Nucleic Acid Synthesis

Question 1

Nucleic Acid Synthesis Inhibitors drugs?

Answer 1

1. Fluroquinolones
2. Metronidazole

Question 2

Nucleic Acid Synthesis Inhibitors drugs Function?

Answer 2

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

Question 3

Fluoroquinolones

1. Adjunct admission and substantiation
2. MOA
3. MOA for bacteria

Answer 3

1. Take on an empty stomach to increase absorption
2. Inhibit topoisomerase 2 and topoiosmerase 4
3. Bacteriosidal(kill bacteria)

Question 4

Fluoroquinolones absorption impaired by?

Answer 4

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

Question 5

What is another name for topoisomerase?

Answer 5

DNA gyrase

Question 6

Fluoroquinolones and pH or urine?

Answer 6

Fluoroquinolones are acidic

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

Question 7

Fluoroquinolones suffix?

Answer 7

-“-floxacin”

Question 8

Fluoroquinolones drugs?

Answer 8

COMGL–floxacin

Ciprofloxacin
Ofloxacin
Moxifloxacin
Gemifloxacin
Levofloxacin

Question 9

Ciprofloxacin & Ofloxacin

1. Gram
2. CYP450

Answer 9

1. Gram-negative aerobes only
2. CYP450 Inhibitor

Question 10

Ciprofloxacin & Ofloxacin

1. Indications & Prophylaxis
2. Non-indication

Answer 10

1. Typhoid fever, cystitis, mycobacteria , lower resp tract infections and Nienongococcal prophylaxis
2. Not for gonorrhea

Question 11

Fluoroquinolones CYP450?

Answer 11

CYP450 Inhibtor

Question 12

Fluoroquinolone CYP450 and different intensities?

Answer 12

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

Question 13

Moxifloxacin, Gemifloxacin and Levofloxacin

1. Gram bacteria
2. CYP450
3. Indications + for TB
4. Usuage for pseudomonas
5. B-lactam allergy

Answer 13

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

Question 14

Nalidixic acid and quinolones?

Answer 14

Nalidixic acid is used to form quinolones

Question 15

Nalidixic acid and gram bacteria?

Answer 15

Gram -ve bacteria

Question 16

Nalidixic acid indications?

Answer 16

-Acute and chronic lower urinary tract infections

Question 17

Nalidixic acid mother substance?

Answer 17

Quinolone is the mother substance

Question 18

Nalidixic acid and quinolone resistance?

Answer 18

Can cause quinolone resistance if not used for a long time

Question 19

Nalidixic acid S/E?

Answer 19

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

Question 20

Nalidixic acid resistance(2) ?

Answer 20

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

Question 21

Fluoroquinolones resistant organisms?

Answer 21

SPS

-Staphylococci
-Psedomonas
-Serratia

Question 22

Fluoroquinolones S/E-7?

Answer 22

H2PQ SAT

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

Question 23

Fluoroquinolones DI-5?

Answer 23

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)

Question 24

Fluoroquinolones CI(6) ?

Answer 24

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

Question 25

Metronidazole 1. Incidence of resistance 2. Type of bacteria 3. Admission 4. CSF

Answer 25

1. Decreased incidence of resistance 2. Anaerobic bacteria 3. Orally, IV, rectal & topical 4. Metronidazole can enter the CSF

Question 26

Metronidazole antiprotozoal action?

Answer 26

Trophozoites of: 1. Entamoeba histolytica 2. Trichomonas vaginalis

Question 27

Helicobacteria treatment regime?

Answer 27

Helicobacter pylori (Peptic ulcers) -Metronidazole + Amoxicillini/Azythromycin + PPI (Lansoprazole) (For penicilli allergy)

Question 28

Metronidazole uses?

Answer 28

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

Question 29

Metronidazole MOA?

Answer 29

Production of reactive intermediates Nitroradical anion (Bactericidal)

Question 30

Metronidazole S/E?

Answer 30

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

Question 31

Metronidazole Disulfiram-like effects?

Answer 31

-Increased acetaldehyde levels -Inhibits alcohol metabolism All the above cause disulfiram side effects

Question 32

Metronidazole DI-5?

Answer 32

1. Moderate CYP2C99 inhibitors-Warfarin 2. Alcohol, Lithium (Increased plasma levels) 3. Phenytoin 4.Cimetidine (CYP450 Inhibitor) 5. Phenobarbitone (CYP450 Inducer)

Question 33

Metronidazole CI?

Answer 33

1. Alcohol-inhibits metabolism of alcohol therefore cannot be taken with alcohol (1st trimester of pregnancy & breastfeeding) 2. CNS Conditions

Question 34

Nitrofurantoin I?

Answer 34

Treatment of uncomplicated lower. urinary tract infetions

Question 35

Nitrofurantoin CI?

Answer 35

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

Question 36

Nitrofurantoin DI-4?

Answer 36

-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

Question 37

Nitrofurantoin S/E?

Answer 37

GIT: Anorexia, nausea, vomiting Respiratory involvement: -Tachycardia CNS: Headache, dizziness

Question 38

Mechanisms of inhibition of DNA synthesis-5?

Answer 38

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

Question 39

Ciprofloxacin absorption?

Answer 39

Absorbed rapidly( 7-80%)

Question 40

Ciprofloxacin DI with Theophylline?

Answer 40

Ciprofloxacin inhibits the cytochrome P450 enzyme system Theophylline toxicity-asthma patient

Question 41

Metronidazole mechanism of resistance -4?

Answer 41

1. Decreased uptake 2. Increased removal 3.Decreased activation in bacteria 4. Altered enzymes that convert active metronidazole