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USMLE Step 1 Pharmacology

Subjects : health-sciences, usmle-step-1

Instructions:

Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
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This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Ethacrynic Acid - toxicity?
Spironolactone - Triamterene - Amiloride (the K+ STAys)
AV nodal cells
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
physostigmine

2. Resistance mechanisms for Aminoglycosides
Modification via Acetylation - Adenylation - or Phosphorylation
Suramin
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.
hypertension - CHF - diabetic renal disease

3. What patients are at risk for life threatening hypotension When taking Sildenafil (Viagra)?
Bacitracin - Vancomycin
Methicillin - Nafcillin - and Dicloxacillin
Rifampin (DOC) - minocycline
Those patients who are taking nitrates.

4. What are the major toxic side effects of the Cephalosporins?
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
Quinolones
local anesthetic. CNS stimulation or depression. CV depression.
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)

5. MOA: Disrupt fungal cell membranes
Amphotericin B - Nystatin - Fluconazole/azoles
AZT
Butyrophenone (neuroleptic).
Erythromycin - Azithromycin - Clarithromycin

6. List the mechanism - clinical use - & toxicity of Nitrosureas.
Beta - lactam antibiotics
Interstitial nephritis
- Alkalate DNA - Brain tumors - CNS toxicity
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma

7. How is Rifampin used clinically?
Nephrotoxicity
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
Interferes with microtubule function - disrupts mitosis - inhibits growth
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs

8. Hydralazine - class and mechanism?
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances

9. What is the MOA for Rifampin?
Binds to the Pyrophosphate Binding Site of the enzyme
Inhibits DNA dependent RNA polymerase
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
No

10. List the specific antidote for this toxin: Lead
prevention of nodal arrhythmias (SVT)
Due to the presence of a bulkier R group
- EDTA - dimercaprol - succimer - & penicillamine
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.

11. What is the MOA for the Tetracyclines?
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
- Daunorubicin & Doxorubicin
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
- Glucagon

12. MOA: Bactericidal antibiotics
DHPG (dihydroxy-2- propoxymethyl guanine)
Inhibition of 50S peptidyl transferase - Bacteriostatic
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole

13. What is the mechanism of action of the glucocorticoids?
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
Nitrates
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.

14. List the mechanism - clinical use - & toxicity of 6 MP.
- Shifts the curve to the right - increases Km
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
- N- acetylcystine
Alpha -1 antagonist

15. Beta Blockers - CNS toxicity?
sedation - sleep alterations
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
Carbenicillin - Piperacillin - and Ticarcillin
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

16. Which drug(s) cause this reaction: Fanconi's syndrome?
Minor hepatotoxicity - Drug interactions (activates P450)
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
- Tetracycline
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins

17. How is Griseofulvin used clinically?
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
Oral treatment of superficial infections
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis

18. Which of epi - norepi - or isoproterenol results in bradycardia?
Methylxanthine.
- Tamoxifen
Neutropenia
Norepinephrine

19. Common toxicities associated with Fluoroquinolones?
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
- Atropine & pralidoxime
GI upset - Superinfections - Skin rashes - Headache - Dizziness
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.

20. What is the mechanism of action of the Sulfonylureas?
Ganciclovir is more toxic to host enzymes
Binds ergosterol - Disrupts fungal membranes
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Choline acetyltransferase

21. Antiarrhythmic class IV- effects?
INH: Injures Neurons and Hepatocytes
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
- NaHCO3
decrease conduction velocity - increase ERP - increase PR interval

22. Which antimicrobial classes inhibit protein synthesis at the 30S subunit? (2)
GI disturbances.
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
RESPIre

23. Which drug(s) cause this reaction: Tubulointerstitial Nephritis (5)?
- Aminocaproic acid
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
1. In liver - increases storage of glucose as glycogen. 2. In muscle - stimulates glycogen and protein synthesis - and K+ uptake. 3. In adipose tissue - facilitates triglyceride storage.

24. List the specific antidote for this toxin: Benzodiazepines
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
- Chlorpromazine - thioridazine - haloperidol
- Flumazenil
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria

25. List the specific antidote for this toxin: Carbon monoxide
- Fluoroquinolones
Pentamidine
-100% oxygen - hyperbaric
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia

26. List the mechanism - clinical use - & toxicity of Paclitaxel.
check PFTs - LFTs - and TFTs
Ataxia - Dizziness - Slurred speech
Aplastic anemia (dose independent) - Gray Baby Syndrome
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.

27. What is a prerequisite for Acyclovir activation?
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Nitrates
It must be Phosphorylated by Viral Thymidine Kinase

28. What are three complications of Warfarin usage?
Protease inhibitor.
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Oral treatment of superficial infections
GI upset

29. How are the Latent Hypnozoite (Liver) forms of Malaria (P. vivax - P.ovale) treated?
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
Primaquine
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)

30. How is Acyclovir used clinically?
Blocks Influenza A and RubellA; causes problems with the cerebellA
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
- Methylene blue
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis

31. Is resistant to penicillinase?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
proximal convoluted tubule - thin descending limb - and collecting duct
Fast vs. Slow Acetylators
Imipenem

32. What is the category of drug names ending in - azepam (e.g. Diazepam)
Benzodiazepine.
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
first dose orthostatic hypotension - dizziness - headache
They inhibit reuptake of NE at the nerve terminal (as does cocaine).

33. What is the mechanism of action of Acetaminophen?
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
Polymyxin B - Polymyxin E
Hydralazine and Minoxidil

34. Which diuretics cause alkalosis?
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
loop diuretics - thiazides
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.

35. Adverse effects of Nifedipine - verapamil?
- Shifts the curve to the right - increases Km
Local anesthetic.
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
dizziness - flushing - constipation (verapamil) - nausea

36. How does NE modulate its own release? What other neurotransmitter has this same effect?
Dopamine
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
not a sulfonamide - but action is the same as furosemide
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.

37. How do you calculate maintenance dose?
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.

38. How is Ribavirin used clinically?
for RSV
all of them
loop diuretics - thiazides
Inhibit viral DNA polymerase

39. Why are Methicillin - Nafcillin - and Dicloxacillin penicillinase resistant?
prevention of nodal arrhythmias (SVT)
Due to the presence of a bulkier R group
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.

40. List the mechanism - clinical use - & toxicity of Vincristine.

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41. Ibutilide - toxicity?
Dopamine
Same as penicillin. Extended spectrum antibiotics
Protease Inhibitors and Reverse Transcriptase Inhibitors
torsade de pointes

42. K+ sparing diuretics - site of action?
amphetamine and ephedrine
Heparin catalyzes the activation of antithrombin III.
cortical collecting tubule
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs

43. Name the common Aminoglycosides (5)
- Oxalic acid - Acidosis & nephrotoxicity
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
It must be Phosphorylated by Viral Thymidine Kinase
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.

44. Which diuretics increase urine NaCl?
Epinephirine(Alpha1 -2 and Beta 1 -2)
all of them
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
- Haloperidol - chlorpromazine - reserpine - MPTP

45. What should not be taken with Tetracyclines? / Why?
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
Phosphorylation by a Viral Kinase
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut

46. MOA: Block protein synthesis at 30s subunit
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
Ganciclovir is more toxic to host enzymes
Aminoglycosides - Tetracyclines
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin

47. What is the most common cause of Pt noncompliance with Macrolides?
Ipratropium
carbonic anhydrase inhibitors - K+ sparing diuretics
GI discomfort
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.

48. Which cancer drugs inhibit nucleotide synthesis(3)?
- Physostigmine salicylate
Fast vs. Slow Acetylators
- Methotrexate - 5 FU - 6 mercaptopurine
- Disulfram & also sulfonylureas - metronidazole

49. ACE inhibitors - toxicity?
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
AZT - to reduce risk of Fetal Transmission

50. What are five possible toxic effects of Aspirin therapy?

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