Biochem- GOOD

Question 1

6MP, mycophenolate, and ribavirin have what in common?

Answer 1

All inhibit purine synthesis

Question 2

Drug that inhibits dihydroorotate dehydrogenase?
What is its most common use?
Purine or pyrimidines effected?

Answer 2

• Leflunomide inhibits dihydroorotate dehydrogenase/ orotic acid formation in the pyrimidine synthesis pathway.
• Most commonly used to treat RA.

Question 3

Drug that inhibits ribonucleotide Reductase?
What conditions are treated by this drug?
Purine or pyrimidines effected?

Answer 3

• Hydroxyurea inhibits ribonucleotide Reductase and therefore the synthesis of both purines/pyrimidines.
• Used in various cancers and SICKLE CELL.

Question 4

What is the mechanism of action for:

Methotrexate, trimethoprim, and pyrimethamine?

Answer 4

Inhibit Dihydrofolate Reductase and therefore PYRIMIDINE synthesis.

Question 5

Mechanism of action: 5FU

Answer 5

Inhibits thimidylate synthase & therefore pyrimidine synthesis

Question 6

Azathioprine is a prodrug for?
Do these drugs block the synthesis of PURINES or PYRIMIDINES?
Reaction blocked?

Answer 6

• azathioprine is a prodrug for 6MP

- both block PURINE synthesis (blocks PRPP –> IMP)

Question 7

Mycophenolate and ribavirin Inhibit what enzyme?

Answer 7

-Block inosine monophosphate (IMP) dehydrogenase;
(prevents IMP –> GMP)
-Prevent PURINE synthesis

Question 8

Leflunomide, Trimethoprim, methotrexate, and 5 FU have what in common?

Answer 8

All four inhibit DNA synthesis, specifically pyrimidine synthesis

Question 9

Two drugs that block xanthine oxidase?
Are they competitive or noncompetitive inhibitors?
What pathway do these drugs effect and what is one genetic condition they may treat?

Answer 9

• Allopurinol and febuxostat block XO competitively.
• Work on the purine salvage path to prevent hypoxanthine –> xanthine –> Uric acid.
• Important treatment in lesch nyhan (HGRPT mutation)

Question 10

What are three drugs that work on topoisomerase?

For each drug: is prokaryotic or eukaryotic topoisomerase targeted?

Answer 10

FQs: prokaryotic topo 2 & 4
Etoposide/teniposide: eukaryotic topo 2
Irinotecan/topotecan: eukaryotic topo 1

Question 11

Drugs that inhibit:
Prokaryotic RNA Pol
Eukaryotic AND prokaryotic RNA Pol

Answer 11

Prokaryotic: (R)ifampin blocks (R)NAP

Euk & Pro: Actinomyces D

Question 12

TCN effects which ribosomal subunit?

Chloramphenicol?

Answer 12

TCN: 30s
Chloramphenicol: 50s

(Prokaryotic)

Question 13

Drugs that inhibit microtubules: (6)

Answer 13

Microtubules Get Constructed Very Very poorly
Mebendazole
Griseofulvin
Colchicine
Vincristine
Vinblastine
Paclitaxel (“taxes stabilize society”= stabilize microtubles)

Question 14

Vitamin A (retinol) can be used to treat what conditions? (3)

Answer 14

Acne (decreases sebaceous glands formation)
APL- M3 type (Auer Rods) = t(15,17)
Wrinkles

(i’m pretty sure measles and psoriasis too)

Question 15

What must be done before starting a patient on retinoid therapy?

Answer 15

2 negative pregnancy tests. 2 forms of contraception.

Highly teratogenic. (Cleft lip/palate and cardiotox.)

Question 16

Treatment for Wernickes Korsakoff

Answer 16

B1 and THEN glucose

Question 17

N-acetyl cysteine is used to treat what 3 conditions?

Answer 17

‘N’-‘A’cetyl’C’ysteine

1. Nephropathy (from contrast)
2. Acetaminophen OD
3. CF (mucolytic)

Question 18

CF treatments

*just read this. Don’t freak out about memorizing.

Answer 18

Albuterol, abx (azithro), pancreatic enzymes, dornase alpha (DNAase), hypertonic saline.

Question 19

Niacin:

Use and 3 relevant ADRs

Answer 19

Dislipidemia

• flushing (“VANCE refrigerators”)
• ^^glucose
• ^^uric acid (“Painful Tophi and Feet Need Care”)

(Imagine that this is rarely useful since most with Hyperlipidemia also are diabetic/prediabetic?)

Question 20

Drug that causes low B6

Answer 20

Isoniazid– give with pyridoxine

Question 21

Vitamin C is used as a drug in the treatment of what condition?

Answer 21

Methemoglobinemia, converts Fe 3+ –> Fe 2+

Question 22

Vitamin E may have the same effect as what drug?

What is this drug’s MOA?

Answer 22

Warfarin! Both vitamin E and warfarin inhibit vitamin K, which is required for synthesis of clotting factors 2,7,9,10

Question 23

Vitamin K is used for the treatment of? (2)

Answer 23

• ^^warfarin (toxic dose)

- Neonatal hemorrhage (neonates have sterile intestines, no bacteria present to make Vit K = hemorrhage)

Question 24

Fomepizole:
MOA and use?
Site of action?

Answer 24

Inhibits alcohol dehydrogenase in the cytosol

Used to treat methanol/ethylene glycol poisoning

Question 25

Disulfiram:
MOA/location of action
Use?
Another drug that may be used to treat the same condition?

Answer 25

• Inhibits acetaldehyde dehydrogenase in the mitochondria
• Treats alcoholism
• Naltrexone (opioid antagonist) can also treat alcoholism.

Question 26

Inhibitors of: 
ETC complex 1 
complex 3
complex 4 
complex 5/ATP Synthase

Answer 26

RotenONE blocks One
Antimycin (an3mycin) blocks 3
CO/CN block 4 (4 letters)
Oligomycin blocks 5

Question 27

Three “uncouplers” + what are their effects?

Answer 27

2,4 dinitrophenol (weight loss)
Aspirin
Thermogenin
Cause decreased ATP production but normal O2 consumption = heat!

Aspirin OD = fever; brown fat= warmth

Question 28

Lys/leu can be used to treat what metabolic condition?

Answer 28

Pyruvate dehydrogenase deficiency

Question 29

Lactulose:

MOA & use

Answer 29

Acidifies GI tract, allows for ^^ ammonia excretion in cars of hyperammonemia

Question 30

Rifaximin: MOA and use

Answer 30

Decreases colonic ammoniagenic bacteria; useful in hyperammonemia

Question 31

Three drugs that bind ammonia and increase its excretion

Answer 31

• benzoate
• phenylacetate
• phenylbutyrate

Question 32

What step of catecholamine synthesis is blocked by carbidopa?

Answer 32

Dopa –> dopamine
(DOPA Decarboxylase- requires B6)
*Parkinsons Tx

Question 33

Statins inhibit what step of cholesterol synthesis?

Competitive or noncompetitive?

Answer 33

HMG CoA –> mevalonate
(RLS)
Competitively inhibit HMG CoA Red.