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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 are the major toxic side effects of Imipenem/cilastatin?
Antifungal.
GI distress - Skin rash - and Seizures at high plasma levels
Inhibit Ergosterol synthesis
Hypersensitivity reactions

2. Which drug(s) cause this reaction: G6PD hemolysis(8)?
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
TMP- SMZ (DOC) - aerosolized pentamidine
Acute gout.
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol

3. For Warfarin What is the Onset of action
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
Aminoglycosides
Slow - limited by half lives of clotting factors
sedation - sleep alterations

4. What is Ketoconazole specifically used for?
amphetamine and ephedrine
- Physostigmine salicylate
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)

5. List the specific antidote for this toxin: Amphetamine
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.
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
- Ammonium Chloride
cyanide toxicity (releases CN)

6. Adverse effects of Hydrochlorothiazide?
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
Decreases synthesis of Mycolic Acid
Large anionic polymer - acidic
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.

7. 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.
torsade de pointes - excessive Beta block
Quinolones
sedation - depression - nasal stuffiness - diarrhea

8. What organisms does Griseofulvin target?
Nucleosides
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
Dermatophytes (tinea - ringworm)
Na/K ATPase

9. What is Niclosamide used for?
No
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
Antileukotriene; blocks synthesis by lipoxygenase.
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH

10. Name the common Nucleoside Reverse Transcriptase Inhibitors
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Stimulates beta adrenergic receptors
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone

11. Describe first - order kinetics?
Constant FRACTION eliminated per unit time.(exponential)
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
- Nitrate - hydroxocobalamin thiosulfate
Topical and Oral - for Oral Candidiasis (Thrush)

12. What is the mechanism of Leuprolide?
Blocks Norepi - but not Dopamine
GnRH analog with agonist properties When used in pulsatile fashion and antagonist properties When used in continuous fashion - causing a transient initial burst of LH and FSH
bradycardia - AV block - CHF
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

13. What is the mechanism of action of the H2 Blockers?
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.
Reversible block of histamine H2 receptors
- Chlorpromazine - thioridazine - haloperidol
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species

14. What drug is given for Pneumocystis carinii prophylaxis?
Neurotoxicity - Acute renal tubular necrosis
Pentamidine
- Fluoroquinolones
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents

15. How can Vancomycin - induced 'Red Man Syndrome' be prevented?
Pretreat with antihistamines and a slow infusion rate
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
- Clindamycin
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.

16. What is action of insulin in the liver - in muscle - and in adipose tissue?
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
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.
Lovastatin - Pravastatin - Simvastatin - Atorvastatin

17. What are the clinical uses for 1st Generation Cephalosporins?
- Atropine & pralidoxime
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
- Physostigmine salicylate
GI disturbances.

18. What are the clinical indications for Azole therapy?
Paranteral (IV - SC)
Systemic mycoses
- Isoniazid
Tendonitis and Tendon rupture

19. Antiarrhythmic class IB- effects?
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system

20. ADH antagonists - site of action?
collecting ducts
hypertension - CHF - diabetic renal disease
Protamine sulfate
Leukotrienes increasing bronchial tone.

21. What is treated with Chloroquine - Quinine - Mefloquine?
viral kinase
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Malaria (P. falciparum)

22. Name two classes of drugs for HIV therapy
Aminoglycosides
Hemolytic anemia
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.
Protease Inhibitors and Reverse Transcriptase Inhibitors

23. MOA: Block DNA topoisomerases
Foscarnet = pyroFosphate analog
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Paranteral (IV - SC)
Quinolones

24. For Warfarin What is the Duration of action
With an amino acid change of D- ala D- ala to D- ala D- lac
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
Forms toxic metabolites in the bacterial cell - Bactericidal
Chronic (weeks or months)

25. What is the mechanism of action of NSAIDs other than Aspirin?
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
They inhibit reuptake of NE at the nerve terminal (as does cocaine).
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.

26. List the mechanism - clinical use - & toxicity of Paclitaxel.
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Anaerobes
- acetylation - glucuron. - & sulfation - Conjugation - Polar product

27. Name three ACE inhibitors?
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.
Captopril - Enalapril - Lisinopril
Epinephirine(Alpha1 -2 and Beta 1 -2)
Methylation of rRNA near Erythromycin's ribosome binding site

28. What is the mechanism of action of Allopurinol used to treat chronic gout?
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
propanolol - esmolol - metoprolol - atenolol - timolol
- Isoniazid
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).

29. What type of patient should not take Misoprostol and why?
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
Blocks Influenza A and RubellA; causes problems with the cerebellA
thiazides - amiloride
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.

30. What are the clinical uses for 2nd Generation Cephalosporins?
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
post MI and digitalis induced arrhythmias
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD

31. Can Heparin be used during pregnancy?
Yes - it does not cross the placenta.
Chronic gout.
Systemic mycoses
Local anesthetic.

32. List the mechanism - clinical use - & toxicity of 6 MP.
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
Hypersensitivity reactions
- N- acetylcystine
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.

33. What is the MOA for Carbenicillin - Piperacillin - and Ticarcillin?
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
Same as penicillin. Extended spectrum antibiotics
Ganciclovir is more toxic to host enzymes

34. What populations are Floroquinolones contraindicated in? Why?
Rapid (seconds)
Pregnant women - Children; because animal studies show Damage to Cartilage
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
GI upset - Superinfections - Skin rashes - Headache - Dizziness

35. What are four thrombolytics?
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
Because they require some residual islet function.
thiazides - amiloride
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.

36. What are five toxicities associated with Tacrolimus (FK506)?
Phosphorylation by a Viral Kinase
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
prevention of nodal arrhythmias (SVT)

37. Side effects of Isoniazid (INH)?
- Methylene blue
- Niacin - Ca++ channel blockers - adenosine - vancomycin
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
Beta - lactam antibiotics

38. Verapamil has similar action to?
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
Beta Blockers
Epinephrine
Pentamidine

39. Resistance mechanisms for Tetracycline
Fast vs. Slow Acetylators
Decreased uptake or Increased transport out of cell
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia

40. What are common toxicities associated with Tetracyclines?

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41. What is the MOA for Vancomycin?
Inhibits cell wall mucopeptide formation - Bactericidal
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
The PT.
physostigmine

42. Which drug(s) cause this reaction: Cinchonism (2)?
- Quinidine - quinine
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
1. Pioglitazone 2. Rosiglitazone.
Captopril - Enalapril - Lisinopril

43. What is combined with Ampicillin - Amoxicillin - Carbenicillin - Piperacillin - and Ticarcillin to enhance their spectrum?
cholestyramine - colestipol
Clavulanic acid
sedation - positive Coombs' test
Digitoxin 168hrs Digoxin 40 hrs

44. What beta 2 agonist will help your 21yo Astma pt?
Cilastatin
- Penicillin
Albuterol - tertbutaline
Pyridoxine (B6) administration

45. What are the major structural differences between Penicillin and Cephalosporin?
BM suppression (neutropenia - anemia) - Peripheral neuropathy
Paranteral (IV - SC)
Interstitial nephritis
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)

46. What drugs target anticholinesterase
Competitive inibitor of progestins at progesterone receptors.
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
Cephalosporins
Neurotoxicity - Acute renal tubular necrosis

47. What is are two clinical uses of Cyclosporine?
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
Lipoxygenase

48. Which drug(s) cause this reaction: Anaphylaxis?
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
decrease conduction velocity - increase ERP - increase PR interval
- Penicillin

49. What are three types of antacids and the problems that can result from their overuse?
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia
cyanide toxicity (releases CN)
- Daunorubicin & Doxorubicin

50. Which diuretics decrease urine Ca2+?
CL= (rate of elimination of drug/ Plasma drug conc.)
thiazides - amiloride
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
hyperaldosteronism - K+ depletion - CHF