Flashcards in Pharm and Physiology Deck (38)
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?
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?
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
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?
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
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?
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)