Urinary Antiseptics & Metronidazole Flashcards

1
Q

MOA of Fluoroquinolones?

A

Targets…

i) DNA gyrase (Gram -ve)
ii) Topoisomerase IV (Gram +ve)

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2
Q

Administration of Fluoroquinolones

A

Oral/IV (2h before/6h after food, best on empty stomach)

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3
Q

Oral bioavailability of Fluoroquinolones

A

Good, generally well absorbed after oral administration

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4
Q

Clearance of Fluoroquinolones

A

Renal (Moxifloxacin - Hepatic)

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5
Q

Use of Ciprofloxacin

A

Most active: Gram -ve & enteric coliform

1) P. aeruginosa (HIGHLY ACTIVE)
2) Traveller’s diarrhoea due to E.Coli
3) Typhoid fever due to Salmonella typhi
4) Bacillus anthracis
5) Protstatitis

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6
Q

Use of Levofloxacin & Moxifloxacin

A

Better coverage for Gram +ve & Aytipicals
“Respiratory quinolones”

1) S. pneumoniae (HIGHLY ACTIVE)
2) 2nd line M.TB
(don’t give if suspicious of TB, can mask symptoms)

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7
Q

Adverse Drug Effects of Fluoroquinolones

A

1) Aortic dissections
2) Increased risk of C. diff colitis (especially w cipro)
3) Phototoxicity
4) Arthropathy
5) QTc interval prolongation
6) Tendinitis
7) GIT (Most common)
8) Risk of dysglycaemia
9) HA, dizziness
10) Peripheral neuropathy

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8
Q

Contraindications for Fluoroquinolones

A

Pregnancy (breastfeeding not recc)
< 18yo
Myasthenia gravis

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9
Q

What are the Anti-Folate drugs?

A

Sulfonamides, Trimethoprim, Cotrimoxazole

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10
Q

MOA of sulfonamides

A

Competitive inhibitors of dihydropteroate synthase

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11
Q

ADE of sulfonamides

A

1) Crystalluria - Hydrate well/alkanise urine
2) Hypersensitivity
3) Hemolytic anaemia with G6PD Deficiency
4) Kernicterus

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12
Q

Contraindications for sulfonamides

A

Pregnant women at term & newborns < 2months

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13
Q

MOA of trimethorpin

A

Inhibits reduction of dihydrofolic acid by dihydrofolate reductase to its active form

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14
Q

Use of trimethorpin

A

Bacterial prostatitis (ciprofloxacin preferred)

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15
Q

Resistance for trimethorpin?

A

1) Altered dihydrofolate reductase with lower affinity for trimethorpin
2) Efflux pumps

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16
Q

Administration of Cotrimoxazole

A

Oral (take with full cup of H2O)/ IV

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17
Q

Distribution of Cotrimoxazole

A

Good bioavailability & CSF penetration

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18
Q

Clearance of Cotrimoxazole

A

Renal

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19
Q

Use of Cotrimoxazole

A

1) 1st line for UTI (E.coli)
2) RTI caused by Haemophilus sp, Klebseilla penumonia
3) MRSA & community-acquired skin & soft tissue infections
4) Pneumocystis pneumonia caused by Pneumocystis jiroveci

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20
Q

ADE of Cotrimoxazole

A

1) Photosensitivity
2) Hemolytic anaemia
3) Megaloblastic anemia, leukopenia, thromocytopenia
(Give folinic acid for FA deficiency)
4) Skin reactions, N/V

USE WITH CAUTION in pregnancy (1st & 3rd trimester)

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21
Q

MOA of Nitrofurantoin

A

Bacteria reduces nitrofurantoin to highly active intermediate -> Inhibits various enzymes -> Disrupt synthesis of proteins, DNA, RNA & metabolic processes

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22
Q

Administration of Nitrofurantoin

A

Oral (Very good F)

23
Q

Distribution of Nitrofurantoin

A

Achieves high [urinary] while limiting systemic exposure

24
Q

Use of Nitrofurantoin

A
  • *1st line for UTI**
    1) E.coli
    2) Enterococci
25
Q

ADE of Nitrofurantoin

A

1) Leukopenia, hemolytic anaemia (G6PD Deficiency)
2) Cholestatic jaundice & hepatocellular damage
3) Elderly more susceptible to pulmonary toxicity of nitrofurantoin
4) N/V, Diarrhoea
5) Hypersensitivity reaction

26
Q

Which agent causes urine discolouration?

A

Nitrofurantoin - Brown

Rifampicin - Orange

27
Q

Which of the Urinary antiseptics can be administered orally?

A

Fluoroquinolones, FA synthesis inhibitors, Nitrofurantoin, Fosfomycin

28
Q

MOA of polymyxins

A

Disrupt structure of c.m phospholipids & increase cell permeability

29
Q

Use of polymyxins

A
  • *MDR-Gram -ve bacteria**
    1) Inhaled CMS (Pseudomonas)
    2) Resp infections & severe pneumonia

Polymixin B - UTI & Blood Infections due to P.aeruginosa

30
Q

Antimicrobial spectrum of polymyxins

A

MDR Gram -ve organisms

31
Q

Administration of Polymyxin B

A

IV

CMS - Inhalation therapy for cystic fibrosis

32
Q

Elimination of Polymyxins

A

Renal

Colistin - dosing adjustments
polymyxin B - NIL

33
Q

ADE of Polymyxins

A

1) Neuro & nephrotoxicity
2) DO NOT use with neuromuscular blockage agents & in myasthenia gravis

Aerosolised CMS: Sore throat, cough, bronchoconstriction, chest tightness

34
Q

Which agents will cause phototoxicity?

A

Fluoroquinolones

Tetracyclines

35
Q

Which agents will cause ototoxicity?

A

Vancomycin
Aminoglycosides
Macrolides (Azithromycin)

36
Q

Which agents will cause nephrotoxicity?

A

Vancomycin
Aminoglycosides
Polymyxins

37
Q

MOA of Fosfomycin

A

Bacteriacidal antibiotic

- Interferes with c.w synthesis by inhibiting initial step involving phosphoenolpyruvate synthase

38
Q

Spectrum of Fosfomycin

A

Broad
(+): Staphylococcus aureus, Enterococcus
(-): Pseudomonas aeruginosa, Klebsiella pneumoniae

39
Q

Use of Fosfomycin

A

1) UTI (E.coli / Enterococcus faecalis)
2) (+) Other antibiotics for nosocomial infections due to resistant Gram (+)/(-) strains
3) Additive/synergistic effects with B-lactams

40
Q

Administration of Fosfomycin

A

Oral (Fosfomycin tromethamine -> Fosfomycin), take on empty stomach

41
Q

Distribution of Fosfomycin

A

Widely distributed in CSF & Bile

42
Q

Elimination of Fosfomycin

A

Renal (30-60%)

43
Q

Adverse effects of Fosfomycin

A

1) GI (Nausea, diarrhea)
2) Headache
3) Vaginitis

44
Q

Urinary antiseptic for Pregnancy?

A

B-lactams (1st gen ceph)
Amoxicillin-CA (Augmentin)
Nitrofurantoin (not if at term)
Cotrimoxazole (not for 1st & last trimester)

45
Q

Contraindications for Nitrofurantoin

A

Pregnancy at term
Infants < 1 months
Impaired renal function

46
Q

Therapeutic agents for Amebiasis

A

Luminal - Parasite in lumen of bowel
Systemic - Amoebas in the intestinal wall & liver
Mixed - Effective against both, though [luminal] too low for single-drug treatment

47
Q

MOA of Metronidazole

A

Nitro group serves as electron acceptor, forming cytotoxic free radicals that results in protein & DNA damage

48
Q

Use of Metronidazole

A
  • *Anaerobes & Protozoa**
    1) Anaerobes such as Bacteroides species & Clostridium difficle (2nd line)
    2) Amebic infections due to Protozoa - Entamoeba histolytica, Trichomonas vaginalis, Giardia lamblia
    3) H.Pylori
    4) Surgical prophylaxis
49
Q

Administration of Metronidazole

A

Oral

50
Q

Distribution of Metronidazole

A

Distributes well, CSF fluid

51
Q

Metabolism & Excretion of Metronidazole

A

Metabolism:
Hepatic (Accumulates in severe hepatic disease)

Excretion:
Parent drug & metabolites in urine

52
Q

Adverse effects of Metronidazole

A

1) GIT
2) Oral moniliasis (yeast infection of mouth)
3) Central & peripheral nervous system effects

Unpleasant metallic taste

53
Q

Is Metronidazole safe for pregnancy?

A

Yes, but avoid in 1st trimester