Quinolones, Folic acid antagonists and Urinary antiseptics Flashcards
Fluoroquinolone targets _________ in Gram negatives and _________ in Gram positive bacteria
DNA gyrase, topoisomerase IV
Name 3 fluoroquinolones
ciprofloxacin, levofloxacin, moxifloxacin
Fluroquinolones should be administered at least _________ hours before consumption of dairy products or substances that contain divalent cations
2 hours
Best on empty stomach
- just like tetracycline
Indications for fluroquinolones
Ciprofloxacin (2nd gen)
- gram -ve & enteric coliforms (GNR)
- traveller’s diarrhoea (e coli)/food pois (salmo)
- X UTI, MRSA (resistance)
- prostatitis (high [ ] in prostatic tissue)
Levo & moxifloxacin– Gram +ve & atypicals
Name the two respiratory quinolones
Levofloxacin and moxifloxacin
Name at least 3 adverse effects associated with the use of fluroquinolones.
- Phototoxicity
- Tendinitis or tendon rupture
- Prolong QT interval
- Peripheral Neuropathy
- GI distress– CDAD
- Arthropathy
Which antibiotics are known to cause phototoxicity?
Tetracyclines, fluoroquinolones
Fluoroquinolones are contraindicated in _________
- Children < 18 years old
- Pregnant/Lactating women
- Myasthenia gravis pt
Name 3 folate synthesis inhibitors
Sulfonamides (sulfamethoxazole), trimethoprim, cotrimoxazole
Folic acid is vitamin B9 that is needed in humans to produce healthy ___________
red blood cells
Which enzyme does sulfonamide inhibit?
Dihydropteroate synthase (thus humans aren’t affected)
Which enzyme does trimethoprim inhibit?
Dihydrofolate reductase
decrease tetrahydrof acid–> aa, purine, thymidine
Cotrimoxazole is a combination of which 2 antibiotics, and in what ratio?
Trimethoprim and sulfamethoxazole, 1:5 respectively
Combination of sulfonamide & trimethoprim has _______ effect
synergistic
bactericidal as block tetrahydrofolate pathway
**Sulfonamides are only effective in bacteria that synthesize their own __________?
folic acid
Sulfonamides can cause nephrotoxicity as a result of __________?
crystalluria
sulfonamide acetylated & conj in liver - retains toxicity to ppt at neutral/acidic pH
Trimethoprim can cause __________ deficiency in humans
folic acid deficiency–> megaloblastic anemia, leukopenia, thrombocytopenia
AVOID in 1st & 3rd trimester pregnancy
Usage of sulfonamides in last trimester can cause __________ in newborns
kernicterus
G6PD deficient patients using sulfonamides can suffer from __________
hemolytic anemia
Adverse effects of sulfonamides
- Hemolytic anaemia in G6PD deficient pt
- Crystalluria (cloudy urine)– nephrotoxicty: can alkalinise urine or hydration
- Kernicterus newborns: drug taken late in preg
- Hypersensitivity
Folic acid deficiency caused by trimethoprim can be managed by giving the patients _____________ .
Folinic acid (does not take part in pathway but is interchangeable conversion to tetrahydrf)
Name at LEAST two indications for cotrimoxazole
- Uncomplicated UTI
- Pneumocystis pneumonia (Pneumocystis jiroveci)
- MRSA
? meningitis as good CSF penetration/ cross BBB
Name at LEAST 3 adverse effects related to the use of cotrimoxazole
other than that of sulf & trimethoprim
- Glossitis
- Rash
What’s a urinary antiseptic agent?
Nitrofurantoin