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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 the common Fluoroquinolones (6)
Binding to the presynaptic alpha 2 release modulating receptors
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
VACUUM your Bed Room'
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia

2. What is Imipenem always administered with?
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Only in limited amounts
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
Cilastatin

3. What are the clinical uses for 1st Generation Cephalosporins?
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)

4. Furosemide increases the excretion of What ion?
Increase target cell response to insulin.
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
- Dimercaprol - succimer
Ca2+ (Loops Lose calcium)

5. Isopoterenol was given to a patient with a developing AV block - why?
Stimulates beta adrenergic receptors
Protease Inhibitors and Reverse Transcriptase Inhibitors
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.

6. MOA: Block cell wall synthesis by inhib. Peptidoglycan cross - linking (7)
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
Stimulates beta adrenergic receptors
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.

7. Which of the following would atropine administration cause? Hypothermia - bradycardia - excess salivation - dry flushed skin - or diarrhea
IV vitamin K and fresh frozen plasma
ACE inhibitor.
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)

8. ACE inhibitors - toxicity?
Inhibits Viral DNA polymerase
- N- acetylcystine
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Chronic gout.

9. Digoxin v. Digitoxin: bioavailability?
Digitoxin>95% Digoxin 75%
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
Early myocardial infarction.
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)

10. What is the category of drug names ending in - azol (e.g. Ketoconazole)
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
Carbachol - pilocarpine - physostigmine - echothiophate
Antifungal.

11. Which drug(s) cause this reaction: Agranulocytosis (3)?
torsade de pointes - excessive Beta block
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
Topical and Oral - for Oral Candidiasis (Thrush)
- Cloazapine - carbamazapine - colchicine - PTU

12. How is Amantadine used clinically?

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13. What is the MOA for the Cephalosporins?
Beta lactams - inhibit cell wall synthesis - Bactericidal
PT
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
Peptic ulcer disease.

14. Which drug(s) cause this reaction: Gingival hyperplasia?
Inhibt Assembly of new virus by Blocking Protease Enzyme
- Phenytoin
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine

15. What are Aminoglycosides synergistic with?
Beta - lactam antibiotics
Polymyxin B - Polymyxin E
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
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.

16. What is the mechanism of action of Cyclosporine?
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
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.
Blood
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.

17. How would you reverse the effect of a neuromuscular blocking agent?
Systemic mycoses
Give an antichloinesterase - neostigmine - edrophonium - etc
torsade de pointes - excessive Beta block
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)

18. What are are the Sulfonylureas (general description) and What is their use?
proarrhythmic
new arrhythmias - hypotension
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
reversible SLE- like syndrome

19. Why are the Sulfonylureas inactive in IDDM (type -1)?
Same as penicillin. Extended spectrum antibiotics
Same as penicillin. Act as narrow spectrum antibiotics
Intrathecally
Because they require some residual islet function.

20. MOA: Block protein synthesis at 50s subunit
- Atropine & pralidoxime
dry mouth - sedation - severe rebound hypertension
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
For serious - Gram + multidrug - resistant organisms

21. What is the difference in receptor affinity of epinephrine at low doses? High doses?

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22. For Heparin What is the Structure
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
1. Pioglitazone 2. Rosiglitazone.
Large anionic polymer - acidic

23. Steady state concentration is reached in __ number of half - lifes
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
Only in limited amounts
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
The only local anesthetic with vasoconstrictive properties.

24. List the mechanism - clinical use - & toxicity of Tamoxifen.
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
It inhibits release of NE.
Binding to the presynaptic alpha 2 release modulating receptors
Babiturate.

25. When is Rifampin not used in combination with other drugs?
- Vinca alkaloids(inhibit MT) - Paclitaxel
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
Edrophonium
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'

26. What is the mechanism of action of Probenacid used to treat chronic gout?
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
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.
Inhibits reabsorption of uric acid.
- Clindamycin

27. What enzymes are inhibited by NSAIDs - acetaminophen and COX II inhibitors?
Cyclooxygenases (COX I - COX II).
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
check PFTs - LFTs - and TFTs
Diuresis in pateints with sulfa allergy

28. How is Trimethoprim used clinically?
Used in combination therapy with SMZ to sequentially block folate synthesis
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia

29. What are the clinical uses for 2nd Generation Cephalosporins?
Beta lactams - inhibit cell wall synthesis - Bactericidal
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
Sotalol - Ibutilide - Bretylium - Amiodarone
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).

30. Preferential action of the Ca2+ channel blockers at cardiac muscle?
Forms toxic metabolites in the bacterial cell - Bactericidal
Inhibits reabsorption of uric acid.
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
cardiac muscle: Verapamil>Diltiazem>Nifedipine

31. What are the major structural differences between Penicillin and Cephalosporin?
Protease Inhibitors and Reverse Transcriptase Inhibitors
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)
Mg = Must go to the bathroom.
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels

32. List the mechanism - clinical use - & toxicity of Doxorubicin.

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33. What is the MOA for Acyclovir?
Sildenafil fills the penis
Inhibit viral DNA polymerase
HTN - CHF - calcium stone formation - nephrogenic DI.
Because they require some residual islet function.

34. What is the clinical use for Clomiphene?
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
Tricyclic antidepressant.
Sulfonamides - Trimethoprim
Treatment of infertility.

35. Which cancer drugs work at the level of mRNA(2)?
Blocks Norepi - but not Dopamine
- Steroids - Tamoxifen
For serious - Gram + multidrug - resistant organisms
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia

36. What is a common drug interaction associated with Griseofulvin?
No
Neurotoxicity - Acute renal tubular necrosis
Increases coumadin metabolism
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.

37. List the mechanism - clinical use - & toxicity of Methotrexate.
Protease Inhibitors and Reverse Transcriptase Inhibitors
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
- Alkalate DNA - Brain tumors - CNS toxicity

38. What is the memory key to remember Which pathway (extrinsic vs. intrinsic) and Which lab value Warfarin affects?
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
- Ethosuxamide - sulfonamides - lamotrigine
- Isoniazid

39. What is the MOA of Ribavirin?
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
AZT - to reduce risk of Fetal Transmission

40. Adverse effects of Nifedipine - verapamil?
Small lipid - soluble molecule
dizziness - flushing - constipation (verapamil) - nausea
Malaria (P. falciparum)
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia

41. MOA: Block peptidoglycan synthesis
No - it inhibits the release of Nor Epi
Benzathine penicillin G
Penicillin - G
Bacitracin - Vancomycin

42. What are the classic symptoms of cholinesterase inhibitor poisoning (parathion or other organophosphates)?
thiazides - amiloride
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
Hypersensitivity reactions

43. What is the category and mechanism of action of Zileuton in Asthma treatment?
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
Prevents the release of Ca from SR of skeletal muscle
- Dimercaprol - succimer
Antileukotriene; blocks synthesis by lipoxygenase.

44. Digoxin v. Digitoxin: excretion?
Modification via Acetylation
Diarrhea
Digoxin=urinary Digitoxin=biliary
Ipratropium

45. Resistance mechanisms for Macrolides

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46. Antiarrhythmic class IV- primary site of action?
AV nodal cells
Inhibits DNA dependent RNA polymerase
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.

47. What physiological effects was the Anes using Atropine to tx
- Methylene blue
Acetylcholinesterase; ACh is broken down into choline and acetate.
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions

48. What beta 2 agonist will help your 21yo Astma pt?
Inhibits CMV DNA polymerase
It must be Phosphorylated by Viral Thymidine Kinase
Albuterol - tertbutaline
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.

49. What are the clinical indications for bethanechol?
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
block Na+ channels in the cortical collecting tubule
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
- Vinca alkaloids(inhibit MT) - Paclitaxel

50. Foscarnet toxicity?
TMP- SMZ (DOC) - aerosolized pentamidine
Nephrotoxicity
Cimetidine is a potent inhibitor of P450; it also has an antiandrogenic effect and decreases renal excretion of creatinine. Other H2 blockers are relatively free of these effects.
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT