Antibiotics IV: NN Flashcards
What are examples of Fluroquinolones?
- Levofloxacin, moxifloxacin, ciprofloxacin, ofloxacin – IV, PO, topical
What is the target of Fluroquinolones?
- DNA gyrase inhibitor
(respon. For making spiral/coil) – INHIBITS RELAXATION of supercoiled DNA and PROMOTES BREAKAGE of DNA strands
What are the features of Fluroquinolones?
- Levofloxacin and ciprofloxacin-adjust dose in renal impairment (not moxi)
- Distributes widely into body tissues and fluids (moxi not for kidney infections)
- BacterioCIDAL
- CONCENTRATION DEPENDENT (want to get good concentrations), post-antibiotic effect
- *EXCELLENT PO absorption (can switch from IV as long as they are okay to swallow pills)
- Absorption affected by DIVALENT cations, metal cations (Fe)-separate in time
What is the Spectrum of Activity of Fluroquinolones?
- Variable gram positive coverage, good gram negative coverage, good atypical coverage, tuberculosis (cipro has unreliable strep pneumo coverage, but covers pseudomonas
- (can add to list of what we can use for CAP)
What are the adverse effects of Fluroquinolones?
- US boxed warning re: tendinitis, tendon rupture, peripheral neuropathy, CNS effects; also QTc prolongation, dysglycemia (unpredictable – sometimes goes up or down) , photosensitivity, increased risk of aortic dissection or rupture
What are examples of Trimethoprim/Sulfamethoxazole?
- Trimethoprim/Sulfamethoxazole – IV, PO (combo)
What is the target of Trimethoprim/Sulfamethoxazole?
- Both interfere with bacterial folic acid synthesis
What are the features of Trimethoprim/Sulfamethoxazole?
- Sulfamethoxazole is a PABA analog & inhibits the synthesis of dihydrofolic acid
- Trimethoprim inhibits later in the pathway by binding to bacterial dihydrofolate reductase (& prevents formation of tetrahydrofolic acid)
- Synergistic combination
- Bactericidal/static
- Time/concentration dependent
What is the Spectrum of Activity of Trimethoprim/Sulfamethoxazole?
BROAD
* Gram + (incl. MRSA), gram -, Pneumocystis jirovecii, NOT anaerobes
What are the adverse effects of Trimethoprim/Sulfamethoxazole?
- Cystalluria, rashes can be severe (SJS, TEN rare but serious), photosensitivity (careful when in summer – use sunscreen), hyperkalemia, increased serum creatinine, renal failure
What is the target of Nitrofurantoin?
- Reduced by bacterial flavoproteins to reactive intermediates that inactivate/alter ribosomal proteins
- *This results in numerous effects incl. impaired protein synthesis, aerobic energy metabolism, DNA, RNA & cell wall synthesis
- Used for uncomplicated UTIs but kidney function must be good enough otherwise drug will not get into the urine in high enough concentrations. *CANNOT use for pyelonephritis
What are the features of Nitrofurantoin?
- Bacteriocidal
What is the Spectrum of Activity of Nitrofurantoin?
- Gram + incl. MRSA, few gram –‘s, NOT anaerobes
What are the adverse effects of Nitrofurantoin?
- Hepatotoxicity (prolonged use), pulmonary fibrosis (prolonged use), hematologic toxicity (elderly?)
What is the target of Metronidazole?
- Disrupts DNA which inhibits nucleic acid synthesis
What are the features of Metronidazole?
- Bacteriocidal
- Concentration dependent
What is the Spectrum of Activity of Metronidazole?
NARROW
* Anaerobes incl. c. difficile, protozoa, amoeba
What are the adverse effects of Metronidazole
- Metallic taste (makes everything taste a bit off)
- Disulfiram like rxn
- Headache
What are Anti-Tubercular Drugs used for?
M. tuberculosis
* Acid fast bacillus
* Very slow growing
* Resistant to most antibiotics
* Resistant to host defences
* Spread via inhaled droplet nuclei
(diff. to treat b/c grows slowly & resistant)
What are the Anti-Tubercular Drugs?
1st line drugs RIPE, must use combo therapy due to drug resistance
1. Rifampin
2. Isoniazid
3. Pyrazinamide
4. Ethambutol
- Direct Observed Therapy
o Public health nurse will come & observe you taking it for like 9 months (v. serious)
o Follow all protocols if TB is in hospital
What is the target of Rifampin?
Also rifabutin
*Used for both in initial & continuation phase of treatment
- Binds to beta subunit of DNA-dependent RNA polymerase thereby blocking RNA transcription & inhibiting bacterial RNA synthesis
What are the features of Rifampin?
- Bacteriocidal
- *Body fluids (tears, urine, sweat etc.) may turn red-orange, hepatitis
- Induces many CYP P450 enzymes incl. being a strong inducer of 3A4 & 2C19 (cause other drugs to be cleared quickly & if you stop it the enzyme will dose down & you can end up with an overdose)
o lots of drug interactions (careful when starting & stopping it – BIG inducer)
What is the Spectrum of Activity of Rifampin?
- Gram + & some gram -, M. tuberculosis
What is the target of Isoniazid?
*Used for both initial & continuation phase of treatment
- Inhibits mycolic acid synthesis (required for cell wall) resulting in mycobacterial cell death
What is the Adverse Effects of Isoniazid?
- Hepatotoxicity, peripheral neuropathy (give in combo with pyridoxine), rash (baseline before treatment)
- Bacteriocidal against actively growing M. tuberculosis
What is the target of Pyrazinamide?
- Converted to pyrazinoic acid – inhibits mycolic acid synthesis which results in mycobacterial cell death
What are the features of Pyrazinamide?
Bactericidal
Typically used for 1st 2 months of tx
Adjust interval in renal impairment
What is the Adverse Effects of Pyrazinamide?
- Anorexia, muscle aches, rash, hepatotoxicity, gout, photosensitivity (some don’t feel great with this, take baseline)
What is the target of Ethambutol?
- Impairs mycobacterial wall synthesis by inhibiting arabinosyl transferase
What is the Adverse Effects of Ethambutol?
- Bacteriostatic
- Initial therapy, may be discontinued if no drug resistance to isoniazid (typ. dropped quite quickly)
- Adjust interval in renal impairment
- Optic neuritis, loss of central vision (baseline eye exam & monitor throughout therapy)
