Antimicrobials Flashcards
Penicillin
-cillin Bactericidal β-lactam ring Interferes w/ peptidoglycan synthesis Renal excretion *Hypersensitivity Cross-reactivity w/ Cephalosporins
Penicillin Dose
100mg/kg PO or IV
Cephalosporin
Bactericidal Inhibits bacterial cell wall synthesis Low toxicity Renal excretion Broad spectrum *Cross-reactivity w/ Penicillins
Cephalosporin 1st Generation
Cefazolin (Ancef)
Cephalosporin 2nd Generation
Cefuroxime
Cephalosporin 3rd Generation
Cefotaxime
Cephalosporin 4th Generation
Cefepime
Most effective
Ancef Dose
<50kg weight-based
50-70kg 1g
70-120kg 2g
>120kg 3g
Macrolides
-thromycin
BacterioSTATIC
Binds to 50S & blocks translocation step in protein synthesis
Used to treat gram+ bacilli, mycoplasma, upper/lower respiratory infections, ulcers, STDs
N/V when taken on empty stomach
Potential liver toxicity
Erythromycin
Macrolide Bacteriostatic OR bactericidal depending on the organism & dose Inhibits bacterial protein synthesis CYP450 metabolism Excretion 1° via bile
Erythromycin SE
GI intolerance most common
IV infusion → severe N/V
↑gastric emptying time
QT effects (prolongs cardiac repolarization)
Thrombophlebitis w/ prolonged IV use
Inhibits P-450 (drug interactions) & ↑QTc
Clindamycin
Linomycin antibiotic
BacterioSTATIC
Binds to 50S & inhibits peptidyl transferase & translocation
Hepatic metabolism
10% excreted unchanged via urine 90% inactive
Half-life 2.5hr
DOSE 900mg
Clindamycin Clinical Uses
Female GU surgery most common Oral infections Lung abscess Aspiration pneumonia Necrotizing fasciitis GYN or pelvic infections MRSA
Clindamycin SE
Skin rash
Prolonged pre & post junction effects at NMJ w/o NDMR (prolongs NMBD & muscle weakness)
N/V or diarrhea
Fever or rash
C Diff enterocolitis
Pseudomembranous colitis → severe diarrhea (discontinue therapy)
Vancomycin
Glycopeptide derivative Bactericidal Impairs cell wall synthesis 90% excreted unchanged via urine Elimination 1/2 time 6hr (prolonged in renal failure)
Vancomycin Dose
10-15mg/kg IV over 60min
1g mixed in 250mL
Infuse over pump
Vancomycin Clinical Uses
Gram+ bacteria
Drug of choice to treat MRSA
Severe staph infections
Cardiac/ortho procedures using prosthetic devices
CSF & shunt related infections
Synergistic action w/ Aminoglycosides
Penicillin/Cephalosporin β-lactam allergy
Reserved for bacterial infections resistance to other antibiotics or patients w/ severe hypersensitivity
Red Man Syndrome
Occurs after rapid (<30min) Vancomycin infusion → profound hypotension d/t histamine release
Intense facial & truncal erythema (flushing)
Treatment 1mg/kg Diphenhydramine + 4mg/kg Cimetidine 1hr prior to admin to limit histamine release
Aminoglycosides
-mysin
Bactericidal
Irreversible protein synthesis 30S inhibition
Effective against aerobic gram+/- bacteria
Mycobacterium tuberculosis
*Administer w/ cell wall synthesis inhibitor
Extensive renal excretion
Elimination 1/2 time 2-3hr (↑20-40x w/ renal failure)
Aminoglycosides SE
Ototoxicity Nephrotoxicity Skeletal muscle weakness NDMR blockade potentiation (relaxation) Paralysis usually reversible w/ calcium gluconate or Neostigmine Pregnancy category C
Fluroquinolones
-floxacin
Bactericidal
Inhibits DNA gyrase & topoisomerase IV
GI absorption rapid & excellent tissue penetration
Renal excretion (↓dose in renal dysfunction)
Elimination 1/2 time 3-8hr
Broad spectrum used to treat enteric gram negative, mycobacterium, & complicated GI/GU infections
Ciprofloxacin Clinical Uses
Fluroquinolone
Systemic infection including bones, soft tissue, & respiratory tract
Tuberculosis
Anthrax
Moxifloxacin
Fluroquinolone
Long-acting treatment
Acute sinusitis, bronchitis, & complicated abdominal infections
Complications include QT prolongation, peripheral neuropathy, psychosis, Stevens-Johnson syndrome, & Achilles tendon rupture
Fluroquinolones SE
Mild GI disturbances N/V CNS dizziness or insomnia Achilles or tendon rupture Muscle weakness in patients w/ myasthenia gravis Pregnancy category C
Sulfonamides
BacterioSTATIC
Sulfamethoxazole-trimethoprim (Bactrim)
Inhibit folate production microbial synthesis
Partial acetylated in liver & other renal excretion
↓dose w/ renal disease
Used to treat UTIs, inflammatory bowel disease, & burns
Sulfonamides SE
Skin rash (anaphylaxis) Photosensitivity Allergic nephritis Drug fever Hepatotoxicity Acute hemolytic anemia Thrombocytopenia ↑PO anticoagulant effect
Nitroimidazole
Bactericidal Metronidazole (Flagyl) Anaerobic gram- bacilli clostridium Good PO absorption Widely distributed in tissues (including CNS)
Flagyl Clinical Uses
Nitroimidazole
CNS infections
Abdominal/pelvis sepsis
Pseudomembranous colitis (C Diff) → combination therapy w/ Vancomycin
Endocarditis
Recommended preop colorectal surgery prophylaxis
Flagyl SE
Dry mouth
Metallic taste
Nausea
Avoid alcohol
Antimycobacterial Agents
Rifampin
Ethambutol
Pyrazinamide
Isoniazid (INH)
Distributed through tissues & CSF
1st line agents
*Combination therapy to treat active or latent TB
Initial 3-4 agents x2 mos
Followed by 2 agents x4 mos minimum therapy
BacterioSTATIC antibiotics require longer treatment course
Rifampin
Bactericidal Hepatic enzyme induction Hepato-renal toxicity Enzyme inducer Thrombocytopenia/anemia Discoloration (teeth, saliva, sweat, sputum, urine, feces)
Ethambutol
BacterioSTATIC
Optic neuritis
Pyrazinamide
BacterioSTATIC
Liver toxicity
Isoniazid
BacterioSTATIC
Bactericidal when bacteria are actively dividing
Hepato-renal toxicity
Antifungal
Amphotericin B Poor PO absorption Slow renal excretion Renal toxic → 80% patients renal function impaired - Most recover after drug stopped - Possible permanent damage ↓GFR Monitor plasma creatinine levels Used to treat yeast or fungal infection
Acyclovir
Antiviral
Selectively inhibits HSV1/2 replication & varicella zoster virus
Difficult to kill virus & not host cell
Potential drug therapy at cell surface receptors unique to the virus
Used to treat herpes
Interferons
Antiviral
Glycoproteins produced in response to viral infections
Bind to receptors on host cell membranes & induce enzyme production that inhibits viral replication → degrade viral mRNA
Used to treat chronic hepatitis B/C
Interferons SE
Flu-like symptoms Hematologic toxicity Depression or irritability Impaired mental concentration Autoimmune conditions development Rashes/alopecia Changes to CV, thyroid, or hepatic function (similar to chemo) VERY difficult treatment
Antiretroviral
Nucleoside/non-nucleotide reverse transcriptase inhibitors (NRTIs/NNRTIs Delavirdine) Protease inhibitors (Ritonavir) Fusion inhibitors (Enfuvirtide) CCR5 receptors antagonists Integrase inhibitors (Lamivudine)
HIV treatment regimen
Triple therapy approach
Antiretroviral SE
Liver toxicity Peripheral neuropathy Nephrotoxicity Neuromuscular weakness Interactions w/ other medications
