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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. Mg+- clinical use?
scopolamine
effective in torsade de pointes and digoxin toxicity
bradycardia - AV block - CHF
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)

2. List the mechanism - clinical use - & toxicity of 6 MP.
Phosphorylation by a Viral Kinase
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
block Na+ channels in the cortical collecting tubule
- inhibits HGPRT (pur. Syn.) - Luk - Lymph

3. Which drug(s) cause this reaction: Extrapyramidal side effects (3)?
- Chlorpromazine - thioridazine - haloperidol
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
Sildenafil fills the penis
Alpha -1 antagonist

4. Mannitol - mechanism?
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
NO
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.

5. What are common serious side effects of Aminoglycosides and What are these associated with?
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
- Flumazenil
Impairs the synthesis of vitamin K- dependent clotting factors

6. What are three toxicities of Propylthiouracil?
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
decrease
severe hypertension - CHF
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia

7. List the specific antidote for this toxin: Iron
- Deferoxamine
Chronic Hepatitis A and B - Kaposi's Sarcoma
cortical collecting tubule
aPTT (intrinsic pathway)

8. ACE inhibitors - clinical use?
hypertension - CHF - diabetic renal disease
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
Oral treatment of superficial infections
- B51Naloxone / naltrexone (Narcan)

9. For Heparin What is the Treatment for overdose
Protamine sulfate
hypertension - CHF - diabetic renal disease
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
- Steroids - Tamoxifen

10. Resistance mechanisms for Vancomycin
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.)
- N- acetylcystine
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.

11. What is the memory key for the effect of magnesium hydroxide overuse?
Ceftriaxone
penicillinase resistant
Mg = Must go to the bathroom.
It affects beta receptors equally and is used in AV heart block (rare).

12. What is the clinical use for Ampicillin and Amoxicillin?
Doxycycline - because it is fecally eliminated
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
Bleeding.

13. How do you calculate maintenance dose?
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
Doxycycline - because it is fecally eliminated
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins

14. Name the common Nucleoside Reverse Transcriptase Inhibitors
- Tetracycline - amiodarone - sulfonamides
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise

15. How does angiotensin II affect NE release?
It acts presynaptically to increase NE release.
Inhibits DNA dependent RNA polymerase
Botulinum
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.

16. What is the memory aid for subunit distribution of ribosomal inhibitors?

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17. Name two bile acid resins.
GET on the Metro
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
cholestyramine - colestipol
Ipratropium

18. Acetazolamide - toxicity?
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
Treatment of infertility.
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy

19. Beta Blockers - site of action?
Prevents the release of Ca from SR of skeletal muscle
fetal renal toxicity - hyperkalemia
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Beta adrenergic receptors and Ca2+ channels (stimulatory)

20. Spironolactone - mechanism?
- Cloazapine - carbamazapine - colchicine - PTU
post MI and digitalis induced arrhythmias
Does not cross
competitive inhibirot of aldosterone in the cortical collecting tubule

21. What are two processes Corticosteroids inhibit leading to decreased inflammation?
Teratogenic - Carcinogenic - Confusion - Headaches
- Haloperidol - chlorpromazine - reserpine - MPTP
Non - Nucleosides
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes

22. What are Polymyxins used for?
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
Resistant Gram - infections
- Daunorubicin & Doxorubicin
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis

23. What are three complications of Warfarin usage?
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts

24. Adverse effects of Guanethidine?
Gram + and Anerobes
pulmonary edema - dehydration
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)

25. Name three Antiarrhythmic drugs in class IC.
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
Disulfiram - like reaction with EtOH - Headache
Flecainide - Encainide - Propafenone
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts

26. MOA: Disrupt fungal cell membranes
Modification via Acetylation
Stimulates beta adrenergic receptors
Corticosteroids; prevent production of leukotrienes from arachodonic acid by blocking phospholipase A2. Drugs of choice in a patient with status asthmaticus (in combination with albuterol.)
Amphotericin B - Nystatin - Fluconazole/azoles

27. Digitalis - site of action?
Na/K ATPase
not a sulfonamide - but action is the same as furosemide
hyperaldosteronism - K+ depletion - CHF
Inhibits CMV DNA polymerase

28. What is the most common cause of Pt noncompliance with Macrolides?
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
check PFTs - LFTs - and TFTs
propanolol - esmolol - metoprolol - atenolol - timolol
GI discomfort

29. What antimicrobial class is Aztreonam syngergestic with?
Constant FRACTION eliminated per unit time.(exponential)
Pregnant women - Children; because animal studies show Damage to Cartilage
Aminoglycosides
- Halothane - Valproic acid - acetaminophen - Amantia phalloides

30. Side effects of Isoniazid (INH)?
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
- Vinca alkaloids(inhibit MT) - Paclitaxel
Prevents the release of ACh - Which results in muscle paralysis.
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.

31. Are penicillinase resistant
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.
Methicillin - Nafcillin - and Dicloxacillin
Increase target cell response to insulin.
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.

32. Name the common Aminoglycosides (5)
- Penicillamine
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin

33. What is the MOA of Ribavirin?
CL= (rate of elimination of drug/ Plasma drug conc.)
Sildenafil fills the penis
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
is resistant

34. What is the receptor affinity and clinical use of isoproterenol?
Same as penicillin. Act as narrow spectrum antibiotics
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
It affects beta receptors equally and is used in AV heart block (rare).
Chronic anticoagulation.

35. List the specific antidote for this toxin: Copper
Reversible block of histamine H2 receptors
Heparin catalyzes the activation of antithrombin III.
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.
- Penicillamine

36. IV Penicillin
Penicillin - G
Teratogenic - Carcinogenic - Confusion - Headaches
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.
carbonic anhydrase inhibitors - K+ sparing diuretics

37. What is Clindamycin used for clinically?
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
Pregnant women - Children; because animal studies show Damage to Cartilage
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.
YES

38. What is the loading dose formula?
Triple sulfas or SMZ
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.

39. What is the category - mechanism of action - and effect of Ipratroprium in Asthma treatment?
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
Bethanechol - Neostigmine - physostigmine
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.

40. What is the mechanism of action of Aspirin?
troponin - tropomyosin system
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
pulmonary edema - dehydration

41. Clinical use of Isoniazid (INH)?
1. Antiandrogen 2. Nausea 3. Vomiting
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Liver

42. What are the nondepolarizing neuromuscular blocking drugs?
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Protamine sulfate

43. Which drug(s) cause this reaction: Fanconi's syndrome?
- Tetracycline
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
Scopolamine
Pretreat with antihistamines and a slow infusion rate

44. What is the mecanism of action of Sucralfate?
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
- Antipsychotics
Acts as a wide spectrum carbapenem
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.

45. Triamterene and amiloride - mechanism?
Inhibt Assembly of new virus by Blocking Protease Enzyme
Interferes with microtubule function - disrupts mitosis - inhibits growth
block Na+ channels in the cortical collecting tubule
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux

46. What cholinergic inhibitor acts by directly inhibiting Ach release at the presynaptic terminal
Botulinum
Penicillin - G
Hypersensitivity reactions
Benzodiazepine.

47. List the specific antidote for this toxin: Heparin
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
- Protamine
It acts presynaptically to increase NE release.
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)

48. What are two conditions in Which COX-2 inhibitors might be used?
Activates antithrombin III
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
Inhibit viral DNA polymerase
Rheumatoid and osteoarthritis.

49. What is the MOA for Carbenicillin - Piperacillin - and Ticarcillin?
Same as penicillin. Extended spectrum antibiotics
Prevents the release of ACh - Which results in muscle paralysis.
Beta1 more than B2
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia

50. What is the possible mechanism and effect of Metformin in treating diabetes?
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
- ACE inhibitors (Losartan>no cough)
Abortifacient.
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide