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67 Cards in this Set
- Front
- Back
3 most common causative organisms in ABRS.
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S. pneumoniae (20-43%)
H. influenzae (22-35%) M. catarrhalis (2-10%) |
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Possible sequelae of failed antibiotic therapy in immunocompromised patients:
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Orbital cellulitis
Meningitis Septicemia |
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About S. pneumoniae
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Gram positive diplococcus.
Most common cause of ABRS, CAP and AOM. |
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About H. influenzae
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Gram negative bacillus.
Commonly causes ABRS, CAP, and AOM. |
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What factors favor H. influenzae as the causative agent?
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Tobacco use.
Recurrent infection. |
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About M. catarrhalis.
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Gram negative coccus
Significantly less frequent cause of ABRS, CAP and AOM. |
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Mechanism of resistance to penicillin of S. pneumo.
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Altered binding sites. This can be overcome by increasing drug concentration.
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Percent penicillin resistance of S. pneumo.
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25%
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Risk factors for DRSP.
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Antimicrobial use within 4-6 weeks.
Exposure to child in day care. Elderly. |
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Percent penicillin resistance of H. influenzae.
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30%
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Percent penicillin resistance of M. catarrhalis.
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90%
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Mechanism of penicillin resistance of M. cat and H. inf
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Beta lactamase. This is overcome by adding clavulanate to amoxicillin or using a non-penicillin class drug.
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Expected course of a viral URI.
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Some improvement by day 5. Lingering cough at day 7 is normal.
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When does viral replication peak in a URI?
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Day 2-3.
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Timing of symptoms that suggests bacterial etiology.
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Symptoms lasting > 7-10 days or worsening after 5-7 days.
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What is considered antimicrobial treatment failure?
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No improvement after 72 hours. Be sure to question about adherence.
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What organisms does amoxicillin treat?
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At 1.5 g/d, only susceptible organisms.
At 4.0 g/d, some DRSP and susceptible gram-negatives. Does NOT treat beta-lactamase producing gram-negatives. |
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What organisms does amoxicillin/clavulanate treat?
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At low dose this covers beta-lactamase producing gram negatives but not DRSP.
At high dose, it covers DRSP and resistant gram-negatives. |
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Which cephalosporins are recommended for ABRS?
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cefpodoxime (Vantin) - 3rd gen
cefuroxime axetil (Ceftin) - 2nd gen cefdinir (Omnicef) - 3rd gen |
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What organisms do the cephalosporins for ABRS treat?
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Gram positives.
beta-lactamase producing gram negatives. |
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What is the main factor that limits amoxicillin/clavulanate use?
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It causes significant GI upset. Counsel patients to take medication with food, especially fatty foods.
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What drugs are options for penicillin-allergic patients with mild disease and no antibiotic use in the last 4-6 weeks?
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TMP/SMX
Doxycycline a macrolide |
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First-line therapy for moderate ABRS or abx use in the last 4-6 weeks.
Alternates. |
High dose amoxicillin/clavulanate (4 g/day).
Respiratory fluroquinolone Clindamycin + rifampin Ceftriaxone IM |
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Can patients with penicillin allergy take cephalosporins?
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No.
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Are cephalosporins stable in the presence of beta lactamase?
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Yes.
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What are the respiratory fluroquinolones?
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moxifloxacin
levofloxacin |
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Why is clindamycin + rifampin not a preferred treatment?
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clindamycin has a high risk for GI side effects including C. diff colitis.
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Clindamycin is included in the drug regimen to cover:
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DRSP.
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What organisms are covered by respiratory fluroquinolones?
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DRSP and beta-lactamase producing gram-negatives.
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Best drug choice for a 25 year old college student with mild disease.
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low dose amoxicillin eg. 875 mg bid.
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Best ABRS drug choice for a 35 year old mother of a 3 year old in daycare with no recent antibiotic use.
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High dose amoxicillin (4 g daily)
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Best ABRS drug choice for a 50 year old male who was prescribed amoxicillin for sinusitis 4 weeks ago.
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HD amoxicillin/clavulanate
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Best ABRS drug choice for a very sick patient who is allergic to penicillin.
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respiratory fluroquinolone
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Best ABRS drug choice for a middle-aged man with uncertain medication history who is allergic to penicillin.
a) clarithromycin b) azithromycin c) amoxicillin d) cefdinir |
b) azithromycin.
Clarithromycin is a CYP inhibitor and should be avoided if drug interactions cannot be managed. |
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Which of the macrolides is NOT a CYP inhibitor?
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azithromycin
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Possible consequence of concomitant clarithromycin and atorvastatin use:
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Rhabdomyolysis from increased atorvastatin (CYP substrate) levels.
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Marked eyelid edema in the context of ABRS is suggestive of
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Extension of infection beyond the sinuses to periorbital cellulitis.
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Best ABRS drug choice for a 45 year old with 35 pack-year smoking history.
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Amoxicillin/clavulanate.
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When is CT of the sinuses indicated in w/u of ABRS?
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Only if there is treatment failure after escalating to strong therapy such as fluroquinolones or clindamycin + rifampin.
Not recommended for initial diagnosis. |
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What is the most important component of allergic rhinitis/conjunctivitis therapy?
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Allergen avoidance.
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During what time of the day is the allergen concentration highest?
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In the morning, as pollen is released at night.
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Mechanism of action of decongestants:
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Vasoconstriction.
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Oral decongestants are contraindicated in these patients.
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Patients with CV disease or uncontrolled HTN.
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Why are first-generation antihistamines more sedating than second-generation?
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They penetrate the blood-brain barrier better.
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What classes of allergic rhinitis drugs are recommended for use as controller therapy?
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Nasal corticosteroid spray (most potent, as it works on the most inflammatory mediators)
Leukotriene modifiers. Mast cell stabilizers. |
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Name the leukotriene modifier medications used in allergic rhinitis.
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montelukast (Singluair) PO
zafirlukast (Accolate) PO |
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Name the mast cell stabilizers used in allergic rhinitis.
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cromolyn (NasalCrom intranasal and Opticrom optic). These are OTC.
nedocromil (Alocril optic) Rx. Note that inhaled cromolyn (Intal) is approved for asthma, NOT allergic rhinitis. |
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What is one limitation of allergic rhinitis controller therapy?
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It requires 1-4 weeks to become effective.
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Name two first-generation antihistamines.
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diphenhydramine (Benadryl)
chlorpheniramine (Chlor-Trimeton) |
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Are first or second generation antihistamines more effective as rescue therapy for allergic rhinitis?
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First generation antihistamines are more effective but also more sedating.
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Name 5 second generation antihistamines.
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loratadine (Claritin)
desloratadine (Clarinex) cetirizine (Zyrtec) fexofenadine (Allegra) levocetirazine (Xyzal) |
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Name the classes of drugs used in allergic rhinitis for PO rescue therapy aimed at deactivating formed inflammatory mediators.
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1st and 2nd generation antihistamines.
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Name classes of drugs used in allergic rhinitis for symptom relief targeted at profuse nasal discharge.
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Anticholinergic nasal spray
Antihistamine nasal spray |
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Name classes of drugs used in allergic rhinitis for symptom relief targeted at nasal congestion.
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Oral decongestants
Nasal decongestants |
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Name an anticholinergic nasal spray.
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Ipratropium nasal (Atrovent nasal)
Note ipratropium inhaled (Atrovent HFA) is approved for COPD and asthma, NOT allergic rhinitis. |
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Name an antihistamine nasal spray.
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azelastine hydrochloride (Astelin, Astepro)
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Name an antihistamine for opthalmic use.
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olopatadine hydrocholride (Patanol)
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Name two nasal decongestants.
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phenylephrine (Neo-Synephrine and other trade names)
oxymetazoline (Afrin, Dristan, other trade names) |
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Some information about Afrin.
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Afrin is a nasal decongestent/vasoconstrictor with generic name oxymetazoline. It can be used safely for up to 10 days, but may cause rebound stuffiness.
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Name two oral decongestants.
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pseudoephedrine (Sudafed)
phenylephrine (Sudafed PE) |
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Anticholinergic drugs should be avoided in this population, if possible.
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Elders.
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Mnemonic for anticholinergic side effects.
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Dry as a bone (dry mouth)
Red as a beet (flushing) Mad as a hatter (confusion) Hot as a hare (hyperthermia) Can's see (mydriasis/blurred vision) Can't pee (urinary retention) Can't spit (dry mouth) Can't shit (constipation) |
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When is urinary retention from anticholinergic use most concerning?
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In elderly male patients with BPH. It rarely occurs in younger patients.
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About agitation secondary to anticholinergic medications.
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Agitation occurs in 10% of the population. It is an atypical side effect, as 90% will experience sedation.
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Mechanism of action of decongestants.
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They are vasoconstrictors and alpha-adrenergic agonists.
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Therapeutic effect of anticholinergic nasal spray.
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Dries secretions.
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Safety considerations in prescribing antihistamine rescue therapy for allergic rhinitis.
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First generation antihistamines should be used only when there is no risk from sedation ie. not driving or operating machinery.
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