Antibacterials 6

Question 1

Clinical applications of trimethoprim

Answer 1

UTI’, bacterial prostatitis and vaginitis

Question 2

_____________ is an adverse effect of trimethoprim

Answer 2

Neural tube defects because it has antifolate effects (contraindicated in pregnancy)

Question 3

Cotrimoxazole is a combination of ___________ and ____________ and what does it affect?

Answer 3

Trimethoprim and sulfamethoxazole

Synergistic effect on sequential steps in the tetrahydrofolic acid synthesis

Question 4

Cotrimoxazole is the DOC for treating _________ but also can be used to treat _________ infections

Answer 4

Uncomplicated UTI’s

Opportunistic infections

Other: upper respiratory, ear and sinus infections

Question 5

What organisms does metronidazole have activity against?

Answer 5

Anaerobic bacteria;

It is antimicrobial, amebicide and antiprotozoal

Question 6

MOA of metronidazole

Answer 6

It’s nitro groups undergo reductive bioactivation by ferredoxin → forms cytotoxic groups that interfere with nucleic acid synthesis → damage DNA

Question 7

__________ (drug) causes DNA damage by cytotoxic products formed by _______

Answer 7

Metronidazole; ferredoxin which reduces the nitro group

Question 8

Clinical application of metronidazole

Answer 8

• pseudomembranous coliti s
• anaerobic or mix intra abdominal infections
• vaginitis
• brain abscesses
• h. Pylori eradication

Question 9

What is the route of elimination of metronidazole

Answer 9

Hepatic

Question 10

Adverse effects of metronidazole

Answer 10

• disulfiram like effect (like 2nd generation cephalosporins: cefamandole, cefotetan)
• headache, dark colored urine, metallic taste
• peripheral neuropathy
• GI irritation
• leukopenia, dizziness, ataxia
• usually not advised to be used in the 1st trimester (no solid evidence)

Question 11

Polymyxin B has activity against gram _________ bacteria

Answer 11

NEGATIVE;

Gram positive bacteria are resistant to polymyxin B

Question 12

Polymyxin acts as a _______________ and binds to an inactivates _________

Answer 12

Cationic detergent; ENDOtoxins (unique to gram negative bacteria)

Question 13

Polymyxin B is mainly used to treat _________

Answer 13

Infected superficial skin lesions so it is given topically

Question 14

If polymyxin B is given systemically it is extremely _______

Answer 14

Nephrotoxic

Question 15

What is the use of urinary antiseptics

Answer 15

Use is limited to prophylaxis and treatment because it concentrates in the urine but not systematically

Question 16

What kind of drug is nitrofurantoin and what is its MOA

Answer 16

Urinary antiseptic

Bacteria reduces the drug in the urine an dleads to reactive intermediates that damage bacterial DNA

Question 17

Adverse effects of nitrofurantoin

Answer 17

• anorexia, nausea and vomiting

- neuropathies, hemolytic anemia’s

Question 18

What kind of patients should NOT be given nitrofurantoin to treat a lower UTI?

Answer 18

• G6PD patients because one of the adverse effects is hemolytic anemia
• DO not give to newborns or pregnant women close to term (38 - 42 weeks) but can prescribe before 38 weeks
• patients with significant renal insufficiency

Question 19

Which one has better oral bioavailbitly: amoxicillin or ampicillin

Answer 19

Amoxicillin

Question 20

Oral cephalosporins: (3)

Answer 20

Cephalexin, cefaclor, cefixime

Question 21

What are the “big guns” used for life threatening infections

Answer 21

• vancomycin
• streptogramins
• ceftaroline

Question 22

Drugs that can treat multi drug resistant

Answer 22

• vanocymin
• daptomycin
• linozelid
• ceftaroline
• quinepristine (streptogramins)

Question 23

___________ is used for surgical prophylaxis

Answer 23

Cefazolin

Question 24

Anti staph penicillins are good against β lactamase producting bacteria.
What are the anti staph pencillins

Answer 24

• methicillin
• nafcillin
• dicloxacillin (ORAL ROUTE OF ADMINISTRATION)
• oxicillin

Question 25

Which drug families are effective against β lactamase producing bacteria?

Answer 25

• anti staph pencillins (mainly gram positive)
• carbapenems (both gram positive and negative)
• aztreonam (gram negative) which is a monobactam

Question 26

____________ is a β lactam drug that can safely given to pencillin allergic patients dealing with gram __________ infections due to its monocyclic structure

Answer 26

Aztreonam; GRAM NEGATIVE

Question 27

What drug would you give to a penicillin allergic patient dealing with a gram positive infection?

Answer 27

Macrolides, tetracyclines

Question 28

Drugs used for prophylaxis of meningitis

Answer 28

• ceftraixone
• ciprofloxacin
• rifampin