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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 Griseofulvin?
Oral
- Normalize K+ - Lidocaine - & Anti - dig Mab
Interferes with microtubule function - disrupts mitosis - inhibits growth
GI disturbances.

2. Adenosine - clinical use?
Rare.
cholestyramine - colestipol
Does not cross
DOC in diagnosing and abolishing AV nodal arrhythmias

3. Which of epi - norepi - or isoproterenol results in bradycardia?
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Norepinephrine
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
Penicillin.

4. What are three complications of Warfarin usage?
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
Stimulates beta adrenergic receptors
Chronic anticoagulation.
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions

5. How is Foscarnet used clinically?
CMV Retinitis in IC pts When Ganciclovir fails
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
post MI and digitalis induced arrhythmias
Epinephirine(Alpha1 -2 and Beta 1 -2)

6. What are two Alpha - glucosidase inhibitors?
Benzodiazepine.
Oral treatment of superficial infections
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
1. Acarbose 2. Miglitol

7. What is the mechanism of action of the glucocorticoids?
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
cortical collecting tubule
Pseudomembranous colitis (C. difficile) - fever - diarrhea
Those patients who are taking nitrates.

8. What are four thrombolytics?
YES
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.

9. How do Sulfonamides act on bacteria?
Dermatophytes (tinea - ringworm)
Gram + and Anerobes
- Protamine
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic

10. Which drug(s) cause this reaction: Tubulointerstitial Nephritis (5)?
Small lipid - soluble molecule
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
Gram + cocci - Gram - rods - and Anerobes
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)

11. What anticholinesterase crosses the blood - brain - barrier?
Beta lactams - inhibit cell wall synthesis - Bactericidal
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
physostigmine
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.

12. Name three Antiarrhythmic drugs in class IV.
Verapamil - Diltiazem - Bepridil
Babiturate.
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia

13. What are the Anti - TB drugs?
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.

14. List the mechanism - clinical use - & toxicity of Methotrexate.
Rapid (seconds)
Binds ergosterol - Disrupts fungal membranes
1. Buffalo hump 2. Moon facies 3. Truncal obesity 4. Muscle wasting 5. Thin skin 6. Easy bruisability 7. Osteoporosis 8. Adrenocortical atrophy 9. Peptic ulcers
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression

15. Antiarrhythmic class II- toxicity?
- Glucagon
As an anticholinesterase it increases endogenous ACh and thus increases strength.
hypertension - CHF - diabetic renal disease
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia

16. Clonidine is the preferred sym pathomimetic tx of HTN in pts with renal disease - why??
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
For serious - Gram + multidrug - resistant organisms

17. Digoxin v. Digitoxin: half life?
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
Digitoxin 168hrs Digoxin 40 hrs
- Oxalic acid - Acidosis & nephrotoxicity

18. Why would a patient with cog - wheel rigidity and a shuffling gait be given benztropine?
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
Antibiotic - protein synthesis inhibitor.
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
- Ethosuxamide - sulfonamides - lamotrigine

19. What is the category of drug names ending in - azepam (e.g. Diazepam)
- Hydralazine - Procainamide - INH - phenytoin
Benzodiazepine.
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
Prophylaxis for Influenza A - Rubella; Parkinson's disease

20. How can the t1/2 of INH be altered?
- Daunorubicin & Doxorubicin
Fast vs. Slow Acetylators
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels

21. Ethacrynic Acid - mechanism?
not a sulfonamide - but action is the same as furosemide
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
Delirium - Tremor - Nephrotoxicity
Beta1 more than B2

22. Which diuretics decrease urine Ca2+?
edrophonium (extremely short acting anticholinesterase)
thiazides - amiloride
Norepinephrine (Alpha1 -2 and beta 1)
Onchocerciasis ('river blindness'-- rIVER- mectin)

23. List some specifics of lead poisoning(4)?
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
Norepinephrine
Treatment of infertility.

24. What are two conditions in Which COX-2 inhibitors might be used?
Antileukotriene; blocks synthesis by lipoxygenase.
Heparin catalyzes the activation of antithrombin III.
Used in combination therapy with SMZ to sequentially block folate synthesis
Rheumatoid and osteoarthritis.

25. What is the MOA for Methicillin - Nafcillin - and Dicloxacillin?
Long.
Rifampin (DOC) - minocycline
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
Same as penicillin. Act as narrow spectrum antibiotics

26. MOA: Block nucleotide synthesis
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
Beta antagonist.
Sulfonamides - Trimethoprim
Sotalol - Ibutilide - Bretylium - Amiodarone

27. Can Warfarin be used during pregnancy?
RESPIre
No - warfarin - unlike heparin - can cross the placenta.
Antifungal.
1. Antipyretic 2. Analgesic 3. Anti - inflammatory

28. What is used to reverse the action of Heparin?
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
Directly of indirectly aid conversion of plasminogen to plasmin Which cleaves thrombin and fibrin clots. (It is claimed that tPA specifically converts fibrin - bound plasminogen to plasmin.)
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels

29. What are the clinical indications for bethanechol?
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
TMP- SMZ (DOC) - aerosolized pentamidine
Praziquantel

30. What enzyme is responsible for the breakdown of ACh in the synaptic cleft?
Acetylcholinesterase; ACh is broken down into choline and acetate.
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Indirect agonist - uptake inhibitor

31. Which drug(s) cause this reaction: Osteoporosis (2)?
-100% oxygen - hyperbaric
- Corticosteroids - heparin
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.

32. Which drug(s) cause this reaction: Atropine - like side effects?
- Tricyclic antidepressants
sedation - positive Coombs' test
Antibiotic - protein synthesis inhibitor.
Premature infants - because they lack UDP- glucuronyl transferase

33. What are the clinical indications for Azole therapy?
Oxygen
Antileukotriene; blocks leukotriene receptors.
Reversible block of histamine H2 receptors
Systemic mycoses

34. Adverse effects of ganglionic blockers?
- Tricyclic antidepressants
Indomethacin is used to close a patent ductus arteriosus.
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
Long.

35. What are the major toxic side effects of the Cephalosporins?
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
Quinolones
Pyridoxine (B6) administration
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.

36. Why is there a drop in systolic - mean - and diastolic bp with infusion of isoproterenol?
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
Protease Inhibitors and Reverse Transcriptase Inhibitors
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.

37. Which drug(s) cause this reaction: Extrapyramidal side effects (3)?
loop diuretics - spironolactone
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
- Chlorpromazine - thioridazine - haloperidol

38. How do you treat coma in the ER (4)?
Tricyclic antidepressant.
Cardiac glycoside (inotropic agent).
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD

39. What is the mechanism of action of Ticlopidine - Clopidogrel
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
Staphlococcus aureus
Those patients who are taking nitrates.
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.

40. List the specific antidote for this toxin: Heparin
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
Polymyxin B - Polymyxin E
1. Reliable (<1% failure) 2. Lowers risk of endometrial and ovarian cancer 3. Decreased incidence of ectopic pregnancy 4. Lower risk of pelvic infections 5. Regulation of menses
- Protamine

41. Acetazolamide - mechanism?
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
Binding to the presynaptic alpha 2 release modulating receptors
Methylxanthine.

42. Beta Blockers - CNS toxicity?
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
blocks SR Ca2+ channels
Cell membrane Ca2+ channels of cardiac sarcomere
sedation - sleep alterations

43. If a patient is given hexamethonium - What would happen to his/her heart rate?
It would increase to ~ 100 beats/min. Both sympathetic and vagal stimulation would be knocked out - but the SA node has an intrinsic pace of 100 beats/min - Which is normally checked by vagal stimulation.
- Oral Contraceptives
Inhalational general anesthetic.
first dose orthostatic hypotension - dizziness - headache

44. What cholinomimetics might your pt be taking for his glaucoma
Carbachol - pilocarpine - physostigmine - echothiophate
Dopamine; causes its release from intact nerve terminals
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
Inhalational general anesthetic.

45. Ethacrynic Acid - clinical use?
Beta Blockers
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
Diuresis in pateints with sulfa allergy
- Clindamycin

46. For Heparin What is the Treatment for overdose
Pyridoxine (B6) administration
PT
Protamine sulfate
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).

47. Which drug(s) cause this reaction: Focal to massive hepatic necrosis (4)?
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
Due to the presence of a bulkier R group
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
- Penicillamine

48. What are common side effects of Protease Inhibitors?
Tricyclic antidepressant.
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis

49. What are two toxicities of the Sulfonylureas?
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
Interferes with microtubule function - disrupts mitosis - inhibits growth
sedation - sleep alterations

50. Why is reserpine effective in treating HTN?
Beta - lactamase cleavage of Beta - lactam ring
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.