Pharmacology - Antimicrobial Therapy II & III - Jeffrey Steele Flashcards
What cephalosporins cover Pseudomonas?
Cefepime
Ceftazidine
Use: Ceftaroline (5th gen)
MSSA, MRSA
E. faecalis
S. pneumoniae
Complicated SSTI
Approved for CAP
Class: Avibactam
Novel beta-lactamase inhibitor
Use: Ceftolazone/Tazobactam
Pseudomonas and non-beta-lactamase producing enterobacteriaceae;
Complicated UTI;
Complicated intra-abdominal infection
Class: Imipenem-cilastatin; Meropenem; Ertapenem; Doripenem
Carbapenems
What carbapenem is not recommended for use against Pseudomonas?
Ertapenem
What carbapenem is recommended for use against E. faecalis?
Imipenem
Use: Carbapenems
cUTI; cIAI; CAP; Bone and SSTI; Bacterial meningitis, post-surgical (Miripenem) meningitis
What class of antibiotics is most likely to cause seizures (1%)?
Carbapenems
Often in patients with renal dysfunction, when drug is used in high doses
What Carbapenem is most effective against Pseudomonas?
Doripenem
Class: Aztreonam
Monobactam
Spectrum: Aztreonam
Gram negs only - Enterobacteriaceae and Pseudomonas
Class: Vancomycin
Glycopeptide
MOA: Vancomycin
Inhibits late stages of cell wall synthesis
– Binds to the D-Ala-D-Ala terminus of the nascent peptidoglycan pentapeptide
– Inhibits transglycosylase preventing elongation of peptidoglycan and cross-linking
Spectrum: Vancomycin
MRSA MSSA (less effective than beta-lactam) Coag-neg staph ie Staph epidermidis; Strep; Enterococci; Bacillus spp; Corynebacterium spp; – Peptostreptococcus – Actinomyces – Propionibacterium – Clostridium
Does Vancomycin have gram neg activity?
No
If MRSA is suspected, such as in a purulent cellulitis, what drug is recommended?
Vancomycin
Uses: Vancomycin
– SSTI, Especially when MRSA is suspected (purulent cellulitis)
• Bacteremia & Endocarditis
– Caused by Enterococcus, MRSA, coagulase-negative Staph
• Meningitis & Ventriculitis
– Community-acquired (for cephalosporin-resistant S. pneumoniae) – Hospital-acquired (for skin flora, MRSA)
• Pneumonia
– HAP, HCAP
• Bone & Joint Infection
• Neutropenic Fever
• Surgical prophylaxis
• C. difficile colitis (ORAL FORM ONLY)
Side effects: Vancomycin
• Nephrotoxicity – Concomitant nephrotoxins, e.g aminoglycosides, amphotericin • Infusion reactions – Redman syndrome • Secondary to histamine release • Maculopapular rash – SJS, TEN • Drug fever • Phlebitis • Neutropenia • Thrombocytopenia
Only use PO Vancomycin for:
C. Diff colitis, because it’s a big molecule –> poorly absorbed
MOA: Daptomycin
Insertion into the gram-positive cell membrane causing depolarization and ultimate cell death
• Disclaimer: unique MOA. Not a cell-wall active agent
Spectrum: Daptomycin
MSSA, MRSA, VISA
Strep
Enterococci including VRE
Has activity against gram pos anaerobes
Does Daptomycin have gram neg activity?
NO
Why is Daptomycin not effective for use in pneumonia?
Pulmonary surfactant inactivates the drug
Use: Daptomycin
SSTI
Staph aureus bacteremia and endocarditis;
Osteoarticular infection;
Enterococcal infections
Side effects: Daptomycin
Paresthesia
Peripheral neuropathy;
Eosinophilic pneumonia;
CPK elevation and possible skeletal muscle damage
Class: Gentamicin (IV)
Aminoglycosides
Class: Tobamycin (IV/inh)
Aminoglycosides
Class: Amikacin (IV/inh)
Aminoglycosides
Class: Streptomycin (IM)
Aminoglycosides
MOA: Aminoglycosides
Bind to the 30S subunit of bacterial ribosomes and interfere with an initiation complex between mRNA (messenger RNA) and the 30S subunit, inhibiting protein synthesis
Spectrum: Aminoglycosides
Gram-negative
– Enterobacteriaceae & Pseudomonas
• Gram-positive
– Synergy with cell wall active agent against Enterococcus. CANNOTGIVEAS MONOTHERAPY
What aminoglycoside is recommended for use against mycobacteria and Nocardia?
Amikacin
Do aminoglycosides have activity against anaerobes?
No
Side effects: Gentamicin, Amikacin
Nephrotixicity;
Ototoxicity - risk increased with loop diuretics;
Neuromuscular damage
Class: Minocycline (IV/PO)
Tetracycline
MOA: Tetracyclines
Passive diffusion through porins in gram- negative organism;
Bind to 30S ribosomal subunit preventing protein synthesis
What drug class is recommended for atypical organisms such as Chlamydia pneumoniae and Mycoplasma pneumoniae?
Tetracyclines
What drug class is recommended for spirochetes such as Borrelia burgdorferi, Leptospira, and Treponema pallidum?
Tetracyclines
What drug class is recommended for the rickettsiae?
Tetracyclines
Spectrum: Tetracyclines
Atypical Organisms – Chlamydia pneumoniae – Mycoplasma pneumoniae • Spirochetes – Borrelia burgdorferi – Leptospira – Treponema pallidum • Rickettsiae • Gram positive – S. pneumoniae (although resistance may be an issue) – CA-MRSA • Gram negative – H. influenzae – Neiserria spp. • Rapidly growing Mycobacteria
Uses: Tetracyclines
Tick-borne illness (DOC) – Lyme disease – Ehrlichiosis – Anaplasmosis • CAP – Patients with low risk of S. pneumoniae resistance • SSTI caused by CA-MRSA • Combination therapy for H. pylori • Prophylaxis – Exposure to anthrax, tularemia, plague, Q fever, brucellosis
Side Effects: Tetracyclines
Photosensitivity; Hyperpigmentation Blue discoloration of skin; Nephrotoxocity; Neurotoxicity with Minocycline; Erosive esophagitis
Why should tetracyclines not be given to children?
Discoloration of teeth AND inhibition of bone growth in infants (reversible)
What kind of neurotoxicity occurs with tetracyclines?
Vertigo, Tinnitus;
Pseudotumor cerebri with prolonged use
What kind of nephrotoxicity can occur with tetracycline use?
Expired tetracycline resulting in reversible Fanconi-like syndrome (doesn’t happen with current formulation)
What drugs should be avoided when tetracyclines are administered?
Antacids
Sucralfate
Multivitamins
Iron
Class: Tigecycline
Glycylcycline
MOA: Tigecycline
9-glycl substitution enables tigecycline to overcome two major types of resistance
– Efflux pumps
– Ribosomal protection
Spectrum: Tigecycline
Broad-spectrum;
gram-negative, gram-positives, anaerobes (includes MRSA, VRE & Acinetobacter)
What 4 gram negative bugs canNOT be treated with Tigecycline?
– Pseudomonas
– Proteus
– Providencia
– Morganella
Side effects: Tigecycline
• GI
– Significant nausea (~25%), vomiting (18%), diarrhea
• Transaminitis
• Increased mortality
– Black Box warning regarding
– Use in situations when alternative agents are not suitable
Class: Azithromycin (IV/PO)
Macrolide
Class: Clarithromycin (PO)
Macrolide
Class: Erythromycin (IV/PO)
Macrolide
Not used much anymore
Class: Macrolides
Reversible binding to 50S subunit of ribosome
Spectrum: Macrolides
• Gram-positive – S. pneumoniae (significant resistance) – Significant resistance in β-hemolytic strep • Gram-negative – H. influenzae, M. catarrhalis • Atypicals – Legionella, Chlamydia, Mycoplasma • Anaerobes – Actinomyces
Uses: Macrolides
• Uncomplicated upper & lower respiratory tract infections
– Usually in patients without prior antibiotics due to risk of resistant S. pneumoniae
• Mycobacterial infection – M. avium (seen in HIV crowd)
• H. pylori (clarithromycin>azithromycin) in combination with other agents
Side effects: Macrolides
• GI – Erythromycin>azithromycin,clarithromycin – Abdominal cramps, N/V, diarrhea • Thrombophlebitis (IV) – Erythromycin • Cardiac – QT-prolongation • Torsades de pointes
Class: Clindamycin
Lincosamide
MOA: Clindamycin
Binding to 50S ribosomal subunit preventing protein synthesis
Are Clindamycin effective against gram neg bugs?
NO, Gram pos only
Why is Clindamycin indicated for use in TSS Strep?
Mitigates toxin production
Side effects: Clindamycin
- Diarrhea (up to 20% of patients)
* Pseudomembranous colitis
Class: Linezolid (IV/PO)
Oxazolidinones
Class: Tedizolid (PO)
Oxazolidinones
MOA: Oxazolidinones (Linezolid, Tedizolid)
Binds to 23 S ribosomal RNA of the 50S subunit inhibiting protein synthesis
Why should Linezolid be avoided in the treatment of Staph aureus bacteremia?
• Vancomycin or daptomycin are recommended as 1st- line therapy
Use: Linezolid
– Enterococcal infection including bacteremia
– Nosocomial pneumonia caused by S. aureus
– CAP caused by S. aureus
– SSTI
Use: Tedizolid
SSTI
T/F: Linezolid has gram negative activity.
FALSE Linezolid use is: – Staphylococci • S. aureus (MRSA, MSSA) • Coagulase-negative – Enterococci including VRE – Streptococci
Side effects: Linezolid
• Hematologic toxicity • Reversible myelosuppression – Thrombocytopenia (most common) – Anemia • MitochondrialToxicity – Peripheral neuropathy, optic neuropathy – Lactic acidosis • Serotonin Syndrome (SS) – Inhibition of MAO can result in SS when given with serotonergic agents
Name the three nucleic acid synthesis inhibitors.
Fluoroquinolones;
Metronidazole;
Rifamycins
Class:
– Rifampin
– Rifabutin
– Rifaximin
Rifamycin - Nucleic acid synthesis inhibitors
Class:
– Ciprofloxacin
– Levofloxacin
– Moxifloxacin
Fluoroquinolones - Nucleic acid synthesis inhibitors
Class: Metronidazole
No technical class - Nucleic acid synthesis inhibitor
MOA: Fluoroquinolones
- Inhibit DNA gyrase
* Inhibit topoisomerase IV
What are the ONLY oral antipseudomonal agents?
Fluoroquinolones
– Ciprofloxacin
– Levofloxacin
– Moxifloxacin
Spectrum: Fluoroquinolones
– S. pneumoniae
• levofloxacin & moxifloxacin;
– Enterobacteriaceae
– H. influenzae
– P. aeruginosa: Ciprofloxacin & levofloxacin
– Atypicals (Legionella, Chlamydia, Mycoplasma);
• Mycobacterium
Resistance in what bugs is an issue for Fluoroquinolone use?
Resistance in Enterobacteriaceae problematic
What is the antibiotic of choice for anthrax?
Fluoroquinolones
– Ciprofloxacin
– Levofloxacin
– Moxifloxacin
What is the recommended adjunctive therapy in MDR pulmonary TB?
Fluoroquinolones
– Ciprofloxacin
– Levofloxacin
– Moxifloxacin
T/F: Fluoroquinolones are just as effective PO as IV.
True
Good drug for transitioning out of the hospital
Avoid Ciprofloxacin in conjunction with what drugs?
Theophylline –> Seizure
Tizanidine –> Hypotension
MOA: Metronidazole
Interacts with DNA to cause a loss of helical DNA structure and strand breakage resulting in inhibition of protein synthesis
Spectrum: Metronidazole
• Anaerobes – B. fragilis – Clostridial species including difficile • Protozoa – Trichomonas – Giardia – Entamoeba histolytica
Side effects: Metronidazole
- Metallic taste
- Minor GI disturbances
- Peripheral neuropathy (with long-term use or very high doses)
- Disulfiram reaction with alcohol
Use: Metronidazole
- C. difficile diarrhea
- Intra-abdominal infections in combination with other agents
- Surgical prophylaxis in colon surgery (with other agents)
- Trichomoniasis
MOA: Rifamycins
Bind to DNA-dependent RNA polymerase inhibiting RNA synthesis
T/F: Rifamycins such as Rifampin inhibit biofilms.
True
Spectrum: Rifamycin
• Gram-positive – Staphylococci – Streptococci – C. difficile – Listeria • Gram-negative – H. influenzae – N. meningitidis – H. pylori • Mycobacterium
Use: Rifampin
– M. tuberculosis infection
– Other Mycobacterium infections
– Adjunctive treatment in prosthetic valve endocarditis (S. aureus) and for prosthetic joint infection
– Prophylaxis N. meningitidis
Use: Rifaximin
– Hepatic encephalopathy
– Recurrent C. difficile
– Traveler’s diarrhea
Side effects: Rifampin
– Rifampin-associated flulike syndrome • Onset is latent
– Thrombocytopenia, hemolysis
– Renal failure
– Transaminitis
• Increased incidence of hepatotoxicity when combined with INH
or pyrazinamide
Rifampin interacts with what liver enzymes, lowering the concentration of other drugs?
3A4*
1A2
2C
2D6
What are the main anti-TB drugs?
- Isoniazid (INH)
- Pyrazinamide
- Ethambutol
Side effects: Isoniazid
• Hepatitis – 10-20% of patients have asymptomatic minor transaminitis • Neurotoxicity – Peripheral neuropathy • Pyridoxine can alleviate – Memory loss, psychosis • Hypersensitivity reactions
Class: Trimethoprim-Sulfamethoxazole (Bactrim)
Bacterial anti-metabolites
MOA: Trimethoprim-Sulfamethoxazole
Sulfamethoxazole: Interferes with bacterial folic acid synthesis and growth via inhibition of dihydrofolic acid formation from paraaminobenzoic acid (PABA)
Trimethoprim: inhibits dihydrofolic acid reduction to tetrahydrofolate resulting in sequential inhibition of enzymes of the folic acid pathway
What are the two drugs of choice for listeria?
Ampicillin;
Trimethoprim-Sulfamethoxazole
What is the drug of choice for Stenotrophomonas (hosp)?
Trimethoprim-Sulfamethoxazole
Is Trimethoprim-Sulfamethoxazole effective against anaerobes?
NO
Spectrum: Trimethoprim-Sulfamethoxazole
• Gram-Positive – CA-MRSA/MSSA – S. pneumoniae • Not ideal for β-hemolytic strep – Listeria • Gram-Negative – Enterobacteriaceae (E. coli, Klebsiella, Enterobacter, etc.)-resistance varies – DOC-Stenotrophomonas • Toxoplasmosis, Nocardia, Pneumocystis
Uses: Trimethoprim-Sulfamethoxazole
- Prophylaxis & treatment Pneumocystis jiroveccii pneumonia
- Toxoplasmosis encephalitis
- Urinary tract infection
- Listeria meningitis
- CA-MRSA
Side effects: Trimethoprim-Sulfamethoxazole
RASH - SJS, TEN possible also
more common in HIV patients;
• Hematologic
– Bone marrow suppression (usually at higher doses)
• Renal
– Pseudo-renal failure: TMP can inhibit creatinine secretion
– AIN from sulfamethoxazole
– Hyperkalemia-TMP essentially acts as a K+ sparing diuretic
Avoid warfarin when administering what antibiotic?
Trimethoprim-Sulfamethoxazole
Warfarin (inhibition of CYP 2C9 by TMP/SMX) leading to increase in INR