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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. What is the MOA of the RT Inhibitors?
CMV - esp in Immunocompromised patients
post MI and digitalis induced arrhythmias
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA

2. What are toxicities associated with Chloramphenicol?
Give an antichloinesterase - neostigmine - edrophonium - etc
Erythromycin - Azithromycin - Clarithromycin
Pyridoxine (B6) administration
Aplastic anemia (dose independent) - Gray Baby Syndrome

3. What are two Glitazones?
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
1. Pioglitazone 2. Rosiglitazone.
Indomethacin is used to close a patent ductus arteriosus.
Interferes with microtubule function - disrupts mitosis - inhibits growth

4. What is the category of drug names ending in - oxin (e.g. Digoxin)
Cardiac glycoside (inotropic agent).
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
effective in torsade de pointes and digoxin toxicity

5. When is Rifampin not used in combination with other drugs?
INH: Injures Neurons and Hepatocytes
Prophylaxis for Influenza A - Rubella; Parkinson's disease
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
anticholinesterase glaucoma

6. Why would you use pralidoxime after exposure to an organophosphate?
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
- Quinidine - quinine
Aminoglycosides - Tetracyclines
Pralidoxime regenerates active cholinesterase.

7. What is the memory key for the effect of magnesium hydroxide overuse?
Inhibits Viral DNA polymerase
thiazides - amiloride
Decreases synthesis of Mycolic Acid
Mg = Must go to the bathroom.

8. What is action of insulin in the liver - in muscle - and in adipose tissue?
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
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.

9. What side effect of using atropine to induce pupillary dilation would you expect?
TMP- SMZ
Aluminum sucrose sulfate polymerizes in the acid environment of the stomach and selectively binds necrotic peptic ulcer tissue. Acts as a barrier to acid - pepsin - and bile.
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
TMP- SMZ (DOC) - aerosolized pentamidine

10. Which drug(s) cause this reaction: Stevens - Johnson syn. (3)?
- Ethosuxamide - sulfonamides - lamotrigine
thick ascending limb
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
Sildenafil fills the penis

11. How are the HIV drugs used clinically?

12. What is the mechanism of action of Warfarin (Coumadin)?
Inhibit Ergosterol synthesis
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
Because they require some residual islet function.
Warfarin interferes with the normal synthesis and gamma - carboxylation of vitamin K- dependent clotting factors II - VII - IX - and X - Protein C and S via vitamin K antagonism.

13. Esmolol - short or long acting?
very short acting
Fast vs. Slow Acetylators
-100% oxygen - hyperbaric
check PFTs - LFTs - and TFTs

14. Antiarrhythmic class IC- effects?
Foscarnet = pyroFosphate analog
Benzodiazepine.
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species

15. Mannitol - mechanism?
Digitoxin>95% Digoxin 75%
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
1. Antipyretic 2. Analgesic 3. Anti - inflammatory

16. What are three clinical uses of the NSAIDs?
Vd= (Amt. of drug in body/ Plasma drug conc.)
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
Decreases synthesis of Mycolic Acid
1. Antipyretic 2. Analgesic 3. Anti - inflammatory

17. What do you treat Nematode/roundworm (pinworm - whipworm) infections with?
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Mebendazole/Thiabendazole - Pyrantel Pamoate
proximal convoluted tubule - thin descending limb - and collecting duct
ARF - shock - drug overdose - decrease intracranial/intraocular pressure

18. What are toxic side effects for Metronidazole?
Binds ergosterol - Disrupts fungal membranes
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Disulfiram - like reaction with EtOH - Headache

19. Which cancer drugs work at the level of proteins(2)?
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
Liver
proximal convoluted tubule
- Vinca alkaloids(inhibit MT) - Paclitaxel

20. What is the MOA of Imipenem?
check PFTs - LFTs - and TFTs
Nitrates
Acts as a wide spectrum carbapenem
prevention of nodal arrhythmias (SVT)

21. Which of these three drugs will cause a reflex bradycardia in your pt (Norepi - Epi - or Isoporterenol)
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
- Formaldehyde & formic acid - severe acidosis & retinal damage
Norepinephrine
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole

22. What is the clinical use of Tacrolimus (FK506)?
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Potent immunosuppressive used in organ transplant recipients.
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
Inhibits reabsorption of uric acid.

23. What are three toxicities of Propylthiouracil?
Ca2+ (Loops Lose calcium)
Phenothiazine (neuroleptic - antiemetic).
Dopamine; causes its release from intact nerve terminals
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia

24. Which drug(s) cause this reaction: Cinchonism (2)?
Inhibit Ergosterol synthesis
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
- Quinidine - quinine

25. What beta 2 agonist will help your 21yo Astma pt?
Pralidoxime regenerates active cholinesterase.
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
local anesthetic. CNS stimulation or depression. CV depression.
Albuterol - tertbutaline

26. Adverse effects of Guanethidine?
Antileukotriene; blocks synthesis by lipoxygenase.
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
DHPG (dihydroxy-2- propoxymethyl guanine)

27. How is Foscarnet used clinically?
CMV Retinitis in IC pts When Ganciclovir fails
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
- N- acetylcystine
all of them

28. Adverse effects of Minoxidil?
Beta - lactamase cleavage of Beta - lactam ring
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
Protamine sulfate
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention

29. For Heparin What is the Duration of action
all of them
TMP- SMZ (DOC) - aerosolized pentamidine
DOC in diagnosing and abolishing AV nodal arrhythmias
Acute (hours)

30. What is combination TMP- SMZ used to treat?
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.

31. Name some common Sulfonamides (4)
Succinylcholine
Cilastatin
sedation - depression - nasal stuffiness - diarrhea
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine

32. What is the clinical use for Nystatin?
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
Topical and Oral - for Oral Candidiasis (Thrush)
Same as penicillin. Act as narrow spectrum antibiotics

33. What sympathomimetic would you not prescribe for hypotension in a pt with renal artery sclerosis.
Hypersensitivity reactions
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
Norepinephrine (Alpha1 -2 and beta 1)
Neurotoxicity - Acute renal tubular necrosis

34. What are the products and their toxicities of the metabolism of ethanol by / alcohol dehydrogenase?
Decreases synthesis of Mycolic Acid
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Succinylcholine
- Acetaldehyde - Nausea - vomiting - headache - & hypotension

35. What is a possible toxicity of Alpha - glucosidase inhibitors used in type -2 diabetes?
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
Inhibits Viral DNA polymerase
first dose orthostatic hypotension - dizziness - headache
GI disturbances.

36. What is the category of drug names ending in - operidol (e.g. Haloperidol)
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Butyrophenone (neuroleptic).
Benzathine penicillin G

37. Which drug(s) cause this reaction: Fanconi's syndrome?
- Ethanol - dialysis - & fomepizole
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
- Tetracycline
Inhibit Ergosterol synthesis

38. What is a common drug interaction associated with Griseofulvin?
Increases coumadin metabolism
- Hydralazine - Procainamide - INH - phenytoin
Carbachol - pilocarpine - physostigmine - echothiophate
Rifampin (DOC) - minocycline

39. What is the only depolarizing neuromuscular blocking agent?
- Chlorpromazine - thioridazine - haloperidol
Succinylcholine
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
Chronic Hepatitis A and B - Kaposi's Sarcoma

40. Name three Antiarrhythmic drugs in class IV.
Verapamil - Diltiazem - Bepridil
Chronic gout.
propanolol - esmolol - metoprolol - atenolol - timolol
Selectively inhibit cyclooxygenase (COX) isoform 2 - Which is found in inflammatory cells nad mediates inflammation and pain; spares COX-1 Which helps maintain the gastric mucosa.

41. How is Griseofulvin used clinically?
not a sulfonamide - but action is the same as furosemide
Pyridoxine (B6) administration
Oral treatment of superficial infections
aPTT (intrinsic pathway)

42. What is the mechanism of action of Cyclosporine?
Binds to cyclophilins (peptidyl proline cis - trans isomerase) - blocking the differentiation and activation of T cells mainly by inhibiting the production of IL-2 and its receptor.
Disulfiram - like reaction with EtOH - Headache
Erectile dysfunction.
cross - allergenic

43. What drugs target anticholinesterase
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
- Corticosteroids - heparin
Flecainide - Encainide - Propafenone
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.

44. For Heparin What is the Ability to inhibit coagulation in vitro
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
Chronic anticoagulation.
Yes
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.

45. Why would a patient with cog - wheel rigidity and a shuffling gait be given benztropine?
Neutropenia
Disulfiram - like reaction with EtOH - Headache
TMP- SMZ
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.

46. Cautions When using Amiodarone?
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Decreases synthesis of Mycolic Acid
check PFTs - LFTs - and TFTs

47. How do Sulfonamides act on bacteria?
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
Ganciclovir is more toxic to host enzymes
It affects beta receptors equally and is used in AV heart block (rare).
Yes - it does not cross the placenta.

48. What are Fluoroquinolones indicated for? (3)
- B51Naloxone / naltrexone (Narcan)
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Aminoglycosides - Tetracyclines

49. Ca2+ channel blockers - clinical use?
atropine - homatropine - tropicamide
Pretreat with antihistamines and a slow infusion rate
Acute gout.
hypertension - angina - arrhythmias

50. What are the nondepolarizing neuromuscular blocking drugs?
- Triggers apoptosis - CLL - Hodgkin's in MOPP - Cushing - like syndrome
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias