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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. List the mechanism - clinical use - & toxicity of Paclitaxel.
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Beta antagonist.
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.

2. Which drug(s) cause this reaction: G6PD hemolysis(8)?
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
Antileukotriene; blocks leukotriene receptors.
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.

3. Antiarrhythmic class IB- toxicity?
local anesthetic. CNS stimulation or depression. CV depression.
Hemolytic anemia
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
- Glucocorticoid withdrawal

4. What are four H2 Blockers?
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine
Large anionic polymer - acidic
Imipenem

5. Which antimicrobial classes inhibit protein synthesis at the 30S subunit? (2)
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Digitoxin 168hrs Digoxin 40 hrs
- Chloramphenicol
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD

6. Mannitol - toxicity?
pulmonary edema - dehydration
Protamine sulfate
reversible SLE- like syndrome
Modification via Acetylation

7. Resistance mechanisms for Aminoglycosides
Leukotrienes increasing bronchial tone.
not a sulfonamide - but action is the same as furosemide
Digoxin=urinary Digitoxin=biliary
Modification via Acetylation - Adenylation - or Phosphorylation

8. What is the formula for Volume of distribution (Vd)
Dermatophytes (tinea - ringworm)
Staphlococcus aureus
Vd= (Amt. of drug in body/ Plasma drug conc.)
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.

9. What is the effect of TCA's on the adrenergic nerve?
They inhibit reuptake of NE at the nerve terminal (as does cocaine).
collecting ducts
- Lithium
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)

10. Are Ampicillin and Amoxicillin are not...
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
penicillinase resistant
Used in combination therapy with SMZ to sequentially block folate synthesis
- Isoniazid

11. What is the MOA of the RT Inhibitors?
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
amphetamine and ephedrine
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.

12. Resistance mechanisms for Sulfonamides
Premature infants - because they lack UDP- glucuronyl transferase
Protease inhibitor.
Digitoxin>95% Digoxin 75%
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis

13. What is Imipenem always administered with?
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Nucleosides
Cilastatin

14. What is the category of drug names ending in - tidine (e.g. Cimetidine)
Cardiac glycoside (inotropic agent).
No - warfarin - unlike heparin - can cross the placenta.
H2 antagonist
Gram + and Anerobes

15. What is the category of drug names ending in - azol (e.g. Ketoconazole)
Antifungal.
Inhibits Viral DNA polymerase
amphetamine and ephedrine
Pyridoxine (B6) administration

16. Why would you give a drug like pancuronium or succinylcholine?
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
Useful in muscle paralysis during surgery or mechanical ventilation.
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
- Deferoxamine

17. Antiarrhythmic class IB- effects?
Small lipid - soluble molecule
Chronic anticoagulation.
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Antifungal.

18. What is a common side effect of Misoprostol?
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
- Corticosteroids - heparin
severe hypertension - CHF
Diarrhea

19. What is the only depolarizing neuromuscular blocking agent?
Beta - lactam antibiotics
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
Succinylcholine
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)

20. Adverse effects of beta - blockers?
Slow - limited by half lives of clotting factors
As an anticholinesterase it increases endogenous ACh and thus increases strength.
Enterobacter
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)

21. Which drug(s) cause this reaction: Torsade de pointes (2)?
Oral treatment of superficial infections
Gram + cocci - Gram - rods - and Anerobes
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
- Class III antiarrhythmics (sotalol) - class IA (quinidine)

22. What is the category of drug names ending in - tropin (e.g. Somatotropin)
AluMINIMUM amount of feces.
Pituitary hormone.
Delirium - Tremor - Nephrotoxicity
Those patients who are taking nitrates.

23. Ryanodine - site of action?
not a sulfonamide - but action is the same as furosemide
Onchocerciasis ('river blindness'-- rIVER- mectin)
blocks SR Ca2+ channels
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis

24. What is the MOA of Aztreonam?
Diuresis in pateints with sulfa allergy
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy

25. What are two Alpha - glucosidase inhibitors?
GET on the Metro
1. Acarbose 2. Miglitol
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia

26. For Heparin What is the Onset of action
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
Rapid (seconds)

27. Resistance mechanisms for Macrolides

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28. How is Amphotericin B used clinically?
- Formaldehyde & formic acid - severe acidosis & retinal damage
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
- Nitrate - hydroxocobalamin thiosulfate

29. What microorganisms is Aztreonam not effective against?
Gram + and Anerobes
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
Same as penicillin. Act as narrow spectrum antibiotics
Botulinum

30. What is the category - mechanism of action - and effect of Ipratroprium in Asthma treatment?
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
- Act on same receptor - Full has greater efficacy
Pseudomonas species and Gram - rods

31. List the specific antidote for this toxin: Methemoglobin
GI distress - Skin rash - and Seizures at high plasma levels
Antileukotriene; blocks leukotriene receptors.
anticholinesterase glaucoma
- Methylene blue

32. For Warfarin What is the Onset of action
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
Slow - limited by half lives of clotting factors
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia

33. What is the memory key for the effect of magnesium hydroxide overuse?
Mg = Must go to the bathroom.
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
Flecainide - Encainide - Propafenone
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate

34. What is the mechanism of action of Probenacid used to treat chronic gout?
Chronic Hepatitis A and B - Kaposi's Sarcoma
Inhibits reabsorption of uric acid.
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.
bradycardia - AV block - CHF

35. Which drug(s) cause this reaction: Diabetes insipidus?
- Lithium
- Flumazenil
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
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.

36. Which drug(s) cause this reaction: P450 induction(6)?
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
decrease
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic

37. What enzyme is responsible for the production of Ach from Acetyl CoA and Choline
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity
Choline acetyltransferase
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Protamine sulfate

38. Aztreonam ________ to penicillinase
- Oxalic acid - Acidosis & nephrotoxicity
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
is resistant
- Oral Contraceptives

39. What is the memory key involving the '4 R's of Rifampin?'
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA

40. A fellow passenger on a Carnival cruise ship looks pale and diaphoretic - What antimuscarinic agent would you give them?
ACE inhibitor.
scopolamine
IV vitamin K and fresh frozen plasma
Local anesthetic.

41. What is the MOA for the Cephalosporins?
Onchocerciasis ('river blindness'-- rIVER- mectin)
For serious - Gram + multidrug - resistant organisms
Beta lactams - inhibit cell wall synthesis - Bactericidal
- Oral Contraceptives

42. What is the memory key for Isoniazid (INH) toxicity?
INH: Injures Neurons and Hepatocytes
Gram + - Gram - - Norcardia - Chlamydia
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Bleeding.

43. For Warfarin What is the Mechanism of action
GI upset - Superinfections - Skin rashes - Headache - Dizziness
anuria - CHF
Impairs the synthesis of vitamin K- dependent clotting factors
collecting ducts

44. What are two Glitazones?
decrease conduction velocity - increase ERP - increase PR interval
cardiac muscle: Verapamil>Diltiazem>Nifedipine
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
1. Pioglitazone 2. Rosiglitazone.

45. What are five disadvantages of Oral Contraceptives (synthetic progestins - estrogen)?
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
Acute gout.
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
Neutropenia

46. What additional side effects exist for Ampicillin?
Rash - Pseudomembranous colitis
Pretreat with antihistamines and a slow infusion rate
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
Teratogenic - Carcinogenic - Confusion - Headaches

47. Explain pH dependent urinary drug elimination?
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
AZT
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
sedation - depression - nasal stuffiness - diarrhea

48. What class of drug is echothiophate? What is its indication?
Long.
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
- Triggers apoptosis - CLL - Hodgkin's in MOPP - Cushing - like syndrome
anticholinesterase glaucoma

49. What is the receptor affinity and clinical use of isoproterenol?
It affects beta receptors equally and is used in AV heart block (rare).
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Verapamil - Diltiazem - Bepridil
For serious - Gram + multidrug - resistant organisms

50. List some specifics of lead poisoning(4)?
Mebendazole/Thiabendazole - Pyrantel Pamoate
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
Nevirapine - Delavirdine
amphetamine and ephedrine