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83 Cards in this Set
- Front
- Back
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DRUG SOURCES
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Animal: glands (thyroid hormone, insulin, sex hormones); shells/exoskeletons; beeswax; venoms.
Vegetable: all parts of plants, roots (digitalis); alkaloids or nitrogenous compounds (morphine, atropine); leaves (belladonna, peppermint); seeds (castor oil); and oils, gums, resins, and tannins. Minerals: copper sulfate, aluminum, magnesium sulfate, iodine, iron, gold, etc. Synthetic Drugs: corticosteroids, antianxiety agents, antidepressants, chemotherapeutic agents; recombinant DNA technology |
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Four types of drug studies:
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Dose-response relationships (how much needed to produce effect)
2. Structure-activity relationships (how drugs actions resemble/differ from closely related chemical compounds) 3. Metabolic fate (how body deals with drug) 4. Site/mechanism of action (where & how drug acts in the body) |
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Pharmacology
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study of the interaction of chemicals with living organisms to produce biologic effects
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Pharmacokinetics
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study of how drugs enter the body, reach site of action, and are removed from body (what the body does to the drug): absorptionàdistributionàmetabolismàexcretion.
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Pharmacodynamics
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study of drug action at biochemical & physiologic levels (effects & interactions of drugs with body tissues: what the drug does to the body).
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Pharmacotherapeutics
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the use of drugs to treat disease.
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Toxicology
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study of poisons/noxious effects of drugs.
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Affinity:
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(attraction) ability of drug to bind to receptor; LOCK & KEY theory, critical region of drug
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Efficacy
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capability of drug to cause effect; therapeutic ability.
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Drug receptors
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natural body components intended to respond to a chemical normally present in blood/tissues
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Agonist:
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compound that binds to specific receptor & stimulates biologic response; has affinity & efficacy
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Antagonist:
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prevents stimulation of receptors; has affinity for specific receptors, but lacks efficacy (Narcan given for OD due to increased affinity for narcotic receptors.)
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Desired action
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expected, predictable response
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Side effects/Adverse effects (ADEs):
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unwanted drug reactions, can be expected.
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Toxic effects
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reaction to excessive amounts of drug.
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Drugs do
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not create new functions in the body, but modify existing functions.
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Drugs act by:
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Chemically altering body fluids
Chemically altering cell membranes Binding to specific receptors: lock & key receptor; drug-enzyme interaction; physiochemical activity. |
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Idiosyncratic Reactions
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unusual, unexpected : usu. genetic factor.
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Type I
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soon after exposure, IgE antibodies trigger histamine release: hives (urticaria), ANAPHYLACTIC SHOCKEMERGENCY!!!
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Type II
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delayed reaction, IgM or IgG a-bodies trigger specific cell lysis (autoimmune response) e.g. methlydopa à hemolytic anemia.
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Type III
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serum sickness: urticaria, arthralgia, lymphadenopathy, fever; caused by formation of antigen-antibody complexes.
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Type IV
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cell-mediated response: contact dermatitis; usu. topical
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FDA Pregnancy Risk Categories
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A-- remote risk to fetus
B-- slightly higher risk to fetus than A C-- greater risk than B D-- proven risk for fetal harm Xgreatest risk for fetal harm; contraindicated. |
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Drugs may
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inhibit or activate a process, or replace a missing element.
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Dose-Response Curve
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relationship between drug and effect it produces; response increases as drug concentration increases.
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Threshold
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dose required to produce measurable response
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Plateau
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increased dose will not increase response
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Therapeutic Index (TI)
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margin of safety; high TI = wide safety margin
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Potency
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refers to dose required to produce an effect; strength of the drug
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Efficacy
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important to consider when deciding between 2 drugs with similar actions: which drug works better (e.g. requires fewer doses?)
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Drugs generally act in 1 of 2 ways:
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May alter physics of cell environment
o May alter chemical environment of cells |
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Onset
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time required to produce response, drug begins to act
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Peak
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highest effective drug concentration, maximum effect.
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Duration
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length of time drug able to produce effect
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Half-life
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time required for elimination processes to reduce blood concentration by 50%.
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Plateau Principle
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maintain steady, therapeutic blood level
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Steady-state
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rate of excretion = rate of absorption
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Absorption
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involves transport of drug across biologic membranes (skin, mucous membranes, stomach/intestinal lining, sub q or muscle tissue, etc.) to reach target tissue.
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PO meds absorbed through GI tract via diffusion; rate affected by
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Presence/absence of food
o Drug solubility o Stability of drug in gastric pH o Drug form (liquid, capsule, tablet, XR, SR) o Presence of other drugs o Gut circulation & gastric emptying |
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Parenteral meds
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more rapidly absorbed & more predictable; IV immediate and has 100 % absorption
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Topical meds (skin & mucous membranes)
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has slowest absorption rate
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Bioavailabilty
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proportion of drug available to produce systemic effects
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Distribution.
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process by which drugs transported by blood or body fluids to site of action; depends on protein binding, lipid solubility, & circulation.
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Biotransformation:
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breakdown/metabolism of drug; usu. done per microsomal enzyme system in liver
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Drug broken down into
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metabolitesmay be therapeutic or toxic
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Two phases:
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(1) chemical change in drug molecule. (2) conjugation: altered molecule binds to another chemical group in blood & becomes more water soluble, easier to excrete.
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PO meds undergo first-pass effect
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as the portal system brings the drug from the gut to the liver; the liver breaks down the lions share of the drug before it reaches systemic circulationmay affect dosage determinations (PO doses higher than IV doses)
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Other possible sites of biotransformation
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kidneys, lungs, and intestines.
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Factors influencing biotransformation
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age; hepatic, renal, & CV disease
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Excretion/Elimination
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removal of drug & its metabolite from body
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Most drugs eliminated by
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kidneys, other sites include lungs, intestines, & sweat, salivary, & mammary glands
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Drug Clearance
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rate at which drug is eliminated; influenced by renal function. Some drugs excreted unchanged
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Contraindication
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implies that a drug may cause harm (e.g. allergy).
- May be absolute or relative. - Cautious use means that med is given with extreme caution, & client must be closely monitored |
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Potentiation
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one drug enhances the effects of another drug
§ (similar to 0 + 1 = 2) |
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Synergism
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combined effect of two drugs is greater than either drug alone.
§ (similar to 1 + 1 = 3) |
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Additive
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two drugs together have combined effect (not greater than would be expected).
§ (similar to 1 + 1 = 2) |
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Antagonist
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one drug interferes with, or blocks action of another drug; competitive.
§ (similar to 1 + 1 = 0) |
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Interactions
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May occur with foods, not just other drugs.
o Some drugs may alter/interfere with certain lab studies. o Caution with herbal supplements!!! |
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Side Effects
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Expected, may or may not cause harm.
- May be desired (e.g. ASA for inflammation also acts as anticoagulant, TCA for depression also promotes sleep). |
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Adverse Effects:
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Harmful & unexpected.
- Dependent on specific drug. |
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Toxicity:
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Can occur in any organ/system.
- Assess risk/benefit ratio carefully. - Nephrotoxicity - Ototoxicity - Hepatotoxicity - Neurotoxicity - Blood dyscrasias - Cutaneous reactions |
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Carcinogenicity
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Alteration in DNA
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Idiosyncratic Reactions
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Genetic predisposition
- Unpredictable - Small population - Mandates careful assessment of all clients |
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Peak levels drawn
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drugs highest activity level
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Trough levels drawn
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drugs lowest level of activity; usu. obtained ½ hr. before next dose given
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6 Rights of Medication Administration:
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Right medication
Right client Right dose Right route Right time Right documentation Also: Competent clients right to refuse medication |
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Medication orders
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Date
§ Clients name & address, ID #, age § Superscription: Rx (take thou) § Inscription: drug name, dosage form, amount of dose § Subscription: directions to pharmacist for preparation of drug & total amount to be dispensed (e.g. how many tablets) § Signature (Sig): directions for client including time, frequency, storage info, etc. § Generic equivalent acceptable? § Refill info: # & frequency regulated by federal law § Prescribers signature with title; may need DEA # if controlled substance |
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Oral
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most common & convenient
§ Tablets, capsules, powders, liquids (syrups, elixirs, emulsions, tinctures) |
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Parenteral
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Intradermal (ID)
§ Subcutaneous (SQ, SC, sub Q, sub q) § Hypodermoclysis § Intramuscularly (IM) § Intravenous (IV) § Intrathecal/intraspinal § Intra-articular § Intralesional § Intra-arterial |
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Mucous Membranes
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Rectal
· Inhalation · Mouth/throat sprays, swabs, SL tablets, buccal tablets · Nasal sprays, drops · Vaginal suppositories, douches, foams, creams |
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Topical
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Skin: lotions, ointments, compresses, patches, creams
- Ophthalmic: drops, ointments, and irrigations - Otic: drops, irrigations |
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i. Bacteriostatic
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do not directly kill bacteria; inhibit cells growth/reproduction; must work with hosts immune defenses to destroy organisms.
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ii. Bactericidal
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directly kill bacteria cell; adds to hosts defenses
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- Antimicrobial Spectrum
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range of microorgs. against which drug is effective
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- Minimum Inhibitory Concentration (MIC
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smallest amt. of drug required to halt growth of microorg.
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- Minimum Bactericidal Concentration (MBC
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smallest amt. of drug required to kill microorg.
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- Therapeutic Index
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ratio of drug that kills 50% of test animals to dose that is effective in 50% of test animals (TI=LD50/ED50); high TI safest.
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Actions of ATB's
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- Inhibit bacterial cell wall formation (bacterial cell explodes)
- Block protein synthesis in bacterial cell; form defective protein molecules - Interfere with nucleic acid synthesis - Inhibit metabolic pathways (antimetabolites) - Disrupt bacterial cell membrane (cytoplasm leaks out) |
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i. Important Antibiotic-Resistant Microbes
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1. Methicillin-resistant Staphylococcus aureus (MRSA)
2. Penicillin-resistant Streptococcus pneumoniae 3. Vancomycin-resistant Enterococci (VRE) 4. Multiple drug-resistant Mycobacterium tuberculosis |
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Suprainfection/superinfection
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occurs during ABX therapy and involves resistant organisms; difficult to treat; more common with broad spectrum ABX that upset ecologic balance of normal flora (causes overgrowth of flora e.g. yeast infection)
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Misuse of ABX
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Cannot cure viruses
- Must take full prescribed course! 1. Bacteria proliferate 2. The most resistant microorgs. survive 3. May result in drug resistance - Using leftovers is dangerous 1. Negates reliable cultures 2. May become toxic on shelf 3. Hazardous to children - Do not use someone elses med! |
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- NSAIDs
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: ibuprofen
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- Salicylates
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aspirin (ASA
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