Pharmacology and the Nursing Process7: Antibiotics Flashcards
community-associated infections
- an infection that is acquired by a person who has not been hospitalized or had a medical procedure within the past year
health care-associated infections
- contracted in a hospital or institutional setting
- not present/incubated before a hospital admission
- often more difficult to treat because causative microorganisms are often drug resistant and the most virulent
multi drug resistance
- microbes/ pathogens have mutated to current meds changed adapted making medications/antibiotics less effective
therapeutic drug monitoring
- labs: window of a high and low level in which Rx works the best
minimum inhibitory concentration (MIC)
- concentration of the least amount of the drug that is in the body/blood and still working
what is time dependent killing?
- A property of most antibiotic classes whereby prolonged high plasma drug concentrations are required for effective bacterial kill
What is an example of a time dependent killing antibiotics?
- Z-pak (Azithromycin)
Concentration-dependent killing
- how long a drug stays in the body, how much damage we can do to the pathogen in that period of time
- constant amount of antibiotic in the body to kill that pathogen
multidrug-resistant organisms
- organisms that are resistant to one or more classes of antimicrobial drugs
What are common multidrug-resistant organisms?
- methicillin-resistant staphylococcus aureus (MRSA)
- Vancomycin-resistant Enterococcus (VRE)
- organism producing extended-spectrum betalactamases (ESBLs))
- Organisms producing Klebsiella puemoniae carbapenemase (KPC)
Empiric therapy
- treatment of an infection before specific culture information has been reported or obtained (generally broad spectrum antibiotic used until culture is received)
Definitive therapy
- antibiotic therapy tailored to treat organism identified with cultures
- have culture back, used antibiotics that microbe is sensitive to
Prophylactic therapy
- treatment with antibiotics to prevent an infection, as in intraabdominal surgery or after trauma
Therapeutic response
- decrease in specific s/s of infection are noted (decrease in fever, elevated WBC, redness, inflammation, drainage, pain)
Subtherapeutic response
- s/s of infection do not improve
- pt does not get better---->need to try different antibiotics
What are some antibiotic mechanisms of action?
- interference with cell wall synthesis
- interference with protein synthesis
- interference with DNA replication
- Acting as a metabolite to disrupt critical metabolic reaction inside the bacterial cell
Bactericidal
- kill bacteria
- action of some antibiotics
Bacteriostatic
- inhibit growth of susceptible bacteria, rather than killing them immediately; will eventually lead to bacterial death
- action of antibiotics
Sulfonamides
- often combined with another drugs (synergistic)
- Sulfamethoxazole w trimethoprim (non sulfa antibiotic)= Bactrim, Septra (commonly used)
Sulfonamides:
Mechanism of Action
- bacteriostatic
- prevents synthesis of folic acid required for synthesis of bacterial purines and nucleic acid
- does not affect human cells or production of folic acid
- only affects bacterial organisms that synthesize their own folic acid
Sulfonamides:
Indications
- effective against both gram+ and gram - bacteria
- often used for treatment of UTIs
- URIs
- commonly prescribed for outpatient staphylococcus infections, MRSA
Sulfonamides:
Adverse effects
- Blood: thrombocytopenia
- Integumentary: photosensitivity, Stevens-Johnson syndrome
- GI: n/v, diarrhea, pancreatitis
- other: hepatotoxicity, h/a,cough
Penicillins
- Natural pcn: Penicillin G, Penicillin V
- Penicillinase-resistant drugs: nafcillin, colxacillin, oxacillin, dicloxacillin
- Aminopenicillins: amoxicillin (Amoxil), ampicillin (generic only)
- Extended spectrum drugs: carbenicillin, piperacillin, ticarcillin
* generic all -cillins; some trade names don't include -cillin so be careful &know both
Penicillins
MOA
- bactericidal
- pcns enter bacteria via the cell wall
- inside the cell wall they bind to pcn-binding protein
- once bound, normal cell wall synthesis is disrupted
- RESULT: BACTERIAL CELL DEATH by cell lysis
- do not kill other cells in body
Pencillins:
Indications
- prevention and tx of infections caused by susceptible bacteria
- gram + bacteria, some gram - bacteria, some anaerobic bacteria and spirochetes
Pencillins:
Adverse effects
- allergic reactions to pencilling occur in 0.7% to 4 % of treatment course (urticaria, pruritus angioedema)
- n/v, diarrhea, abd pn
- if pt has a hx of throat swelling/hives from pcn they should not receive cephalosporins; if allergic to pcn there is an ^ risk for allergy to other beta-lactam antibiotics
- if a pt is going to have a reaction it is most likely to happen within the first 15 to 20 min of receiving the antibiotics, good to stay with pt for that period of time
Penicillins:
Interactions
- MANY!
- NSAIDS
- Oral contraceptives
- Warfarin
- ex: coumadin: very loosely protein bound, main drugs knock it off its receptor site
Cephalosporins:
First generation
- good gram+ coverage
- poor gram - coverage
- Parenteral and PO
- examples: Cefazolin (Ancef) (IV or IM) & Cephalexin (Keflex) (PO)
- used for surgical prophylaxis, and susceptible staphylococcal infections
Cephalosporins:
Second Generation
- good gram + coverage
- better gram- coverage than first generation but still not great
- ex: Cefoxitin (Qefoxin) (IM &IV) : used prophylactically for abdominal or colorectal surgeries; also kills anaerobes
- ex: Cefuroxime (Zinacef) (Ceftin): surgical prophylaxis, does not kill anaerobes
Cephalosporins:
Third generation
- most potent group against gram- bacteria
- less active against gram+
- ex: Ceftazidime (Fortaz), Ceftriaxone (Rocephin)
Ceftriaxone (Rocephin)
- cephalosporin 3rd generation
- IV & IM
- long half life,
- once a day dosing
- Elimination is primary hepatic
- easily passes meninges and diffused into CSF t treat CNS infections
Ceftazidime (Ceptaz, Fortaz, Tazidime)
- cephalosporin 3rd generation
- IV & IM
- excellent gram- coverage
- resistance is limiting when we use it
Cephalosporins:
Forth generation
- broader spectrum of antibacterial activity then 3rd generation, especially against gram+ bacteria
- complicated/uncomplicated UTI >>> Cefepime(Maxipime)
Cephalosporins:
Fifth generation
Ceftaroline (Teflaro)
- broader spectrum of antibacterial activity
- effective against a wide variety of organisms (MRSA)
Cephalosporins:
Adverse Effects
- Similar to pcn
- mild diarrhea, abd cramping, rash, pruritus, redness, edema
- potential cross-sensitivity with penicillins if allergies exist
Tetracyclines
- wide spectrum: gram - and gram + organisms
- natural and semisynthetic
- bacteriostatic
- inhibits bacterial protein synthesis
- stops many essential functions of bacteria
- binds (chelate) to Ca+++ , Mg++, & Al+++ ions to form insoluble complexes
- dairy products reduce the absorption of tetracycline ^^^^^^^^
Commonly used Tetracyclines
- oxytetracycline (Terramycin)
- Tetracycline
- doxycycline (Doryx, Vibramycin)
- Tigecycline (tygacil)
Tetracyclines:
Adverse effects
- strong affinity for calcium: discoloration of permanent teeth/tooth enamel in fetuses and children or if nursing infants
- may retard fetal skeletal development if taken during pregnancy
- alteration of intestinal flora: SUPER INFECTION >candida
- diarrhea
- pseudomembranous colitis
- vaginal candidiasis
- gastric upset
- enterocolitis
- maculopapular rash
- others
Aminoglycosides
- poor oral absorption
- very potent antibiotics with serious toxicities
- bactericida; prevent protein synthesis
- kill mostly gram-; some gram +
commonly used Aminoglycosides
- gentamicin
- neomycin (neo-fradin)
- tobramycin (TOBI)
- amikacin
Aminoglycosides
Indications
- used to kill gram - bacteria
- often used in combination with other antibiotics for synergistic effects (often sulfas)
- used for certain gram + infections that are resistant to other antibiotics
- Poorly absorbed through GI tract, given parentally (exception neomycin)
Neomycin
- given orally to decontaminate GI tract before surgical procedures
- used as an enema for ^ purpose
- used to treat hepatic encephalopathy----->liver induced brain disease come with severe cirrhosis
Aminoglycosides:
Adverse Effects
- Nephrotoxicity (renal damage)
- Ototoxicity (auditory impairment and vestibular impairment @ eighth cranial nerve, high frequency)
- h/a
- paresthesia
- fever
- superinfections
- vertigo
- skin rash
- dizziness
Amino glycosides (serum)
- must monitor drug levels to prevent toxicities
- MIC
Metronidazole (flagyl)
- used for anaerobic organisms
- given often in hospital
- intraabdominal and gynecologic infections
- protozoal infections
Vancomycin (Vancocin)
- treatment choice for MRSA and other Gram+ infectionS
- oral vancomycin is indicated for treatment of antibiotic induced colitis (C.Difficle) and for the treatment of staphylococcal enterocolitis
- must monitor blood levels to ensure therapeutic level and prevent toxicity
- MAY CAUSE OTOTOXICITY AND NEPHROTOXICITY
Vancomycin serum levels
- Therapeutic: Peak: 20-40 mpg/mL ; trough 5-10mcg/mL
- Toxic level greater than 40 mph/mL
Vancomycin
- red man syndrome may occur: flushing/itching of head, neck, face, upper trunk; antihistamine may be ordered to reduce effect (often occurs if vancomycin is given too fast, pt will almost turn purple from nipple line up, should be given with a pump to prevent this )
- additive neuromuscular blocking effects in pt receiving neuromuscular blockers
- should be infused over 60 min
- rapid infusion may cause hypotension
NURSING IMPLICATIONS:
Before beginning therapy what should be assess?
- #1: contradictions to any drug: DRUG ALLERGIES
- LABS: BUN, cretinine, liver function tests
- current medications, supplements, diet, pt health history included immune system status
- any prior health condition that my contraindication to antibiotic use or indicate cautious use
- assess for potential drug interactions
NURSING IMPLICATIONS:
What specimen should be obtained prior to beginning antibiotic therapy?

- CULTURE!!!
- 2 separate sites if obtaining blood culture
- if swab culture directly from site of infection
NURSING IMPLICATIONS:
What are some s/s of superinfections?
- fever
- perineal itching
- cough
- lethargy
- any unusual discharge
NURSING IMPLICATIONS:
Sulfonamides
- take with 2000-3000 mL of fluid / 24 hr
- assess RBCs prior to beginning therapy
- take oral does with food
NURSING IMPLICATIONS:
Penicillins
- take oral does with water not juice as acidic fluids may nullify drugs antibacterial actions
- monitor patients taking penicillin for an allergic reaction for at least 30 minutes after administration
NURSING IMPLICATIONS:
Cephalosporins
- assess for penicillin allergy; may have a cross allergy
- give orally administered forms with food to decrease GI upset, even though this will delay absorption
- some of these drugs may cause disulfiram (antabuse) like reaction when taken with alcohol
NURSING IMPLICATIONS:
Macrolides
- highly protein bound and will cause severe interactions with other protein bound drugs
- the absorption of oral erythromycin is enhanced when taken on an empty stomach, and because of the high incidence of GI upset, may drugs are taken after a meal or snack
NURSING IMPLICATIONS:
Tetracyclines
- avoid milk products, iron preparations, antacids, and other dairy products because of the chelations and drug binding that occurs
- take all medications with 6 to 8 oz fluid
- because of photosensitivity avoid sunlight and tanning beds
WBC, total
- Adult: 4,500-10,000 microliters (mm^3)
- child: newborn : 9,000-30,000microliters (mm^3) , 2y/o: 6,000-17,000 microliters (mm^3) ; 10 y/o: 4,500 to 13,500 microliters (mm^3)
WBC, diff
- Neutrophils (total): 50-70%; 2,500-7,000 microliters (mm^3)
- segments: 50-65%; 2,500-6,500 microliters (mm^3)
- bands: 0-5%; 0-500 microliters (mm^3)
- Eosinophils: 1-3%; 100-300 microliters (mm^3)
- Basophils: 0.4-1.0%; 40-100 microliters (mm^3)
- monocytes: 4-6%; 200-600 microliters (mm^3)
- lymphocytes: 25-35% 1,700-3,500 microliters (mm^3) ,