Illegal prescribing?
A healthy 30F presents with dysuria and urinary frequency. UA shows positive leukocyte esterase, positive nitrites, and >20 WBCs/hpf. She has no fever, flank pain, or comorbidities. She is prescribed nitrofurantoin for 5 days.
Stewardship police verdict?
A. Appropriate
B. Not enough
C. Overkill
🟢 Correct answer: A. Appropriate
Why correct:
Uncomplicated cystitis + first-line agent + correct 5-day duration.
Which antibiotic covers anaerobes but does NOT cover Pseudomonas?
A. Cefepime
B. Metronidazole
C. Piperacillin-tazobactam
D. Aztreonam
✅ B. Metronidazole
Metronidazole covers anaerobes and protozoa only — it has no reliable aerobic gram-positive or gram-negative coverage.
Why others are wrong:
Cefepime and aztreonam do not cover anaerobes.
Zosyn (Pip-tazo) covers both anaerobes and pseudomonas.
A patient with uncomplicated cystitis is prescribed an outpatient antibiotic.
Which medication carries an FDA boxed warning for rapid-onset peripheral neuropathy that may be permanent and should be avoided when alternatives exist?
A. Nitrofurantoin
B. TMP-SMX
C. Fosfomycin
D. Ciprofloxacin
🟢 Correct: D. Ciprofloxacin
Fluoroquinolones can cause rapid-onset peripheral neuropathy that may be permanent; FDA advises avoiding them for uncomplicated outpatient infections when alternatives exist.
Why not the others:
A. Nitrofurantoin – First-line for uncomplicated cystitis; does not carry permanent neuropathy boxed warning (main concern = long-term pulmonary/hepatic toxicity).
B. TMP-SMX – Can cause rash, SJS, hyperkalemia, but not irreversible neuropathy risk.
C. Fosfomycin – Safe first-line outpatient option with minimal systemic toxicity and no neuropathy warning.
A 23-year-old woman presents to clinic with 3 days of dysuria and mild lower abdominal discomfort. She is sexually active with one partner and uses condoms inconsistently. She has no fever. Pelvic exam reveals mild cervical motion tenderness and mucopurulent cervical discharge. A nucleic acid amplification test (NAAT) returns positive for Chlamydia trachomatis. Pregnancy test is negative.
What is the most appropriate treatment for this patient?
A. Azithromycin 1 g orally in a single dose
B. Doxycycline 100 mg orally twice daily for 7 days
C. Ceftriaxone 500 mg intramuscularly once
D. Metronidazole 500 mg orally twice daily for 7 days
B. Doxycycline 100 mg orally twice daily for 7 days
First-line treatment (nonpregnant):
Doxycycline 100 mg BID x 7 days → preferred (CDC guidelines)
Azithromycin 1 g single dose (less effective, especially for rectal infection)
Ceftriaxone → treats gonorrhea, not chlamydia
Metronidazole → treats BV or trichomoniasis
You are admitting a patient with community-acquired pneumonia.
EKG shows QTc 545 ms.
Which of the following is the best initial antibiotic choice?
A. Azithromycin + ceftriaxone
B. Levofloxacin
C. Doxycycline + ceftriaxone
D. Moxifloxacin
✅ Correct: C. Doxycycline + ceftriaxone
Maintains full CAP coverage with atypical coverage while avoiding QT-prolonging agents.
Why the others are wrong
A. Azithromycin + ceftriaxone
Azithromycin can further prolong QTc and should be avoided in significant QT prolongation.
B. Levofloxacin
Fluoroquinolones prolong QT and increase risk of torsades in patients with prolonged QTc.
D. Moxifloxacin
Also prolongs QT and carries higher torsades risk in patients with already prolonged QTc.
Patients taking metronidazole are advised to avoid alcohol due to a reaction caused by:
A. Increased ethanol metabolism
B. Inhibition of aldehyde dehydrogenase leading to acetaldehyde accumulation
C. Increased gastric acid production
D. Direct liver toxicity
🟢 Correct answer: B. Inhibition of aldehyde dehydrogenase leading to acetaldehyde accumulation
Clinical explanation:
Metronidazole can cause a disulfiram-like reaction when taken with alcohol.
Normally: ethanol → acetaldehyde → acetate.
Metronidazole inhibits aldehyde dehydrogenase, preventing breakdown of acetaldehyde → buildup of acetaldehyde in the blood.
This leads to classic symptoms within minutes to hours of alcohol intake:
Flushing
Severe nausea/vomiting
Abdominal cramping
Headache
Tachycardia
Hypotension
This reaction can be very uncomfortable and occasionally severe, so patients are advised to avoid alcohol during therapy and for ~48–72 hrs after the last dose.
A patient with community-acquired pneumonia, no prior hospitalizations, and no structural lung disease is started on vancomycin + cefepime because they are “pretty sick.”
Stewardship police verdict?
A. Appropriate
B. Not enough
C. Overkill
🟢 Correct: Overkill
Even severe CAP without MRSA/pseudomonas risk does not require this regimen.
Cefepime is reserved for CAP with pseudomonas risk (recent IV antibiotics, prior pseudomonas, or structural lung disease) — not just because the patient looks sick.
A hospitalized patient is being treated for MRSA pneumonia with an antibiotic that has excellent oral bioavailability.
After 10 days of therapy, the platelet count drops significantly.
Which antibiotic is the most likely cause?
A. Vancomycin
B. Cefepime
C. Meropenem
D. Linezolid
✅ D. Linezolid
Linezolid can cause reversible thrombocytopenia via bone marrow suppression from mitochondrial toxicity, especially with prolonged use (>1–2 weeks).
Why the others are wrong
A. Vancomycin
More commonly associated with nephrotoxicity than thrombocytopenia.
B. Cefepime
Associated with neurotoxicity in renal failure, not thrombocytopenia.
C. Meropenem
Not typically associated with clinically significant thrombocytopenia.
A healthy 28-year-old with acute bronchitis requests medication because her symptoms have not resolved in 3 days. She has no fever, hypoxia, or comorbidities.
What is the best management?
A. Azithromycin
B. Amoxicillin-clavulanate
C. Doxycycline
D. No antibiotics
🟢 D. No antibiotics
Why others are wrong:
Acute bronchitis is usually viral. Antibiotics are not indicated for acute bronchitis unless pertussis is suspected, COPD exacerbation is present, or pneumonia is suspected.
Fun fact:
Antibiotics for bronchitis provide minimal benefit and increase resistance and adverse effects.
A 52-year-old man presents with several months of epigastric discomfort, early satiety, and intermittent nausea. He denies weight loss or vomiting. He has no significant past medical history and is not taking any medications. A urea breath test is positive for Helicobacter pylori. He has no history of macrolide use.
According to current guidelines, which of the following is the most appropriate first-line treatment for this patient?
A. Omeprazole, clarithromycin, and amoxicillin for 14 days
B. Omeprazole, bismuth subsalicylate, tetracycline, and metronidazole for 14 days
C. Omeprazole and amoxicillin for 14 days
D. Omeprazole, levofloxacin, and amoxicillin for 14 days
Correct Answer:
B. Omeprazole, bismuth subsalicylate, tetracycline, and metronidazole for 14 days
First-line (preferred in most patients):
Bismuth-based quadruple therapy x 14 days
Why this is preferred:
-Increasing clarithromycin resistance in the U.S.
Clarithromycin triple therapy (Choice A): Only appropriate if: Low local resistance, No prior macrolide exposure; Less commonly used now
Dual therapy (Choice C): Not recommended due to low eradication rates
Levofloxacin triple therapy (Choice D): Typically salvage therapy, not first-line
A 72F was hospitalized for heart failure. During admission she had acute urinary retention requiring multiple catheterizations.
She now has new fever, dysuria, and flank pain (otherwise stable) and was started empirically on ceftriaxone. Ucx grows Pseudomonas aeruginosa.
What is the most appropriate next step?
A. Continue ceftriaxone
B. Switch to cefepime
C. Switch to meropenem
D. Add vancomycin
✅ Correct answer: B. Switch to cefepime
Why the others are wrong:
A. Continue ceftriaxone
Does not cover Pseudomonas and is inadequate once cultures identify this organism.
C. Switch to meropenem
Provides unnecessary carbapenem coverage in a stable patient without ESBL risk or severe sepsis.
D. Add vancomycin
No concern for resistant gram-positive organisms; vancomycin has no gram-negative coverage.
Azithromycin can improve symptoms in some chronic lung diseases partly due to which additional effect beyond its antibacterial activity?
A. Direct bronchodilation and anti-inflammatory effects
B. Increased surfactant production
C. Beta-agonist receptor stimulation
D. Increased histamine release
✅ A. Direct bronchodilation and anti-inflammatory effects
Clinical explanation (why A is right):
Macrolides like azithromycin have important non-antibiotic immunomodulatory effects that benefit chronic airway diseases (COPD, bronchiectasis, cystic fibrosis, some asthma phenotypes).
↓ Neutrophil recruitment and activation in airways
↓ Pro-inflammatory cytokines (IL-8, TNF-α)
↓ Mucus hypersecretion
Disrupt bacterial biofilms
Improve mucociliary clearance
Reduce airway hyperreactivity
Why the others are wrong:
B. Increased surfactant production – Not a known macrolide mechanism; surfactant is produced by type II pneumocytes and not clinically increased by azithromycin.
C. Beta-agonist receptor stimulation – Macrolides do not stimulate β2 receptors; that’s the mechanism of albuterol.
D. Increased histamine release – Would worsen bronchoconstriction and inflammation, not improve symptoms.
A patient with confirmed ESBL E. coli bacteremia is improving on meropenem.
Therapy is narrowed to piperacillin–tazobactam once susceptibilities return.
Stewardship police verdict?
A. Appropriate
B. Not enough
C. Overkill
Correct: Not enough
Carbapenems remain first-line for serious ESBL infections even if other agents appear susceptible.
Which of the following best describes the antimicrobial coverage of aztreonam?
A. Covers gram-negative organisms including Pseudomonas and provides reliable anaerobic coverage
B. Covers gram-positive and gram-negative organisms but lacks anaerobic coverage
C. Covers gram-negative organisms including Pseudomonas but has no gram-positive or anaerobic coverage
D. Covers gram-negative organisms only and should be avoided in patients with beta-lactam allergy
✅ C. Covers gram-negative organisms including Pseudomonas but has no gram-positive or anaerobic coverage
A 76-year-old woman with recurrent uncomplicated UTIs has received multiple courses of fluoroquinolones over the past year. Her PCP wants to avoid further use unless absolutely necessary.
Which serious adverse effect is most strongly associated with repeated fluoroquinolone exposure in older adults?
A. Hypoglycemia only
B. Tendon rupture and aortic complications
C. Severe neutropenia
D. Renal failure only
🟢 Correct answer: B. Tendon rupture and aortic complications.
Fluoroquinolones are associated with collagen degradation and connective tissue toxicity, leading to:
- Achilles tendonitis/tendon rupture (especially age >60 or on steroids)
- Increased risk of aortic aneurysm and dissection.
Risk increases with age and repeated exposure.
Why others are wrong:
A. Hypoglycemia only – FQs can cause dysglycemia (high and low), but this is not the most serious or characteristic toxicity.
C. Severe neutropenia – Not a classic or major FQ toxicity.
D. Renal failure only – FQs require renal dosing but are not primarily nephrotoxic.
A 27-year-old woman presents with a 24-hour history of tingling and burning on her upper lip, followed by the development of grouped vesicular lesions on an erythematous base. She reports similar episodes in the past, usually triggered by stress. She is otherwise healthy. Physical exam confirms recurrent herpes labialis.
Which of the following is the most appropriate treatment to reduce the duration of this outbreak?
Answer Choices
A. Valacyclovir 2 g orally every 12 hours for 1 day
B. Acyclovir 400 mg orally five times daily for 10 days
C. Famciclovir 500 mg orally three times daily for 7 days
D. Valacyclovir 1 g orally three times daily for 7 days
Correct Answer: A. Valacyclovir 2 g orally every 12 hours for 1 day
-Treat early (prodrome or within 48 hours)
-Goal = shorten symptom duration and viral shedding
Preferred regimen:
Valacyclovir 2 g PO q12h for 1 day
Most convenient, evidence-based regimen for episodic therapy
Why the other choices are incorrect
B. Acyclovir 400 mg PO 5x/day for 10 days
Appropriate for primary infection, not recurrent episodes; Duration is excessive
C. Famciclovir 500 mg TID for 7 days
Too long for episodic therapy; Typical regimen is single-day dosing for recurrence
D. Valacyclovir 1 g TID for 7 days
Dosing is used for herpes zoster (shingles), not herpes labialis
You are covering a patient with suspected perforated diverticulitis and sepsis. You start empiric therapy with Zosyn (piperacillin-tazobactam), but the pharmacy calls because it requires ID approval. It is Saturday night of a holiday weekend, and approval cannot be obtained.
What is the best alternative combination to provide equivalent coverage?
A. Ceftriaxone
B. Cefepime + metronidazole
C. Vancomycin + ceftriaxone
D. Switch to Meropenem
✅ Correct: B — Cefepime + metronidazole
Why the others are wrong:
A. Ceftriaxone
Does not cover Pseudomonas or anaerobes adequately for severe intra-abdominal sepsis.
C. Vancomycin + ceftriaxone
Adds unnecessary gram-positive coverage and still lacks Pseudomonas and reliable anaerobic coverage.
D. Switch to Meropenem
Provides overly broad carbapenem coverage and should be reserved for patients with ESBL risk, severe sepsis, or resistant organisms.
Why can TMP-SMX cause hyperkalemia, especially in older adults?
A. Increased aldosterone secretion
B. Acts like a potassium-sparing diuretic in the distal nephron
C. Causes potassium release from cells
D. Decreases renal perfusion
🟢 B. Acts like a potassium-sparing diuretic in the distal nephron
Clinical explanation:
The trimethoprim component of TMP-SMX structurally and functionally resembles amiloride, a potassium-sparing diuretic.
It blocks epithelial sodium channels (ENaC) in the distal nephron/collecting duct →
↓ sodium reabsorption → ↓ lumen-negative potential → ↓ potassium secretion into urine → potassium retention → hyperkalemia
A 58-year-old man with diabetes is admitted with fever and a large purulent lower-extremity cellulitis with active drainage. He meets sepsis criteria but is hemodynamically stable.
He is started on vancomycin.
In the ED, a urinalysis shows +leukocyte esterase, + nitrites, >50 WBCs. The patient denies dysuria, suprapubic pain, or frequency.
Urine culture later grows >100,000 CFU E. coli.
The team broadens antibiotics to vancomycin + ceftriaxone to treat both infections.
Stewardship police veredict?
A. Appropriate
B. Not enough
C. Overkill
✅ Correct: C. Overkill
Vancomycin appropriately treats purulent cellulitis with MRSA risk.
Treating asymptomatic bacteriuria, even with positive urinalysis and culture, is unnecessary and represents overtreatment.
Which antibiotic covers MRSA and VRE and is available both IV and orally?
A. Vancomycin
B. Daptomycin
C. Linezolid
D. Cefepime
✅ C. Linezolid
Why others are wrong:
Vancomycin does not cover VRE.
Daptomycin does not cover pneumonia well and has no oral form.
Cefepime has no MRSA coverage.
TMP-SMX (trimethoprim-sulfamethoxazole) is an appropriate outpatient treatment for which of the following infections?
A. Pyelonephritis due to Pseudomonas aeruginosa
B. Community-acquired MRSA skin and soft tissue infection
C. Enterococcus faecalis urinary tract infection
D. Streptococcus pyogenes cellulitis
B. Community-acquired MRSA skin and soft tissue infection.
TMP-SMX reliably covers community MRSA, many gram-negatives, PJP, and Nocardia — but not Pseudomonas and not reliable strep coverage.
Why the others are wrong
A. Pyelonephritis due to Pseudomonas aeruginosa
TMP-SMX does not reliably cover Pseudomonas.
C. Enterococcus faecalis urinary tract infection
Enterococcus is not reliably treated with TMP-SMX even if susceptibilities are reported.
D. Streptococcus pyogenes cellulitis
TMP-SMX has unreliable streptococcal coverage and is not first-line monotherapy.
A 29-year-old man presents to clinic after removing a tick from his right thigh earlier that morning. He reports hiking in a wooded area of Connecticut 48 hours ago. He believes the tick was attached for approximately 36–48 hours before removal. On exam, there is a small erythematous papule at the bite site without rash. He is otherwise asymptomatic. The tick is identified as an Ixodes scapularis (deer tick).
Which of the following is the most appropriate management for this patient?
A. Doxycycline 200 mg orally as a single dose
B. Doxycycline 100 mg orally twice daily for 10 days
C. Amoxicillin 500 mg orally three times daily for 14 days
D. No antibiotic treatment; observe only
Correct Answer: A. Doxycycline 200 mg orally as a single dose
Indications for Lyme prophylaxis (ALL must be met):
-Tick is Ixodes species
-Endemic area (e.g., Northeast, upper Midwest)
-Tick attached ≥36 hours
-Prophylaxis started within 72 hours of removal
-No contraindication to doxycycline
→ If all criteria met → Single dose doxycycline 200 mg
Why the other choices are incorrect
B. Doxycycline 100 mg BID x 10 days
Used for early localized Lyme disease (erythema migrans), not prophylaxis
C. Amoxicillin 500 mg TID x 14 days
Alternative treatment for confirmed Lyme disease, especially in pregnancy or children
Not used for prophylaxis
D. No treatment: Appropriate only if criteria for prophylaxis are not met
A hospitalized patient with pneumonia is receiving vancomycin + cefepime for sepsis.
After 48 hours, blood and sputum cultures show no growth, MRSA nares is negative, and the patient is clinically improving.
What is the best next step?
A. Continue vancomycin + cefepime for 7 days
B. Stop vancomycin and continue cefepime
C. Stop cefepime and continue vancomycin
D. De-escalate to meropenem
✅ Correct: B. Stop vancomycin and continue cefepime
Why the others are wrong
A. Continue vancomycin + cefepime
No evidence of MRSA infection; continuing vancomycin increases nephrotoxicity without benefit.
C. Stop cefepime and continue vancomycin
Would remove necessary gram-negative coverage for severe pneumonia and sepsis, while maintaining unnecessary MRSA coverage.
D. De-escalate to meropenem
Meropenem is broader therapy and represents escalation, not de-escalation, in a clinically improving patient without resistant organisms.
Clindamycin is added to beta-lactam therapy in severe invasive Group A streptococcal infections (e.g., necrotizing fasciitis) primarily because it:
A. Maintains antimicrobial activity during high bacterial inoculum and stationary growth phase
B. Suppresses streptococcal exotoxin production by inhibiting 50S ribosomal protein synthesis
C. Enhances beta-lactam penetration into necrotic tissue
D. Provides additional gram-negative coverage in polymicrobial infection
🟢 Correct answer: B. Suppresses streptococcal exotoxin production by inhibiting 50S ribosomal protein synthesis.
Clindamycin inhibits the 50S ribosome → ↓ protein synthesis → ↓ streptococcal exotoxin production → less tissue destruction and shock. This is the main reason it’s added in invasive GAS infections.
Why not the others:
A. Maintains activity in stationary phase – True property of clindamycin but not the primary reason it’s added; toxin suppression is key.
C. Enhances beta-lactam penetration – Clindamycin does not improve beta-lactam tissue penetration.
D. Provides gram-negative coverage – Clindamycin mainly covers gram-positives and anaerobes; added for toxin suppression, not gram-negative coverage.
A urine culture grows Enterococcus faecalis in a symptomatic patient.
The organism is reported susceptible to ceftriaxone, and the patient is treated with ceftriaxone.
Stewardship police verdict?
A. Appropriate
B. Not enough
C. Overkill
🟢 Correct: Not enough
Enterococcus is a gram-positive organism with intrinsic resistance to cephalosporins.
Even if reported “susceptible,” ceftriaxone does not reliably treat Enterococcus and should not be used.
Better options:
Ampicillin or amoxicillin (if susceptible), or vancomycin if needed.
An elderly patient with renal failure is being treated for sepsis with a broad-spectrum antibiotic.
Two days later, he becomes confused with myoclonus and altered mental status.
Which antibiotic is most likely responsible?
A. Piperacillin-tazobactam
B. Cefepime
C. Azithromycin
D. Vancomycin
✅ B. Cefepime
Cefepime crosses the BBB and, when accumulated (esp. in renal impairment), can cause GABA antagonism leading to encephalopathy, confusion, and myoclonus.
Why the others are wrong
A. Piperacillin-tazobactam
Not commonly associated with neurotoxicity or encephalopathy.
C. Azithromycin
Associated with QT prolongation, not encephalopathy.
D. Vancomycin
More commonly causes nephrotoxicity than neurotoxicity.
A 72F with recurrent UTIs presents with several months of progressive dry cough and dyspnea.
She has been treated multiple times for UTIs over the past year.
Chest imaging shows new bilateral interstitial changes. Cardiac workup is normal and infectious evaluation is negative.
Which medication is the most likely cause of her symptoms?
A. Cephalexin
B. Nitrofurantoin
C. Ciprofloxacin
D. TMP-SMX
✅ B. Nitrofurantoin
Repeated nitrofurantoin exposure can cause chronic interstitial lung disease and pulmonary fibrosis due to cumulative pulmonary toxicity, especially in older women with recurrent UTIs.
A 34-year-old woman presents with recurrent episodes of vaginal itching and thick white discharge over the past year. She reports at least 5 similar episodes in the past 12 months, each responding temporarily to over-the-counter antifungal therapy but recurring within weeks. She has no significant medical history and is not pregnant. Pelvic exam shows erythema of the vulva and thick, clumpy white discharge. Vaginal pH is normal, and KOH prep reveals budding yeast and pseudohyphae.
What is the most appropriate treatment regimen for this patient?
A. Fluconazole 150 mg orally as a single dose
B. Fluconazole 150 mg orally every 72 hours for 3 doses, followed by weekly fluconazole for 6 months
C. Metronidazole 500 mg orally twice daily for 7 days
D. Clindamycin 300 mg orally twice daily for 7 days
Correct Answer:
B. Fluconazole 150 mg orally every 72 hours for 3 doses, followed by weekly fluconazole for 6 months
Recurrent vulvovaginal candidiasis (RVVC):
Defined as ≥3–4 episodes in 1 year
Treatment = 2 phases:
Induction therapy:
Fluconazole 150 mg every 72 hours for 3 doses (Days 1, 4, 7)
Maintenance therapy:
Fluconazole 150 mg weekly for 6 months
During the team day off a patient aspirated and was diagnosed with aspiration pneumonia. The covering team started them on Zosyn and Metronidazole. The patient is doing better.
What is the best next step regarding the antibiotics?
A. Continue both until completing 7 days
B. Stop metronidazole
C. Stop zosyn
D. Add vancomycin
✅ Correct answer: B. Stop Metronidazole
Zosyn already covers anaerobes. Metronidazole is duplicate coverage → stop for stewardship.
Why not the others
A. Continue both
Double anaerobic coverage. No added benefit, ↑ side effects.
C. Stop zosyn
Zosyn is the main drug covering gram-negatives + anaerobes. Metronidazole alone misses aerobic bacteria (like strep and many gram-negatives), so it does not provide adequate monotherapy for aspiration pneumonia.
D. Add vancomycin
No MRSA risk factors and patient improving.
Unnecessary escalation.
A patient started on rifampin for treatment of tuberculosis returns to clinic worried that his urine, sweat, and tears have turned orange.
He feels well and liver enzymes are normal.
What is the most likely mechanism for this discoloration?
A. Conversion of rifampin into bilirubin-like metabolites during hepatic metabolism
B. Distribution and excretion of a highly pigmented drug and its metabolites into body fluids
C. Rifampin-induced hemolysis leading to increased urinary pigments
D. Conjugated hyperbilirubinemia from subclinical hepatic injury
✅ B. Distribution and excretion of a highly pigmented drug and its metabolites into body fluids.
Rifampin is a naturally red-orange, highly lipophilic compound that distributes into and is excreted through body fluids such as urine, sweat, saliva, and tears, causing benign discoloration.
Why the others are wrong
A. Conversion of rifampin into bilirubin-like metabolites during hepatic metabolism
Rifampin discoloration is not due to bilirubin or bilirubin-like compounds.
C. Rifampin-induced hemolysis leading to increased urinary pigments
Rifampin does not typically cause hemolysis resulting in orange secretions.
D. Conjugated hyperbilirubinemia from subclinical hepatic injury
Orange discoloration occurs even with normal liver function and is not due to liver injury.