STEP 1 Uworld Drugs Part 2

Question 1

Nitroprusside

Answer 1

IV vasodilator (arteriolar and venous) used for rapid BP control in hypertensive emergency. Metabolized to nitric oxide and cyanide ions (toxic)

Question 2

Mesna

Answer 2

sulfhydryl that binds and inactivates toxic acrolein in urine from nitrogen-mustard based chemotherapy –> prevents hemorrhagic cystitis

Question 3

Phenytoin

Answer 3

long acting anticonvulsant –> reduce ability of sodium channels to recover from inactivation –> decrease neuronal high frequency firing (administered with lorazepam for status epilepticus)

Question 4

Clindamycin

Answer 4

Binds 50s ribosomal sub-unit in bacteria and disrupts protein synthesis - acting against oral anaerobes and aerobic gram (+),

Question 5

BosENtan

Answer 5

competitively antagonizes ENdothelin-1 receptors –> decreases pulmonary vascular resistance

Question 6

Naloxone

Answer 6

pure opioid receptor antagonist, greatest affinity for he mu receptor, competes with narcotics and displaces them form opioid receptors (though binds mu, kappa, and delta)

Question 7

Anastrozole

Answer 7

aromatase inhibitor, decreases the synthesis of estrogen from androgens

Question 8

Phencyclidine (PCP)

Answer 8

primarily a N-methyl-D-aspartate (NMDA) receptor antagonist (also does inhibit some re-uptake of biogenic amines). Causes psychosis, hallucinations, violent trauma, ataxia, and horizontal nystagmus.

Question 9

Cyproheptadine

Answer 9

first generation histamine antagonist with nonspecific 5-HT1 and 5-HT2 receptor antagonistic properties, may treat serotonin syndrome

Question 10

Enoxaparin

Answer 10

low molecular weight heparin (LMWH) that binds and activates antithrombin III (AT III). Activated AT III binds and inhibits factor Xa (no conversion of prothrombin to thrombin).

Question 11

Caspofungin

Answer 11

Echinocadin anti-fungal that blocks glucan synthesis inhibiting cell wall synthesis.

Question 12

Benztropine

Answer 12

centrally acting antimuscarinic agent, often used in drug induced parkinsonionism if the antipsychotic cannot be reduced (In such a situation, levodopa should not be used as it can precipitate psychosis)

Question 13

6-Mercaptopurine

Answer 13

cytotoxic purine analog that inhibits de-novo purine synthesis. It is activated by hypoxanthine-guanic phosphoribosyl transferase (HGPRT) and inactivated by xanthine oxidase (XO) and thiopurine methyltransferase (TPMT)

Question 14

Mifepristone

Answer 14

progesterone antagonist –> necrosis of uterine decidua –> pregnancy termination

Question 15

Diphenoxylate

Answer 15

Opioid anti-diarrheal drug that binds mu opiate receptors in the gut to slow motility (combine with atropine to discourage abuse)

Question 16

Valproate

Answer 16

anticonvulsant and mood stabilizer, blocks voltage-gated sodium channels and enhances GABA synthesis and release (tx: bipolar, absence, myoclonic, generalized tonic-clonic seizures)

Question 17

Argatroban

Answer 17

direct thrombin inhibitor (Tx: heparin-induced thrombocytopenia)

Question 18

Fibrates (gemfibrozil, tenofibrate)

Answer 18

activates peroxisome proliferator-activated receptor alpha (PPAR-a) which decreases hepatic VLDL production and increases LPL activity

Question 19

Omega-3 fatty acids

Answer 19

lower triglycerides by decreasing production of VLDL and apolipoprotein B

Question 20

Digoxin

Answer 20

slows ventricular rate during AF by increasing parasympathetic vagal tone which leads to inhibition of AV nodal conduction (occurs via inhibition of Na/K ATPase pump)

Question 21

Terbinafine

Answer 21

inhibits synthesis of fungal membrane ergosterol by inhibiting squalene epoxidase

Question 22

Abciximab

Answer 22

GP IIb/IIIa receptor antagonist that inhibits binding of this receptor to fibrinogen

Question 23

Ribavirin

Answer 23

nucleoside antimetabolite drug that interferes with duplication of viral genetic material (tx: hepatitis C and RSV)

Question 24

Thiazolinediones

Answer 24

bind peroxisome proliferator-activated receptor-gamma (PPAR-y) which forms a heterodimer complex with the retinoid X receptor –> transcriptional regulation of genes for lipid and glucose metabolism

Question 25

Bosentan

Answer 25

endothelin-receptor competitive antagonist –> blocks endothelin (a vasoconstrictor and stimulates endothelial proliferation) –> lowers pulmonary arterial pressure (tx: idiopathic PAH)

Question 26

Dobutamine

Answer 26

B-adrenergic agonist (B1 > B2 > a1) –> Gs –> increases cAMP. Positive ionotropic effect and positive chronotropic effect.

Question 27

Olanzapine

Answer 27

second generation antipsychotic that blocks dopamine receptors in the CNS, blocks seretonin receptors 5-HT 2A, blocks H1 histamine receptors, and blocks a-1 receptors

Question 28

Tamoxifen

Answer 28

selective estrogen receptor modulator (SERM) - competitive inhibitor of estrogen binding, mixed agonist/antagonist action (however, it has a stimulator effect at endometrial tissue –> risk of endometrial hyperplasia and cancer)

Question 29

Gabapentin

Answer 29

anticonvulsant that inhibits presynaptic voltage-gated calcium channels which inhibits fusion and release of neurotransmitter vesicles

Question 30

Cilostazol

Answer 30

phosphodiesterase inhibitor that inhibits platelet aggregation and acts as a direct arterial vasodilator