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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 is the specific clinical use of Indomethacin in neonates?
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Clavulanic acid
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
Indomethacin is used to close a patent ductus arteriosus.

2. Adverse effects of Minoxidil?
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
severe hypertension - CHF
AZT - to reduce risk of Fetal Transmission
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone

3. What are the classic symptoms of cholinesterase inhibitor poisoning (parathion or other organophosphates)?
hypertension - CHF - diabetic renal disease
Small lipid - soluble molecule
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
bradycardia - AV block - CHF

4. List the mechanism - clinical use - & toxicity of Vincristine.

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5. K+ sparing diuretics - clinical use?
hyperaldosteronism - K+ depletion - CHF
Imipenem
Dermatophytes (tinea - ringworm)
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium

6. List the specific antidote for this toxin: Tricyclic antidepressants
Sulfonamides - Trimethoprim
The PTT.
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
- NaHCO3

7. What type of neurological blockade would hexamethonium create?
Quinidine - Amiodarone - Procainamide - Disopyramide
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic

8. Which diuretics decrease urine Ca2+?
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
thiazides - amiloride

9. Does Warfarin have a long - medium - or short half life?
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
- N- acetylcystine
Long.
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity

10. Which cancer drugs work at the level of proteins(2)?
physostigmine
Binds ergosterol - Disrupts fungal membranes
- Vinca alkaloids(inhibit MT) - Paclitaxel
block Na+ channels in the cortical collecting tubule

11. The MOA for Chloramphenicol is?
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
Aminoglycosides
Inhibition of 50S peptidyl transferase - Bacteriostatic

12. Which drug(s) cause this reaction: Hot flashes?
Chronic Hepatitis A and B - Kaposi's Sarcoma
- Tamoxifen
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic

13. Which RT inhibitors cause Lactic Acidosis?
Bleeding.
Useful in muscle paralysis during surgery or mechanical ventilation.
Amphetamine and Ephedrine
Nucleosides

14. What are three complications of Warfarin usage?
Non - Nucleosides
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
scopolamine
Small lipid - soluble molecule

15. For Warfarin What is the Ability to inhibit coagulation in vitro
Yes - it does not cross the placenta.
Liver
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
No

16. What is the mechanism of action of Clomiphene?
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.
Chronic (weeks or months)
Prevents the release of ACh - Which results in muscle paralysis.
- ED 50 is less than the Km (less than 50% of receptors)

17. What microorganisms are clinical indications for Tetracycline therapy?

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18. What is the clinical use for Penicillin?
Reversible block of histamine H2 receptors
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes

19. 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
Hypersensitivity reactions
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
Chronic Hepatitis A and B - Kaposi's Sarcoma

20. For Warfarin What is the Lab value to monitor
1. Pioglitazone 2. Rosiglitazone.
PT
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
Premature infants - because they lack UDP- glucuronyl transferase

21. A 12yo patient was treated for a reaction to a bee sting - What drug provides the best coverage of sympathomimetic receptors?
Epinephirine(Alpha1 -2 and Beta 1 -2)
Polymyxin B - Polymyxin E
Imipenem
Norepinephrine

22. Common toxicities associated with Fluoroquinolones?
GI upset - Superinfections - Skin rashes - Headache - Dizziness
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
hyperaldosteronism - K+ depletion - CHF
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.

23. What cholinergic inhibitor acts by directly inhibiting Ach release at the presynaptic terminal
blocks SR Ca2+ channels
Prophylaxis for Influenza A - Rubella; Parkinson's disease
Aminoglycosides
Botulinum

24. What is the MOA of Ribavirin?
- Normalize K+ - Lidocaine - & Anti - dig Mab
reversible SLE- like syndrome
Nitrates
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis

25. Which antimuscarinic agents are used in producing mydriasis and cycloplegia?
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
Bacitracin - Vancomycin
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
atropine - homatropine - tropicamide

26. Cautions When using Amiodarone?
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
check PFTs - LFTs - and TFTs

27. Which drug(s) cause this reaction: Tubulointerstitial Nephritis (5)?
GI upset - Superinfections - Skin rashes - Headache - Dizziness
G6PD deficient individuals
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
GI upset

28. Furosemide increases the excretion of What ion?
loop diuretics - spironolactone
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
Primaquine
Ca2+ (Loops Lose calcium)

29. Name four HMG- CoA reductase inhibitors.
Beta lactams - inhibit cell wall synthesis - Bactericidal
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
GI disturbances.

30. Triamterene and amiloride - mechanism?
block Na+ channels in the cortical collecting tubule
propanolol - esmolol - metoprolol - atenolol - timolol
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.

31. What are nine findings of Iatrogenic Cushing's syndrome caused by glucocorticoid therapy?
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
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
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Saquinavir - Ritonavir - Indinavir - Nelfinavir

32. Which drug(s) cause this reaction: Tendonitis and rupture?
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
- Act on same receptor - Full has greater efficacy
sedation - sleep alterations
- Fluoroquinolones

33. What is the memory key for the effect of magnesium hydroxide overuse?
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
Mg = Must go to the bathroom.
Inhibits Viral DNA polymerase
Reversible block of histamine H2 receptors

34. What drug is given for Pneumocystis carinii prophylaxis?
Pentamidine
Reversible block of histamine H2 receptors
Forms toxic metabolites in the bacterial cell - Bactericidal
- Quinidine - quinine

35. What is the MOA of Ganciclovir?
Inhibits CMV DNA polymerase
Scopolamine
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring
- Shifts the curve to the right - increases Km

36. What is Niclosamide used for?
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
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.)
not a sulfonamide - but action is the same as furosemide

37. Adverse effects of Prazosin?
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Inhibits Viral DNA polymerase
first dose orthostatic hypotension - dizziness - headache

38. For Heparin What is the Ability to inhibit coagulation in vitro
Inhibits reabsorption of uric acid.
Yes
Praziquantel
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.

39. Beta Blockers - BP?
- Oral Contraceptives
Potent immunosuppressive used in organ transplant recipients.
Pralidoxime regenerates active cholinesterase.
decrease

40. Digoxin v. Digitoxin: excretion?
Stimulates beta adrenergic receptors
Only in limited amounts
Digoxin=urinary Digitoxin=biliary
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.

41. What neurotransmitter does Amantadine affect? How does it influence this NT?
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
Dopamine; causes its release from intact nerve terminals
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)

42. Which drug(s) cause this reaction: Aplastic anemia (5)?
Hydralazine and Minoxidil
for RSV
- Fluoroquinolones
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin

43. Why is reserpine effective in treating HTN?
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
Inhibits DNA dependent RNA polymerase
Erythromycin - Azithromycin - Clarithromycin

44. What is the mechanism of action of Cyclosporine?
distal convoluted tubule (early)
1. Acarbose 2. Miglitol
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.
Aminoglycosides - Tetracyclines

45. What are the clinical uses for 1st Generation Cephalosporins?
cholestyramine - colestipol
Mebendazole/Thiabendazole - Pyrantel Pamoate
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
Oral

46. What is a sign of toxicity with the use of thrombolytics?
cortical collecting tubule
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Bleeding.
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)

47. Which receptors does phenylephrine act upon?
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
- Niacin - Ca++ channel blockers - adenosine - vancomycin
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
Long.

48. Beta Blockers - site of action?
Beta adrenergic receptors and Ca2+ channels (stimulatory)
- Bleomycin - amiodarone - busulfan
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
Blocks Influenza A and RubellA; causes problems with the cerebellA

49. What cholinomimetics might your pt be taking for his glaucoma
Carbachol - pilocarpine - physostigmine - echothiophate
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
Benzathine penicillin G
edrophonium (extremely short acting anticholinesterase)

50. What conditions would you use dantrolene?
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
amphetamine and ephedrine
thick ascending limb