Medications, Irrigation, and Instillation Therapy
This domain tests drug-specific monitoring, safe instillation practice, and irrigation decisions - areas where small errors produce serious harm.
Symptom medications
- Alpha-1 blockers (tamsulosin, silodosin, alfuzosin, doxazosin, terazosin): work within days; cause orthostatic hypotension, retrograde ejaculation, and intraoperative floppy iris - tell the ophthalmologist.
- 5-alpha-reductase inhibitors (finasteride, dutasteride): up to 6 months for full effect; lower PSA by roughly 50%, so double the measured value when interpreting; teratogenic to a male fetus, so pregnant women should not handle crushed tablets.
- Antimuscarinics: dry mouth, constipation, cognitive impairment in older adults; caution in narrow-angle glaucoma and retention.
- Mirabegron (beta-3 agonist): monitor blood pressure and CYP2D6 interactions.
- PDE5 inhibitors: never combined with nitrates.
Antimicrobials
Nitrofurantoin (avoid with significant renal impairment), single-dose fosfomycin, TMP-SMX, and fluoroquinolones with their tendinopathy, neuropathy, and aortic warnings. Always tailor to culture.
Intravesical therapy
- BCG is live attenuated. Withhold for gross hematuria, UTI, or recent instrumentation; retain 1-2 hours with repositioning every 15 minutes; instruct bleach in the toilet for the first 6 hours; avoid in immunosuppressed patients.
- Mitomycin and gemcitabine require hazardous drug precautions; extravasation is a serious complication.
Irrigation
Continuous bladder irrigation after TURBT uses a three-way catheter, titrated to keep urine light pink. Clots require manual irrigation with a piston syringe. Watch for bladder spasm, hyponatremia from absorption (TUR syndrome), and overdistension. For encrustation, use ordered acidic solutions such as Suby G or Renacidin; never force against resistance.
Worked example
A patient due for BCG reports dysuria and visible clots after recent catheterization. Reasoning: traumatized mucosa increases systemic absorption of live bacilli and the risk of disseminated infection, so BCG is deferred until the symptoms and bleeding resolve. Document, notify the provider, and reschedule.
Traps that cost marks
- Giving BCG without screening for hematuria or UTI.
- Reading PSA without adjusting for finasteride.
- Warning about orthostatic hypotension but not about rising quickly at night.
- Treating antimuscarinics and beta-3 agonists as interchangeable.