MTB Flashcards
Penicillin (G,VK, benzathine)
viridans group streptococci, streptococcus pyogenes, oral anaerobes, syphilis, leptospira
Ampicillin and amoxicillin
cover the same organisms as penicillin, as well as E. coli, Lyme disease, and a few other gram-negative bacilli
Bacterial covered by amoxicillin (HELP)
H. influenzae, e. coli, Listeria, Proteus, and Salmonella
Amoxicillin “best initial therapy” for
Otitis media, dental infection and endocarditis prophylaxis, lyme disease limited to rash, joint, or seventh cranial nerve involvement, UTI in pregnant women, Listeria monocytogenes, Enterococcal infections
Penicillinase-resistant penicillins (PRPs) (oxacillin, cloxacillin, dicloxacillin, and nafcillin used to treat
Skin infections (cellulitis, impetigo, erysipelas) Endocarditis, meningitis, and bacteremia from staphylococci Osteomyelitis and septic arthritis only when the organism is proven sensitive
Piperacillin, ticarcillin, azlocillin, mezlocillin
These agents cover gram-negative bacilli (e.g., E. coli, Proteus) from the large enterobacteriaciae group as well pseudomonads. “Best initial therapy” for:
Cholecystitis and ascending cholangitis
Pyelonephritis
Bacteremia
Hospital-acquired and ventilator-associated pnemonia
Neutropenia and fever
Cephalosporins
The amount of cross-reaction between penicillin and cephalosporins is very small (
First Generation Ceph (Cefazolin, Cephalexin, Cephadrine, Cefadroxyl) used to treat
Staphylococci: methicillin sensitive = oxacillin sensitive = cephalosporin
Streptococci (except Enterococcus)
Some gram-negative bacilli such as E. coli, but not Pseudomonas
Osteomyelitis, septic arthritis, endocarditis, cellulitis
Second Gen Ceph (Cefotetan, Cefoxitin, Cefaclor, Cefprozil, Cefuroxime, Loracarbef)
Cefotetan or cefoxitin: Best initial therapy for pelvic inflammatory disease (PID) combined with doxycycline. Warning: Cefotetan and cefoxitin incrase the risk of bleeding and give a disulfiramlike reaction with alcohol
Cefuroxime, loracarbef, cefprozil, cefaclor: Respiratory infections such as bronchitis, otitis media, and sinusitis
Third Gen Ceph (Ceftrizxone, Cefotaxime, Ceftazidime)
Ceftriaxone: First-line for pnemococcus, including partially insensitive organisms (Meningitis, Community-acquired pneumonia (in combo with macrolides), Gonorrhea, Lyme involving the heart or brain
Avoid ceftriaxone in neonates because of impaired biliary metabolism
Cefotaxime (superior to ceftriaxone in neonates, spontaneous bacterial peritonitis)
Ceftazidime has pseudomonal coverage
Fourth Gen Ceph (Cefepime)
Used to treat Neutropenia and fever, Ventilator-associated pna
Fifth Gen (Ceftaroline)
Gram-negative bacilli and MRSA, not pseudomonas
Adverse effects of Cephalosporins
Cefoxitin and cefotetan deplete prothrombin and increase risk of bleeding
With ceftriaxone, there is inadequate biliary metabolism
Carbapenems (imipenem, Meropenem, Ertapenem, Doripenem)
(Ertapenem does not cover Pseudomonas)
Carbapenems cover gram-negative bacilli, including many that are resistant, anaerobes, strptococci, and staphylococci. They are used to treat neutropenia and fever
Aztreonam
Only drug in the class of monobactams Exclusively for gram-negative bacilli including Pseudomonas No cross-reaction with penicillin
Fluoroquinolones (Ciprofloxacin, Gemifloxacin, Levofloxacin, Moxifloxacin)
Best therapy for community-acquired pneumonia, including penicillin-resistant pneumococcus
Gram-negative bacilli including most pseudomonads
Ciprofloxacin for cystitis and pyelonephritis
Diverticulitis and GI infections, but ciproloxacin, gemifloxacin, and levofloxacin must be combined with metronidazole because they don’t cover anaerobes except for moxifloxacin. Moxifloxacin can be used as a single agent for diverticulitis and does not need metronidazole.
Quinlolones cause
Bone growth abnormalities in children and pregnant women
Tendonitis and Achilles tendon rupture
Gatifloxacin removed because of glucose abnormalities
Aminoglycosides (Gentamicin, Tobramycin, Amikacin)
Gram-negative bacilli (bowel, urine, bacteremia)
Synergistic with beta-lactam antibiotics for enterococci and staphylococci
No effect aginst anaerobes, since they need oxygen to work
Nephrotoxic and ototoxic
Doxycycline
Chlamydia
Lyme disease limited to rash, joint, or seventh cranial nerve palsy
Rickettsia
MRSA of skin and soft tissue (cellulitis)
Primary and secondary syphilis in those allergic to penicllin
Borrelia, Ehrlichia, and Mycoplasma
Adverse effects: tooth discoloration (children), Fanconi syndrome (Type II RTA proximal), photosensitiviy, esophagitis/ulcer
Trimethoprim/Sulfamethoxazole
Cystitis
Pneumocystis pneumonia treatment and prophylaxis
MRSA of skin and soft tissue (cellulitis)
Besides rash, it causes hemolysis with G6PD deficiency and bone marrow suppression because it is a folate antagonist
Beta-Lactam/Beta-Lactamase Combinations
Amoxicillin/clavulanate Ticarcillin/clavulante Ampicillin/sulbactam Piperacillin/tazobactam Beta-lactamase adds coverage against sensitive staplylococci to these agents. They cover anaerobes and are a first choice for mouth and GI abscess
MRSA drugs
Telavancin, Dalbavancin, Tedizolid, Oritavancin
Gram-positive Cocci: Staphylococci and Streptococci
Oxacillin, cloxacillin, dicloxacillin, nafcillin
First-generation, cephalosporins: cefazolin, cephalexin
Fluoroquinolones
Macrolides (azithromycin, clarithromycin, erythromycin) are third-line agents because they have less efficacy than oxacillin or cephalosporins. Erythromycin is also more toxic
Oxacillin (Methicillin)-Resistant Staphylococcus
These are best treated with: Vancomycin Linezolid: reversible bone marrow toxicity Daptomycin: elevated CPK Tigecycline Ceftaroline Telavancin
Anaerobes
Oral(above the diphragm) - Penicillin (G, VK, ampicillin, amoxicillin), clindamycin
Abdominal/gastrointestinal - Metroniadazole, beta-lactam/lactamase combinations
Gram-Negative Bacilli (E. coli, Klebsiella, Proteus, Pseudomonas, Enterobacter, Citrobacter)
These organisms cause infections of the bowel (peritonits, diverticulitis); urinary tract (pyelonephritis); and liver (cholecystitis, cholangitis) All of these agents cover gram-negative bacilli: Quinolones Aminoglycosides Carbapenems Piperacillin, ticarcillin Aztreonam Cephalosporins
