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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. Name four HMG- CoA reductase inhibitors.
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
Rash - Pseudomembranous colitis
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Delirium - Tremor - Nephrotoxicity

2. Which drug(s) cause this reaction: Tardive dyskinesia?
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
- Antipsychotics

3. What is the most common cause of Pt noncompliance with Macrolides?
GI discomfort
Butyrophenone (neuroleptic).
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
- Hydralazine - Procainamide - INH - phenytoin

4. List the specific antidote for this toxin: Acetaminophen
competitive inhibirot of aldosterone in the cortical collecting tubule
- N- acetylcystine
Digitoxin 70% Digoxin 20-40%
Cilastatin

5. Hydrochlorothiazide - clinical use?
HTN - CHF - calcium stone formation - nephrogenic DI.
Aminoglycosides - Tetracyclines
With supplemental Folic Acid
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

6. How are Sulfonamides employed clinically?
Foscarnet = pyroFosphate analog
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Chronic anticoagulation.
Gram + - Gram - - Norcardia - Chlamydia

7. What patients are at risk for life threatening hypotension When taking Sildenafil (Viagra)?
Those patients who are taking nitrates.
- polymyxins
check PFTs - LFTs - and TFTs
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes

8. What are common toxicities associated with Tetracyclines?

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9. Antiarrhythmic class IC- effects?
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
- Tetracycline - amiodarone - sulfonamides
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
Beta1 more than B2

10. Antiarrhythmic class IV- effects?
Aplastic anemia (dose independent) - Gray Baby Syndrome
It acts presynaptically to increase NE release.
decrease conduction velocity - increase ERP - increase PR interval
Tricyclic antidepressant.

11. What type of patient should not take Misoprostol and why?
aPTT (intrinsic pathway)
Mg = Must go to the bathroom.
Large anionic polymer - acidic
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.

12. What is the mechanism of action of Colchicine used to treat acute gout?
Inhibits CMV DNA polymerase
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
Teratogenic - Carcinogenic - Confusion - Headaches
Increases coumadin metabolism

13. Antiarrhythmic class II- mechanism?
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
Ataxia - Dizziness - Slurred speech

14. Which drug(s) cause this reaction: Extrapyramidal side effects (3)?
Digitoxin>95% Digoxin 75%
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
- Glucocorticoid withdrawal
- Chlorpromazine - thioridazine - haloperidol

15. List the specific antidote for this toxin: Heparin
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Constant FRACTION eliminated per unit time.(exponential)
dry mouth - sedation - severe rebound hypertension
- Protamine

16. What are four clinical activities of Aspirin?
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
Pregnant women - Children; because animal studies show Damage to Cartilage

17. List the specific antidote for this toxin: Carbon monoxide
No
Long.
-100% oxygen - hyperbaric
Benzathine penicillin G

18. What antimuscarinic drug is useful for the tx of asthma
Ipratropium
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).

19. What is the category of drug names ending in - azol (e.g. Ketoconazole)
Same as penicillin. Extended spectrum antibiotics
Treatment of infertility.
Epinephrine
Antifungal.

20. How do Sulfonamides act on bacteria?
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
Same as penicillin. Extended spectrum antibiotics
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Saquinavir - Ritonavir - Indinavir - Nelfinavir

21. What are three types of antacids and the problems that can result from their overuse?
Anaerobes
YES
Inhibit DNA Gyrase (topoisomerase II) - Bactericidal
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia

22. Describe Phase II metabolism in liver(3)?
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)

23. What is the mechanism of action of Omeprazole - Lansoprazole?
Binds to the Pyrophosphate Binding Site of the enzyme
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

24. In coma situations you rule out What (7)?

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25. What physiological effects was the Anes using Atropine to tx
collecting ducts
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions

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

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27. Which Aminoglycoside is used for Bowel Surgery ?
edrophonium (extremely short acting anticholinesterase)
Stimulates beta adrenergic receptors
Neomycin
Carbachol - pilocarpine - physostigmine - echothiophate

28. What is the major toxic side effect of Penicillin?
Hypersensitivity reactions
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
Ceftriaxone

29. How does angiotensin II affect NE release?
It acts presynaptically to increase NE release.
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
The PT.

30. What are the side effects of Rifampin?
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)
Minor hepatotoxicity - Drug interactions (activates P450)
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
- Ammonium Chloride

31. What is the memory key for the effect of aluminum hydroxide overuse?
Lidocaine - Mexiletine - Tocainide
- ED 50 is less than the Km (less than 50% of receptors)
AluMINIMUM amount of feces.
Reversible block of histamine H2 receptors

32. Clinical use of Isoniazid (INH)?
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
first dose orthostatic hypotension - dizziness - headache
Hypersensitivity reactions
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

33. What is the mecanism of action of the COX-2 inhibitors (celecoxib - rofecoxib)?
Digitoxin>95% Digoxin 75%
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.
Amphetamine and Ephedrine
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.

34. MOA: Block mRNA synthesis
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine
Rifampin
Give an antichloinesterase - neostigmine - edrophonium - etc
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic

35. What are the nondepolarizing neuromuscular blocking drugs?
Hydralazine and Minoxidil
Ganciclovir is more toxic to host enzymes
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Blocks Norepi - but not Dopamine

36. What enzyme is responsible for the breakdown of ACh in the synaptic cleft?
Acetylcholinesterase; ACh is broken down into choline and acetate.
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.
Beta lactams - inhibit cell wall synthesis - Bactericidal
Gemfibrozil - Clofibrate

37. Mnemonic for Foscarnet?
Quinidine - Amiodarone - Procainamide - Disopyramide
Penicillin - G
Foscarnet = pyroFosphate analog
Gemfibrozil - Clofibrate

38. Mannitol - clinical use?
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine
Acts as a wide spectrum carbapenem
proximal convoluted tubule

39. Which drug(s) cause this reaction: G6PD hemolysis(8)?
Forms toxic metabolites in the bacterial cell - Bactericidal
compensatory tachycardia - fluid retention - lupus - like syndrome
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
Dermatophytes (tinea - ringworm)

40. What enzymes are inhibited by NSAIDs - acetaminophen and COX II inhibitors?
Inhibits reabsorption of uric acid.
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
Cyclooxygenases (COX I - COX II).

41. What side effect of using atropine to induce pupillary dilation would you expect?
Cyclooxygenases (COX I - COX II).
Diuresis in pateints with sulfa allergy
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).

42. What parasitic condition is treated with Ivermectin?

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43. Toxicities associated with Acyclovir?
Delirium - Tremor - Nephrotoxicity
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Does not cross
Lidocaine - Mexiletine - Tocainide

44. What is the mechanism of action of Heparin?
Heparin catalyzes the activation of antithrombin III.
Interferes with microtubule function - disrupts mitosis - inhibits growth
DOC in diagnosing and abolishing AV nodal arrhythmias
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD

45. What are three possible complications of Heparin therapy?
H2 antagonist
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Inhibits reabsorption of uric acid.

46. What is the MOA for Trimethoprim (TMP)?
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
- Phenytoin
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
for RSV

47. If a patient is given hexamethonium - What would happen to his/her heart rate?
Bethanechol - Neostigmine - physostigmine
very short acting
Diarrhea
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.

48. Acetaminophen has What two clinical uses and lacks What one clinical use of the NSAIDs?
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Local anesthetic.
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.

49. What is the memory key for Isoniazid (INH) toxicity?
INH: Injures Neurons and Hepatocytes
Cyclooxygenases (COX I - COX II).
Chronic gout.
GI discomfort

50. Mannitol - toxicity?
pulmonary edema - dehydration
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
Ipratropium
prevention of nodal arrhythmias (SVT)