Quiz 3 Drugs - Folate antagonists, Quinolones, UTI agents

Question 1

2 types of folate antagonist drugs

Answer 1

Sulfonamides and trimethoprim/pyrimethamine

Question 2

Sulfonamides MOA

Answer 2

Inhibit dihydrofolate synthesis (specifically dihydropteroate synthetase)

Question 3

Trimethoprim and pyrimethamine MOA

Answer 3

Inhibitors of folate reduction (inhibit dihydrofolate reductase)

Question 4

How do humans obtain folate?

Answer 4

Obtain reduced folate in diet
This is an example of selective toxicity for many drugs

Question 5

Sulfonamides compete with this for folate synthesis pathway

Answer 5

PABA (p-aminobenzoic acid)

Question 6

Sulfonamides are a ______ inhibitor of nucleic acid synthesis

Answer 6

Indirect

Question 7

Sulfonamides are a _______ inhibitor dihyropteroate synthase which prevents PABA incorporation into folic acid

Answer 7

Competitive

Question 8

Spectrum for sulfonamides

Answer 8

Broad spectrum
But resistance severely limits actual clinical spectrum

Question 9

4 adverse effects of sulfonamides

Answer 9

Crystal formation in urine
Blood problems (esp. with G6P dehydrogenase deficiency)
Hypersensitivity
Kernicterus in infants

Question 10

Glucose-6-P dehydrogenase deficiency is most commonly seen in people from this descent

Answer 10

Mediterranean and African origin

Question 11

Highest risk of acute hemolysis as a result of sulfonamide use is in patients with this

Answer 11

Genetic deficiency in RBC glucose-6-phosphate dehydrogenase (FAVism)

Question 12

Crystal formation in urine, blood problems, hypersensitivity, and kernicterus in infants are adverse effects of this

Answer 12

Sulfonamides

Question 13

Rare medical emergency affecting skin and mucous membranes that can be triggered by sulfonamides
Fever, malaise, erythema multiforme, ulceration of mucous membranes

Answer 13

Stevens-Johnson syndrome

Question 14

What is Stevens-Johnson syndrome?

Answer 14

Rare medical emergency affecting skin and mucous membranes that can be triggered by sulfonamides

Question 15

2 Adverse effects of trimethoprim and pyrimethamine

Answer 15

Skin rashes
Major bone marrow toxicity potential when used chronically but can be reduced with folic acid supplementation (Megaloblastic anemia, Leukopenia, Granulocytopenia)

Question 16

Skin rashes and bone marrow toxicity (megaloblastic anemia, leukopenia, granulocytopenia) are adverse effects to this

Answer 16

Trimethoprim and Pyrimethamine

Question 17

Bone marrow toxicity when trimethoprim and pyrimethamine are used chronically can be reduced with this

Answer 17

Folic acid supplementation

Question 18

Optimal ratio for Trimethoprim-Sulfamethoxazole combination therapy
Produce sequential blockage of folate synthesis; super additive drug interaction

Answer 18

20 parts Sulfa to 1 part Trimethoprim

Question 19

Spectrum of quinolones

Answer 19

Broad spectrum (block DNA synthesis and function)
Effective for gram negative rods in UTIs and GI infections, and some gram positive

Question 20

MOA of quinolones

Answer 20

Inhibit topoisomerase II (DNA gyrase) and IV

Question 21

Quinolones inhibition of this is the primary drug target in gram negative bacteria

Answer 21

DNA gyrase (topoisomerase II)

Question 22

Quinolones inhibition of this is the primary drug target in gram positive bacteria

Answer 22

Topoisomerase IV

Question 23

Quinolones inhibition of DNA gyrase (topoisomerase II) is the primary drug target for this type of bacteria

Answer 23

Gram negative

Question 24

Quinolones inhibition of topoisomerase IV is the primary drug target for this type of bacteria

Answer 24

Gram positive

Question 25

Drugs that chelates with some metals (e.g. antacids containing aluminum hydroxide or magnesium hydroxide: Maalox, Mylanta)

Answer 25

Quinolones

Question 26

Quinolones chelates with this

Answer 26

Some metals (e.g. antacids containing aluminum hydroxide or magnesium hydroxide: Maalox, Mylanta)

Question 27

4 Common problems with quinolone use

Answer 27

Nauseua, vomiting, diarrhea Nephrotoxicity Avoid use with antacids 3 C's

Question 28

Quinolones should avoid use with these

Answer 28

Antacids

Question 29

Drug that should avoid use with antacids

Answer 29

Quinolones

Question 30

3 C's of quinolones

Answer 30

Central nervous system (headaches, malaise, depression, psychosis, hallucinations) Cartilage (ruptured tendons, avoid use in pregnancy and children) Cardiac toxicity (QT prolongation)

Question 31

The 3 C's (central, cartilage, cardiac) describe the adverse effects of this drug

Answer 31

quinolones

Question 32

Quinolones black box (3)

Answer 32

Avoid use in myasthenia gravis Discontinue at first sign of tendon inflammation or pain Tendon rupture

Question 33

Tendon most vulnerable to rupture with quinolone use (all tendons are vulnerable)

Answer 33

Achilles tendon

Question 34

Tendon rupture can occur as early as _____ hours following first dose, and last ______ after last dose with quinolones

Answer 34

Early as 48 hours Last months after last dose

Question 35

Primary elimination of quinolones

Answer 35

Tubular secretion Blocked by probenecid resulting in longer durations of serum antibacterial action

Question 36

Tubular secretion of quinolones is blocked by this, resulting in longer durations of serum antibacterial action

Answer 36

Probenecid

Question 37

Tubular secretion of this drug is blocked by probenecid, resulting in longer durations of serum antibacterial action

Answer 37

Quinolones

Question 38

2 antiseptic agents used to treat UTIs

Answer 38

Nitrofurans Methenamine

Question 39

MOA of nitrofurans

Answer 39

Form reactive intermediates that damage nucleic acid Requires bacterial reduction enzymes (nitroreductases) for activation

Question 40

Nitrofurans require these for activation

Answer 40

Bacterial reduction enzymes (nitroreductases)

Question 41

This limits mammalian toxicity of nitrofurans

Answer 41

High biotransformation potential with rapid renal excretion keeps serum levels low

Question 42

Spectrum of nitrofurans

Answer 42

Mainly used as gram negative agent (narrow spectrum), but some important activity in gram positive (extended spectrum)

Question 43

This keeps serum levels of nitrofurans very low

Answer 43

First pass effect

Question 44

5 adverse effects of Nitrofurans

Answer 44

Nausea/vomiting Hypersensitivity Pulmonary reactions (acute pneumonia, interstitial fibrosis) Peripheral neuropathy Hemolytic anemia with RBC G6PD deficiency Avoid use in late pregnancy

Question 45

2 pulmonary reactions with nitrofurans

Answer 45

Acute pneumonia Interstitial fibrosis

Question 46

MOA of methenamine

Answer 46

Prodrug that is converted to formaldehyde in acid pH of 5.5 or less in urine, denaturing proteins and is toxic to most bacteria

Question 47

Methenamine is converted to this in acid pH of 5.5 or less in urine

Answer 47

Formaldehyde

Question 48

Spectrum of methenamine

Answer 48

Broad spectrum Is converted to formaldehyde, which is toxic to most bacteria

Question 49

Bacteria that alkalize urine and disrupt methenamine mechanism

Answer 49

Proteus bacteria

Question 50

Proteus bacteria disrupt methenamine mechanism by doing this

Answer 50

Alkalize urine

Question 51

Methenamine is often combined with this to optimize activity

Answer 51

Urine acidifier mandelic acid

Question 52

2 contraindications of methenamine

Answer 52

Elevated ammonia levels make this contraindicated in hepatic dysfunction patients Mandelic acid form contrainidicated in renal dysfunction patients to avoid acid crystallization

Question 53

Elevated ammonia levels (contraindicated in hepatic dysfunction patients) and mandelic acid form (contraindicated in renal dysfunction patients) are effects of this drug

Answer 53

Methenamine

Question 54

Urinary analgesic that alleviates symptoms of UTIs

Answer 54

Phenazopyridine (Azo)

Question 55

Phenazopyridine (Azo) is a minor metabolite of this

Answer 55

Acetaminophen

Question 56

This drug is a minor metabolite of acetaminophen

Answer 56

Phenazopyridine (Azo)

Question 57

Adverse effects of Phenazopyridine (Azo)

Answer 57

Body fluid discoloration Not to be used in renal failure

Question 58

Drug that inhibits dihydropteroate synthase, preventing PABA incorporation into folic acid

Answer 58

Sulfonamides

Question 59

Blood problems (acute hemolysis in G6PD deficiency), hypersensitivity and Stevens-Johnson syndrome, and kernicterus in infants are adverse effects of this drug

Answer 59

Sulfonamides

Question 60

Drugs that inhibit dihydrofolate reductase

Answer 60

Trimethoprim and Pyrimethamine

Question 61

Skin rashes and bone marrow toxicity (megaloblastic anemia, leukopenia, granulocytopenia) are adverse effects of this

Answer 61

Trimethoprim and Pyrimethamine

Question 62

Drugs that inhibit topoisomerase II (DNA gyrase) and IV

Answer 62

Quinolones

Question 63

Part of quinolones black box indicates use should be avoided in this

Answer 63

Myasthenia gravis

Question 64

Tendon rupture is a characteristic adverse effect / warning of this drug

Answer 64

quinolones

Question 65

Drug that forms reactive intermediates and damages nucleic acids

Answer 65

Nitrofurans

Question 66

Nausea/vomiting, hypersensitivity, pulmonary reactions (acute pneumonia, interstitial fibrosis), peripheral neuropathy, hemolytic anemia with RBC G6PD deficiency, and avoid use in late pregnancy are adverse effects of this

Answer 66

Nitrofurans