Chapter 28 · Associated Medical Professionals of New York · New York
Perioperative Medications: Anticoagulation and Antibiotic Prophylaxis
Two decisions before every procedure will occupy a large share of your perioperative work: what to do with the blood thinner, and what antibiotic (if any) to give. Getting these wrong causes bleeding, thrombosis, and sepsis — three of the most…
28 pathway steps3 pathways
Your learning progress0 of 31 chapters complete
Saved privately in this browser and shared across state tabs.
Didactics
Shared across all locations
Two decisions
before every procedure will occupy a large share of your
perioperative work: what to do with the blood thinner, and what
antibiotic (if any) to give. Getting these wrong causes bleeding,
thrombosis, and sepsis — three of the most consequential
complications in our specialty. This chapter gives you the framework.
Always confirm against your current institutional protocol and the
prescribing clinician.
28.1 Antithrombotic management — the framework
Every decision
balances the BLEEDING risk of the procedure against the THROMBOTIC
risk of stopping the drug. Do not make it alone: for any patient on
anticoagulation for a high-risk indication, coordinate with the
prescriber (cardiology, hematology, neurology).
Step 1 — Classify the procedure's bleeding risk
Bleeding risk
Urologic examples
LOW — usually can continue anticoagulation
Flexible cystoscopy (diagnostic), urodynamics, catheter
placement/exchange, stent removal, simple office procedures,
vasectomy (case by case), most intravesical instillations
INTERMEDIATE
Ureteroscopy with laser, prostate biopsy (transperineal is lower
risk than transrectal), UroLift, TURBT of a small tumor
HIGH — anticoagulation must be held
TURP / laser enucleation, PCNL, radical prostatectomy,
nephrectomy (partial or radical), cystectomy, large TURBT, any
open/major reconstructive surgery
Step 2 — Classify the patient's thrombotic risk
HIGH
thrombotic risk (do NOT stop without specialist input; bridging may
be needed): a mechanical heart valve (especially mitral), atrial
fibrillation with a high CHA2DS2-VASc score or a prior stroke, a VTE
within the last 3 months, and — critically — a CORONARY STENT
placed recently (within 6–12 months for a drug-eluting stent).
Stopping dual antiplatelet therapy early after a stent can cause
acute stent thrombosis, which is frequently fatal. NEVER stop these
agents unilaterally; call cardiology.
LOW
thrombotic risk: atrial fibrillation with a low score, a remote
single VTE, primary prevention with aspirin.
Step 3 — Typical hold times (verify locally;
adjust for renal function)
Agent
Typical pre-op hold
Notes
Aspirin (81 mg, primary prevention)
Can often be CONTINUED, or hold 5–7 days if bleeding risk is
high
For SECONDARY prevention (known CAD/stent), continuing is usually
safer than stopping — discuss
Clopidogrel / prasugrel / ticagrelor
5–7 days
NEVER stop without cardiology input if there is a recent coronary
stent
Warfarin
5 days; check INR (target < 1.5 for most surgery)
Bridging with LMWH only for HIGH thrombotic risk (mechanical
valve, recent VTE) — bridging causes bleeding and is now used
far less often than it used to be
Apixaban / rivaroxaban (DOACs)
24–48 hours (longer if renal impairment or high bleeding risk)
No bridging needed — their rapid onset/offset is the whole
advantage. Renal function drives the hold time
Dabigatran
24–96 hours depending on renal function
Most renally cleared of the DOACs — hold longer with CKD
Enoxaparin (therapeutic)
24 hours
Prophylactic dose: 12 hours
Resuming:
restart when hemostasis is secure — typically 24–72 hours
after surgery, and later after high-bleeding-risk procedures.
Remember that DOACs reach full anticoagulant effect within hours, so
restarting too early is a real bleeding risk.
Anticoagulation rules that keep patients
safe
NEVER stop antiplatelet
therapy in a patient with a recent coronary stent without
cardiology approval. Stent thrombosis kills.
Most LOW-risk urologic
procedures (diagnostic cystoscopy, catheter changes, urodynamics)
can be done ON anticoagulation. Stopping it “just to be safe”
causes strokes — that is not safe.
Bridging is the exception,
not the rule. It increases bleeding without reducing thrombosis
in most patients.
Document the plan, who approved it, and when the drug is
to be resumed. The most dangerous moment is discharge, when
nobody restarts the anticoagulant.
28.2 Antimicrobial prophylaxis
The purpose of
prophylaxis is to prevent a surgical-site or systemic infection —
not to treat colonization. The principles are simple and consistently
violated: give the RIGHT drug, at the RIGHT time (within 60 minutes
of incision, so tissue levels peak during the case), and STOP it (a
single pre-operative dose is sufficient for most urologic procedures;
continuing antibiotics for days after a clean case causes harm and
prevents nothing).
Procedure
Prophylaxis needed?
Typical agent
Diagnostic cystoscopy (sterile urine)
NOT routinely
None — unless risk factors are present
Urodynamics (sterile urine)
NOT routinely
None — unless risk factors are present
Cystoscopy WITH manipulation (stent placement/removal, biopsy)
Yes
A first-generation cephalosporin, or TMP-SMX
TRANSRECTAL prostate biopsy
YES — mandatory
Targeted prophylaxis based on a RECTAL SWAB culture is best
practice; otherwise a fluoroquinolone ± an aminoglycoside. This
is the highest-infection-risk procedure we do
TRANSPERINEAL prostate biopsy
Yes (but much lower infection risk)
A single dose (e.g., cephalosporin); some centers use none
Ureteroscopy / stone surgery
Yes
A first-generation cephalosporin or an aminoglycoside; broaden if
the urine is infected or a stone is infected
PCNL
Yes
Broader coverage; treat any positive culture beforehand — this
is a high-risk sepsis procedure
TURP / TURBT
Yes
A first-generation cephalosporin, or TMP-SMX
Open/robotic major surgery (with bowel)
Yes
Second-generation cephalosporin, or expanded coverage for bowel
Prosthetic implant (penile prosthesis, AUS, sling, InterStim)
YES — critical
Broad gram-positive AND gram-negative coverage (e.g., vancomycin
+ an aminoglycoside). A prosthetic infection is a catastrophe
requiring explant
The non-negotiables
Sterilize the urine first.
Obtain a pre-operative culture and TREAT a positive one before
any procedure that traumatizes the urothelium. Instrumenting
infected urine causes bacteremia and septic shock. This is the
single most important infection-prevention step, and it outranks
any choice of prophylactic antibiotic.
Give it within 60 minutes of
incision — an antibiotic given after the case has started is a
wasted dose.
Stop it. For most urologic
procedures a SINGLE pre-operative dose is enough. Post-operative
antibiotics “just in case” drive resistance and C. difficile
and prevent nothing.
Prosthetic cases are different — the stakes are much
higher and the protocols are stricter. Follow them exactly.
28.3 Other perioperative medication issues
Medication
Perioperative action
GLP-1 agonists (semaglutide, tirzepatide)
Delay gastric emptying → ASPIRATION RISK under sedation. Hold
per current anesthesia guidance and FLAG for the anesthesia team.
Ask every pre-op patient — many are on these from telehealth
and will not volunteer it (Chapter 24)
Tamsulosin / alpha-blockers
Intraoperative floppy iris syndrome — tell the CATARACT
surgeon. Does not need to be stopped for urologic surgery
Metformin
Hold on the day of surgery; historically held with contrast in
renal impairment (guidance has relaxed — check local protocol)
SGLT-2 inhibitors (empagliflozin, etc.)
Hold 3–4 days before surgery — risk of EUGLYCEMIC diabetic
ketoacidosis, which is easy to miss because the glucose looks
normal
Insulin / sulfonylureas
Adjust per protocol; hold sulfonylureas on the morning of surgery
Chronic steroids
Consider stress-dose steroids for adrenal suppression in major
surgery
ACE inhibitors / ARBs
Often held on the morning of surgery (intraoperative hypotension)
MAOIs, lithium, and herbal supplements
Review with anesthesia; many supplements (ginkgo, garlic,
ginseng, fish oil, vitamin E) increase bleeding — stop ~7 days
prior
Clinical Pathway
Click any node to expand
Two decisions before every procedure — what to do with the blood thinner, and what antibiotic (if any) to give. Getting them wrong causes bleeding, thrombosis, and sepsis. This is the framework; always confirm against your current institutional protocol and the prescribing clinician before acting on any hold time.
Bleeding risk of the procedure against thrombotic risk of stopping the drug — a three-step framework you never work alone.
Select a box to open its teaching details.
The balance
Every decision balances the BLEEDING risk of the procedure against the THROMBOTIC risk of stopping the drug.
Who to involve
For any patient on anticoagulation for a high-risk indication, coordinate with the prescriber — cardiology, hematology, neurology
Pitfalls
Always confirm against your current institutional protocol and the prescribing clinician. The hold times below are typical values, not authority
Ch 28.1 — antithrombotic management
Step 1 — Classify the PROCEDURE's bleeding risk
Urologic examples
Flexible cystoscopy (diagnostic)
Urodynamics
Catheter placement / exchange
Stent removal
Simple office procedures
Vasectomy — case by case
Most intravesical instillations
Pitfalls
Most LOW-risk urologic procedures can be done ON anticoagulation. Stopping it "just to be safe" causes strokes — that is not safe
Ch 28.1 — step 1, bleeding risk
Urologic examples
Ureteroscopy with laser
Prostate biopsy — transperineal is lower risk than transrectal
UroLift
TURBT of a small tumor
Ch 28.1 — step 1, bleeding risk
Urologic examples
TURP / laser enucleation
PCNL
Radical prostatectomy
Nephrectomy — partial or radical
Cystectomy
Large TURBT
Any open / major reconstructive surgery
Ch 28.1 — step 1, bleeding risk
Time-critical
High thrombotic risk
A mechanical heart valve — especially mitral
Atrial fibrillation with a high CHA2DS2-VASc score or a prior stroke
A VTE within the last 3 months
A CORONARY STENT placed recently — within 6–12 months for a drug-eluting stent
The rule
Stopping dual antiplatelet therapy early after a stent can cause acute stent thrombosis, which is frequently fatal. NEVER stop these agents unilaterally — call cardiology. Bridging may be needed.
Ch 28.1 — step 2, thrombotic risk
Low thrombotic risk
Atrial fibrillation with a low score
A remote single VTE
Primary prevention with aspirin
Ch 28.1 — step 2, thrombotic risk
Typical pre-op hold
Aspirin 81 mg (primary prevention) — can often be CONTINUED, or hold 5–7 days if bleeding risk is high
Clopidogrel / prasugrel / ticagrelor — 5–7 days
Notes
For SECONDARY prevention (known CAD/stent), continuing aspirin is usually safer than stopping — discuss
NEVER stop clopidogrel/prasugrel/ticagrelor without cardiology input if there is a recent coronary stent
Uncertainty
These are typical values — verify locally and adjust for renal function, and defer to the prescribing clinician
Ch 28.1 — step 3, typical hold times
Typical pre-op hold
Warfarin — 5 days; check INR (target < 1.5 for most surgery)
Bridging
LMWH bridging only for HIGH thrombotic risk — mechanical valve, recent VTE
Bridging causes bleeding and is now used far less often than it used to be
Pitfalls
Bridging is the exception, not the rule. It increases bleeding without reducing thrombosis in most patients
Ch 28.1 — step 3, typical hold times
Typical pre-op hold
Apixaban / rivaroxaban — 24–48 hours (longer with renal impairment or high bleeding risk)
Dabigatran — 24–96 hours depending on renal function
DOACs need no bridging — their rapid onset/offset is the whole advantage
Renal function drives the hold time
Dabigatran is the most renally cleared of the DOACs — hold longer with CKD
Ch 28.1 — step 3, typical hold times
Resuming
Restart when hemostasis is secure — typically 24–72 hours after surgery
Later after high-bleeding-risk procedures
Why timing matters
DOACs reach full anticoagulant effect within hours, so restarting too early is a real bleeding risk.
Ch 28.1 — resuming
Document
The plan
Who approved it
When the drug is to be resumed
Pitfalls
The most dangerous moment is discharge, when nobody restarts the anticoagulant
Ch 28.1 — anticoagulation rules
The right drug, at the right time, and then STOP it — plus the one step that outranks any antibiotic choice.
Select a box to open its teaching details.
The three principles
Give the RIGHT drug
At the RIGHT time — within 60 minutes of incision, so tissue levels peak during the case
STOP it — a single pre-operative dose is sufficient for most urologic procedures
Pitfalls
Continuing antibiotics for days after a clean case causes harm and prevents nothing
Ch 28.2 — antimicrobial prophylaxis
Time-critical
What to do
Obtain a pre-operative culture
TREAT a positive culture before any procedure that traumatizes the urothelium
Why
Instrumenting infected urine causes bacteremia and septic shock. This is the single most important infection-prevention step, and it outranks any choice of prophylactic antibiotic.