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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 can the toxic effects of TMP be ameliorated?
Competitive inibitor of progestins at progesterone receptors.
ACE inhibitor.
With supplemental Folic Acid
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin

2. Hydralazine - toxicity?
compensatory tachycardia - fluid retention - lupus - like syndrome
Ipratropium
Ganciclovir is more toxic to host enzymes
Antibiotic - protein synthesis inhibitor.

3. Why would you give a drug like pancuronium or succinylcholine?
Useful in muscle paralysis during surgery or mechanical ventilation.
Cephalosporin: 1) has a 6 member ring attached to the Beta lactam instead of a 5 member ring 2)has an extra functional group ( attached to the 6 member ring)
- Fluoroquinolones
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor

4. Adverse effects of Captopril?
thiazides - amiloride
Sildenafil fills the penis
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)

5. Which RT inhibitors cause Lactic Acidosis?
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
Nucleosides
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail

6. ACE inhibitors - clinical use?
Constant FRACTION eliminated per unit time.(exponential)
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
hypertension - CHF - diabetic renal disease
Treatment of infertility.

7. What is the MOA for Vancomycin?
Inhibits cell wall mucopeptide formation - Bactericidal
Leukotrienes increasing bronchial tone.
Severe Gram - rod infections.
Premature infants - because they lack UDP- glucuronyl transferase

8. Which drug(s) cause this reaction: Aplastic anemia (5)?
Erectile dysfunction.
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
- Phenytoin
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori

9. Secretion of What drug is inhibited by Probenacid used to treat chronic gout?
Clavulanic acid
- Tricyclic antidepressants
Captopril - Enalapril - Lisinopril
Penicillin.

10. Name the common Aminoglycosides (5)
Oral
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
Early myocardial infarction.

11. What type of gout is treated with Allopurinol?
Cephalosporin: 1) has a 6 member ring attached to the Beta lactam instead of a 5 member ring 2)has an extra functional group ( attached to the 6 member ring)
- Ammonium Chloride
- Vitamin K & fresh frozen plasma
Chronic gout.

12. Antimicrobial prophylaxis for Syphilis
Benzathine penicillin G
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor

13. How would hemicholinium treatment affect cholinergic neurons?
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
distal convoluted tubule (early)
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.

14. What are common side effects of RT Inhibitors?
BM suppression (neutropenia - anemia) - Peripheral neuropathy
collecting ducts
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
local anesthetic. CNS stimulation or depression. CV depression.

15. Name several common Macrolides (3)
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
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
Erythromycin - Azithromycin - Clarithromycin
- Niacin - Ca++ channel blockers - adenosine - vancomycin

16. List the specific antidote for this toxin: Arsenic (all heavy metals)
Penicillin - G
bradycardia - AV block - CHF
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
- Dimercaprol - succimer

17. Mannitol - clinical use?
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
Sildenafil fills the penis
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
Headache - flushing - dyspepsia - blue - green color vision.

18. 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
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
Digitoxin 70% Digoxin 20-40%
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT

19. Mnemonic for Foscarnet?
collecting ducts
Foscarnet = pyroFosphate analog
VACUUM your Bed Room'
Due to the presence of a bulkier R group

20. Why would you use pralidoxime after exposure to an organophosphate?
Pralidoxime regenerates active cholinesterase.
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
propanolol - esmolol - metoprolol - atenolol - timolol
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.

21. Ibutilide - toxicity?
- Lithium
Beta antagonist.
torsade de pointes
Used in combination therapy with SMZ to sequentially block folate synthesis

22. List the mechanism - clinical use - & toxicity of 5 FU.
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
- Deferoxamine
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.

23. What is the category of drug names ending in - azepam (e.g. Diazepam)
Benzodiazepine.
- Deferoxamine
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.

24. What is the lab value used to monitor the effectiveness of Warfarin therapy?
Polymyxin B - Polymyxin E
The PT.
- Steroids - Tamoxifen
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.

25. What are two Glitazones?
1. Renal damage 2. Aplastic anemia 3. GI distress
1. Pioglitazone 2. Rosiglitazone.
Digoxin=urinary Digitoxin=biliary
Lidocaine - Mexiletine - Tocainide

26. What enzymes are inhibited by NSAIDs - acetaminophen and COX II inhibitors?
Cyclooxygenases (COX I - COX II).
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
Dermatophytes (tinea - ringworm)
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring

27. What is a common drug interaction associated with Griseofulvin?
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Increases coumadin metabolism
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).

28. What would be the effect on blood pressure with infusion of the alpha -2 agonist clonidine?
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
- Clindamycin
Fast vs. Slow Acetylators

29. What neurotransmitter does Amantadine affect? How does it influence this NT?
Inhibits cell wall mucopeptide formation - Bactericidal
PT
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
Dopamine; causes its release from intact nerve terminals

30. How are the Latent Hypnozoite (Liver) forms of Malaria (P. vivax - P.ovale) treated?
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
Primaquine
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
- Lithium

31. Explain differences between full and partial agonists(2).
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
Benzodiazepine.
- Act on same receptor - Full has greater efficacy

32. What patients are at risk for life threatening hypotension When taking Sildenafil (Viagra)?
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
Those patients who are taking nitrates.
Buy AT 30 - CELL at 50'

33. Which drug(s) cause this reaction: Drug induced Parkinson's (4) ?
Minor hepatotoxicity - Drug interactions (activates P450)
It affects beta receptors equally and is used in AV heart block (rare).
- Ethosuxamide - sulfonamides - lamotrigine
- Haloperidol - chlorpromazine - reserpine - MPTP

34. What is the clinical utility of cocaine?
compensatory tachycardia - fluid retention - lupus - like syndrome
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
TMP- SMZ
The only local anesthetic with vasoconstrictive properties.

35. What is the effect of TCA's on the adrenergic nerve?
- Disulfram & also sulfonylureas - metronidazole
They inhibit reuptake of NE at the nerve terminal (as does cocaine).
atropine - homatropine - tropicamide
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system

36. What is action of insulin in the liver - in muscle - and in adipose tissue?
- Chloramphenicol
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.
- Alkalate DNA - Brain tumors - CNS toxicity
Neurotoxicity - Acute renal tubular necrosis

37. Describe Phase II metabolism in liver(3)?
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
not a sulfonamide - but action is the same as furosemide
Penicillin.
- acetylation - glucuron. - & sulfation - Conjugation - Polar product

38. Ca2+ channel blockers - toxicity?
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
cardiac depression - peripheral edema - flushing - dizziness - constipation
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
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic

39. Quinidine - toxicity?
Megaloblastic anemia - Leukopenia - Granulocytopenia
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
pulmonary edema - dehydration

40. What is the clinical utility of clonidine?
Acute (hours)
torsade de pointes
Prevents the release of Ca from SR of skeletal muscle
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).

41. Name three K+ sparing diuretics?
- Chlorpromazine - thioridazine - haloperidol
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
Spironolactone - Triamterene - Amiloride (the K+ STAys)

42. What is the most common cause of Pt noncompliance with Macrolides?
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
GI discomfort
NO
- acetylation - glucuron. - & sulfation - Conjugation - Polar product

43. What are four Sulfonylureas?
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
Acetylcholinesterase; ACh is broken down into choline and acetate.
Praziquantel

44. MOA of Succinylcholine
Digitoxin 70% Digoxin 20-40%
Prevents the release of Ca from SR of skeletal muscle
Doxycycline - because it is fecally eliminated
Dry flushed skin - due to inhibition of sympathetic post - ganglionic blockade on muscarinic receptors of sweat glands. All others are opposite of What would be expected.

45. Name four HMG- CoA reductase inhibitors.
Same as penicillin. Extended spectrum antibiotics
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Reversible block of histamine H2 receptors

46. Which drug(s) cause this reaction: Torsade de pointes (2)?
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
cortical collecting tubule
Polymyxins
Severe Gram - rod infections.

47. K+ sparing diuretics - clinical use?
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
It affects beta receptors equally and is used in AV heart block (rare).
hyperaldosteronism - K+ depletion - CHF
Methicillin - Nafcillin - and Dicloxacillin

48. Name the common Fluoroquinolones (6)
loop diuretics - thiazides
Botulinum
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
ARF - shock - drug overdose - decrease intracranial/intraocular pressure

49. Resistance mechanisms for Sulfonamides
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.

50. Adverse effects of Losartan?
Clavulanic acid
fetal renal toxicity - hyperkalemia
Binds to the Pyrophosphate Binding Site of the enzyme
- Act on same receptor - Full has greater efficacy