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Flashcards in Pharm and Physiology Deck (38)
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Which penicillins are penicillinase-stable (resistance to beta-lactamase cleavage)?

Oxacillin, nafcillin, and methicillin


How does S. aureus become resistant to most penicillins? How does MRSA become resistant to penicillinase-resistant pencillins?

Most penicillins - S. aureus produces beta-lactamase which cleaves the beta-lactam ring

Nafcillin/methicillin/oxacillin - alterations in penicillin-binding protein (PBP) structure with greatly reduced affinity for all beta-lactam antimicrobials

both reduce cell wall synthesis by interfering with PBP crosslinking of peptidoglycans


What is the drug suffix for receptor molecules? monoclonal antibodies? kinase inhibitors?

receptor molecules: "-cept"
monoclonal antibodies: "-mab"
kinase inhibitors: "-nib"


What is etanercept and what does it do?

TNFalpha inhibitor, acts as a decoy receptor
fusion protein linking a soluble TNFa receptor to the Fc component of human immunoglobulin G1 (IgG1)


Pt recently diagnosed with psychiatric disorder - head now tilted to one side and cannot straighten without considerable pain?

typical antipsychotics are D2 receptor blockers
(Haloperidol + "-azines", trifluoperazie, fluphenazine, thioridazine, chlorpromazine)

extrapyramidal symptoms with typical antipsychotic use due to resulting cholinergic excess in the striatum when D2 blocked!


Pt back from vacation with white spots all over otherwise tanned body - what fungus? Identification? Treatment?

Malassezia furfur causing pityriasis versicolor / tinea versicolor

KOH preparation of skin scrapings show "spaghetti and meatballs"

Tx: topical miconazole, selenium sulfide


Most common cause of hematogenous osteomyelitis? Most common age group, mechanism, and location?

S. aureus
predominantly disease of children
affects the long bones most frequently
usually secondary to a bacteremic event

Strep. pyogenes (group A strep) second most common cause


What organism is responsible for gas gangrene? What other affliction does it cause?

Clostridium perfringens

also causes late-onset, toxin-mediated food poisoning, characterized by a transient watery diarrhea


What is the main toxin of C. perfringens and what does it do?

Lecithinase (also known as alpha toxin)
catalyzes the splitting of phospholipid molecules (hydrolyzes lecithin-containing lipoprotein complexes in the PM)

degrades lecithin, a component of cellular phospholipid membranes, leading to membrane destruction, cell death, and widespread necrosis and hemolysis


Pt with fracture and osteoporosis - past medical history of HTN and CHF - what drug could've been used to help prevent?

increases absorption of Ca2+ from DCT
(ideal agent for treatment of HTN/CHF in women at risk for osteoporosis)


Diuretics that have an effect on calcium homeostasis? Ideal pts to be used for?

Hydrochlorothiazide - increases absorption and decreases excretion at DCT

Furosemide - loop diuretic that increases excretion (Loops Lose calcium)

HCT ideal for pts with osteoporosis or pts with renal stones
Furosemide ideal for pts with hypercalcemia


Ecthyma grangrenosum?

Pseudomonas aeruginosa
associated with bacteremia or septicemia, typically in immunocompromised pts

rapidly progressive, necrotic cutaneous lesions due to perivascular invasion and release of exotoxins to cause edema and necrosis


Pt with diffuse pruritic papulopustular rash, friend also had it. Pustular fluid = oxidase+, gram negative rods with pigment on culture epithelium? Source?

Pseudomonas aeruginosa - "hot tub folliculitis"
water source, blue-green pigment

motile, non-lactose fermenting, and grape-like odor


Treatment of acute gout? Side effects?

NSAIDs, glucocorticoids, colchicine

Colchicine side effects: GI - nausea and diarrhea


What is the mechanism of S. aureus's virulence factor?

Protein A
binds the Fc portion of IgG at the complement-binding
prevents the activation of complement, resulting in decreased C3b production and thus impaired opsonization


Sickle cell pt with osteomyelitis?

Salmonella most common, followed by E. coli (then by S. aureus)


What are the encapsulated bacteria? What vaccinations are available for asplenic pts?

Strep.pneumo, H.influenza, Neisseria meningitidis, E.coli
Salmonella, Klebsiella, group B Strep.


Pyrrolidonyl arylamidase (PYR)-positive organism? Bacitracin sensitivity?

Group A Strep
Strep. pyogenes

Bacitracin sensitive


Which organisms use an adenylate cyclase toxin?

Bacillus anthracis (Edema factor)
Bordetella pertussis (Adenylate cyclase toxin)

Both increase cAMP production to cause edema and phagocyte dysfunction


What preventative drugs are used in chronic gout? Mechanism? Name them.

Xanthine oxidase inhibitors (Allopurinol, Febuxostat)
inhibits conversion of xanthine to uric acid

Uricosuric drugs (Probenecid)
inhibits reabsorption of uric acid in the PCT


Pt treated for acute gout with diarrhea and nausea?

Colchicine - MT inhibitor


What are the toxicities of hydrochlorothiazide?

Hypokalemic metabolic alkalosis (manifests as muscle weakness and cramping)
Hyponatremia (manifests with neurological symptoms like altered mental status, seizures, etc.)



What is succinylcholine and what is it used for?

depolarizing NMJ blocking drug
strong ACh receptor agonist that produces sustained depolarization and prevents muscle contraction

used for muscle paralysis in surgery or mechanical ventilation


How can succinylcholine NMJ blockade be reversed?

administration of a cholinesterase inhibitor (e.g., neostigmine) during PHASE 2

Phase I (prolonged depolarization) - neostigmine augments block and prolongs paralysis
Phase II (repolarized but blocked, so ACh receptors available but desensitized) - neostigmine reverses the block


26yo athlete with comedonal and inflammatory nodular eruption on face, chest, back? What drugs cause this?

Acne at later age, suspect:
anabolic steroids (e.g. methyltestosterone) which are androgens --
after conversion to DHT, promote both follicular epidermal hyperproliferation and excessive sebum production (two of the major elements of acne pathophysiology)

also EGFR inhibitors and lithium


What is piperacillin-tazobactam and what is it used for?

antipseudomonal with a beta-lactamase inhibitor

used for Pseudomonas and gram-negative rods (including anaerobes like Bacteroides fragilis)


56yo female with joint pain and swelling gets treatment - weeks later presents with hemoptysis and acid-fast bacilli?

Treated for RA with TNFalpha inhibitor most likely
decreases macrophage function and may cause Tb reactivation

PPD should be performed to screen for latent Tb before starting therapy


What are bisphosphonates analogs of? Side effects?

Pyrophosphate analogs
bind hydroxyapatite in bone (major component, makes it more insoluble), inhibiting osteoclast activity

- corrosive esophagitis
(caustic and poor GI absorption -- drink plenty of water while fasting, sit up for 30min after to prevent reflux)
- osteonecrosis of the jaw


Treatment for pt with joint pain and history of facial palsy?

Lyme disease - easily treated with doxycycline or penicillin-type antibiotics (e.g. ceftriaxone)


Pt with low bone density and family history of breast cancer - treatment?

Raloxifene - selective estrogen receptor modulator
agonist at bone
antagonist at breast and uterus