When to intubate in GCS?

GCS ≤ 8 requires intubation for airway protection. The patient cannot protect their own airway at this level of consciousness. Motor score is the most prognostically important component.

What is the best initial fluid for sepsis resuscitation?

Lactated Ringer's (LR) is the preferred resuscitation fluid. The SMART trial (2018) showed balanced crystalloids reduced death, new renal failure, and persistent renal dysfunction compared to normal saline.

When to start vasopressors in septic shock?

Start norepinephrine (first-line vasopressor) if MAP remains < 65 mmHg after initial 30 mL/kg crystalloid resuscitation, or earlier if patient is profoundly hypotensive. Do not delay pressors to complete full fluid resuscitation.

Why can serum uric acid be normal during acute gout?

During acute inflammation, IL-6 increases renal urate excretion and redistributes urate from plasma to tissues. Up to 40% of acute gout flares have normal serum uric acid. Joint aspiration with polarized microscopy is needed for definitive diagnosis.

How do you distinguish lupus flare from infection in SLE?

Key clues: CRP is low/normal in flare but elevated in infection. Complement (C3/C4) drops in flare but is normal/elevated in infection. Procalcitonin is elevated in bacterial infection but normal in flare. Anti-dsDNA rises in flare, stable in infection.

What is the difference between DKA and HHS?

DKA features acidosis (pH 600), hyperosmolality (> 320), and minimal ketosis -typically in Type 2 DM. DKA requires insulin drip; HHS requires aggressive fluid resuscitation first.

When to give tPA in acute ischemic stroke?

IV alteplase (tPA) can be given within 4.5 hours of last known well time in eligible patients. CT head must rule out hemorrhage first. For large vessel occlusion, mechanical thrombectomy can be performed up to 24 hours with favorable imaging.

What antibiotics for community-acquired pneumonia?

Inpatient non-ICU: ceftriaxone + azithromycin. ICU: ceftriaxone + azithromycin (add vancomycin if MRSA risk). Outpatient healthy: amoxicillin. Outpatient with comorbidities: augmentin + azithromycin or respiratory fluoroquinolone. Duration: 5 days if clinically stable for 48 hours.

How to interpret iron studies?

Iron deficiency: low ferritin (< 30), high TIBC, low iron, low transferrin saturation (< 20%). Anemia of chronic disease: normal/high ferritin (acute phase reactant), low TIBC, low iron. A ferritin of 50-100 in an inflamed patient may still represent iron deficiency.

What is the correction rate for hyponatremia?

Correct sodium no more than 8 mEq/L in 24 hours to avoid osmotic demyelination syndrome (ODS). For symptomatic severe hyponatremia with seizures, give 3% hypertonic saline 100-150 mL bolus over 10-20 minutes. If overcorrected, use D5W + DDAVP rescue protocol.

When to start antibiotics in meningitis?

Within 30-60 minutes. Do NOT delay antibiotics for LP or CT. Draw blood cultures, start empiric antibiotics (vancomycin + ceftriaxone ± ampicillin if > 50 or immunocompromised), then perform LP when possible. Dexamethasone should be given before or with the first antibiotic dose.

DOACs vs warfarin in antiphospholipid syndrome?

DOACs are contraindicated in APS. The TRAPS trial (2018) showed rivaroxaban was inferior to warfarin with more thrombotic events in triple-positive APS patients. Warfarin with INR target 2-3 is the standard for APS, indefinitely.

How to manage scleroderma renal crisis?

ACE inhibitors (captopril) are life-saving -start immediately and titrate aggressively. Do NOT hold for rising creatinine. Steroids > 15 mg prednisone per day precipitate scleroderma renal crisis. ARBs are NOT a substitute -evidence is only for ACEi.

What are the 4 pillars of heart failure treatment?

Guideline-directed medical therapy (GDMT) for HFrEF: (1) ARNI or ACEi/ARB, (2) beta-blocker (carvedilol, metoprolol succinate, or bisoprolol), (3) MRA (spironolactone or eplerenone), (4) SGLT2 inhibitor (dapagliflozin or empagliflozin). All four should be initiated and titrated to target doses.

Antibiotic Guide -Empiric Coverage by Infection -RoundsRx

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🎯 Empiric Antibiotics by Condition

🫁 Pneumonia (CAP / HAP / VAP)

5 regimens

›

Setting	First-Line	Alternatives / Severe	Duration
CAP -outpatient, healthy	Amoxicillin (Amoxil) 1g TID	Doxycycline 100 mg BID if penicillin allergy	5 days
CAP -outpatient, comorbidities	Augmentin 875 BID + azithromycin	Respiratory FQ monotherapy (levofloxacin 750 mg daily)	5 days
CAP -inpatient (non-ICU)	Ceftriaxone (Rocephin) 1–2g IV + azithro 500 IV	Add vancomycin if MRSA risk	5 days (if stable ×48h) Short-Course CAP Trial, 2016
CAP -ICU (severe)	Ceftriaxone (Rocephin) 2g IV + azithro 500 IV	+ vanc or linezolid if MRSA (linezolid preferred -better lung penetration). + pip-tazo/cefepime if Pseudomonas risk.	7 days
HAP / VAP	Pip-tazo 4.5g q6h or cefepime 2g q8h	+ vancomycin or linezolid for MRSA (linezolid if severe -better lung penetration). Pip-tazo if anaerobic concern (abscess/empyema). Cefepime preferred with vanc (↓ AKI ACORN, 2024). Need cefepime + anaerobes → add metronidazole.	7 days ATS/IDSA, 2016

🔬 Urinary Tract Infections

3 regimens

›

Setting	First-Line	Alternatives	Duration
Uncomplicated cystitis	Nitrofurantoin (Macrobid) 100 mg BID	TMP-SMX DS BID × 3d. Fosfomycin 3g × 1. Avoid FQ for cystitis.	3–5 days
Pyelonephritis -outpatient	Ciprofloxacin (Cipro) 500 BID	Ceftriaxone 1g IM × 1 + oral step-down	5–7 days
Pyelonephritis -inpatient	Ceftriaxone (Rocephin) 1g IV daily	Pip-tazo or meropenem if ESBL/MDR risk	FQ 5–7d, TMP-SMX 7–10d, beta-lactam 10–14d (total duration depends on PO step-down agent)

ASB (asymptomatic bacteriuria) = do NOT treat -except in pregnancy and pre-urologic procedure. Nitrofurantoin: avoid if CrCl < 30.

🩹 Skin & Soft Tissue Infections

2 regimens

›

Type	First-Line	Alternatives	Duration
Cellulitis (non-purulent)	Cefazolin (Ancef) 2g IV q8h (inpatient) or cephalexin (Keflex) 500 QID (outpatient)	Purulent/abscess → I&D + TMP-SMX or doxycycline for MRSA	5–7 days
Necrotizing fasciitis SURGICAL EMERGENCY	Vanc + pip-tazo + clindamycin	Clindamycin inhibits toxin production (Group A strep). EMERGENT surgical debridement.	Until source controlled

🫃 Intra-Abdominal Infections

2 regimens

›

Setting	First-Line	Alternatives	Duration
Community intra-abdominal	Ceftriaxone (Rocephin) 2g + metronidazole (Flagyl) 500 q8h	Pip-tazo 4.5g q6h (single agent). Meropenem if ESBL.	4 days (post source control) STOP-IT, 2015
SBP* *= Spontaneous Bacterial Peritonitis	Ceftriaxone (Rocephin) 2g IV daily	Pip-tazo or meropenem if nosocomial/FQ* failure *FQ = Fluoroquinolone (ciprofloxacin, levofloxacin, moxifloxacin)	5 days

🧠 CNS Infections

1 regimen

›

Setting	First-Line	Alternatives	Duration
Bacterial meningitis (adult)	Vanc + ceftriaxone 2g q12h	+ ampicillin 2g q4h if age >50 or immunocompromised (Listeria). Dex before/with 1st abx dose European Dexamethasone Meningitis Trial, 2002.	10–14 days (S. pneumo); 7 days (N. meningitidis)

Antibiotics within 30–60 min. Do NOT delay for LP or CT. Get blood cultures → start abx → then LP.

❤️ Endocarditis

1 regimen

›

Setting	Empiric	Culture-Directed	Duration
Native valve (empiric)	Vanc + ceftriaxone	MSSA → nafcillin/cefazolin. MRSA → vanc or daptomycin. Enterococcus → ampicillin + gentamicin or ampicillin + ceftriaxone.	4–6 weeks

3 sets of blood cultures from 3 sites before antibiotics. Daptomycin is an alternative to vanc for right-sided MRSA endocarditis -but NOT for left-sided (poor penetration through vegetations).

🚨 Sepsis & Febrile Neutropenia

2 regimens

›

Setting	First-Line	Alternatives / Add-On	Duration
Sepsis (unknown source)	Vanc + cefepime or vanc + pip-tazo	Meropenem if ESBL risk or critically ill. Add antifungal if immunocompromised + no improvement day 4–7.	Source-dependent
Neutropenic fever (ANC < 500 + T ≥ 38.3)	Cefepime (Maxipime) 2g IV q8h	+ vanc if hemodynamic instability, line infection, MRSA. + antifungal day 4–7 if persistent fever.	Until ANC recovery + afebrile ≥48h

Antibiotics within 1 hour in sepsis and neutropenic fever. Every hour of delay increases mortality. Empiric broad → narrow based on cultures at 48–72h.

🦠 C. difficile

2 regimens

›

Severity	First-Line	Alternatives	Duration
Non-severe	Fidaxomicin 200 mg BID PREFERRED	Vancomycin PO 125 mg QID	10 days
Fulminant (ileus, megacolon, shock)	Vanc PO 500 QID + metronidazole IV 500 q8h	± vanc enemas if ileus. Surgical consult for colectomy.	Until resolved

Soap and water for hand hygiene (alcohol sanitizer does NOT kill C. diff spores). Fidaxomicin has lower recurrence rate than vanc IDSA/SHEA, 2021.

🦠 Spectrum of Activity

Gram-Positive Coverage

Drug	MSSA	MRSA	Strep	Enterococcus	Notes
Cefazolin (Ancef) / Cephalexin (Keflex)	✓	✗	✓	✗	Best anti-staphylococcal cephalosporin. First-line MSSA.
Nafcillin / Oxacillin	✓✓	✗	✓	✗	Gold standard MSSA bacteremia / endocarditis.
Vancomycin (Vancocin)	✓	✓	✓	✓ (not VRE)	Workhorse MRSA drug. Nephrotoxic. Target AUC/MIC 400–600 (trough-based monitoring is outdated per 2020 ASHP/IDSA).
Linezolid (Zyvox)	✓	✓	✓	✓ (incl VRE)	Covers VRE. PO = IV bioavailability. Serotonin syndrome risk. Thrombocytopenia >2 weeks.
Daptomycin (Cubicin)	✓	✓	✓	✓ (incl VRE)	Inactivated by surfactant -do NOT use for pneumonia. Check CK weekly (rhabdo).
TMP-SMX (Bactrim)	✓	✓ (CA-MRSA)	Variable	✗	Good oral MRSA option for skin/soft tissue. Not reliable for strep.

Gram-Negative Coverage

Drug	Enterobacteriaceae	Pseudomonas	ESBL	Anaerobes	Notes
Ceftriaxone (Rocephin)	✓✓	✗	✗	✗	Workhorse for community GNR. No Pseudomonas. No anaerobes.
Cefepime (Maxipime)	✓✓	✓	✗	✗	Anti-pseudomonal cephalosporin. Neurotoxic in renal failure (seizures).
Pip-tazo (Zosyn)	✓✓	✓	Variable	✓	Broadest non-carbapenem. Covers Pseudomonas + anaerobes. Workhorse for abdominal/polymicrobial.
Meropenem (Merrem)	✓✓	✓	✓	✓	Broadest spectrum. Reserve for ESBL, MDR, failing empiric therapy. Does NOT cover MRSA.
Aztreonam	✓	✓	✗	✗	Safe in penicillin allergy (monobactam, no cross-reactivity). GNR only -no gram-positive, no anaerobes.
Fluoroquinolones	✓	✓ (cipro)	✗	✗ (moxi has some)	Rising resistance. FDA black box warnings. Save for specific indications (pyelo, prostatitis, Legionella).
Metronidazole (Flagyl)	✗	✗	✗	✓✓	Anaerobe specialist. Also covers C. diff (fulminant, IV), Giardia, amebiasis. Disulfiram reaction with alcohol.

Daptomycin is inactivated by pulmonary surfactant -NEVER use for pneumonia. This is a classic boards and real-life mistake. Use vancomycin or linezolid for MRSA pneumonia.

💊 Renal Dose Adjustments

Drug	Normal Dose	CrCl 10–30	HD	Key Notes
Vancomycin (Vancocin)	15–20 mg/kg q8–12h	15–20 mg/kg q24–48h (by levels)	Re-dose by levels post-HD	Target AUC/MIC 400–600. Check troughs. Nephrotoxic -avoid with pip-tazo if possible ACORN, 2024.
Pip-tazo (Zosyn)	4.5g IV q6h	2.25g IV q6h	2.25g q6h + dose after HD	Extended infusion (4h) improves outcomes in critically ill.
Cefepime (Maxipime)	2g IV q8h	1g IV q12–24h	1g IV q24h + dose after HD	Neurotoxic in renal failure (encephalopathy, myoclonus, seizures). Monitor closely.
Meropenem (Merrem)	1g IV q8h	500 mg IV q12h	500 mg IV q12h + dose after HD	Lower seizure threshold than imipenem.
Levofloxacin (Levaquin)	750 mg IV/PO daily	750 mg q48h	500 mg q48h	Not removed by HD. Avoid in myasthenia.
TMP-SMX (Bactrim)	DS BID (UTI) or 15 mg/kg/day (PCP)	Half dose if CrCl 15–30. Avoid <15.	Dose after HD	Causes hyperkalemia (blocks ENaC). Falsely ↑ Cr (blocks tubular secretion).
Nitrofurantoin (Macrobid)	100 mg BID	AVOID if CrCl < 30		Ineffective (can't concentrate in urine) + pulmonary toxicity risk.
Metronidazole (Flagyl)	500 mg q8h	No adjustment needed	Dose after HD	Hepatically metabolized. No renal adjustment.
Linezolid (Zyvox)	600 mg q12h	No adjustment needed	No adjustment	Not renally cleared. 100% PO bioavailability = IV.
Daptomycin (Cubicin)	6–10 mg/kg IV daily	6–10 mg/kg IV q48h	Dose after HD	Check CK weekly. Not for pneumonia.

🧠 Stewardship Pearls

Always get cultures before antibiotics -but never delay antibiotics for cultures in sepsis or meningitis
De-escalate within 48–72h based on culture/sensitivity. Broad empiric → narrow targeted is the rule.
Shorter is better: CAP 5 days, UTI 3–5 days, intra-abdominal 4 days post-source-control, HAP/VAP 7 days. Longer courses don't improve outcomes and increase resistance + C. diff.
IV to PO switch: switch to oral when afebrile ×48h, tolerating PO, improving clinically. Most antibiotics have excellent oral bioavailability (FQ, linezolid, metronidazole, TMP-SMX, fluconazole).
Vanc + pip-tazo may increase AKI compared to vanc + cefepime ACORN, 2024. Prefer vanc + cefepime when both cover the suspected pathogens.
"Bug-drug mismatch" -common errors: ceftriaxone doesn't cover Pseudomonas; cefazolin doesn't cover MRSA; daptomycin doesn't work in the lung; nitrofurantoin doesn't work above the bladder.
Allergies: ~90% of "penicillin allergies" are not true IgE-mediated. Cephalosporin cross-reactivity is < 2%. Get allergy history details (rash vs anaphylaxis). Consider allergy testing.

Linezolid vs Vancomycin -When to Choose Which

Both cover MRSA. But they are NOT interchangeable. Choosing wrong = treatment failure, unnecessary toxicity, or worse outcomes. Know when each one wins.

Feature	Vancomycin	Linezolid (Zyvox)
MOA	Cell wall synthesis inhibitor -binds D-Ala-D-Ala terminus of peptidoglycan precursors, preventing cross-linking. Bactericidal (slowly).	Protein synthesis inhibitor -binds 23S rRNA of the 50S ribosome, blocking formation of the 70S initiation complex → prevents translation. Bacteriostatic. Also a weak reversible MAOi (inhibits monoamine oxidase → serotonin syndrome risk).
Route	IV only for systemic infections (PO only for C. diff -not absorbed)	IV and PO -100% oral bioavailability (PO = IV)
MRSA	✓ Gold standard	✓ Equivalent
VRE* *= Vancomycin-Resistant Enterococcus	✗ No	✓ Yes -one of very few VRE options
Lung penetration	Poor (~25%)	Excellent (~100%)
CSF penetration	Moderate (needs inflamed meninges)	Good
Renal dosing	YES -must adjust. AUC/MIC-guided dosing (target 400-600).	No renal adjustment. No drug levels needed.
Key toxicity	Nephrotoxicity, Red Man Syndrome (infuse over ≥1h), ototoxicity, DRESS (rare)	Thrombocytopenia (#1 -dose-dependent, usually > 14 days), serotonin syndrome (MAOi activity), lactic acidosis (mitochondrial toxicity), peripheral neuropathy (may be irreversible), optic neuritis (vision loss -check visual acuity if > 28 days), myelosuppression (anemia, leukopenia)
Duration limit	No hard limit	≤ 14 days preferred. > 14d: ↑ thrombocytopenia. > 28d: ↑↑ neuropathy, optic neuritis, lactic acidosis. If > 2 weeks needed → monitor closely or switch to vanc.
Monitoring	Trough AUC/MIC 400–600, BMP, CBC	CBC twice weekly (platelets). If > 14d: weekly lactate, visual acuity, neuro exam for neuropathy symptoms (numbness, tingling). No drug levels needed.
Drug interactions	Nephrotoxics (aminoglycosides, pip-tazo)	SSRIs, SNRIs, MAOIs, tramadol, meperidine → serotonin syndrome
Cost	Cheap	Expensive

🏆 Choose Vancomycin

MRSA bacteremia -bactericidal, proven outcomes
Endocarditis -need bactericidal activity
Osteomyelitis -long-duration therapy OK
Empiric broad MRSA coverage -default first-line
Cost-sensitive settings

🏆 Choose Linezolid

MRSA pneumonia -far superior lung penetration ZEPHyR, 2012
VRE infections -vanc is useless against VRE
CKD / AKI -no renal adjustment, won't worsen kidneys
No IV access -100% PO bioavailability
Outpatient MRSA Tx -go home on PO instead of IV vanc
Vancomycin failure or allergy

Never use daptomycin for pneumonia. Pulmonary surfactant inactivates it. For MRSA pneumonia your choices are vancomycin or linezolid -and linezolid is likely better due to lung penetration.

Linezolid + serotonergic drugs = serotonin syndrome. Always check the med list for SSRIs, SNRIs, MAOIs, tramadol, meperidine before starting linezolid. If the patient is on an SSRI and needs MRSA coverage → use vancomycin.

⚠️ Linezolid Toxicity Timeline:
• > 14 days: thrombocytopenia (check CBC twice weekly), myelosuppression, lactic acidosis (check weekly lactate)
• > 28 days: peripheral neuropathy (numbness/tingling -may be irreversible), optic neuritis (blurred vision, color vision loss -check visual acuity weekly)
• Any duration: serotonin syndrome if on SSRIs/SNRIs/MAOIs/tramadol (linezolid is a weak MAOi)
If you need > 2 weeks of MRSA therapy (endocarditis, osteo), vancomycin is safer for long courses.

Toxin suppression -linezolid & clindamycin. Both are protein synthesis inhibitors (50S ribosome) → they suppress bacterial toxin production even before the bacteria die. This is why clindamycin is always added in necrotizing fasciitis (suppresses Group A strep exotoxins), toxic shock syndrome (suppresses TSST-1 and strep pyrogenic exotoxins), and PVL-producing MRSA (Panton-Valentine leukocidin). Linezolid has the same mechanism and can substitute when clindamycin resistance is a concern. Vancomycin kills the bacteria but does NOT suppress toxin production -in toxin-mediated disease, bactericidal alone is not enough.

⏱ Duration by Infection

Respiratory

Infection	Duration	Key Notes / Evidence
CAP (uncomplicated)* *= No ICU admission, no empyema/abscess, no bacteremia, immunocompetent, clinically improving	5 days	If afebrile ≥48h + ≤1 sign instability (HR, RR, BP, SpO₂, mental status)
CAP (complicated)* *= Empyema, lung abscess, necrotizing pneumonia, cavitation, or inadequate clinical response by day 3–5	2–6 weeks	Depends on drainage adequacy and imaging resolution. Empyema needs chest tube + abx
HAP* / VAP* HAP = Hospital-Acquired Pneumonia (≥48h after admission) VAP = Ventilator-Associated Pneumonia (≥48h after intubation)	7 days	ATS/IDSA 2016. Shorter courses reduce resistance
COPD exacerbation (with abx)	5 days	Only if ≥2 Anthonisen criteria
Lung abscess	4–6 weeks	Until imaging improvement

Urinary

Infection	Duration	Key Notes / Evidence
Simple cystitis (women)	3–5 days	Nitrofurantoin (Macrobid) 5d, TMP-SMX (Bactrim) 3d, fosfomycin 1 dose
Complicated UTI* *= UTI extending beyond the bladder (pyelonephritis, urosepsis) OR occurring in a host with impaired urinary tract clearance (male, pregnant, anatomic abnormality, obstruction, catheter, immunocompromised, renal transplant)	7–14 days	Depends on source control. Broader coverage needed (FQ or beta-lactam)
Pyelonephritis (uncomplicated)	5–7 days	FQ 5d, TMP-SMX 7d, beta-lactam 10–14d
Catheter-associated UTI	7 days	Remove or replace catheter. 10–14d if slow response
Prostatitis (acute)	2–4 weeks	FQ or TMP-SMX preferred (prostate penetration)

Bloodstream

Infection	Duration	Key Notes / Evidence
Uncomplicated gram-negative bacteremia = Source identified & controlled, no endovascular infection, no prosthetic material, immunocompetent, defervesced within 72h, cultures cleared	7 days	From first negative blood culture. ALL criteria must be met
Complicated gram-negative bacteremia = Undrainable source, endovascular, prosthetic material, immunocompromised, persistent bacteremia >72h, or metastatic infection	14 days	Any ONE feature makes it complicated → 14 days
*Staph aureus bacteremia (MSSA/MRSA)* MSSA = Methicillin-Sensitive Staph aureus MRSA = Methicillin-Resistant Staph aureus	≥4 weeks (minimum)	ALWAYS. TTE/TEE required. ID consult mandatory
Coag-negative staph (true infection)	5–7 days + line removal	Often contaminant -need 2+ positive cultures
Enterococcal bacteremia	7–14 days	Longer if endocarditis not excluded
Candidemia	14 days from first negative culture	Ophthalmology consult. Remove all central lines. Echo

S. aureus bacteremia is NEVER uncomplicated enough for short-course therapy. Minimum 4 weeks IV. Always echo. Always ID consult.

Skin / Soft Tissue

Infection	Duration	Key Notes / Evidence
Simple cellulitis	5 days	Extend to 7–10d if slow response
*Purulent SSTI / abscess** *SSTI = Skin and Soft Tissue Infection	*I&D ± 5–7 days** *I&D = Incision and Drainage	I&D is primary treatment
Necrotizing fasciitis	Until debridement complete	Surgical emergency
Diabetic foot (soft tissue)	1–2 weeks	If no osteomyelitis
Diabetic foot (osteo)	6 weeks	Based on bone culture

Intra-abdominal

Infection	Duration	Key Notes / Evidence
Intra-abdominal (adequate source control)	4 days	STOP-IT, 2015. NOT 7–14 days
Cholangitis / cholecystitis	Source control + 4–5 days	Cholecystectomy within 72h
SBP* *= Spontaneous Bacterial Peritonitis	5 days	Ceftriaxone. Albumin day 1 and 3
C. difficile (initial)	10 days	Fidaxomicin preferred
C. difficile (fulminant)	Until improving	PO vanc 500mg q6h + IV metronidazole

Bone / Joint

Infection	Duration	Key Notes / Evidence
Osteomyelitis (native bone)	6 weeks	IV → PO step-down OK (OVIVA trial)
*Prosthetic joint (DAIR)** *DAIR = Debridement, Antibiotics, Implant Retention	6 wk IV + chronic suppression	Rifampin backbone if staph
Septic arthritis (native)	3–4 weeks	GPC* 3wk, GNR* 4wk. I&D essential GPC = Gram-Positive Cocci (staph, strep, enterococcus) GNR = Gram-Negative Rods (E. coli, Klebsiella, Pseudomonas)

CNS

Infection	Duration	Key Notes / Evidence
Bacterial meningitis	7–21 days	Meningo 7d, pneumo 10–14d, Listeria 21d, GNR 21d
Brain abscess	6–8 weeks	Often need surgical drainage
Epidural abscess	6–8 weeks	Surgical drainage + IV abx

Endocarditis

Infection	Duration	Key Notes / Evidence
Native valve (strep)	4 weeks	2wk if uncomplicated + gent synergy
Native valve (staph)	6 weeks	Nafcillin for MSSA, vanc for MRSA
Prosthetic valve	≥6 weeks	Rifampin + gentamicin backbone

Other

Infection	Duration	Key Notes / Evidence
TB (standard)	6 months	2 months RIPE* → 4 months RI *RIPE = Rifampin, Isoniazid, Pyrazinamide, Ethambutol
TB (meningitis / bone)	9–12 months	Extended duration
Febrile neutropenia	*Until afebrile + ANC ≥500 × 2d** *ANC = Absolute Neutrophil Count	Min 7 days if documented infection