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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. List the specific antidote for this toxin: TPA & Streptokinase
- Aminocaproic acid
Same as penicillin. Extended spectrum antibiotics
No - it inhibits the release of Nor Epi
No

2. Which drug(s) cause this reaction: Tardive dyskinesia?
- Methylene blue
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
- Antipsychotics
1. Antiandrogen 2. Nausea 3. Vomiting

3. What is the MOA for the Macrolides?
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Pretreat with antihistamines and a slow infusion rate
- Flumazenil

4. 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
- Clindamycin
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
Beta adrenergic receptors and Ca2+ channels (stimulatory)

5. What two vasodilators require simultaneous treatment with beta blockers to prevent reflex tachycardia and diuretics to prevent salt retention?
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
Hydralazine and Minoxidil
AV nodal cells
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain

6. Which drug(s) cause this reaction: Cough?
Resistant Gram - infections
- ACE inhibitors (Losartan>no cough)
first dose orthostatic hypotension - dizziness - headache
1. Reliable (<1% failure) 2. Lowers risk of endometrial and ovarian cancer 3. Decreased incidence of ectopic pregnancy 4. Lower risk of pelvic infections 5. Regulation of menses

7. What reversal agent could a Anes give to reverse the effects of Atropine
Bethanechol - Neostigmine - physostigmine
- Physostigmine salicylate
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).

8. What are common serious side effects of Aminoglycosides and What are these associated with?
Aplastic anemia (dose independent) - Gray Baby Syndrome
Beta - lactamase cleavage of Beta - lactam ring
toxic
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)

9. Acetazolamide - toxicity?
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Digitoxin 70% Digoxin 20-40%
Ganciclovir is more toxic to host enzymes
Short.

10. List the specific antidote for this toxin: Cyanide
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
- Nitrate - hydroxocobalamin thiosulfate
They inhibit reuptake of NE at the nerve terminal (as does cocaine).
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity

11. What are common side effects of RT Inhibitors?
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
physostigmine
Acute (hours)
BM suppression (neutropenia - anemia) - Peripheral neuropathy

12. How do spare receptors effect the Km?
- ED 50 is less than the Km (less than 50% of receptors)
hyperaldosteronism - K+ depletion - CHF
GI side effects. (Indomethacin is less toxic - more commonly used.)
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)

13. Resistance mechanisms for Macrolides

14. K+ sparing diuretics - site of action?
Indomethacin is used to close a patent ductus arteriosus.
cortical collecting tubule
Foscarnet = pyroFosphate analog
Pretreat with antihistamines and a slow infusion rate

15. Triamterene and amiloride - mechanism?
Benzathine penicillin G
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
block Na+ channels in the cortical collecting tubule
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.

16. Which drug(s) cause this reaction: Cardiac toxicity?
- Daunorubicin & Doxorubicin
Blood
The PTT.
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine

17. Why is Cilastatin administered with Imipenem?
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
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
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
Scopolamine

18. Which of these three drugs will cause a reflex bradycardia in your pt (Norepi - Epi - or Isoporterenol)
Norepinephrine
The only local anesthetic with vasoconstrictive properties.
DOC in diagnosing and abolishing AV nodal arrhythmias
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)

19. What is the MOA for the Azoles?
Malaria (P. falciparum)
Inhibit Ergosterol synthesis
TCA
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )

20. Acetaminophen has What two clinical uses and lacks What one clinical use of the NSAIDs?
- B51Naloxone / naltrexone (Narcan)
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
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

21. How is Ribavirin used clinically?
Yes
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
for RSV
Alpha -1 antagonist

22. For Heparin What is the Ability to inhibit coagulation in vitro
Mg = Must go to the bathroom.
Yes
decrease
- Vinca alkaloids(inhibit MT) - Paclitaxel

23. Name several common Macrolides (3)
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
Interstitial nephritis
- Disulfram & also sulfonylureas - metronidazole
Erythromycin - Azithromycin - Clarithromycin

24. What conditions are treated with Metronidazole?
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
Alpha -1 antagonist
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas

25. For Warfarin What is the Route of administration
Oral
Suramin
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
- Tetracycline

26. What is used to reverse the action of Heparin?
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Inhibit viral DNA polymerase
As an anticholinesterase it increases endogenous ACh and thus increases strength.
Norepinephrine

27. What are major side effects of Methicillin - Nafcillin - and Dicloxacillin?
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
Hypersensitivity reactions
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine

28. ACE inhibitors - mechanism?
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
Prevents the release of Ca from SR of skeletal muscle
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression

29. What is the category of drug names ending in - oxin (e.g. Digoxin)
Imipenem
- Formaldehyde & formic acid - severe acidosis & retinal damage
Cardiac glycoside (inotropic agent).
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).

30. Adverse effect of Nitroprusside?
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
for RSV
No - it inhibits the release of Nor Epi
cyanide toxicity (releases CN)

31. What is the category - method of use - and adverse effects of Salmeterol in Asthma treatment?
severe hypertension - CHF
- N- acetylcystine
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
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

32. Preferential action of the Ca2+ channel blockers at vascular smooth muscle?
cardiac muscle: Verapamil>Diltiazem>Nifedipine
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil

33. Antimicrobial prophylaxis for Gonorrhea
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
Ceftriaxone
Local anesthetic.
cardiac muscle: Verapamil>Diltiazem>Nifedipine

34. What is the category - desired effect - and adverse effect of Isoproterenol in the treatment of Asthma?
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
Megaloblastic anemia - Leukopenia - Granulocytopenia
- Corticosteroids - heparin

35. What is the MOA for the Tetracyclines?
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
Lipoxygenase
Quinidine - Amiodarone - Procainamide - Disopyramide
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity

36. What enzyme is responsible for the degredation of Ach
viral kinase
Acetylcholine esterase
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
Bleeding.

37. Explain differences between full and partial agonists(2).
Paranteral (IV - SC)
Constant FRACTION eliminated per unit time.(exponential)
It must be Phosphorylated by Viral Thymidine Kinase
- Act on same receptor - Full has greater efficacy

38. Resistance mechanisms for Chloramphenicol
Quinolones
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
Norepinephrine
Modification via Acetylation

39. What microorganisms is Aztreonam not effective against?
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Gram + and Anerobes
proximal convoluted tubule - thin descending limb - and collecting duct
GI side effects. (Indomethacin is less toxic - more commonly used.)

40. Loop diuretics (furosemide)- site of action?
No - hemicholinum block the uptake of Choline and thus Ach synthesis
- Shifts the curve to the right - increases Km
thick ascending limb
- B51Naloxone / naltrexone (Narcan)

41. Nifedipine has similar action to?
Nitrates
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
Binding to the presynaptic alpha 2 release modulating receptors
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic

42. What antimuscarinic agent is used in asthma and COPD?
Nephrotoxicity
Ipratropium
BM suppression (neutropenia - anemia) - Peripheral neuropathy
Suramin

43. What are nine findings of Iatrogenic Cushing's syndrome caused by glucocorticoid therapy?
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
Botulinum
Gram + - Gram - - Norcardia - Chlamydia
Antileukotriene; blocks leukotriene receptors.

44. What is the MOA of the RT Inhibitors?
blocks SR Ca2+ channels
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
check PFTs - LFTs - and TFTs
Rifampin

45. Digoxin v. Digitoxin: bioavailability?
Prevents the release of Ca from SR of skeletal muscle
Bleeding.
Digitoxin>95% Digoxin 75%
Benzathine penicillin G

46. Why would you give a drug like pancuronium or succinylcholine?
Useful in muscle paralysis during surgery or mechanical ventilation.
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
Bacitracin - Vancomycin

47. What are Amantadine - associated side effects?
Short.
- Quinidine - quinine
Ataxia - Dizziness - Slurred speech
Cephalosporins

48. Toxicities associated with Acyclovir?
- Oral Contraceptives
Delirium - Tremor - Nephrotoxicity
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.

49. Clonidine is the preferred sym pathomimetic tx of HTN in pts with renal disease - why??
compensatory tachycardia - fluid retention - lupus - like syndrome
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Decreased uptake or Increased transport out of cell
Useful in muscle paralysis during surgery or mechanical ventilation.

50. What effect would atropine have on a patient with peptic ulcer disease?
They inhibit reuptake of NE at the nerve terminal (as does cocaine).
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).
Hemolytic anemia