Preoperative Alpha-Blocker Selection and Initial Dosing for PPGL
STEP 1 — Gather Information
Collect biochemical confirmation of PPGL (elevated fractionated metanephrines or catecholamines), document clinical need for preoperative BP control, note planned surgery/adrenalectomy, record baseline BP and HR, assess orthostatic hypotension risk, review concomitant medications (especially drugs affecting catecholamine metabolism).
STEP 2 — Rule In / Rule Out
Is catecholamine overproduction biochemically confirmed? If yes, proceed to alpha-blocker initiation; if unclear, perform a comprehensive clinical assessment before considering alpha-blockers (per I-4-5).
STEP 3 — Classify or Stratify
For confirmed PPGL, select a selective alpha-blocker (e.g., doxazosin) as first-line; if BP reduction insufficient, add a calcium antagonist or metyrosine; if tachycardia/tachyarrhythmia present, add a beta-blocker only after adequate alpha-blockade.
STEP 4 — Decide
Initiate selective alpha-blocker (doxazosin 1–2 mg PO daily) at bedtime; titrate every 2–3 days to target BP <130/80 mmHg and HR 60–70 bpm sitting; add calcium antagonist or metyrosine if needed; start normal salt diet (9 g/day) or saline infusion (1–2 L) on the third day of alpha-blocker therapy; continue for at least 7–14 days preoperatively.
Clinical Guardrails / Mimics / Pitfalls
Do not administer a beta-blocker before an alpha-blocker (risk of hypertensive crisis); avoid nonselective alpha-blockers (phenoxybenzamine) as unavailable in Japan; do not use alpha-blockers if catecholamine overproduction is unclear without comprehensive assessment; monitor for orthostatic hypotension after the first dose; avoid abrupt withdrawal of alpha-blockers perioperatively.
Concrete Clinical Example
A 45-year-old with biochemically confirmed PPGL (urinary normetanephrine 5× ULN) scheduled for laparoscopic adrenalectomy in 10 days starts doxazosin 1 mg at bedtime, titrates to 4 mg daily over 6 days, achieves BP 122/78 mmHg, adds amlodipine 5 mg if needed, maintains normal salt diet, and proceeds to surgery with stable vitals.
Source: Japan Endocrine Society Clinical Practice Guideline for the Diagnosis and Management of Pheochromocytoma and Paraganglioma 2025, Japan Endocrine Society, 2025, doi:10.1507/endocrj.EJ25-0165