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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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1. What are three toxicities of Leuprolied?
cardiac muscle: Verapamil>Diltiazem>Nifedipine
1. Antiandrogen 2. Nausea 3. Vomiting
Dopamine; causes its release from intact nerve terminals
Botulinum

2. ADH antagonists - site of action?
collecting ducts
Acute (hours)
Beta - lactamase cleavage of Beta - lactam ring
AZT - to reduce risk of Fetal Transmission

3. Which drug(s) cause this reaction: Photosensitivity(3)?
- Tetracycline - amiodarone - sulfonamides
Ipratropium
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
Potent immunosuppressive used in organ transplant recipients.

4. Acetaminophen has What two clinical uses and lacks What one clinical use of the NSAIDs?
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
cardiac muscle: Verapamil>Diltiazem>Nifedipine

5. How would you reverse the effect of a neuromuscular blocking agent?
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.
scopolamine
Give an antichloinesterase - neostigmine - edrophonium - etc
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.

6. What is a possible result of overdose of Acetaminophen?
The PTT.
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.

7. Ca2+ channel blockers - mechanism?
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
cardiac muscle: Verapamil>Diltiazem>Nifedipine

8. Is toxicity rare or common whith Cromolyn used in Asthma prevention?
Neutropenia
Rare.
Large anionic polymer - acidic
- Alkalate DNA - Brain tumors - CNS toxicity

9. What is the category - desired effect - and period of use of albuterol in the treatment of Asthma?
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Praziquantel
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
No

10. What are the clinical uses for Ticlopidine - Clopidogrel?
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
Cephalosporins

11. What is the category of drug names ending in - navir (e.g. Saquinavir)
Blood
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
Protease inhibitor.
Stimulates beta adrenergic receptors

12. What are common toxicities associated with Tetracyclines?

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13. List the mechanism - clinical use - & toxicity of Etoposide.
Inhalational general anesthetic.
- Fluoroquinolones
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.

14. List the specific antidote for this toxin: Digitalis
- Normalize K+ - Lidocaine - & Anti - dig Mab
Nitrates
Topical and Oral - for Oral Candidiasis (Thrush)
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain

15. What are two Alpha - glucosidase inhibitors?
1. Acarbose 2. Miglitol
Same as penicillin. Act as narrow spectrum antibiotics
aPTT (intrinsic pathway)
Ibuprofen - Naproxen - and Indomethacin

16. What is the category - mechanism of action - and particular use of beclomethasone and prednisone in Asthma treatment?
Malaria (P. falciparum)
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.)
- Phenytoin
Succinylcholine

17. What is the MOA for Metronidazole?
pulmonary edema - dehydration
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
Forms toxic metabolites in the bacterial cell - Bactericidal
Chronic anticoagulation.

18. What type of neurological blockade would hexamethonium create?
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
distal convoluted tubule (early)
Norepinephrine (Alpha1 -2 and beta 1)

19. What are the clinical uses for Imipenem/cilastatin?
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
sedation - positive Coombs' test
Gram + cocci - Gram - rods - and Anerobes

20. Acetazolamide - site of action?
Ipratropium
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
- Shifts the curve to the right - increases Km
proximal convoluted tubule

21. Reserpine will block the syntheis of this drug and but not its precursor.
Yes
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
decrease
Blocks Norepi - but not Dopamine

22. What is Imipenem always administered with?
Cilastatin
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
aPTT (intrinsic pathway)

23. Name four HMG- CoA reductase inhibitors.
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
Hypersensitivity reactions
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
bradycardia - AV block - CHF

24. What are three possible toxicities of NSAID usage?
Non - Nucleosides
1. Renal damage 2. Aplastic anemia 3. GI distress
Epinephirine(Alpha1 -2 and Beta 1 -2)
- Hydralazine - Procainamide - INH - phenytoin

25. What is the MOA of Imipenem?
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
Cardiac glycoside (inotropic agent).
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
Acts as a wide spectrum carbapenem

26. MOA: Disrupt bacterial/fungal cell membranes
Polymyxins
Chronic anticoagulation.
Beta Blockers
PT

27. Why is there a drop in systolic - mean - and diastolic bp with infusion of isoproterenol?
torsade de pointes
- Aminocaproic acid
- Corticosteroids - heparin
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.

28. What is Ketoconazole specifically used for?
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Pentavalent Antimony
-100% oxygen - hyperbaric
Peptic ulcer disease.

29. Name four Antiarrhythmic drugs in class III.
Sotalol - Ibutilide - Bretylium - Amiodarone
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
cortical collecting tubule
Acts as a wide spectrum carbapenem

30. List the specific antidote for this toxin: Cyanide
Flecainide - Encainide - Propafenone
- Nitrate - hydroxocobalamin thiosulfate
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
- Ethosuxamide - sulfonamides - lamotrigine

31. What is Fluconazole specifically used for?
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
ACE inhibitor.
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.

32. What is the category of drug names ending in - caine (e.g. Lidocaine)
Peptic ulcer disease.
Amphotericin B - Nystatin - Fluconazole/azoles
Local anesthetic.
Immediate anticoagulation for PE - stroke - angina - MI - DVT.

33. What is the mechanism of action of Clomiphene?
Mg = Must go to the bathroom.
- Vinca alkaloids(inhibit MT) - Paclitaxel
Digitoxin>95% Digoxin 75%
Clomiphene is a partial agonist at estrogen receptors in the pituitary gland. Prevents normal feedback inhibition and increses release of LH and FSHfrom the pituitary - Which stimulates ovulation.

34. Which antimicrobial classes inhibit protein synthesis at the 30S subunit? (2)
Beta -2 agonist.
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
Methicillin - Nafcillin - and Dicloxacillin
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic

35. Which diuretics cause acidosis?
carbonic anhydrase inhibitors - K+ sparing diuretics
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)
Disulfiram - like reaction with EtOH - Headache
Hemolytic anemia

36. What is a possible toxicity of Alpha - glucosidase inhibitors used in type -2 diabetes?
GI disturbances.
decrease conduction velocity - increase ERP - increase PR interval
dry mouth - sedation - severe rebound hypertension
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.

37. Common toxicities associated with Fluoroquinolones?
severe hypertension - CHF
GI upset - Superinfections - Skin rashes - Headache - Dizziness
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms

38. What additional side effects exist for Ampicillin?
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
bradycardia - AV block - CHF
AZT - to reduce risk of Fetal Transmission
Rash - Pseudomembranous colitis

39. What is the clinical use for Clomiphene?
Treatment of infertility.
Digitoxin 70% Digoxin 20-40%
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.

40. Why are Methicillin - Nafcillin - and Dicloxacillin penicillinase resistant?
Due to the presence of a bulkier R group
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
Penicillin.
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome

41. List the specific antidote for this toxin: Copper
- Penicillamine
hypertension - angina - arrhythmias
- Nitrate - hydroxocobalamin thiosulfate
dizziness - flushing - constipation (verapamil) - nausea

42. Mg+- clinical use?
Used in combination therapy with SMZ to sequentially block folate synthesis
torsade de pointes
effective in torsade de pointes and digoxin toxicity
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens

43. List the specific antidote for this toxin: Methemoglobin
- Methylene blue
-100% oxygen - hyperbaric
- Ethanol - dialysis - & fomepizole
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.

44. How is Chloramphenical used clinically?
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention

45. What is Niclosamide used for?
Leukotrienes increasing bronchial tone.
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
DOC in diagnosing and abolishing AV nodal arrhythmias

46. What patients are at risk for life threatening hypotension When taking Sildenafil (Viagra)?
Choline acetyltransferase
edrophonium (extremely short acting anticholinesterase)
Those patients who are taking nitrates.
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.

47. Common toxicities associated with Griseofulvin?
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
Teratogenic - Carcinogenic - Confusion - Headaches
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil

48. Why are the Sulfonylureas inactive in IDDM (type -1)?
Because they require some residual islet function.
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)

49. Which drug(s) cause this reaction: P450 inhibition(6)?
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
The only local anesthetic with vasoconstrictive properties.
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
- Tricyclic antidepressants

50. What are Aminoglycosides used for clinically?
Inhibits reabsorption of uric acid.
Nevirapine - Delavirdine
Polymyxin B - Polymyxin E
Severe Gram - rod infections.