ANTIBIOTICS A brief overview for DMAT PA-1

Report
ANTIBIOTICS
A brief overview for DMAT PA-1
DEFINITIONS
*Antibiotic- agents derived from natural sources (bacteria or molds) used to
treat infection by suppressing or destroying the causative microorganism
*Antimicrobial- those anti-infective agents which are derived from synthetic
substances
* these two terms are now used interchangeably
Antiseptic- an agent used to inhibit bacterial growth
Bacteria- microscopic single-celled organisms containing DNA and cell walls
Bactericidal- kills the bacteria
Bacteriostatic- inhibits the growth of the bacteria
Disinfectant- an agent used to kill bacteria
Normal flora-non-pathogenic bacteria that live on human skin and mucous
membranes
Pathogen-bacteria that cause disease
Spectrum of activity- a product’s range of antimicrobial activity
CLASSIFICATION OF BACTERIA
I. Shape
Spherical (cocci)
single cells (micrococci)
pairs (diplococci)
clusters (staphylococci)
chains (streptococci)
cubical groups (sarcinae)
Rod-like (bacilli)
oval shapes (coccobacilli)
chains (streptobacilli)
Spiral (spirochetes)
rigid (spirilla)
flexible (spirochetes)
curved (vibrios)
II. Stain
(gram-stain)
gram-positive (stains blue)
* gram-negative (stains pink)
* have a unique outer membrane that prevents many drugs from penetrating them—making them more resistant
to antibiotics
III. Use of oxygen
aerobic—require oxygen to live
anaerobic---live in the absence of oxygen
thrive in areas of the body with low levels of oxygen (intestines, decaying tissue, deep and dirty wounds—they
tend to invade skin and muscle tissue that has been damaged)
facultative---can live and grow in the presence or absence of oxygen
COMMON EXAMPLES
Gram-positive aerobes
streptococcus pneumoniae
*pericarditis,pneumonia,acute sinusitis, meningitis, otitis media, septicemia
enterococcus faecalis
*burn wound sepsis, infective endocarditis
staphylococcus aureus
*pneumonia, cellulitis, boils, toxic shock, postoperstive bone and joint infections, peritonitis, styes, suppurative conjunctivitis,
staphylococcus epidermis
*human bites,burns,IV line infections, postoperative bone and joint infections
bacillus anthracis
*anthrax
corynebacterium diphtheriae
*pharyngitis, tonsilitis, diphtheria
streptococcus agalactiae (group B streptococcus)
*bacterial sepsis and meningitis in newborns, endometritis and fever in postpartum
streptococcus pyogenes (group A streptococcus)
*diabetic foot ulcers, pharyngitis, tonsilitis, burns, cellulitis, decubitus ulcers, impetigo, toxic shock, necrotizing fasciitis, scarlet fever,
rheumatic fever
Gram-positive anaerobes
clostridium difficile
*pseudomembraneous colitis
clostridium botulinum
*botulism
clostridium tetani
*tetanus
clostridium perfringens
*gas gangrene
Gram-negative aerobes
neisseria meningitidis
*meningitis
escherichia coli
*urinary tract infections, pyelonephritis, septicemia, gastroenteritis, peritonitis
neisseria gonorrhoeae
*gonorrhea, pelvic inflammatory disease
pseudomonas aeruginosa
*puncture wounds, complicated urinary tract infections (catheter related), burns, pneumonia (ventilator related)
haemophilus influenzae
*pneumonia, meningitis, otitis media, acute sinusitis
moraxella catarrhalis
*pneumonia
klebsiella pneumoniae
* wounds, otitis media, aspiration pneumonia
legionella sp.
* Legionnaires’ disease
shigella sp.
*severe diarrhea, gastroenteritis
salmonella sp.
*severe diarrhea, gastroenteritis, salmonella bacteremia
campylobacter jejuni
*diarrhea
Gram-negative anaerobes
bacteroides fragilisclo
*sepsis
CLASSIFICATION OF
ANTIBACTERIAL AGENTS
Aminoglycosides
B-lactams
*Penicillins
*Cephalosporins
*Carbapenems
Macrolides
Quinolones
Sulfonamides
Tetracyclines
Miscellaneous Agents
*Vancomycin
*Clindamycin
*Metronidazole
*Fluconazole
*Terconazole
*Miconazole
*Nystatin
*Rifaximin
*Nitrofurantoin
*Mebendazole
*Bacitracin
*Triple antibiotic ointment
*Neomycin/polymyxin B/hydrocortisone otic suspension
AMINOGLYCOSIDES
Miscellaneous facts:
bactericidal
*”concentration-dependent killing”—the bactericidal effect increases as the antibiotic concentration increases
*”post-antibiotic effect” – continues to inhibit bacterial growth for several hours after aminoglycoside concentrations are no longer detectable
higher doses at longer intervals
often used in combination with B-lactam antibiotics to achieve antibacterial synergy to treat serious pneumococcal and enterococcal
endocarditis
no oral absorption – must give IV/IM
rapid renal excretion
poor CNS penetration
clinical differences among the agents are subtle
Spectrum:gram-negative enterobacteria
no activity against anaerobes
Therapeutic uses: suspected sepsis, pneumonia, meningitis, complicated urinary tract infections, osteomyelitis, bacteremia, peritonitis
Drawbacks: very limited by their toxic potential
ototoxic (irreversible) and nephrotoxic
nephrotoxicity: more common than ototoxicity, often reversible, most common in the elderly and those concurrently receiving amphotericin B,
cephalosporins, or vancomycin
accumulate in the proximal tubule of the kidney –mild renal dysfunction occurs in 25% of patients on these drugs for several days or more
once daily dosing has been reported to be effective and less nephrotoxic
caution in patients with decreased renal function
caution with other ototoxic and nephrotoxic drugs
neuromuscular blockade can occur with high doses, rapid IV administration, in addition to neuromuscular blocking agents or anaesthetics,
hypocalcemia, myasthenia gravis, and with blood transfusions
Pregnancy category D
Monitoring parameters:blood draws—peaks & troughs, BUN, serum creatinine levels
BLACK BOX WARNING
nephrotoxicity & ototoxicity
Gentamicin(Garamycin)IV/IM
More active than tobramycin against serratia organisms (septicemia)
Activity against mycobacterium and e.coli
Used in combination with other antibiotics to treat staph. aureus and certain species of streptococcus
Serum concentrations are unpredictable after IM administration—IV is the preferred route
Gentamicin ophth soln (Garamycin)
Potential ocular irritation and burning
Tobramycin (Nebcin)IV/IM
Better activity than gentamicin against pseudomonas aeruginosa (puncture wounds,urinary tract infections,burns,
pneumonia)
Some studies suggest it is less nephrotoxic than gentamicin—not firmly established
Used in combination with other antibiotics to treat staph. aureus and certain species of streptococcus
IV is the preferred route of administration
Amikacin
Kanamycin
Neomycin
Netilmicin
Streptomycin
Paromomycin
B-LACTAMS
Miscellaneous facts:
contain a unique 4 member ring that is essential for antibacterial activity
certain bacteria produce and enzyme (B-lactamase) that breaks the ring and inactivates the
antibiotic
B-lactamase producing bacteris: staph. Aureus
h. influenzae
bacteroides sp.
pseudomonas sp.
legionella sp.
drug interaction with probenecid—probenecid inhibits renal excretion of the antibiotics causing
higher, prolonged serum levels
anaphylactic reactions are common
(urticaria, laryngeal edema,bronchospasm)
*Penicillins
*Cephalosporins
*Carbapenems
PENICILLINS
Miscellaneous facts:bactericidal
Four Subdivisions
*Natural Penicillins
*Aminopenicillins
*Penicillinase-Resistant Penicillins
*Extended-Spectrum Penicillins
Spectrum:broad spectrum
gram-positive and gram-negative
Therapeutic uses:oropharyngeal infections, sexually transmitted diseases, pharyngitis, otitis
media, sinusitis, bacteremia, anthrax, skin and soft tissue infections, mild respiratory infections, uncomplicated
urinary tract infections
Drawbacks: resistance
hypersensitivity reactions (occur in up to 10% of people receiving penicillins)
bone marrow depression
gastrointestinal distress
potential to cause seizures when given in high doses to patients with renal dysfunction
ticarcillin and carbenicillin can cause platelet dysfunction
NATURAL PENICILLINS
Miscellaneous facts:
highly active against gram-positive cocci and gram-negative cocci
most common use is for streptococcus sp.
Penicillin G Sodium (Pfizerpen) IV/IM
Penicillin VK (Veetids) oral
Penicillin G procaine
repository form IM use only
Penicillin G benzathine
repository form IM use only
AMINOPENICILLINS
Miscellaneous facts:
broad-spectrum penicillins
their spectrum is similar to but broader than that of the natural and penicillinase-resistant penicillins
ineffective against most staphylococcal organisms
commonly used for upper respiratory infections, uncomplicated urinary tract infections and otitis media
Amoxicillin oral capsules & suspension
semisynthetic agent
better absorption and less frequent dosing than ampicillin
better bioavailability than penicillin—more stable to gastric acid
Amoxicillin/clavulanic acid (Augmentin)oral chewables, tablets and suspension
clavulanic acid—no antibacterial activity, it inhibits B-lactamase by binding to it and inactivating it-therefore
increasing the spectrum of activity of amoxicillin
clavulanic acid causes a high incidence of gastrointestinal effects
more effective than amoxicillin against staph. aureus, klebsiells sp., and bacteroides fragilis
Ampicillin sodium IV/IM
more effective than amoxicillin against shigellosis sp.
Ampicillin sulbactam (Unasyn) IV
PENICILLINASE-RESISTANT
PENICILLINS
Miscellaneous facts:
active against gram-positive aerobes
limited activity against gram-negative and anaerobic bacteria
are not inactivated by B-lactamase
less potent than natural penicillins against organisms susceptible to natural penicillins– cannot substitute for natural penicillins
complete cross-resistance exists among the group
all are identical except for their route of administration
commonly used for bacteremia, skin and soft tissue infections, respiratory tract infections, bone and joint infections, urinary tract
infections
ineffective against MRSA/MRSE
Dicloxacillin(Dynapen)oral capsule
food decreases oral bioavailibility—administer on an empty stomach
Nafcillin(Nallpen)IM/IV
semisynthetic
metabolized by liver – useful in patients with renal impairment
associated with neutropenia in 10 to 20% of patients
multiple drug interactions (warfarin,etc.)
Cloxacillin
Methicillin
Oxacillin
EXTENDED-SPECTRUM
PENICILLINS
Miscellaneous facts:
also known as antipseudomonal penicillins
have broadest spectrum of all penicillins
used to treat serious infections caused by gram-negative aerobes
ineffective against staphylococci sp.
hypersensitivity reactions are more common in this subdivision
all inhibit platelet aggregation– result in bleeding
Piperacillin
Piperacillin/tazobactam (Zosyn)IV
tazobactam—no antibacterial activity, inhibits B-lactamase therefore enhancing
the intrinsic activity of piperacillin—increased gastrointestinal side effects
most potent extended-spectrum penicillin against pseudomonas sp.
effective in treatment of nosocomial pneumonia
Ticarcillan
Ticarcillin/clavulanic acid
CEPHALOSPORINS
Miscellaneous facts:
B-lactam antibiotics
bactericidal
4 generations
classified according to their spectrum of activity
each generation increases its gram-negative activity but, loses activity against grampositive organisms
popular due to their low toxicity and activity against serious infections
Spectrum: gram-positive and gram-negative
no activity against MRSA
Therapeutic uses:perioperative prophylaxis, urinary tract infections, acute otitis media,
sinusitis, etc
Drawbacks: most are eliminated via renal excretion—adjust dosages in renal insufficiency
hypersensitivity reactions (fever, maculopapular rash, anaphylaxis, & hemolytic
anemia)
gastointestinal effects
hypoprothrombinemia
potential for nephrotoxicity
cross-sensitivity with penicillins in up to 10% of patients receiving cephalosporins
1st GENERATION
CEPHALOSPORINS
Miscellaneous facts:
oldest cephalosporins
gram-positive activity & basic gram-negative activity (except
enterococci)
widely used for perioperative prophylaxis
used to treat klebsiella sp., skin and soft tissue infections,
respiratory tract infections, otitis media
Cefazolin(Ancef)IM/IV
compared to other 1st generation cephalosporins it achieves higher blood
levels after administration, has greater gram-positive coverage and requires
less frequent dosing
Cephalexin(Keflex) oral capsules ,oral suspension
primarily used for otitis media and respiratory tract infections
Cephadroxil
Cephradine
2nd GENERATION
CEPHALOSPORINS
Miscellaneous facts:
less gram-positive coverage & more gram-negative coverage than 1ST
generation cephalosporins
also active against B-lactamase producing strains of haemophilius
influenzae
Cefaclor
Cefoxitin
Cefprozil
Cefuroxime
Cefotetan
3rd GENERATION
CEPHALOSPORINS
Miscellaneous facts:
increased gram-negative coverage & decreased gram-positive coverage over 2nd generation cephalopsorins
best CNS penetration of all cephalosporins—very valuable in treatment of meningitis caused by meningococci,
pneumococci, haemophilus influenzae, and enteric gram-negative bacilli
especially useful for gram-negative upper respiratory tract infections, otitis media, urinary tract infections and skin
infection
empiric therapy for life-threatening infections in which resistant organisms are the most likely cause
treatment of sepsis of unknown origin in immunosuppressed patients
initial therapy in mixed bacterial infections
Cefotaxime(Claforan)IM/IV
commonly used to treat empiric gram-negative meningitis, serious bacteremias, pneumonia, and communityacquired infections
Ceftriaxone(Rocephin)IM/IV
longest half-life of all cephalosporins allowing for once daily dosing
DOC=neisseria gonorrhoeae
Cefdinir
Cefixime
Cefoperazone
Cefopodoxime proxetil
Ceftazidime
Ceftibuten
Ceftizoxime
Cefditoren
4th Generation Cephalosporins
Miscellaneous facts:
newest cephalosporins
same coverage as 3rd generation cephalosporins with additional coverage
against pseudomonas sp
high degree of resistance to B-lactamase producing organisms
good activity against organisms that are resistant to 3rd generation
cephalosporins
commonly used for febrile neutropenic patients
Cefepime (Maxipime)
CARBAPENEMS
•
•
•
•
•
•
Miscellaneous facts:
B-lactam antibiotics
bactericidal
Spectrum:gram-positive cocci, gram-negative rods, and anaerobes
broader spectrum than most B-lactams
Therapeutic uses:urinary tract infections, lower respiratory tract infections,
gangrene, sepsis, pneumonia,intra-abdominal infections, gynecological infections,
etc.
•
Drawbacks: anaphylactic reactions, seizures, confusion, dizziness,
gastrointestinal issues
•
•
•
Imipenem/cilastatin
Ertapenem
Meropenem
MACROLIDES
Miscellaneous facts:
mostly bacteriostatic—can be bactericidal
newer macrolides-better absorption and less gastrointestinal effects
Spectrum: gram-positive cocci and bacilli & some gram-negative cocci
mycoplasma pneumoniae, chlamydia trachomatis, legionella sp., corynebacterium
diphtheriae, campylobacter sp., treponema pallidum, propionibacterium acnes, &
borrelia burgdorferi
DOC=group A streptococcal and pneumococcal infections when penicillin cannot be
used
Therapeutic uses:
Legionnaires disease, dental prophylaxis , chlamydial infections, ance, diphtheria, pertussis,
ocular infections
Drawbacks:
numerous drug interactions – erythromycin inhibits the hepatic metabolism of other
drugs (theophylline, digoxin, corticosteroids, carbamazepine, cyclosporin, lovastatin,
etc.)
cardiac issues—causes QT prolongation and torsade de pointes
gastrointestinal disturbances (dose-related),skin rashes, eosinophilia, tinnitus,
dizziness, reversible hearing loss
Erythromycin base (ERYTAB) oral tablet
enteric coated, delayed-release tabs (do not crush)
DOC=Legionnaire’s disease, mycoplasma pneumonia and chlamydial infections
drug interactions with terfenadine, astemizole, pimozide, etc.
dose must be decreased with decreased liver function
pregnancy category B
Erythromycin ethylsuccinate(EES) oral suspension
Erythromycin ophth oint.
superficial ocular infections
prophylaxis of neonatal ophthalmia due to neisseria gonorrhoeae or chlamydia trachomatis
Azithromycin(Zithromax, Z-Pak) oral suspension,oral tablets
semisynthetic macrolide
less active than erythromycin against gram-positive organisms
more active than erythromycin against haemophilus influenzae and other gram-negative organisms
concentrates in cells– tissue levels are higher than serum levels—increased efficacy and duration of action-less tendency to cause drug interactions
once daily dosing
less gastrointestinal issues than with other macrolides
very useful in nongonococcal urethritis caused by chlamydia, lower respiratory tract infections, mycobacterium avium complex infection, pharyngitis, pelvic
inflammatory disease, nongonococcal urethritis caused by chlamydia, Legionnaire’s disease
pregnancy category B
Clarithromycin(Biaxin) XL oral tablets, oral suspension semisynthetic macrolide
same spectrum as erythromycin –more potent
enhanced activity against haemophilus influenzae and mycobacterium avium complex
also active against toxoplasma gondii, and cryptosporidium sp.
metalic aftertaste
pregnancy category C
Erythromycin estolate
Erythromycin stearate
Dirithromycin
QUINOLONES
Miscellaneous facts:
bactericidal (concentration dependent)
4 generations – each generation adds coverage for a new group of pathogens
different mechanism of action -- thus, no cross resistance with other classes of antibiotics
produce a false-positive urine screening result for opiates when using a commercially available immunoassay kit
Spectrum: highly active against gram-negative aerobes & gram-positive activity
no activity for most anaerobes
Therapeutic uses:
urinary tract infections, lower respiratory tract infections, sinusitis, otitis media, infectious diarrhea, prostatitis, empiric use in febrile
neutropenic patients
Drawbacks:
relatively free of side effects and toxicity
phototoxicity
not recommended in children under 18 years of age (cartilage malformations were found in studies in immature
animals),tendon rupture, cardiac QT prolongation( associated with 2nd and 3rd generations), CNS stimulation,
hypoglycemia, seizures, anaphylactic reactions, pseudomembraneous colitis, can cause exacerbation of
myasthenia gravis
multiple drug interactions – theophylline, antacids, iron, multivitamins,
warfarin, NSAIDs (potential to increase risk of seizure), antiarrhythmic drugs
pregnancy category C
1st GENERATION QUINOLONES
Miscellaneous facts:
bactericidal
gram-negative coverage (excluding pseudomonas)
limited use due to the development of bacterial resistance
poor oral availability limits its systemic use
common uses include urinary tract infections
Nalidixic acid
2nd GENERATION QUINOLONES
(FLUOROQUINOLONES)
Miscellaneous facts:
bactericidal
increased gram-negative coverage (including pseudomonas),
gram-positive cocci, and mycobacteria
addition of fluorine ion to the quinolone structure
=fluoroquinolones
QT prolongation and torsade de pointes
Ciprofloxacin (cipro)oral tablets/IV
good penetration into bone—useful in osteomyelitis
urinary tract infections, lower respiratory tract infections, sinusitis,
empiric use in febrile neutropenia, typhoid fever, infectious diarrhea,
prostatitis, bacterial conjunctivitis, corneal ulcers, nosocomial
pneumonia
indicated for use in mycobacterium avium complex in patients with
AIDS
2nd GENERATION QUINOLONES
(FLUOROQUINOLONES)
used in combination with other drugs to treat multi-drug-resistant
tuberculosis
most potent flouruquinolone against pseudomonas aeruginosa
no longer drug of choice for neisseria gonorrhoeae (becoming resistant)
absolute contraindication: tendon pain, tendon rupture, tendonitis
oral dosage
250mg q12h
500mg q12h
750mg q12h
equivalent IV dosage
200mg IV q12h
400mg IV q12h
400mg IV q8h
Ofloxacin (Floxin,Ocuflox)
oral/ophth/otic use
less potent than ciprofloxacn against most gram-negative bacteria
most active 2nd generation against chlamydia trachomatis
Norfloxacin (Noroxin, Chibroxin)
3rd GENERATION QUINOLONES
(FLUOROQUINOLONES)
Miscellaneous facts:
QT prolongation
bactericidal
extended gram-positive coverage (particularly against penicillin-sensitive and penicillin-resistant
streptococcus pneumoniae, mycoplasma pneumoniae & chlamydia pneumoniae)
gram-negative coverage (including pseudomonas sp.)
decrease dosage in renal impairment
treatment of community-acquired pneumonia, acute sinusitis, acute exacerbations of chronic
bronchitis, bacterial conjunctivitis
Gatifloxacin
ophthalmic, bacterial conjunctivitis
Levofloxacin
oral, IV, ophthalmic
less QT prolongation than with other fluoroquinolones
Moxifloxacin
oral,IV, ophthalmic
not used for urinary tract infections
approved for treatment of complicated intra-abdominal infections
4th GENERATION QUINOLONES
(FLUOROQUINOLONES)
Miscellaneous facts:
bactericidal
gram-positive & gram-negative
significant coverage against anaerobes
Trovafloxacin (Trovan)
restricted by FDA to serious life-or-limb-threatening infections due to
serious drug induced hepatic adverse effects
BLACK BOX WARNING:
treatment restriction limitations—hospitals and long term care facilities
liver injury leading to liver transplantation and or death
SULFONAMIDES
Miscellaneous facts:
bacteriostatic
Spectrum: mostly gram-positive, some gram-negatives
also activity against certain strains of chlamydia trachomatis, nocarida, actinomyces, & bacillus anthracis
Therapeutic uses: animal and human bites, urinary tract infections, otitis media, chronic bronchitis, travelers’ diarrhea,
sexually transmitted bacterial infections, ocular infections and burns
Drawbacks:photosensitivity, can cause Stevens-Johnson syndrome, hypersensitivity reactions, blood dyscrasias,
caution in patients with G6PD deficiency (can cause acute hemolysis), crystalluria, hematuria
drug interactions with phenytoin, oral anticoagulants, & sulfonylureas
cross-allerginicity between the individual sulfonamides
discontinue at first sign of skin rash or other reaction
SMZ/TMP(Bactrim,BactrimDS)
(sulfamethoxazole/trimethoprim)->synergistic combination
bacteriostatic-in combination with trimethoprim=bactericidal
DOC=treatment and prophylaxis of pneumocystis carinii
useful in acute gonococcal urethritis, acute exacerbation of chronic bronchitis
Sodium Sulfacetamide 10% ophth soln
Used to treat conjunctivitis or superficial bacterial eye infections,corneal ulcers
can cause a delay in corneal wound healing
local irritation, burning, stinging
Silver sulfadiazine1% cream(Silvadene)
bactericidal
gram-positive & gram-negative --- some effectiveness against yeast
adjunct for prevention and treatment of wound sepsis in patients with 2 nd & 3rd degree burns
TETRACYCLINES
Miscellaneous uses:
bacteriostatic
cross-resistance with the group is extensive
Spectrum: gram-negative & gram-positive
broad spectrum agents—coverage includes spirochetes, rickettsia, mycoplasma
pneumonia, chlamydia sp., & certain protozoa species
Therapeutic uses:
DOC=rickettsial (Rocky Mountain Spotted Fever), chlamydial, mycoplasmal infections, anthrax
frequently used for acne and periodontitis
useful alternative to penicillin in treatment of anthrax, syphilis, gonorrhea, Lyme disease, and h.
influenzae respiratory infections
Drawbacks: photosensitivity
gastrointestinal distress, hypersensitivity reactions, hepatoxic (especially in pregnant women),
pregnancy category D, tooth discoloration (binds to calcium in teeth & bones-enamel hypoplasia
can also occur), not recommended in children<8 years old, cannot give with antacids or milk,
cannot use tetracycline after expiration date(causes renal tubular dysfunction which can lead to
renal failure), take with fluids to avoid esophageal irritation
Doxycycline (Vibramycin) oral tablets
excreted mainly in feces –very useful in patients with poor renal function
Minocycline
Tetracycline
MISCELLANEOUS AGENTS
Vancomycin (Vancocin)IV
peaks:20-40mcg/ml
Miscellaneous facts: bactericidal
troughs:5-15mcg/ml
very useful in patients allergic to penicillins or cepphalosporins
Spectrum: gram-positive organisms including MRSA/MRSE and enterococci
Therapeutic uses:serious infections—endocarditis, osteomyelitis, staphylococcal pneumonia, treatment of pseudomembranous colitis caused by c.difficile or
s.aureus enterocolitis
oral form used only for c. difficile
Drawbacks: ototoxicit y
increased ototoxicity & nephrotoxicity when given with other ototoxic and nephrotoxic drugs
monitor blood levels
hypersensitivity reactions
facial flushing and hypotension with too rapid infusion of the drug (red man syndrome)
Clindamycin (Cleocin)oral/IV/IM
Miscellaneous facts: bacteriostatic
cross resistance with macrolides is common
reserve for serious infections in patients with penicillin allergies
does not diffuse into cerebrospinal fluid—do not use for meningitis
Spectrum:most gram-positive & many anaerobic organisms
bacteroides fragilis
Therapeutic uses: skin, respiratory tract, and soft tissue infections caused by staphylococci, pneumococci, and streptococci, dental infections, acne, bone &
joint infections, bacterial vaginosis
Drawbacks: limited by its toxicities
gastrointestinal issues, blood dyscrasias, Stevens-Johnson syndrome
dose must be decreased with impaired hepatic function
potentiates the effects of neuromuscular blocking agents
BLACK BOX WARNING
first antibiotic to be associated with pseudomembraneous colitis
c. difficile associated diarrhea (pesudomembranous colitis)
alters the colon flora which leads to c.difficile overgrowth
c.difficile produces toxins A and B which contribtes to c.difficile associated diarrhea
Metronidazole(Flagyl) oral/IV
Miscellaneous facts:antibacterial and antiprotozoal agent
amebicide—amebicidal and trichomonacidal
Spectrum:anaerobic gram-positive and anaerobic gram-negative
certain protozoan parasites (trichomonas vaginalis, entamoeba histolyticass, giardia lamblia,etc.)
DOC=c.difficile, bacterial vaginosis (gardnerella vaginalis), c. tetani
Therapeutic uses:amebic dysentery, giardiasis, trichomoniasis, intra-abdominal, pelvic, soft tissue, periodontal, and odontogenic infections,
lung abscess, acne, meningitis, bacterial septicemia, lower respiratory tract infections, endocarditis
Drawbacks: hepatic metabolism-dosage adjustment in patients with liver dysfunction
gastrointestinal distress, headache, dark coloration of urine, leukopenia, dizziness, ataxia disulfiram-like reaction with ethanol
inhibits warfarin metabolism-increased bleeding
metallic taste
use cautiously in pregnancy (avoid in first trimester)
drug interactions: warfarin, phenytoin, phenobarbital, cimetidine, lithium, etc.
absolute contraindication in breast feeding
use with caution in patients with evidence of or history of hematological disease
Fluconazole(Diflucan) oral tablet
Miscellaneous facts: azole antifungal agent
fungistatic
Spectrum:active against many fungi, including yeasts, dermatophytes, actinomycegtes, and some phycomycetes, cryptococcus, candida, aspergillis
Therapeutic uses:vaginal candidiasis, oropharyngeal and esophageal candidiasis, systemic candida infections and cryptococcal meningitis
DOC=cryptococcal meningitis
Drawbacks:gastrointestinal disturbances, skin rashes, hepatic necrosis, Stevens-Johnson syndrome, anaphylaxis, alopecia
multiple drug interactions: phenytoin, cyclosporine, warfarin,sulfonylureas, etc
pregnancy category C
Terconazole cream (vaginal)
Miscellaneous facts: fungicidal
Spectrum:candida albicans
active against dermatophytes, yeasts, and at high concentrations gram-positive & gram-negative bacteria
Therapeutic uses: complicated and uncomplicated vulvovaginal candidiasis
Drawbacks: pruritis, irritation-vulvovaginal burning, headache, body pain
pregnancy category C (not recommended during first trimester)
Miconazole cream 2%
Miscellaneous facts: imidazole antifungal agent
fungistatic
topical or intravaginal use
Spectrum:broad spectrum
blastomyces dermatitidis, candida sp., cryptococcus neoformans, coccidioides immitis, histoplasma capsulatum, paracoccidioides brasiliensis, sporothrix
schenckii
Therapeutic uses: for topical and vaginal fungal infections
(vaginal candidiasis, tinea infections, cutaneous candidiasis)
Drawbacks: pregnancy category C
Nystatin cream
Miscellaneous facts: antifungal agent
fungicidal and fungistatic
Spectrum: primary activity against candida sp.
ineffective against bacteria, protozoa, trichomonads, and viruses
Therapeutic uses: treatment of oropharyngeal, cutaneous, mucocutaneous and vulvovaginal candidiasis
poor oral absorption, good local activity—great choice for oral and esophageal candida infections
Drawbacks: oral form causes gastrointestinal distress
contact dermatitis, Stevens-Johnson syndrome
not administered systemically due to potential toxicity
Rifaximin(Xifaxan) oral tablets
Miscellaneous facts: rifamycin antibiotic
non-systemically absorbed-no significant drug interactions
Spectrum: gram-positive, gram-negative, aerobes, anaerobes
Therapeutic uses: Traveler’s diarrhea caused by non-invasive strains of e.coli
Drawbacks: do not administer to patients with diarrhea complicated by fever or blood in the stools
flatulence, headache, abdominal pain, nausea, constipation, pyrexia
caution in patients allergic to any of the rifamycin antimicrobial agents
not for use in children under 12 years of age
pregnancy category C—if necessary—only in 2nd and 3rd trimesters
poor GI absorption-no systemic bioavailability-no drug interactions
200mg tid for 3 days
Loperamide(Imodium) oral capsules
Miscellaneous facts: synthetic antidiarrheal for oral use
prolongs transit time of the intestinal contents (decreases peristalsis), reduces daily fecal volume, increases viscosity and bulk density---diminished loss
of fluids and electrolytes
Spectrum:
Therapeutic uses: control and symptomatic relief of acute nonspecific diarrhea and of chronic diarrhea associated with inflammatory bowel disease—also
used for reducing the volume of discharge from ileostomies
Drawbacks: dry mouth, flatulence, abdominal cramps and colic
not recommended in infants under 24 months of age
2 capsules initially then, 1 capsule after each loose stool
max 8 capsules (16mg) capsules per 24 hour
make sure patient receives appropriate fluid and electrolyte replacement
tolerance to the antidiarrheal effect has not been observed
Nitrofurantoin
Miscellaneous facts: bacteriostatic-can be bactericidal in high concentrations
urinary tract antiseptic/bladder antiseptic
concentrates in the renal tubules and bladder – doesn’t achieve blood levels high enough to treat systemic infections
Spectrum:gram-positive and gram-negative
Therapeutic uses:prevention and treatment of uncomplicated urinary tract infections caused by escherichia coli or staphylococcus
saprophyticus
Drawbacks:gastrointestinal issues fairly common
hypersensitivity reactions, headache, vertigo, dizziness
polyneuropathy ---with high doses or patients with renal impairment
monitoring parameters BUN, CrCl, LFT’s
Mebendazole (vermox) oral tablet
Miscellaneous facts: anthelmintic
death of the worm is slow—complete gastrointestinal clearance up to 3 days after therapy
retreatment necessary if patient not cured in 3 weeks
Spectrum: ancylostoma duodenale (hookworm)
ascaris lumbricoides (roundworm)
enterobius vermicularis (pinworm)
necator americanus (American hookworm)
trichuris trichiura (whipworm)
Therapeutic uses: DOC= GI hematodes
Drawbacks: drug interactions : carbamazepine and phenytoin
abdominal pain, nausea, diarrhea
myelosuppression can occur with high doses
Bacitracin ointment
Miscellaneous facts: bacteriostatic– potential to be bactericidal
Spectrum: gram-positive bacteria
Therapeutic uses: topical use to prevent superficial skin infections following minor
injuries on small areas of the body
Drawbacks: caution in patients with neomycin hypersensitivity
maximum duration of use = 7 days
incidence of contact dermatitis is about 2 %
Triple antibiotic ointment
Miscellaneous facts: (neomycin/polymyxin B/bacitracin)
Spectrum: gram-positive and gram-negative
(neomycin & polymyxin B both have gram-negative coverage)
Therapeutic uses: superficial skin infections
Drawbacks: can cause allergic dermatitis
neomycin containing products can cause allergic reactions in about 1 in 20
people
Neomycin/polymyxin/hc otic susp
Miscellaneous facts: antibacterial & anti-inflammatory
Spectrum:gram-negative aerobes
MRSA coverage
Therapeutic uses: superficial bacterial infections of the external auditory canal
maximum use = 10 days
Drawbacks: caution in patients with tympanic membrane perforation or
chronic otitis media – risk of ototoxicity
allergic skin reactions
pregnancy category c
QUIZ
1.Which antibiotic is associated with “red man syndrome”?
A.) clindamycin
B.) vancomycin
C.) penicillin
D.) ciprofloxacin
2.Which injectable cephalosporin is the drug of choice for neisseria gonorrhea?
A.) Ancef
B.) Rocephin
C.) Claforan
D.) Mefoxin
3. Why should you not use tetracycline after the expiration date?
A.) renal failure
B.) hepatic failure
C.) QT prolongation
D.) diarrhea
4.Which antibiotic is not included in the DMAT cache?
A.) Rocephin
B.) Amoxicillin
C.) Levaquin
D.) Cephalexin
5. How many generations of quinolones are there?
A.) 1
B.) 2
C.) 3
D.) 4
References
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Beers M, Porter R, Jones T, Kaplan J, Berkwits M, The Merck Manual,18th edition, 2006
Shargel L, Mutnick A, Souney P, Swanson L, Comprehensive Pharmacy Review, 6th edition, 2007
Gilbert D,Moellering R, Eliopoulos G, Chambers H, Saag M, The Sanford Guide To Antimicrobial Therapy 2009 (39th edition), 2009
Trevor A, Katzung B, Masters S, Pharmacology Examination and Board Review, 8th edition, 2008
Clinical Pharmacology, online version, @ www.clinicalpharmacology.com
Epocrates Online, online version @ www.epocrates.com
Doxycycline hyclate capsules package insert. Eatontown, NJ; West-ward Pharmaceutical Corp.; 2006 July
Fluconazole tablets package insert. Miami, Fl; Ivax Pharmaceuticals, Inc.;2006
Azithromycin tablets package insert. Peapack, NJ;Greenstone Ltd.;2007 August
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Nystatin package insert. Ontario, Canada; Taro Pharmaceuticals Inc.;2005 June
Erythromycin ophth. Ointment package insert. Melville, NY;E.Fougera & Co.;1999
Metronidazole tablets package insert.Pomona NY; Pliva Krakow Pharmaceutical Company;2007 May
Ciprofloxacin package insert. Miami,Fl.:Ivax Pharmaceuticals Inc;2007 Feb
Terconazole vaginal cream package insert.Hawthorne NY;Taro Pharmaceuticals; 2003 July
Dicloxacillin sodium package insert. Toronto, Canada.; Novopharm Limited;2006 Jan
Nitrofurantoin capsules package insert. Morgantown, Wv; Mylan Pharmaceuticals; 2004 August
Amoxicillin and clavulanate potassium tablets package insert. Princeton,NJ; Sandoz Inc: 2007 June
Clindamycin package insert. Sellersville, Pa; Teva Pharmaceuticals; 2004 Nov
Neomycin and polymyxin B sulfates and hydrocortisone otic susp. USP package insert. Tampa, Fl; Bausch & Lomb Inc; 2003 Nov.
Xifaxan package insert. Morrisville, NC; Salix Pharmaceuticals; 2008 March
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