Antibiotics Flashcards
Beta-Lactams
Penicillin, Cephalosporin
Fluoroquinolones
Ciprofloxacin Gemifloxacin levofloxacin Lomefloxacin Moxifloxacin norfloxacin Olfloxacin
Aminoglycoside
Amikacin (Amikin) Gentamycin (garamycin) Kanamycin (Kantrex) Neomycin (mycifradin) Streptomycin Tobramycin (Nebcin, Tobrex)
Lincosamides
Clindamycin (Cleocin)
Macrolides, Ketolides
Azithromycin Erythromycin Clarithromycin Dirithromycin Telithromycin
Sulfonamides
sulfaslazine (azulfidine)
Mafenide (Sulfamylon)
Sulfadiazine (Silvadene)
trimethoprim
proloprim
Trimpex
nitrofurantoin
Furadantin
macrodantin
Fosfomycin (Monurol)
Trimethoprim-sulfamethoxazole (Combo med)
Bactrim
septra
TMP-SMZ
Tetracyclines
Doxycycline
Minocycline
Oxytetrecycline
Tetracycline
Lipoglycopeptides
Vancomycin
Telavancin (Vibativ)
Dalbavancin (zeven)
Antimycobacterials
Capreomycin (IM) Ethambutol Ethionamide Isoniazide (IM/PO) Pyrazinamide Rifampine Rifabutin Rifapentine Strepomycin (IM)
causes of antimicrobial resistance
Recent use of antibiotics overuse of broad spectrum antibiotics Age younger than 2 OR older than 65 daycare center attendance exposure to young children multiple medical comorbidities immunosuppression
How are local resistance patterns identified
by monitoring the antibiogram in the local laboratory
what vaccine has decreased resistance
Pneumococcal vaccine
natural or intrinsic resistance
Microorganism that do not act on a specific enzyme system or biological system are not affected by the particular drug that attack this system
the ways anti-resistance develops
- produces an enzyme that deactivates the drug
- changing cellular permeability to prevent the drug from entering the cell
- alter transport systems to exclude the drug from active transport into the cell
- alter binding sites on the membrane or ribosomes which no longer accept drugs
- producing a chemical that acts as an antagonist to the drug
way to prevent antibiotic resistance
- limit the use of antimicrobial agents to treatment of specific pathogens sensitive to the drug being used
- make sure dose is high enough and duration is long enough
- be cautious about the indiscriminante use of antiinfectives
identification of pathogen
by culture
-swab is done and put on agar plate to grow, staining technique and microscopic exam to identify bacterium
sensitivity of pathogen
- this can show what drugs are capable of controlling the particular microorganism (especially important for microorganism that are known to have resistant strains)
- this is done along with a culture and it identifies the pathogen and proper drug for tx
factors that can affect prescribing anti-infectives
- identification of wrong pathogen
- selection of right drug (causes the least complications for pt, and most effective against the pathogen involved)
Synergistic
Synergism comes from the Greek word “synergos” meaning working together. It refers to the interaction between two or more “things” when the combined effect is greater than if you added the “things” on their own
combination therapy
- uses smaller dosages of each drug
- some of these drugs are synergistic
- used in infections caused by more than one microorganism, and may react to different anti-infectives
- the combined effects of different drugs delay emergence of resistant strains
when are prophylaxis anti-infectives used
- people traveling to an area with malaria
- pt under going GI or genitourinary sx
- pt with known cardiac valve disease, valve replacement, and other conditions require invasive procedures
pharmocodynamics: PCN
inhibit the biosynthesis of peptidoglycan bacterial cell wall (cell wall destroyer)
4 PCN subclasses
1) penicillinase-sensitive or natural pcn’s
2) Aminopenicillins
3) Penicillinase-resistant or anti staphylococcal pcn’s
4) Anti-pseudomonal or extended-spectrum pcn’s
Bacteriostatic agent
A bacteriostatic agent or bacteriostat, abbreviated Bstatic, is a biological or chemical agent that stops bacteria from reproducing, while not necessarily killing them otherwise
natural PCN sensitivity
- Streptococcus
- some Enterococcus
- some non-Penicillinase-producing Staphlococcus
Aminopenicillins
more gram negatives; used for gram negative urinary and GI pathogens -E coli, -proteus mirabilis -salmonella -some Shigella -Enterococcus faecalis Active against gram negative respiratory pathogens; -Moraxella catarrhalis -Haemophilus influenza type B
what are some beta-lactamase inhibitors used in combination with PCN to help broaden their spectrum
- Clavulanate
- slbactam
- tazobactam
pharmacokinetics of penicllins
-well absorbed in GI tract (but unstable in acid)
dicloxacllin, and amoxicillin better absorbed than ampicillin
-bound to proteins with good distribution to most tissues
-small amount is metabolized, most excreted in urine
probenecid prolongs half-life and increases risk for toxicity
adverse drug reactions of penicillins
Adverse reactions
- a maculopapular rash occurs 7-10 days into treatment
- GI diarrhea N/V
- fungal overgrowth
- c-difficile colitis
desensitization therapy
Through your body’s exposure to small, injected amounts of a particular allergen, in gradually increasing doses, your body builds up immunity to the allergen(s) to which you are allergic
Allergic reaction: to PCN
- they occur within 2-30 mins
- patients maybe given desensitization therapy
what category in pregnancy is PCN
Category B
Clinical use PCN
- commonly used for infections seen in primary care
- amoxicillin is first line for acute otitis media
- PCN for streptococcal pharyngitis
- amoxicillin/clavulanate first line for infection in any kind of bites
PCN monitoring
return to office for evaluation of symptom relief, are they getting better?
Cephalosporins
Beta-Lactams
Cephalosporins Pharmacodynamics
inhibit mucopeptide synthesis in the bacterial cell wall
first generation cephalosporin
- used for skin and soft tissue infections
- primarily active against gram-positive bacteria S Aureus and S. epidermidis
second generation cephalosporin
active against same as 1st generation. Plus Klebsiella, Proteus, E coli
third generation cephalosporin
- used for broader indications
- more active against gram negative bacteria
fourth generation cephalosporin
- resistant to beta-lactamase
- primarily active against gram positive bacteria
cephalosporins pharmacokinetics
oral absorbs from GI tract, widely distributes to most tissues, some highly bound to proteins, some are metabolized to less active compounds, most excreted via kidneys in various degrees
Cephalosporin adverse drug reactions
allergies skin rashes arthralgia (pain in the joint) coagulation abnormalities anemia neutropenia leukopenia thrombocytosis (body produces to much platelets) fever seizures renal/hepatic failure
clinical use of cephalosporin
- used for therapeutic failure in AOM
- 1st generation for strep pharyngitis and skin infections
- cephalexin, cefpodoxime, cefixime can be prescribed as second line for UTI
- ceftriaxone and cefixime used for GC/chlamydia
- cefpodoxime, cefuroxime or parenteral ceftriaxone followed by oral cefpodoxime are used for community acquired pneumonia
monitoring for cephalosporin
monitor for diarrhea (c-diff)
renal function if prolonged therapy
patient education for cephalosporin
use as prescribed
fluoroquinolones pharmacodynamics
interfere with bacterial enzymes required for synthesis of bacterial DNA (noted for extensive gram negative activity)
fluoroquinolones are not recommended for what age?
no longer recommended for what resistant strains
G/C
resistant TB
Fluoroquinolones pharmacokinetics
well absorbed, take on empty stomach for best absorption
Adverse drug reactions of Fluoroquinolones
-BLACK BOX warning for tendonitis/tendon rupture
elderly at a higher risk, can have delayed onset 120 days to months after administration
-GI-pseudo membranous colitis
-CNS; sleep disorders, dizziness, acidosis
-renal/hepatic failure
-CV angina, atrial flutter
-avoid pregnancy
-do not prescribe to children under 18
clinical use for Fluoroquinolones
- complicated UTI, pyelonephritis, infections, chronic bacterial prostatitis
- pneumonia/bronchitis exacerbation
- PCN resistant S pneumonia, skin infections bone/joint infections, complicated intra-abdominal, infectious diarrhea
Monitoring Fluoroquinolones
watch for prolonged use, ECG with at risk patients before prescribing moxifloxacin, alcohol use, monitor for tendinitis/rupture
Fluoroquinolones patient education
- food delays absorption
- many drug interactions
- take a full glass of water
- may cause dizziness
- if tendon tenderness occurs stop medication
Aminoglycosides
A group of powerful antibiotics used to treat serious infections caused by gram-negative aerobic bacilli (bactericidal)
Aminoglycosides action
inhibits protein synthesis in susceptible strains of gram-negative bacteria causing cell death
Aminoglycosides Pharmacokinetics
- poorly absorbed in GI tract, but rapidly absorbed after IM injection reaching peak within 1 hour
- widely distributed throughout the body crossing placenta and entering breast milk
- excreted unchanged in the urine and have an average half-life of 2-3 hours
- depend on the kidney for excretion and are toxic to the kidney
aminoglycosides contraindications
known allergies
renal or hepatic disease
hearing loss
Aminoglycosides adverse effects
ototoxcity and nephrotoxcity
Aminoglycosides drug to drug interactions
Diuretics
neuromuscular blockers
Lincosamides: Clindamycin pharmacodynamics
inhibits protein synthesis: no gram negative activity, has gram positive activity: corynebacterium acnes, gardnarella vaginalis, some MRSA
Clindamycin pharmacokinetics
PO dosing completely absorbed not affected by gastric acid
Clindamycin Adverse effects
Black Boxed warning for severe colitis derm:rash burning itching erythema (reddening of skin) transient eosinophelia neutropenia thrombocytopenia
Clindamycin Clinical use
1st line therapy for MRSA in some area
infection in PCN allergic pt
DSRP infections
Dental infections
Clindamycin Rational drug selection
considered second line therapy narrow spectrum of aerobic activity
** first line in special population (pregnancy and children)
Clindamycin monitoring
stop medication if significant diarrhea occurs
Clindamycin patient education
finishing therapy and warn them of ADR Diarrhea
Erythromycin pharmacodynamics
- Inhibits RNA dependent protein synthesis
- weak bases, activity increases in alkaline media
- Atypical and intracellular organism commonly resistant to beta-lactam antibiotics are often susceptible
- Cross resistance seen to all in class
Erythromycin Pharmacodynamics
- well absorbed in duodenum
- potent inhibitor of CYP 450 3A4
- combined with statins may increase risk for myopathy
- Exhibit enterohepatic recycling which can lead to build up in the system and can cause n/v tissue levels are higher than serum levels
Erythromycin contraindications/ precautions
most are safe in pregnancy and children
Erythromycin ADR’s
Dose related GI: N/V, abd pain, cramping, diarrhea
Skin: urticara, Bullous eruptions, eczema, and stevens johnsons syndrome
Erythromycin Drug interactions
inhibitors of CYP 3A4
Clinical use of Erythromycin
- drug choice for community acquired pneumonia (Mycoplasma)
- chlamydia
- pertussis
- H. Pylori
- Chronic bronchitis
Erythromycin rational drug selection
- often as alternatives for PCN allergies
- increasing resistance
- not appropriate for treating AOM or sinusitis
Erythromycin monitoring
- monitored for altered response to concurrent medications metabolized by CYP 450 3A4 or 2C9
- Hepatic/Renal impairment
- hearing loss
Erythromycin patient education
ADR’s
drug interactions
Sulfonamides
block folic acid synthesis
Trimethoprim
inhibits DNA synthesis
Nitrofurantoin
may inhibit acetyl co enzymes
Sulfonamides, Trimethoprim, and Nitrofurantoin Inhibits what bacteria
inhibit both gram positive and gram negative bacteria
E-coli, S. Pyogenes, S pneumoniae, H influenza, and some protozoa. resistance an issue
Sulfonamides, Trimethoprim, and Nitrofurantoin ADR’s
GI: Anorexia, N/V, diarrhea, stomatitis, rashes, increased hypersensitivity reactions, dizziness, drug interactions
Sulfonamides, Trimethoprim, and Nitrofurantoin; what to avoid?
G6PD deficiency
Clinical uses: Sulfonamides, Trimethoprim, and Nitrofurantoin
- most commonly used with UTI infections
- MRSA is susceptible in some areas
rational drug selection: Sulfonamides, Trimethoprim, and Nitrofurantoin
low cost alternative for > 2months and PCN allergy
monitoring: Sulfonamides, Trimethoprim, and Nitrofurantoin
culture and sensitivity-if treating UTI
long term use check CBC
CXR for Pt’s that develop a cough when on nitrofurantoin
Pt education: Sulfonamides, Trimethoprim, and Nitrofurantoin
Finish full course ADR’s resistance
Tetracycline pharmacodynamics
tetracycline and doxycycline, they bind reversibly to the 30S subunit of the bacterial ribosome
Tetracycline pharmacokinetics
food decreases absorption
milk and cheese decreases absortion of tetracycline
Tetracycline precautions/contraindications
Do not prescribe to pregnant or lactating women.
do not prescribe to children
Tetracycline drug interactions
many drug interactions
Tetracycline: clinical use
- Doxycycline is considered first line of therapy for C. trachomatis and ureaplasma urealyticum
- tetracycline and minocycline used to treat P. acnes
- Some H. Pylori regimens include tetracycline
Tetracycline: rational drug selection
Doxycycline and minocycline can be taken with food
Tetracycline: PATIENT EDUCATIONS
administration, ADR’s, avoid in pregnancy
Lipoglycopeptides: Pharmacodynamics
- used for severe gram positive infectionssucha as MRSA resistant to first line antibiotics
- inhibits cell wall synthesis
Lipoglycopeptides: pharmacokinetics
Poor oral absorption, given IV
Lipoglycopeptides: ADR’s
Ototoxicity (transient or permanent)
Nephrotoxcity
“Red Man” Syndrome if infused too fast
Lipoglycopeptides: clinical use
serious gram positive resistant to other medications
Lipoglycopeptides: monitoring
hearing and renal function
Lipoglycopeptides: pt education
administration
ADR’s
