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Exam 1 Drugs DPPHuckT > Sulfanomides > Flashcards

Sulfanomides Flashcards

1
Q

Sulfanomides are absolutely selectively toxic, why?

A

they block organisms that synthesize folic acid and humans do not synthesize folic acid

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2
Q

what enzyme do sulfanomides block and reaction does this enzyme catalyze?

A

pteroate synthetase, this enzyme normally catalyzes the reaction of PABA+pteridine to become pteroic acid(folic acid)

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3
Q

what are the list of enzymes involved in the process of converting PABA+pteridine into Purines, Amino acids, and Thymidines?

A
  1. pteroate synthetase 2. Dihydrofolate synthetase 3. Dihydrofolate reductase
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4
Q

how is tetrahydrafolate and dihydrofolate formed?

A

it is the conversion from dihydrofolate to tetrahydrofolate via the dihydrofolate reductase

dihydrofolate is formed via the synthesis of pteroic acid(folic acid)+glutamic acid using dihydrofolate synthetase

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5
Q

what are the structural requirements for the sulfanomide molecule? List 5

A
  1. N4 must be a free amino group with no attachments
  2. The amino groups must be in the para position
  3. the only active ring structure allowed is the benzene ring. All others must be inactive.
  4. Substitutions on the benzene ring reduce its activity
  5. Substitutions are allowed on the N1 compound but it must be heterocyclic increasing the SO2’s electronegativity.
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6
Q

What are the three resistance mechanisms of sulfanomides?

A
  1. Decreased uptake of sulfonamide(which is the most common)
  2. Decrease the affinity for pteroate synthetase
  3. Increase the concentration of PABA to overcome the competitive inhibition of sulfonamides
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7
Q

List all of the representative sulfonamides?

A

Triple Sulfa: sulfadiazine, sulfamerazine, sulfamethazine

Sulfisoxazole

Sulfamethoxazole

Sulfacetamide

Silver Sulfadiazine

Sulfasalazine

Sulfadoxine+pyrimethamine

Sulfadiazine+pyrimethamine

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8
Q

prophylaxis of burn patients, little or no pain

A

silver sulfadiazine

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9
Q

how is sulfasalazine activated?

A

split by intestinal flora to yield 5-amino-salicylate and sulfapyridine

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10
Q

usually administered as fixed-ratio combination with trimethoprim

A

sulfamethoxazole

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11
Q

highest urine solubility, short acting, most commonly used single sulfa

A

sulfisoxazole

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12
Q

what is the upside with using triple sulfa

A

single dosage contianing equal amounts of sulfa; reduces indent of cystatturia

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13
Q

chloroquine-resistant falciparum malaria. High incidence of drematits

A

sulfadoxine+pyrimethamine

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14
Q

treatment of toxoplasmosis

A

sulfadiazine + pyrimithanine

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15
Q

which sulfanomide has the longest half-life

A

sulfadoxine-it treats chloroquin resistant plasmodium falciprum

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16
Q

What does our body do to sulfanomides and how does it affect its solubility?

A

N-Acetylates it however, it is not that much water soluble first with this. Our body also conjugates it with glucoronic acid

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17
Q

what are some of the adverse effects including the serious rare conditions of sulfonamides?

A

you can get drug allergy such as rashes, eosinophilia, drug fever

can get steven johnson’s syndrome

renal toxicity because of crystullaria(not being able to dissolve in water)

can also get displacement of bilirubin(deposits on axons and kills them) in a complication called kernicterus

drug interactions occur

if patient is G6PDH deficient they can get hemolytic anemia

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18
Q

what drug interaction does sulfanomides have?

A

with oral anticoagulants, uricosuric, and severe reactions with methotrexate

Displaces these drugs from albumin or decrease their clearance

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19
Q

trimethoprim is a competitive inhibitor of what?

A

dihydrofolate reductase

the enzyme that catalyzes the DHF to THF then eventually to purines, thymidines, and amino acids

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20
Q

Trimethoprim and sulfonamides have what type of effect? Also what should you avoid with trimethoprim?

A

Sulfonamides and trimethoprim are synergistic.

You should avoid giving pregnant women trimethoprim because of the need of folic acid between the child and the mother.

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21
Q

what are three advantages to this synergy between TMP-SMZ?

A

potency

increased spectrum

decreased resistance

22
Q

what are the therapeutic uses for Sulfonamides by theirselves

A

UTIs(mainly from e-coli)

Norcadiosis

Chlamydia Infection (trachomatis)

23
Q

what are the therapeutic uses for the synergist drugs TMP and SMZ and pyrimethamine

A

UTI

Respiratory and ear Infections (strep pneumonia and H influenzae)

Shigella and Salmonella

Pneumocystis jiroveci pneumonia

toxoplasmosis and plasmodial infections

24
Q

what are some of the structure features of fluoroquinolones

A
  1. Positions 2,3, 4 are inviolate
  2. The fluorine at position 6 confers resistance
  3. x=can be C or N
  4. if there is a halogen on positon 8 you get phototoxicity
  5. R7 is nitrogen containing saturated ring
25
Q

What are some of the resistant mechanisms against fluoroquinolones? 2 ways

A

Point mutation on the DNA gyrase

and actively pumping the drug out of the organism

26
Q

what organisms actively pump the fluoroquinolones out?

A

Mycobacterium, Staph aureus, Pseudomonas Arginosum

27
Q

Out of the fluoroquinolones, which one has non renal elimination and which one can penetrate the CSF

A

Moxifloxacin has non-renal elimination and levofloxacin is the only fluoroquinolone that can penetrate the CSF

28
Q

which fluoroquinolone has the longest half life and which has the shortest

A

Moxifloxacin has the longest at 10 hours. Ciprofloxacin is at 3-4 hours. Levofloxacin is at 5 hours.

29
Q

what are some of the adverse effects in taking fluoroquinolones?

A

GI effects(most common)

May have some CNS effects like dizziness, agitation and headache

May also have some rash (pruritis)

tendonitis

arthropathy(not sure yet only in animal models)

crystallurias

QT elongation

beware of drug interactions

30
Q

what happens with cystic fibrosis patients and fluoroquinolones?

A

Fluoroquinolones are used as a substitute for aminoglycosides in Cystic fibrosis patients who get a lot of pulmonary infections; the activity by the oral route is the advantage when treating chronic reinfections in cystic fibrosis

31
Q

what drug interaction causes tendonitis in patients taking fluoroquinolones

A

fluoroquinolones and corticosteroids

32
Q

fluoroquinolones cause crystalluria in what environment

A

in akaline pH

33
Q

which fluroquinolones cause QTc prolongation

A

Levo and moxi

34
Q

What are the three drug interactions that fluoroquinolones can have?

A

Do not mix with antacids because it reduces the oral absorption

can form chelates with magnesium, aluminum, iron and zinc which creates a large impermeable molecule

cipro and levo cause a reduced metabolism of warfarin and theophylline

35
Q

which types of fluoroquinolones can have a patient presentation with the person feeling agitated or excessive bleeding?

A

levofloxacin and ciprofloxacins interaction with warfarin and theolyphins

36
Q

list all the things that can reduce the absorption of fluoroquinolones

A

antacids

chelate forming

sulcrate which is the coating for the stomach(GI tract)

37
Q

what are fluoroquinolones treated against

A

UTIs caused by E.coli, pseudomonas aeruginosa, Proteus and K. pnuemonia

Prostatitis because it can penetrate the prostate tissue

STDs with N. gonorrhea

GI problems such as infection via sigella , and salmonella

Respiratory problems: #1 for community acquired pneumonia due to H. influenza

Used for multidrug resistant TB

used to treat bone infections because of its ability to penetrate

38
Q

which fluoroquinolone is useful to treat against penicillnase producing strep pneumoniae

A

trovafloxacin

39
Q

which fluoroquinolone can be used as prophylaxis for pulmonary anthrax

A

ciprofloxacin

40
Q

moxifloxacin is unique in that it has

A

non-renal elimination and it is used to treat against anaerobic bacteria

41
Q

describe the structure and what treatment methanamine is used against

A

it is used to treat UTI

42
Q

what is the active form of methamine and what are its disadvantages?

A

formaldehyde; it takes a long time to dissociate in water, takes 3 hours to reach 90% of its equilibrium, its pH dependent (prefers acid)

43
Q

what are the adverse effects of taking methenamine

A

GI symptoms

bladder irritation at high doses

contraindicated for hepatic insufficiency because of ammonia production

contraindicated for renal insufficiency because of crystalluria

drug interaction with formaldehyde and sulfas produce an insoluble product

44
Q

what is an improtant drug interaction that could cause adverse effects in usage of methenamine

A

with sulfas because the formaldehyde and sulfas produce an insoluble product

45
Q

Explain the structure and list 3 attributes of the UTI treatment drug nitrofurantoin

A
  1. bacteriostatic(ecoli UTi infections)
  2. Rapidly excreted
  3. Resistance rarely develops
46
Q

what are the adverse effects of nitrofurantoin

A

NVD

fever, chills, allergic pneumonitis(elderly)

Neurological: vertigo, headche, nystagmus

High dose-polyneuropathy of motor and sensory nerves

Hemolytic anemia in G-6-PDH deficient

Colors urine brown

47
Q

what do you use for the discomfort of UTIs and when do you use it?

A

Use it early and it is an analgesic

48
Q

what is the color of urine when the patient is taking nitrofurantoin vs phenazopyridine

A

Nitrofurantoin-brown

Phenazopyridine-orange red

49
Q

which UTI treatment can be used in pregnancy with no harm

A

fosfomycin

50
Q

what is the mechanism of action of fosfomycin and what is its structure?

A

Inhibitor of pyruval transferase which is important in the assembly of the muramic acid monomer of the peptidoglycan cell wall

Exam 1 Drugs DPPHuckT (8 decks)

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