Walters

Question 1

How do Bacteristatic antibiotics kill bacteria?

Answer 1

do not directly kill bacteria. Instead, they inhibit metabolic pathways thus weakening the organisms and then relying on the patient’s immune system to clear the infection.

Question 2

How do Bactericidal antibiotics kill bacteria?

Answer 2

Mostly by causing lysis.

Question 3

Name factors to consider when choosing an antibiotic.

Answer 3

Age, Hepatic function, Pregnancy, Disease condition, Genetics, Resistance, Route of administration, and Site of infection

Question 4

Explain a) Acetylation.

Answer 4

Acetylation is one route of drug metabolism. Asians are fast acetylators.

Question 5

Low levels of Glucose-6-phosphate dehydrogenase (G6PD) can cause pts to be at risk for what?

Answer 5

Sulfonamides, nitrofurantoin & chloramphenicol have a greater risk of causing hemolysis if low levels of G6PD.
(G6PD protects cells from free radicals.)

Question 6

Sulfonamides are structurally similar to which drugs?

Answer 6

Sulfonamides are structurally similar to sulfonoureas, which stimulate the release of insulin and can cause hypoglycemia.

Question 7

Tetracyclines

Answer 7

• readily cross the placenta, secreted in breast milk.
• They deposit in teeth and bone where they chelate with calcium phosphate causing a permanent brown discoloration of teeth
• Can slow bone growth

Question 8

Why are Fluoroquinolones not used in prepubertal kids?

Answer 8

Because they cause cartilage damage and arthropathy and are, therefore, not used in prepubertal kids.

Question 9

T/F: In older patients, penicillins can cause neurotoxicity due to reduced renal function.

Answer 9

True.

Question 10

What is kernicterus?

Answer 10

kernicterus is a form of jundice. In neonatas, Sulfamides can increase the amount of free bilirubin which readily crosses the blood brain barrier and deposits in neonatal basal ganglia and other areas causing generalized CNS depression —> kernicterus.

Question 11

T/F : Aminoglycosides should not be given to pregnant women because they are nephrotoxic and ototoxic.

Answer 11

True

Question 12

What is the rationale for multiple Rx therapy?

Answer 12

• ↓ Risk selecting for resistant organisms
• Multiple organism infections not covered by a single Rx
• Synergism (two drugs producing an effect that is greater than the sum of either drug alone).

Question 13

Describe the mechanisms of sulfonmides.

Answer 13

Sulfonoamides inhibit dihydropteropate synthase, the first step in the synthesis of folic acid. i.e. the joining of PABA with pteridine to form dihydropteroic acid, the immediate precursor of folic acid.

Question 14

True or False. SULFAS are generally used with a DHFR INHIBITOR (DHFRI) for a synergistic effect

Answer 14

True

Question 15

Name four DHFRIs (dihydrofolate reductase Inhibitors).

Answer 15

1- TRIMETHOPRIM– inhibits bacterial DHFR. Side effects: blood dyscrasias
2- PYRIMETHAMINE– antimalarial – inhibits protozoal DHFR
3- METHOTREXATE – inhibits mammalian, bacterial & protozoal DHFR. Used to treat psoriasis and various cancers.
4- PRALATREXATE – for T cell lymphomas

Question 16

Name there oral ORAL SULFONAMIDES.

Answer 16

SULFISOXAZOLE, SULFAMETHOXAZOLE, DAPSONE

Question 17

Name 3 topical sulfonamides & their uses.

Answer 17

1. SULFACETAMIDE : for Ulcerative blepharitis or bacterial conjuntivitis
2. SILVER SULFADIAZINE :for burns to prevent sepsis
3. MAFENIDE : for burns. Use limited – can cause metabolic acidosis by inhibiting carbonic anhydrase -> loss of HCO3- & thus loss of buffering capacity.

Question 18

Name 5 general side effects of sulfonamides.

Answer 18

Crystalluria, Kernicterus, Blood dyscrasias, Hyperkalemia, and Hypersensitivity.

Question 19

FLUOROQUINOLONES

Answer 19

Broad spectrum CIDAL agents used mostly for G- & some G

Question 20

Which enzymes do Fluroquinolones inhibit in G- and G+ bacteria?

Answer 20

Fluroquinolones inhibit DNA gyrase in G- and
topoisomerase V in G+.
*both pathways are active in both gram + and -. These inhibitions are the main forms.