route of drugs (fastest to slowest)
1)parenteral 2)enteral 3) topical
parenteral route
any route other than GI tract, most commonly injection. (IV, IM, SQ, ID injections)
intravenous injection
delivers drug directly into circulation where it is distributed with blood throughout body.
enteral route
drug is absorbed into systemic circulation through mucosa of stomach or intestines. (sublingual or buccal)
topical route
application of medications to various body surface, slower onset and prolonged duration - ointments, gels, creams. (applied to skin, eyes, ears, nose, lungs, rectum or vagina)
transdermal route
adhesive patches used for systemic drug effects. (topical route)
inhaled route
delivered to lungs. (topical route)
liver
organ most responsible for metabolism of drugs.
skeletal muscle, kidneys, plasma, intestinal mucosa
other metabolic tissues that aid in metabolism of drugs.
kidney
primary organ for elimination of drugs.
liver, bowel
other organs that aid in elimination of drugs.
drug distribution
transport of a drug by the bloodstream to its site of action. (distributed first to areas most extensively supplied with blood)
heart, liver, kidneys, brain
areas of rapid distribution.
muscle, skin, fat
areas of slower distribution.
6 rights of medication administration
1)right patient 2)right drug 3)right dose 4)right route 5) right time 6)right documentation
pharmacodynamics
study of what the drug does to the body; both biochemical and physical. (involves drug receptor interactions)
pharmacokinetics
study of what body does to the drug molecules. (involves process of absorption, distribution, metabolism, excretion)
pharmacotherapeutics
clinical use of drugs to prevent and treat diseases. It defines the principles of drug actions - the cellular processes that change in response to the presence of drug molecules.
onset of action
time required for drug to elicit therapeutic response.
peak
time required for a drug to reach its maximum therapeutic response. (highest blood level)
trough
lowest blood level of drug.
duration of action
length of time drug concentration is sufficient to elicit a therapeutic response.
bioavailability
measure of the extent of drug absorption for given drug and route (0-100%); amount of drug circulating after first-pass effect.
FDA drug approval Phase I
(small # of healthy subjects) purpose to determine optimal dosage range and pharmacokinetics of drug. (absorption, distribution, metabolism, excretion)
FDA drug approval Phase II
(large # with disease/ailment that drug will treat) Therapeutic dosage ranges are refined.
FDA drug approval Phase III
(large # of patients - medical research centers) provide information about rare adverse effects not observed in smaller studies. Objectives to establish drug's clinical effectiveness, safety and dosage range.
FDA drug approval Phase IV
further proof of therapeutic and adverse effects of new; compares safety of drug with other drugs in same therapeutic category.
receptor interactions
reactive site on surface or inside cell; interact with others in different ways to elicit or block a physiologic response.
enzyme interactions
reactions with substances that catalyze nearly every biochemical reaction in cell. (drugs can produce effects by interacting with enzyme systems; may either inhibit (more common) or enhance the action of enzymes.)
nonselective interactions
main targets are cell membranes and various cell processes, metabolic activities. (do not interact with receptors or enzymes)
liver (to small intestine into blood system to liver)
major site of absorption for most oral medication
factors that can alter enterally administered drugs
1)acid changes in stomach 2)absorption changes in intestines 3)presence or absence of food and fluid
what determines drug distribution?
whether bound to plasma proteins or freely distributed outside blood vessels to reach site of action.
albumin
most common blood protein that carries majority of protein-bound drug molecules.
result of decreased or delayed metabolism
accumulation of the drug and prolongation of the effects of the drug, can lead to drug toxicity.
how does protein binding capacity of drug affect the drug?
protein bound medications may compete for binding sites on the albumin molecule. Competition causes more free, unbound drug, which leads to drug-drug interaction.
drug-drug interaction
presence of one drug decreases or increases the actions of another drug administered at same time.
half-life
time required for 50% of drug to be removed from body; measure of rate at which drug is eliminated from body.
When will drug be totally removed from body?
After about 5 half-lives, drugs are considered effectively removed from body. (approx. 97%)
parenteral route
fastest route for drug to be absorbed.
pharmacology
study of all interactions between drugs and living things.
dissolution
how solids (such as tabs) become soluble and are absorbed. (PO drugs need stomach enzymes and acids to dissolve)
absorption
process from when drug enters the body to when it enters the bloodstream.
bioavailability
extent of drug absorption; affected by dosage, route and GI function (pH of stomach, blood flow to small intestine, GI motility)
generic name
drug's official name, used in most official drug summaries to list drugs.
PDR, drug guide, journals, websites
sources of drug information (for nurse's use)
agonist
drug that binds to and stimulates activity of one or more receptors in body.
antagonist
drug that binds to and inhibits the activity of one or more receptors in body.
adverse drug event
any undesirable occurrance related to administering or failing to administer a prescribed medication.
polypharmacy
the use of many different drugs concurrently in treating a patient, who often has several health problems.
absorption effected by
1)route of administration 2)impairment in circulation 3)weight of patient 4)age 5)gender
first pass effect
phenomonon occurs after giving only oral drugs; large amount of drug becomes inactive in liver after giving through GI tract.
high first-pass effect
oral and rectal - decreased amount of active drug to tissue; when drugs are highly metabolized into inactive metabolites from liver into circulation.
protein binding
determined by albumin levels; drugs can only go to extravascular tissue if not bound to protein. (malnourished person = more free unbound drug)
drug to bone distribution
difficult to distribute across blood-brain barrier; some drugs more bound to protein than others - causes slow distribution and slow onset of action.
steady state
amount of drug eliminated with each dose is equal to the amount absorbed with each dose. (takes 4 half lives to reach)
pharmacotherapy
use of a drug to treat a disease. Includes assessment, implementation, monitoring and reassessment.
factors effecting drug effects
-weight,age, gender, genetics -drug-drug interactions -drug-food interactions -psychological factors -dosage, route of administration -physiologic factors
Receptor theory of drug action
drugs travel through the blood on protein carriers; drug leaves the protein carrier and floats in the blood until it locks into the receptor.
additive effect
drugs with similar actions are given together, so may need lower doses of each med. (ex. tylenol with codeine)
iatrogenic
medically induced reaction to drug.
requires drug interval and dosage adjustments
geriatric considerations due to decline in organ functions,
< liver enzymes and metabolism, prolonged drug half-life,
< body weight, > fat content, prolonged drug effect, less acidic gastric pH, < GI motility and emptying, < blood flow by 40-50%, < protei
empiric therapy
treatment of an infection before specific culture information has been reported or obtained.
definitive therapy
antibiotic therapy tailored to treat organism identified with cultures.
prophylactic antibiotic therapy
antibiotics taken before anticipated exposure to an infectious organism in an effort to prevent the development of infection. (ex. intraabdominal surgery or after trauma)
superinfection
antibiotic kills good bacteria; overgrowth of bacteria not susceptible to antibiotic used. (secondary microbial infection that occurs after primary infection often due to weakening of immune system by first infection)
handwashing, antiseptics, disinfectants
prevents healthcare-associated infections
classes of Antibiotics
1)Sulfonamides 2)Penicillins 3)Cephalosporins 4)Macrolides 5)Quinolones 6)Aminoglycosides 7)Tetracyclines
humoral immunity
mediated by B lymphocytes.
cellular immunity
mediated by T lymphocytes.
immunosuppressant drugs
drugs that decrease or prevent an immune response; work by suppressing the immune system; suppresses T lymphocytes.
autoimmune or immune-mediated disease
immune system attacks itself. (ex. kidney, liver and heart transplants)
immunosuppressive therapy
suppresses the immune system; used to selectively eradicate certain cell lines that play a major role in the rejection of a transplanted organ. (cells must be targeted and selectively altered or suppressed or organ rejection will occur.)
cyclosporine
immunosuppressant drug of choice; works by inhibiting the production and release of IL-2.
Imuran (azathioprine)
blocks T-cells by inhibiting the purine synthesis.
Prograf (tacrolimus)
works by inhibiting T-lymphocyte activation in response to antigenic stimulation and inhibits antibody production, which suppresses T-cell proliferation.
Nursing Assessment before administering Immunosuppressants
1)Patient assessment - vital signs and weight 2)Lab Results - Renal (BUN and Creatinine) Hepatic Function - ALP, AST, ALT and bilirubin levels Cardiovascular - EKG electrolytes- K,Na, Cl
Immunosuppressant Considerations
1)Oral immunosuppressants should be taken with food to minimize GI upset. 2)Oral antifungal med may be ordered to prevent candidiasis 3)Styrofoam cups should be avoided; adheres to side of cup. 4)When administed by IV, cyclosporines should be diluted and
antigen
foreign proteins that stimulate the host to produce antibodies.
antibodies
immunoglobulin molecules that have an antigen-specific amino acid sequence. (in response to antigen, attack and destroys molecules of antigen)
immunoglobulins
glycoproteins synthesized and used by the humoral immune system (B cells) to attack and kill all substances foreign to the body.
active immunizing drugs
consist of vaccines and toxoids that may be administered either orally or intramuscularly and work by stimulating the humoral immune system.
adverse effects of immunizing drugs
minor: fever, adenopathy, minor rash, arthritis
severe: fever >103, encephalitis, convulsions, anaphylactic, rash, dyspnea, cyanosis
carcinoma
arise from epithelial tissue throughout the body. (skin, mucosal lining of GI tract, and lining of bronchial tree (lungs).
sarcoma
malignant tumors that arise primarily from connective tissues. (bone, cartilage, muscle, and lymphatic and vascular structures)
lymphoma
cancers within the lymphatic tissues.
leukemia
arise from the bone marrow and are cancers of blood and bone marrow.
antineoplastic drugs
(3) major drawbacks: 1)Hair loss 2)nausea and vomiting 3)bone marrow toxicity all healthy cells die with the bad cells
myelosuppression
also know as bone marrow suppression or bone marrow depression. this is an unwanted affect of antineoplastics. This can lead to leukopenia (reduced wbc count)
nadir
the lowest level of wbc's in the blood following chemotherapy (or radiation) treatment.
nadir occurance
normally occurs 10-28 days after dosing.
antimetabolites
inhibit cellular growth by interfering with the synthesis (dna, rna and protein) or actions of three classes of compounds critical to cellular reproduction: the vitamin folic acid, the purines, and the pyrimidines.
methotrexate ( (MTX)
most-used folate antagonist; high dose of drug is associated with bone marrow suppression, and it is always given in conjunction with the "rescue" .
Leucovorin
antidote for folic acid antagonist
fluorouracil (5-FU) (Efudex)
used in a variety of treatment regimens, including the palliative treatment of cancers of the colon, rectum, stomach, breast, and pancreas.
mitotic inhibitors
plant derived. (most widely used alkylating drugs - Taxol, vincristine)
Taxol
treatment of ovarian cancer, breast cancer, lung cancer and Kaposi's sarcoma; kills off good cells as well. (plant derived)
vincristine
treatment of lymphotic leukemia and other cancers; used b/c lack of bone marrow suppression. (intrathecal route may result in death)
Adverse effects of Antineoplastics
1)stomatitis or excessive oral mucosa dryness and irritation - a)oral hygeine before and after meals b)lemon, glycerin, peroxide, alcohol products avoided. 2)nausea and vomiting
3)alopecia - scarves, hats, wigs 4)bone-marrow suppression - anemia, leukopen
Zofran (ondansetron)
drug of choice for cancer patients to treat nausea.
alkylating drugs
prevent cancer cells from reproducing and alter at DNA level.
extravasation
occurs when an IV catheter punctures the vein and medication leaks (infiltrates) into the surrounding tissues. (stop infusion immediately and notify dr.)
Cytoxan (cyclophosphamide) and Platinol (cisplatin)
classic alkylators (nitrogen mustards)
Alkylating drugs and Cytotoxic antibiotics
2 broad classes of cell-cycle non-specific Antineoplastic (cancer drugs).
cytotoxic antibiotics
...
main toxicities of cisplatin
nephrotoxicity, peripheral neuropathy, ototoxicity
Avastin (bevacizumab)
antineoplastic cancer drug recently pulled off the market.
Treatment of doxorubicin extravasation
1)Cool the site to pt tolerance for 24h 2)Elevate and rest extremity for 24-48h, then have pt resume normal activity as tol. 3)If pain, erythema, or swelling persists beyond 48h, discuss with dr the need for surgical intervention or other treatments.
doxorubicin (Adriamycin)
most used chemotherapy drug. (contraindication - risk for severe cardiac toxoicity)
Indications of Oncologic Emergency
fever >100, chills, new sores or white patches in mouth or throat, swollen tongue (cracks, bleeding), bleeding gums, scratchy or swollen throat, cough (new and persistent), changes in bladder function or pattern, blood in urine, changes in GI or bowel pat
antibiotic resistance
due to overuse of broad spectrum antibiotics. (always use the most narrow-spectrum drug based on lab cultures)
sulfonamides
broad spectrum; bacteriostatic; used to treat gram+ and gram- treatment of UTIs (E.coli);antimetabolite - prevents synthesis of folic acid and metabolic pathway. (often combined with another antibiotic) (ex. Bactrim (sulfamethoxazole))
sulfonamides adverse effects
photosensitivity, mucocutaneous, GI, hepatic, renal, hematological.
Beta-lactam antibiotics
penicillins, cephalosporins, carbapenems, monobactams
penicillins
bactericidal; allergic reactions, NVD, abdominal pain, other effects are not common.
cross-sensitivity
penicillins and cephalosporins
penicillin interactions
NSAIDS, oral contraceptives, warfarin
cephalosporins adverse effects
diarrhea, abdominal cramps, rash, edema (similar to penicillins)
ototoxicity
toxicity to the ears, often drug induced and manifesting as varying degrees of hearing loss that is more likely to be permanent.
nephrotoxicity
toxicity to the kidneys, often drug induced and manifesting as compromised renal function.
anaphylaxis associated drug
symptoms include flushing, itching, hives, anxiety, fast pulse, throat and tongue swelling. (penicillins and sulfonamides)
tetracyclines mechanism
bacteriostatic; inhibits bacterial protein synthesis; wide spectrum - gram +, -
tetracycline adverse effects
tooth discoloration, photosensitivity, bone degeneration,GI upset (avoid milk, antacids, Fe salts; do not prescribe to pregnant, nursing or children)
penicillins mechanism
bacteriocidal; interferes with cell wall synthesis.
cephalosporin mechanism
(structure and pharmacology of penicillins) broad spectrum, interferes with cell wall synthesis
carbapenems
broadest spectrum; may cause seizures; administered parenterally - no PO.
ex. meropenem (Merrem), ertapenem (Invanz)
macrolides
bacteriostatic; strep infections
ex. erythromycin, Z-pack (azithromycin), clarithromycin (Biaxin)
macrolides adverse effects
GI effects, hepatotoxicity.
Ketolide
only drug in class; Ketek (telithromycin); severe liver disease .
tetracyclines
doxycycline(Doryx), tigecycline (Tygacil)
monobactams
aerobic gram (-) bacteria; bactericidal; parenteral use only;
monobactams adverse effects
nausea, diarrhea, vomiting.
monobactams
aztreonam (Azactam) ; moderately severe systemic infections, UTIs
aminoglycosides
bactericidal;prevents protein synthesis; used with penicillins; treats mostly gram(-) and synergistic for gram (+); nephrotoxicity and ototoxicity; monitor peak and trough
sulfonamide assessments
1)Take with 2000-3000 mL of fluid 24h 2)Assess RBCs prior 3)Take with food
tetracycline assessments
1)before therapy, assess drug allergies, renal, liver and cardiac function 2)pt health history - immune status 3)assess for contraindications to antibiotic use 4)assess for potential drug interactions
penicillin assessments
1take only with water (not acidic juices) 2)Monitor pt for at least 30 min for allergic reaction
cephalosporins assessments
1)Give with food - GI upset 2)may cause disulfiram (Antabuse) - like reaction when taken with alcohol
macrolides assessments
1)highly protein-bound and will cause severe interactions with other protein-bound drugs 2)enhanced on empty stomach - but b/c of GI upset taken after snack
aminoglycosides
gentamicin (Garamycin), neomycin (Neo-fradin) PO (all others are parenterally - poorly absorbed)
quinolones (fluoroquinolones) mechanisms
bactericidal; alters DNA of bacteria - does not effect human DNA; gram (-), some gram (+); do not give to children under 18
quinolones adverse effects
black box warning: increased risk of tendonitis and tendon rupture; caution with cardiac pts. - EKG; absorption by antacids, vitamins, zincs; Infuse over 1-11/2 h to reduce adverse effects.
vancomycin
drug of choice for MRSA; bactericidal; ototoxicity and nephrotoxicity
neutrophil count
normal is >1500; neutropenia is <500 - At Risk for infection - follow standard precautions - handwashing, fever - early sign of infection, take temp q4h, report temp >101
beta-lactamase
enzyme that provides mechanism for bacterial resistance to the beta lactam antibiotics.