Nucleic Acid Synthesis Flashcards

1
Q

Nucleic Acid Synthesis Inhibitors drugs?

A
  1. Fluroquinolones
  2. Metronidazole
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2
Q

Nucleic Acid Synthesis Inhibitors drugs Function?

A

A nucleic acid inhibitor is a type of antibacterial that acts by inhibiting the production of nucleic acids.

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3
Q

Fluoroquinolones

  1. Adjunct admission and substantiation
  2. MOA
  3. MOA for bacteria
A
  1. Take on an empty stomach to increase absorption
  2. Inhibit topoisomerase 2 and topoiosmerase 4
  3. Bacteriosidal(kill bacteria)
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4
Q

Fluoroquinolones absorption impaired by?

A

-Divalent acids
-Shouldn’t be taken with divalent acids like milk, yogurt because that decreases absorption

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5
Q

What is another name for topoisomerase?

A

DNA gyrase

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6
Q

Fluoroquinolones and pH or urine?

A

Fluoroquinolones are acidic

Excessive alkalinity of urine must be avoided as this will increase excretion of drug

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7
Q

Fluoroquinolones suffix?

A

-“-floxacin”

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8
Q

Fluoroquinolones drugs?

A

COMGL–floxacin

Ciprofloxacin
Ofloxacin
Moxifloxacin
Gemifloxacin
Levofloxacin

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9
Q

Ciprofloxacin & Ofloxacin

  1. Gram
  2. CYP450
A
  1. Gram-negative aerobes only
  2. CYP450 Inhibitor
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10
Q

Ciprofloxacin & Ofloxacin

  1. Indications & Prophylaxis
  2. Non-indication
A
  1. Typhoid fever, cystitis, mycobacteria , lower resp tract infections and Nienongococcal prophylaxis
  2. Not for gonorrhea
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11
Q

Fluoroquinolones CYP450?

A

CYP450 Inhibtor

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12
Q

Fluoroquinolone CYP450 and different intensities?

A

Levofloxacin and Ciprofloxacin both inhibit CYP450 BUT Levofloxacin inhibit to a lesser extent

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13
Q

Moxifloxacin, Gemifloxacin and Levofloxacin

  1. Gram bacteria
  2. CYP450
  3. Indications + for TB
  4. Usuage for pseudomonas
  5. B-lactam allergy
A
  1. Gram-positive bacteria
  2. CYP450 Inhibitor
  3. M tuberulosis (Moxifloxacin, Levofloxacin), Lower resp tract, skin & urinary infections sinusitis cacute)
  4. Not for pseudomonas (moxifloxacin)
  5. Reserved for B-lactam allergy
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14
Q

Nalidixic acid and quinolones?

A

Nalidixic acid is used to form quinolones

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15
Q

Nalidixic acid and gram bacteria?

A

Gram -ve bacteria

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16
Q

Nalidixic acid indications?

A

-Acute and chronic lower urinary tract infections

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17
Q

Nalidixic acid mother substance?

A

Quinolone is the mother substance

18
Q

Nalidixic acid and quinolone resistance?

A

Can cause quinolone resistance if not used for a long time

19
Q

Nalidixic acid S/E?

A

-Neurotoxic
-Seizures
-Photosensitivity (main S/E)

20
Q

Nalidixic acid resistance(2) ?

A
  1. Change in permeability
    If bacteria can not enter
    bacteria then it can not be
    active
  2. One or more point mutations in quinolone binding region of target enzyme
21
Q

Fluoroquinolones resistant organisms?

A

SPS

-Staphylococci
-Psedomonas
-Serratia

22
Q

Fluoroquinolones S/E-7?

A

H2PQ SAT

-Seizures(Ciprofloxacin)
-QT-interval prolongation
-Hypoglycaemia/ Hyperglycaemia
-Arthropathy(damage to growing cartilage)
-Hallucinations(rare)
-Tendinitis(rare)
-Photosensitivity

23
Q

Fluoroquinolones DI-5?

A
  1. Probenecid-Increase in t1/2 Fluoroquinolones
  2. NSAIDS-Decrease Seizure threshold and increases likelihood of seizures
  3. Antacids/Minerals-decrease absorption of fluoroquinolones
  4. Drugs metabolized by CYP450:
    -Warfarin
    -Theophylline
  5. Oral hypoglycaemic age(Glibenclamide)
24
Q

Fluoroquinolones CI(6) ?

A
  1. G6PD deficiency (risk of haemolytic)
  2. Pregnancy/Lactation
  3. Babies/Children(<18yrs)
  4. Epilepsy & Porphyria-Nalidixic acid
  5. Hepatic/Renal failure
  6. Elderly patients

(2 & 3 effecct teh development of cartilage

25
Q

Metronidazole

  1. Incidence of resistance
  2. Type of bacteria
  3. Admission
  4. CSF
A
  1. Decreased incidence of resistance
  2. Anaerobic bacteria
  3. Orally, IV, rectal & topical
  4. Metronidazole can enter the CSF
26
Q

Metronidazole antiprotozoal action?

A

Trophozoites of:

  1. Entamoeba histolytica
  2. Trichomonas vaginalis
27
Q

Helicobacteria treatment regime?

A

Helicobacter pylori (Peptic ulcers)

-Metronidazole + Amoxicillini/Azythromycin + PPI (Lansoprazole) (For penicilli allergy)

28
Q

Metronidazole uses?

A

GAPH

  1. Helicobacter pylori (Peptic ulcers)
    -Metronidazole + Amoxicillini/Azythromycin + PPI (Lansoprazole) (For penicilli allergy)
  2. Giardiasis-a diarrheal disease
  3. Acute necrotising ulcerative gingivitis

4.Pseuedomembranous colitis

29
Q

Metronidazole MOA?

A

Production of reactive intermediates

Nitroradical anion (Bactericidal)

30
Q

Metronidazole S/E?

A
  1. Dry mouth
  2. Metallic taste
  3. CNS effects
  4. Disulfiram-like effects
31
Q

Metronidazole Disulfiram-like effects?

A

-Increased acetaldehyde levels

-Inhibits alcohol metabolism

All the above cause disulfiram side effects

32
Q

Metronidazole DI-5?

A
  1. Moderate CYP2C99 inhibitors-Warfarin
  2. Alcohol, Lithium (Increased plasma levels)
  3. Phenytoin

4.Cimetidine (CYP450 Inhibitor)

  1. Phenobarbitone (CYP450 Inducer)
33
Q

Metronidazole CI?

A
  1. Alcohol-inhibits metabolism of alcohol therefore cannot be taken with alcohol

(1st trimester of pregnancy & breastfeeding)

  1. CNS Conditions
34
Q

Nitrofurantoin I?

A

Treatment of uncomplicated lower. urinary tract infetions

35
Q

Nitrofurantoin CI?

A

-Renal impairment
-G6PD deficiency
-Known hypersensitivity
-Porphyria
-Paediatrics infants >3 months
-Pregnancy(neonatal haemolytic anaemia
-Lactation

36
Q

Nitrofurantoin DI-4?

A

-Neurotoxic agents: increased potential for neurotoxicity with concurrent use

-Probenecid and sulfinpyrazone: Urinary excretion of nitrofurantoin reduced, efficacy reduced and risk of toxicity increased

-Quinolone antibacterials:Antagonist in vitro antimicrobial action affected

Magnesium trisilicate: Reduced absorption nitrofurantoin

37
Q

Nitrofurantoin S/E?

A

GIT: Anorexia, nausea, vomiting

Respiratory involvement:
-Tachycardia

CNS: Headache, dizziness

38
Q

Mechanisms of inhibition of DNA synthesis-5?

A
  1. Via the inhibition of nucleotide synthesis
  2. By altering the base-pairing characteristics of the template
  3. DNA or RNA polimerse inhibition
  4. Topoismerase II(DNA gyrus) AND 4 inhibition
39
Q

Ciprofloxacin absorption?

A

Absorbed rapidly( 7-80%)

40
Q

Ciprofloxacin DI with Theophylline?

A

Ciprofloxacin inhibits the cytochrome P450 enzyme system

Theophylline toxicity-asthma patient

41
Q

Metronidazole mechanism of resistance -4?

A
  1. Decreased uptake
  2. Increased removal
    3.Decreased activation in bacteria
  3. Altered enzymes that convert active metronidazole