: side effects |
predictable -can occur at therapeutic doses *different from adverse effects by severity |
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Prevention of adverse effects |
- obtain thorough Med Hx -assess pt and diagnosing data -prevent med errors -monitor - know all current drugs being taken |
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Allergic reactions |
caused by hyperresponse of immune system -severity not propartional to dose of drug -allergy symptoms are non specific to drug -anaphylaxis has same symptoms for all drugs -previous drug exposure necessary |
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Drug classes most likely to cause allergic reactions |
- penicillin and related antibiotics -insulin -Contrast with iodine -NSAIDS(nonsteroidal anti inflammatory drugs) -Chemo - Preservatives |
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Idiosyncratic Reactions |
unusual drug responses often caused by genetic differences -not related to pharmacologic action of the drug -not allergies= not immune related -unpredictable vary pt to pt -genetic mutations |
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Teratogens |
potential to cause birth defects |
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Risk benefit ratio |
drug benefit outweighs long term risk -some cancer causing drugs approved by FDA -treatment prolongs life |
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Different Toxicities |
-Nephrotoxicity- kidneys -Neurotoxicity- brain: ex depression, hallucinations, seizures -Ototoxicity- hearing impair 8th cranial nerve -Hepatotoxicity- liver, common -Dermatologic-skin, rash,urticaria (hives) lead to anaphylaxis - Bone marrow tox- life threatening -cardiotox- damage to cardiac muscle -skeletal muscle and tendon tox- rare |
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The most frequent categories of error |
- error in pt assess -inaccurate prescribing -errors in administration (route and time) |
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IMPORTANT: 5 Rights of Medication Administration |
-Right Patient -Right Drug -Right Dosage -Right Route -Right Time |
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educational points for reducing med errors |
- know names, uses, doses, how and when to take -know adverse reactions and what to report immediately -read drug label prior to each admin |
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Patient education for med error |
- carry list of all meds -use one pharmacy -consult pharmacist |
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Nursing Process for Medication Administration |
*Assessment- assess all factors that might interfere with same drug admin *Planning- minimize factors that contribute to med errors *Implementation- be aware of stressful situations and distractions - positively verify pt identity -correct procedures and techniques for all routes of admin - calculate dose correctly - open meds immediately prior to admin - record on MAR immediately after admin -confirm that oral meds were swallowed *evaluation- assess pt for expected outcomes and adverse reactions to the drug |
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Analytical Tools used to identify risk and analyze errors |
-health care failure mode and effect analysis(HFMEA) - identify process where error may occur- prescription, dispensing, admin each process at risk for failure analyzed - Root Cause analysis (RCA) - focus on causes of error rather than person responsible, what happened, why, how to prevent |
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Rationale for drug use during pregnancy and lactation |
consider therapeutic value of drug balanced against the potential adverse effects |
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Pharm during pregnancy |
-physiological changes during pregnancy can alter normal pharm response -speeding up -slowing down |
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Preg Absoption |
*Increase levels of progesterone cause a decrease in gastric tone and intestinal motility, resulting in delayed gastric emptying = extended absorption time for oral drugs -progesterone increase pulmonary blood flow, respiratory tidal volume and minute volume by 40%=higher serum drug levels, and resp agents cromolyn *high estrogen level=increase hydrochloric acid= affect acid labile drugs *increased time prolongs the onset and duration time of oral drugs *nausea& vomiting=unable to take oral meds |
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Preg Distribution |
- changes in total body water= increase by over 50%--> leads to greater hemodilution of plasma proteins and drugs -dilution of proteins= few availability to bind w/ drugs: higher concentration of free drug, more molecules to transfer across the placenta and pass into breast milk -highly liophilic drugs go into lipid rich breast milk -maternal HR increase 15 beats per min =greater distribution |
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Preg Metabolism |
- least affected - CY450 and other enzymes present in placenta -placenta and fetal liver contribute to overall drug metabolism -Nicotine increases amount of placental enzymes- affect drug metab - dose modification |
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Preg Excretion |
-enhanced -increase: renal plasma flow, glomular filtration rate, creatine clearance, renal tubular reabsorption |
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Placenta |
- 10% of mother cardiac output circulates in it - maternal blood does NOT circulate through fetus -protective filtration: allows vitamins, fatty acids, glucose freely pass |
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Placental transfer of drugs |
- cross by simple diffusion, few pass by active * drugs do not have to cross the placenta to enter fetal blood to cause fetal abnormalities - drugs can cause constriction of blood vessels impaires nutrient exchange |
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Factors impacting transfer of drugs across placenta |
- solubility: High lipid sol cross more easily than water soluble - molecular size: small less than 300MW cross easily ( alcohol) 500 MW slow, 1000MW dont pass -protein binding- molecules too large to cross membrane highly bound to plasma proteins -drug ionization- pH of mom higher than fetus - drugs with weak bases become ionized in acidic environ trapping them of fetal side of placenta - ionized drugs cant pass placenta (trapping) - blood flow to placenta: decrease may cause trapping= fetal effects, drug accumulation in fetus -aorta and vena cava pressure obstruct uterine= pt needs to lay lateral during contractions |
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Preimplantation period |
-wk 1-2 of 1st tri - embryo not established blood supply with mother - all or none period(teratogen will cause death or no effect) -organs not developed - drugs less likely to cause malformations here except nicotine=retardation |
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Embryonic period |
- @3-8 wks -rapid development of internal structures -period of max sensitivity to teratogens= malformations and spontaneous abortion -specific abnormality here= organ formation |
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Fetal period |
-9-40wks or until birth -planeta membranes thinner -max transfer of substances from maternal circulation to fetal blood - know difference between normal symptoms of preg and adverse effects |
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Transfer of drugs into breast milk |
- alveolar cells in breast= larger gaps during 1st wk= substances allowed to enter milk, 2nd wk close gaps=reduced ability to enter milk - standard practice- GIVE LOWEST POSSIBLE DOSE |
