1. Antibiotics: Part II

2. Introduction to Antibiotics: Part II
Cephalosporins
1st generation
2nd generation
3rd generation
4th generation
Sulfonamides
Lincosamides
Aminoglycosides
Fluroquinolones
Oxazolodinoes
Miscellaneous
Vancomycin
Metronidazole

3. Drugs to Know garamycin/Gentamicin Neomycycin amikacin (Amikin) IV
Cephalo-
sporins
beta lactam abx
4 generations
Sulfonamides
Narrow spectrum
Lincosamides
Antibacterial & antiprotozoa
Aminoglycosides
Very potent
Serious SE!
NARROW THERAPEUTIC INDEX
cephalexin (Keflex) PO 1st
trimethoprim + sulfisoxazole (TMP/SMP, Bactrim) po
clindamycin (Cleocin) po, IV
Effective against bacteria AND protozoa
Neomycycin
amikacin (Amikin) IV
cefazolin Ancef
IV 1st
garamycin/Gentamicin
cefuroxime Ceftin
PO 2nd
cefoxitin Mefoxin
IM/IV 2nd `
cefixime Suprax
PO 3rd
cefitraxone Rocephin
IM/IV 3rd
cefepime Maxipime
IV 4th

4. More Drugs to Know Fluoroquinolones Oxazolidinones Misc Agents
ciprofloxacin (Cipro)
IV/PO
levofloxacin (Levaquin)
linezolid (Zyvox) IV / PO
Considered the “last line drug”
vancomycin (Vancocin)
IV/po
Formerly the “last line drug”
Requires ‘peak & trough’ levels
metronidazole (Flagyl)
Abx and antiparasitic

5. CEPHALOSPORINS
The cephalosporins are divided into four generations which progressively become broader spectrum
Look for “cef” prefix
Like penicillins, many cephalosporins have a beta-lactam structure
The first generations of cephalosporins are sensitive to betalactamase producing bacteria
Thus, these drugs are RENDERED INEFFECTIVE by bacteria that produce betalactamase

6. Adverse Reactions: Cephalosporins (all generations)
Low toxicity, well tolerated
Adverse Reactions
Hypersensitivity (similar to and 10% cross-reactive with penicillin hypersensitivity)
*GI (N-V-D)
ANTABUSE EFFECT (interaction with ETOH)
Nephrotoxicity
Increased bleeding by interfering with vitamin K metabolism. Monitor PT/INR
Adverse reactions may occur up to 72H after last dose (delayed reaction)
Prolonged use may cause a superinfection

7. What is the Antabuse Effect?
disulfiram/Antabuse
Is a drug that increases the sensitivity to alcohol
Discovered in the 1920’s
Used to support the treatment of chronic alcoholism
Blocks the processing of alcohol in the body by inhibiting acetaldehyde dehydrogenase
Causes INTENSE negative effects of alcohol
N/V, H/A, dizziness
Some drugs (cephalosporins and Flagyl) may cause this same effect when taken with ETOH

8. Cephalosporins: therapeutic uses
Indications VARY depending on generation
Treatment of mild to severe skin infections
URI and pneumonia
Surgical prophylaxis
Meningitis
Cellulitis–mild to severe
Often d/t strep or staph
A serious soft tissue infection that would require the use of 2nd generation such of Mefoxin
A fairly mild skin infection (cellulitus)
Could be tx with a 1st generation
cephalosporin such as Keflex

9. 1st Generation Cephaloporins
NARROW SPECTRUM
Good gram (+) coverage. Poor gram (-) coverage
MINIMALLY effective against betalactamase producing bacteria
Indications:
Used to treat UTIs, SIMPLE skin infections, strep throat
Can be used for surgical prophylaxis
ALTERNATIVE TO PENICILLIN (mild allergy only) for staph and strep infections
PO: cephalexin (Keflex)
IM/IV: cefazolin sodium (Ancef)

10. 2nd Generation Cephalosporons
BROADER SPECTRUM
good gram (+) AND good gram (-) coverage
But limited application b/c NOT effective against betalactamase producing bacteria
Indications:
Used to treat septicemia, bone and joint infections, and respiratory infections
PO: cefuroxime (Ceftin) otitis, sinusitis, and respiratory tract infections
IM/IV: cefoxitin sodium (Mefoxin)  abdominal and pelvic infections

11. 3rd Generation Cephalosporins
NARROW spectrum
Good for gram (-) infections only
nosocomial infections mostly d/t gram (-) infections
able to penetrate the CSF (meninigitis)
MINIMALLY effective against beta-lactamase bacteria
DOES CROSS BLOOD BRAIN BARRIER!!
PO: cefixime (Suprax)
IM/IV: ceftriaxone (Rocephin)
Rocephin has a long half life and can be given once or twice a day

12. 4th generation Cephalosprins
BROADEST spectrum
Effective against MOST gram (+) and gram
AND… Able to resist MOST beta-lactamase producing bacteria
CROSSES BLOOD BRAIN BARRIER!!
Is effective against MRSA and enterobacter
IM/IV: cefepime (Maxipime) IV

13. SULFONAMIDES MOA - inhibit the synthesis of folic acid
Indications:
Sulfonamides are commonly Rx for UTIs
Achieve high concentration in the KIDNEYS (UTI’s)
May be used as an alternative for clients allergic to penicillin
MOA - inhibit the synthesis of folic acid
Bacteria use folic acid to synthesize their DNA

14. Indications: Sulfa drugs are commonly used to treat urinary tract infections
cystitis
Pyleonephritis
Normal kidney

15. Sulfonamides Indications:
Narrow spectrum
Most common – UTI’s and Chlamydia, pneumocytis carinii pneumonia, rheumatic fever
Caution: cross sensitivity with THIAZIDES and SULFONYLUREAS
**Patient allergic to sulfa antibiotics may also be allergic to thiazides and/or diabetic sulfa containing drugs

16. Sulfonamides Common drugs: Trimethomprim
Bacteriostatic when used alone
Commonly used WITH SULFA for synergistic effect rendering them bacterocidal
* trimethroprim + sulfisoxazole (TMP/SMP)
(Septra, Bactrim)

17. SULFONAMIDES
Adverse Effects
*Anorexia, N-V-D
photosensitivity
Crystalluria (kidney stones can form)
Bone marrow suppression, hemolytic anemia
Renal failure
Skin rashes
Hypersensitivity – vascular lesions, rash, eruptions, drug fever
Interactions: displaces protein bound anticoagulants  clotting times (PTINR) toxic to the kidney (need to drink lots!)
Encourage lots of water
Sulfa drugs can be toxic to
the kidney.

18. Lincosamide
clindamycin/Cleocin is effective against BOTH bacteria and PROTOZOA such as trichomoniasis
Indications:
Used to tx diseases of the skin, vagina, resp tract and abdomen
Is effective against skin infections d/t MRSA!
Is a powerful inhibitor of toxin synthesis
Often used WITH a bacteriocidal agent
As the bacteriocidal agent and toxins are released the clindamycin inhibits the toxin formation
SE: Frequently causes C. diff colitis!!

19. Lincosamides MOA: inhibits bacterial protein synthesis Indications:
Bacterostatic at low doses and bacterocidal at higher doses
clindamycin (Cleocin)
NARROW SPECTRUM
Indications:
Used to treat gram (+) infection, including staph, and anaerobic organisms
SE:
*N-V-D
Rash
Colitis (c dif) and anaphylactic shock

20. What does a MRSA infection look like?
MRSA can look like a spider bite, a boil, pustules.
It can get into the lungs causing pneumonia, into the bladder/kidney causing UTI,
or can cause serious blood borne infections. MRSA can be fatal!

21. AMINOGLYCOSIDES Indications: Destroy bacteriatrue bactericidal agents
IV only
Cannot be given po d/t poor absorption
Indications:
Used to treat SERIOUS INFECTIONS d/t aerobic bacilli and gram (-) organisms
*Very potent and capable of serious side effects!!
Nursing Alert: Do not mix in the same container with penicillins and cephalosporins

22. Aminoglycosides
MOA: Inhibits bacterial protein synthesis -Bactericidal
NARROW SPECTRUM
Only active against gram (-) bacteria
Pseudomonas
Indication:
Primarily used in nosocomial infections

23. Aminoglycosides (cont)
Do not penetrate CSF
Cross the blood brain barrier in children but not adults
Excreted RENALLY by glomerular filtration
**Narrow therapeutic index drug**
*Requires constant monitoring
“PEAK/TROUGH LEVELS”

24. What is a Peak and Trough level?
PEAK = greatest concentration of the drug in the BLOOD (30 min AFTER infusion)
TROUGH = greatest concentration of the drug in the TISSUE (30 min PRIOR to next infusion)
Therapeutic levels are desired
Risk for serious SE increases with high trough levels
High trough levels? – the next dose may be held and peak and trough repeated

25. Aminogylcosides Potential Serious Adverse Effects
Ototoxicity – vestibular and auditory
may be irreversible
Nephrotoxicity – potentially reversible
 BUN & Creatinine
Both toxicities dependent on HIGH “TROUGH” LEVELS

26. Aminoglycosides
*gentamicin sulfate (Garamycin) – available in topical, opthalmic, and IV forms
amikacin (Amikin): (IV only) –
often used to rx infections resistant to gentamicin, little resistance so far to Amikin
neomycin (Mycifradin) – a milder aminoglycoside
Indications:
suppress GI bacteria pre-op (colon surgery)
a topical agent to treat wound infections

27. Pseudomonas infection: serious infections
Pseudomonas infections are
resistant to many antibiotics

28. Quinolones/Fluoroquinolones
MOA: interfere with bacterial DNA
Bacteriocidal
Quinolones developed first
Have a narrow spectrum
Seldom used today
Fluoroquinolones developed by adding a fluorine atom to basic quinolone structure
BROADER SPECTRUM

29. What infections are floroquinolones commonly prescribed for?
Indications:
Many gram (-), some anerobes, atypicals
UTIs, bone and joint infections, bronchitis, pneumonia, gonorrhea
Good for people allergic to erythromycin (EES)
Enterobacter, Pseudomonas, MRSA
Now seeing FQRP (fluoquinolone resistant pseudomonas)
Accumulates well in urine and prostate

30. Florquinolones Adverse Effects: Drug Interactions
Both serious and bothersome:
N-V-D, dyspepsia
H/a, dizziness, rashes
Hepatotoxicity (LFTs)
Drug Interactions
Can inhibit theophylline and warfarin metabolism increasing the levels of these drugs

31. Fluoroquinolones Look for “floxacin” suffix Common drugs
*ciprofloxacin (Cipro) PO and IV
levofloxacin (Levaquin) PO and IV
** NURSING ALERT** IV Levaquin is sensitive to light and will break down if exposed to light
 use a brown plastic bag to cover IVPB

32. What is the hype about Vancomycin?
NARROW SPECTRUM GM (+)
Vancomycin is used IV to treat serious infections (MRSA) and Enterococci
Vancocin is used po to treat C. difficile colitis
Was previously considered the LAST RESORT DRUG
Resistance is now being noted to infections caused by Enterococcus (VRE) and staph aureus (VRSA)
Super Bug is resistant to Vancomycin

33. Miscellaneous Agent: Vancomycin
vancomycin IV (Vancocin) PO
A glycopeptide antibiotic structurally different from other available antibiotics
SE: (potential and serious)
Petechiae and Thrombocytopenia
Ototoxicity and nephrotoxicity
Peak and trough levels periodically monitored
Rapid IV administration can cause “RED MAN SYNDROME”

34. What is Red Man Syndrome?
An ADR to vancomycin IV that may occur with the FIRST dose of vancomycin ,OR when the drug is administered TOO FAST
Sx: flushing of face and neck, pruritus, hypotension
Prevention: slow the rate of infusion
Vancomycin should be given over AT LEAST lH
higher doses often ordered over 90 min
If Red Man Syndrome develops, the nurse should
stop the infusion and notify the HCP.
Benadryl is often ordered to decrease the effect of the reaction.

35. Vancomycin Resistance Enterococci (VRE)

36. Oxazolidinones Indication: Newer class of antibiotic
Developed in 1999 primarily to treat vancomycin -resistant enterococcus (VRE)
Enterococci is a gram (+) bacterium in our GI tract that can be highly aggressive , esp in post-op pts
Enterococci causes UTI, septicemia, endocarditis and infects wounds
Oxazolidinones are also used to treat infections d/t MRSA
Is now considered “THE LAST LINE ANTIBIOTIC”

37. Oxazolidinones linezolid (Zyvox) (po,IV)
Inhibits bacterial protein synthesis
New “Last line drug”
Adverse effects:
*Pseudomembranous colitis (C. Difficile colitis)

38. Misc Antibiotic: metronidazole/Flagyl
Flagyl is considered both an ANTIBIOTIC and an Anti-parasitic agent
Indications:
Flagyl is commonly prescribed to treat infections d/t anaerobic bacteria and some protozoa
Also, commonly used for abdominal and pelvic infections; as well as liver abcess

39. More Indications: metronidazole/Flagyl
Flagyl is also the first line treatment for C. diff colitis
an anerobic bacteria that causes profuse diarrhea in some patients who take certain antibiotics
Adverse Reactions: Generally well tolerated
Antabuse effect may occur if ETOH consumed while taking Flagyl.