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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.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

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. How do spare receptors effect the Km?
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
- Penicillamine
- Penicillin
- ED 50 is less than the Km (less than 50% of receptors)

2. What is the memory key for Metronidazole's clinical uses?
sedation - sleep alterations
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
GET on the Metro

3. What are the clinical uses for 1st Generation Cephalosporins?
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
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.

4. What is the effect of the Glitazones in diabetes treatment?
Prevents the release of Ca from SR of skeletal muscle
cyanide toxicity (releases CN)
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
Increase target cell response to insulin.

5. MOA: Disrupt bacterial/fungal cell membranes
Same as penicillin. Extended spectrum antibiotics
Polymyxins
Pentavalent Antimony
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma

6. Would blockade of muscarininc receptors in the bladder be useful in treating urinary retention?
Protamine sulfate
Acts as a wide spectrum carbapenem
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole

7. What are two clinical uses of Azathioprine?
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
Treatment of infertility.
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes

8. Why would dopamine be useful in treating shock?
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
Slow - limited by half lives of clotting factors
Staphlococcus aureus
proximal convoluted tubule - thin descending limb - and collecting duct

9. MOA: Block protein synthesis at 30s subunit
collecting ducts
Competitive inibitor of progestins at progesterone receptors.
Aminoglycosides - Tetracyclines
Stimulates beta adrenergic receptors

10. What drug is used during the pregnancy of an HIV+ mother? - Why?
distal convoluted tubule (early)
cyanide toxicity (releases CN)
AZT - to reduce risk of Fetal Transmission
TMP- SMZ

11. Why are albuterol and terbutaline effective in tx of acute asthmatic attacks?
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
These B-2 agonists cause respiratory smooth muscle to relax.
severe hypertension - CHF
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).

12. What is action of insulin in the liver - in muscle - and in adipose tissue?
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.
- Chloramphenicol
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

13. Hydrochlorothiazide - clinical use?
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
HTN - CHF - calcium stone formation - nephrogenic DI.
- Quinidine - quinine
competitive inhibirot of aldosterone in the cortical collecting tubule

14. What are three toxicities of Leuprolied?
- Alkalate DNA - Brain tumors - CNS toxicity
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
atropine - homatropine - tropicamide
1. Antiandrogen 2. Nausea 3. Vomiting

15. Are not penicillinase resistant
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
Carbenicillin - Piperacillin - and Ticarcillin
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load

16. List the mechanism - clinical use - & toxicity of Etoposide.
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Cimetidine is a potent inhibitor of P450; it also has an antiandrogenic effect and decreases renal excretion of creatinine. Other H2 blockers are relatively free of these effects.

17. What do Aminoglycosides require for uptake?
Beta -2 agonist.
first dose orthostatic hypotension - dizziness - headache
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
Oxygen

18. What is the MOA of Griseofulvin?
CL= (rate of elimination of drug/ Plasma drug conc.)
- Penicillamine
DHPG (dihydroxy-2- propoxymethyl guanine)
Interferes with microtubule function - disrupts mitosis - inhibits growth

19. Antiarrhythmic class IV- effects?
toxic
decrease conduction velocity - increase ERP - increase PR interval
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
- Protamine

20. What drugs target anticholinesterase
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Those patients who are taking nitrates.
not a sulfonamide - but action is the same as furosemide

21. What is the MOA of Polymyxins?
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
Digitoxin>95% Digoxin 75%
reversible SLE- like syndrome
Saquinavir - Ritonavir - Indinavir - Nelfinavir

22. What are three toxicities of Propylthiouracil?
Same as penicillin. Extended spectrum antibiotics
decrease conduction velocity - increase ERP - increase PR interval
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
The only local anesthetic with vasoconstrictive properties.

23. Which H2 Blocker has the most toxic effects and What are they?
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
depresses ectopic pacemakers - especially in digoxin toxicity
Cimetidine is a potent inhibitor of P450; it also has an antiandrogenic effect and decreases renal excretion of creatinine. Other H2 blockers are relatively free of these effects.
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.

24. Toxic effects of TMP include?
Cell membrane Ca2+ channels of cardiac sarcomere
Megaloblastic anemia - Leukopenia - Granulocytopenia
Captopril - Enalapril - Lisinopril
Increases coumadin metabolism

25. What is the mecanism of action - effective period - and ineffective period of use for Cromolyn in treating Asthma?
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
Because they require some residual islet function.
GI discomfort

26. Name common Polymyxins
Polymyxin B - Polymyxin E
INH: Injures Neurons and Hepatocytes
Suramin
Megaloblastic anemia - Leukopenia - Granulocytopenia

27. What is the mechanism of action of Aspirin?
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
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

28. What is the category and mechanism of action of Zileuton in Asthma treatment?
DOC in diagnosing and abolishing AV nodal arrhythmias
sedation - depression - nasal stuffiness - diarrhea
Antileukotriene; blocks synthesis by lipoxygenase.
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.

29. Furosemide - toxicity? (OH DANG)
Nevirapine - Delavirdine
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout

30. What is an additional side effect of Methicillin?
Prophylaxis for Influenza A - Rubella; Parkinson's disease
- Protamine
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux
Interstitial nephritis

31. Which drug(s) cause this reaction: Neuro and Nephrotoxic?
- polymyxins
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
Binds to the Pyrophosphate Binding Site of the enzyme
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis

32. What is the MOA for Metronidazole?
Forms toxic metabolites in the bacterial cell - Bactericidal
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
- Class III antiarrhythmics (sotalol) - class IA (quinidine)

33. What are the nondepolarizing neuromuscular blocking drugs?
Ipratropium
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium

34. Adverse effects of beta - blockers?
Enterobacter
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Acetylcholinesterase; ACh is broken down into choline and acetate.

35. What neurotransmitter does Amantadine affect? How does it influence this NT?
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Dopamine; causes its release from intact nerve terminals
Beta lactams - inhibit cell wall synthesis - Bactericidal
Rash - Pseudomembranous colitis

36. Name two LPL stimulators.
Edrophonium
Gemfibrozil - Clofibrate
carbonic anhydrase inhibitors - K+ sparing diuretics
Ipratropium

37. What are nine findings of Iatrogenic Cushing's syndrome caused by glucocorticoid therapy?
Beta1 more than B2
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
Dobutamine has more of an affintiy for beta -1 than beta -2 - and is used for treating heart failure and shock. Albuterol and terbutaline is the reverse - and is used in treatment of acute asthma.
Na/K ATPase

38. How can the toxic effects of TMP be ameliorated?
With supplemental Folic Acid
Topical and Oral - for Oral Candidiasis (Thrush)
Penicillin - V
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.

39. 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.
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
Aminoglycosides
Teratogenic - Carcinogenic - Confusion - Headaches

40. What are the major toxic side effects of Imipenem/cilastatin?
Severe Gram - rod infections.
AZT
GI distress - Skin rash - and Seizures at high plasma levels
Anaerobes

41. Name three Antiarrhythmic drugs in class IB.
Decreased uptake or Increased transport out of cell
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
GI distress - Skin rash - and Seizures at high plasma levels
Lidocaine - Mexiletine - Tocainide

42. How do the Protease Inhibitors work?
Saquinavir - Ritonavir - Indinavir - Nelfinavir
Inhibt Assembly of new virus by Blocking Protease Enzyme
amphetamine and ephedrine
Antifungal.

43. What is the category of drug names ending in - terol (e.g. Albuterol)
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Cyclooxygenases (COX I - COX II).
Beta -2 agonist.
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).

44. Procainamide - toxicity?
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
reversible SLE- like syndrome
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)

45. What is the MOA for the Azoles?
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
They inhibit reuptake of NE at the nerve terminal (as does cocaine).
Inhibit Ergosterol synthesis
Gram + - Gram - - Norcardia - Chlamydia

46. Ca2+ channel blockers - mechanism?
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Same as penicillin. Extended spectrum antibiotics
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
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.

47. List the mechanism - clinical use - & toxicity of Cyclophosphamide.
- Phenytoin
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Carbenicillin - Piperacillin - and Ticarcillin

48. A group of pts are rushed into the ER complaining of excessive sweating - tearing - salivation - HA - N and V - muscle twitching - difficulty breathing and diarrhea. What drug would be the most effective immediate tx
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Chronic gout.
Antileukotriene; blocks synthesis by lipoxygenase.
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)

49. Classes of antihypertensive drugs?
Epinephrine
Short.
amphetamine and ephedrine
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors

50. What can result due to antacid overuse?
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
very short acting
Prevents the release of ACh - Which results in muscle paralysis.
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.