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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 reversal agent could a Anes give to reverse the effects of Atropine
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
Hypersensitivity reactions
dry mouth - sedation - severe rebound hypertension
Bethanechol - Neostigmine - physostigmine

2. Why would you give a drug like pancuronium or succinylcholine?
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
dizziness - flushing - constipation (verapamil) - nausea
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
Useful in muscle paralysis during surgery or mechanical ventilation.

3. Hydralazine - class and mechanism?
Epinephrine
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Chronic gout.
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).

4. Digoxin v. Digitoxin: excretion?
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
- Oral Contraceptives
As an anticholinesterase it increases endogenous ACh and thus increases strength.
Digoxin=urinary Digitoxin=biliary

5. Ibutilide - toxicity?
torsade de pointes
Because they require some residual islet function.
Blocks Influenza A and RubellA; causes problems with the cerebellA
Erectile dysfunction.

6. Which Tetracycline is used in patients with renal failure? / Why?
Succinylcholine
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
Doxycycline - because it is fecally eliminated

7. Which drug(s) cause this reaction: Photosensitivity(3)?
- Oxalic acid - Acidosis & nephrotoxicity
Dermatophytes (tinea - ringworm)
- Tetracycline - amiodarone - sulfonamides
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions

8. What are common toxicities related to Vancomycin therapy?

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9. What are the clinical uses for 3rd Generation Cephalosporins?
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
GET on the Metro

10. Which drug increases Sys BP w/o affecting Pulse Pressure
Bacitracin - Vancomycin
Buy AT 30 - CELL at 50'
Epinephrine
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma

11. What are five possible toxic effects of Aspirin therapy?

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12. Why is carbachol and pilocarpine useful in treatment of glaucoma?
Cyclooxygenases (COX I - COX II).
- Methotrexate - 5 FU - 6 mercaptopurine
- Dimercaprol - succimer
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).

13. What is the mechanism of Azathioprine?
Inhibits Viral DNA polymerase
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
Protamine sulfate
GI upset - Superinfections - Skin rashes - Headache - Dizziness

14. What are the products and their toxicities of the metabolism of Ethylene Glycol by / alcohol dehydrogenase?
- Oxalic acid - Acidosis & nephrotoxicity
Gemfibrozil - Clofibrate
- Act on same receptor - Full has greater efficacy
- Normalize K+ - Lidocaine - & Anti - dig Mab

15. What is the mechanism of action and clinical use of the antiandrogens Ketoconazole and Spironolactone?
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
- Vitamin K & fresh frozen plasma
GI upset - Superinfections - Skin rashes - Headache - Dizziness
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori

16. Adverse effects of Minoxidil?
Constant FRACTION eliminated per unit time.(exponential)
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
DHPG (dihydroxy-2- propoxymethyl guanine)
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention

17. Ganciclovir associated toxicities?
- Vitamin K & fresh frozen plasma
- Shifts the curve down - reduces Vmax
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
Cilastatin

18. What is the MOA of Ribavirin?
- Tetracycline - amiodarone - sulfonamides
Slow - limited by half lives of clotting factors
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
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.

19. What is the MOA for Nystatin?
Ibuprofen - Naproxen - and Indomethacin
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
Quinolones
Binds ergosterol - Disrupts fungal membranes

20. Decrease Digitoxin dose in renal failure?
- Corticosteroids - heparin
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
NO
Prevents the release of Ca from SR of skeletal muscle

21. What is the MOA for Trimethoprim (TMP)?
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
Fast vs. Slow Acetylators
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.
torsade de pointes - excessive Beta block

22. What are three complications of Warfarin usage?
NO
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
atropine - homatropine - tropicamide

23. Do Tetracyclines penetrate the CNS?
- Shifts the curve to the right - increases Km
Only in limited amounts
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'

24. What is the effect of epinephrine infusion on bp and pulse pressure?
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
As an anticholinesterase it increases endogenous ACh and thus increases strength.
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.

25. What is the mechanism of Tacrolimus (FK506)?
Slow - limited by half lives of clotting factors
Beta antagonist.
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
Forms toxic metabolites in the bacterial cell - Bactericidal

26. Steady state concentration is reached in __ number of half - lifes
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Beta -2 agonist.
blocks SR Ca2+ channels
Aminoglycosides - Tetracyclines

27. What is the effect of the Glitazones in diabetes treatment?
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
CMV - esp in Immunocompromised patients
Epinephirine(Alpha1 -2 and Beta 1 -2)
Increase target cell response to insulin.

28. What drug is used to diagnose myasthenia gravis?
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)
The PT.
edrophonium (extremely short acting anticholinesterase)
cardiac muscle: Verapamil>Diltiazem>Nifedipine

29. What are the clinical uses for 2nd Generation Cephalosporins?
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
1. Antipyretic 2. Analgesic 3. Anti - inflammatory

30. What is the MOA for the Cephalosporins?
Beta lactams - inhibit cell wall synthesis - Bactericidal
Chronic gout.
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.

31. What are the Anti - TB drugs?
VACUUM your Bed Room'
Cell membrane Ca2+ channels of cardiac sarcomere
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
Inhibits cell wall synthesis ( binds to PBP3). A monobactam

32. What is the category of drug names ending in - cillin (e.g. Methicillin)
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
Penicillin.
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.

33. Antiarrhythmic class IA effects?
Abortifacient.
Carbenicillin - Piperacillin - and Ticarcillin
propanolol - esmolol - metoprolol - atenolol - timolol
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.

34. Decrease Digoxin dose in renal failure?
YES
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
hypertension - angina - arrhythmias
Rash - Pseudomembranous colitis

35. List the mechanism - clinical use - & toxicity of Etoposide.
Paranteral (IV - SC)
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
Hypersensitivity reactions

36. Resistance mechanisms for Macrolides

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37. ACE inhibitors - clinical use?
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
Choline acetyltransferase
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
hypertension - CHF - diabetic renal disease

38. Name two bile acid resins.
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
cholestyramine - colestipol
-100% oxygen - hyperbaric
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine

39. What are two toxicities associated with Cyclosporine?
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
Prevents the release of ACh - Which results in muscle paralysis.
Methylxanthine.
Pentamidine

40. Does Heparin have a long - medium - or short half life?
Amphetamine and Ephedrine
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
Short.

41. Antiarrhythmic class IC- effects?
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
Ipratropium
Rifampin
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia

42. IV Penicillin
Disulfiram - like reaction with EtOH - Headache
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.
G6PD deficient individuals
Penicillin - G

43. ADH antagonists - site of action?
Interstitial nephritis
collecting ducts
IV vitamin K and fresh frozen plasma
is resistant

44. Aztreonam ________ to penicillinase
CMV Retinitis in IC pts When Ganciclovir fails
is resistant
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
- Nitrate - hydroxocobalamin thiosulfate

45. What is a mnemonic to remember Amantadine's function?
proximal convoluted tubule
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Blocks Influenza A and RubellA; causes problems with the cerebellA
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).

46. What are the major toxic side effects of the Cephalosporins?
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Protease Inhibitors and Reverse Transcriptase Inhibitors
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)

47. What is the mechanism of action of Acetaminophen?
bradycardia - AV block - CHF
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
Non - Nucleosides
Succinylcholine

48. Specifically - How does Foscarnet inhibit viral DNA pol?
Binds to the Pyrophosphate Binding Site of the enzyme
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
very short acting

49. What are the clinical uses for 1st Generation Cephalosporins?
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
- Methotrexate - 5 FU - 6 mercaptopurine
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
Hydralazine and Minoxidil

50. Name the common Azoles
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
sedation - positive Coombs' test
Acts as a wide spectrum carbapenem
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole