Comprehensive medication guide to Phenoxybenzamine including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
$0–$100 copay with commercial insurance after prior authorization approval; prior auth is typically required due to high cost. Medicare Part D covers phenoxybenzamine; costs apply toward the annual $2,100 out-of-pocket cap in 2026.
Estimated Cash Pricing
$6,700–$7,068 retail for generic phenoxybenzamine 10 mg capsules (60-count, 30-day supply); as low as $598.56 with a GoodRx coupon or approximately $1,631 with a SingleCare card. No manufacturer patient assistance program is currently available.
Medfinder Findability Score
30/100
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Phenoxybenzamine (brand name Dibenzyline) is a prescription medication used to control severe episodes of high blood pressure and excessive sweating caused by pheochromocytoma — a rare, usually benign tumor of the adrenal gland that secretes excess catecholamines (adrenaline and noradrenaline). It belongs to the class of non-selective, irreversible alpha-adrenergic blockers.
Phenoxybenzamine's primary clinical role is preoperative preparation: it is used for 1 to 4 weeks before surgical removal of a pheochromocytoma tumor to prevent life-threatening hypertensive crises during surgery. Without adequate preoperative alpha-blockade, surgical manipulation of the tumor can release a massive surge of catecholamines, triggering stroke, heart attack, or cardiac arrhythmia.
It is available as 10 mg oral capsules (generic phenoxybenzamine hydrochloride by ANI Pharmaceuticals; brand Dibenzyline). Off-label uses include neurogenic bladder, urinary retention, and carcinoid tumor management.
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Phenoxybenzamine works through irreversible, non-competitive antagonism of alpha-adrenergic receptors. In the body, it is converted to a reactive intermediate called an aziridinium ion, which forms a permanent covalent chemical bond with both alpha-1 and alpha-2 adrenergic receptors on blood vessels and other tissues.
Unlike most drugs that reversibly bind to receptors, phenoxybenzamine's bond is permanent — it cannot be displaced by adrenaline or noradrenaline even in massive quantities. This makes it uniquely protective during pheochromocytoma surgery, where tumor manipulation can trigger huge catecholamine surges. Alpha-receptor blockade relaxes blood vessels, lowers blood pressure, and reduces sweating. Because phenoxybenzamine also blocks alpha-2 receptors (feedback receptors on nerve endings), it often causes reflex tachycardia as a side effect.
Only about 20-30% of an oral dose is absorbed in active form. Effects last until the body synthesizes new alpha receptors (approximately 24 hours), which means once-daily to twice-daily dosing provides sustained blockade. The drug is metabolized in the liver and primarily excreted in the urine.
10 mg — capsule
Starting dose: 10 mg twice daily. Titrate by 10-20 mg every 2-3 days. Usual maintenance: 20-40 mg 2-3 times daily (total 40-120 mg/day).
Phenoxybenzamine is one of the most difficult medications to find at a standard retail pharmacy in the United States. Most CVS, Walgreens, Rite Aid, and independent retail pharmacies do not stock it. Pheochromocytoma is diagnosed in only about 500-1,000 Americans per year, and treatment is typically short-term — meaning most pharmacies have no financial reason to maintain inventory of a drug that costs over $6,700 per 30-day supply.
As of 2026, phenoxybenzamine is not on the FDA active drug shortage list for the U.S. market. However, in Australia, brand Dibenzyline was listed as unavailable on the TGA Medicine Shortages database in 2025-2026. The best sources in the U.S. are hospital outpatient pharmacies at academic medical centers, oncology specialty pharmacies, and licensed compounding pharmacies.
Because finding phenoxybenzamine can take days of calling pharmacies one by one, many patients turn to medfinder — a service that calls pharmacies near you to check which ones can fill your prescription and texts you the results, saving hours of frustrating phone calls.
Phenoxybenzamine is not a controlled substance, so any licensed physician, nurse practitioner, or physician assistant with prescribing authority can technically write a prescription. However, because pheochromocytoma is a complex, rare condition requiring specialist-level diagnosis and surgical planning, phenoxybenzamine is in practice almost always prescribed by specialists at tertiary care centers.
Typical prescribers include:
Endocrinologists (most common managing specialists for pheochromocytoma)
Endocrine surgeons (manage the surgical preparation and adrenalectomy)
Urologic oncologists (at centers where urologists perform adrenalectomy)
Surgical oncologists (at NCI-designated cancer centers managing adrenal tumors)
Internists/hospitalists (in hospital settings managing acute pheochromocytoma crises)
Telehealth is not appropriate for initiating phenoxybenzamine — pheochromocytoma diagnosis requires in-person biochemical testing and imaging. Once the diagnosis and surgical plan are established, some specialists offer telehealth follow-up for medication titration monitoring.
No. Phenoxybenzamine is not a controlled substance under the DEA Controlled Substances Act and has no DEA schedule designation. It does not require special paper prescriptions, triplicate forms, or DEA number verification at the pharmacy — unlike scheduled drugs such as stimulants, benzodiazepines, or opioids.
However, phenoxybenzamine is still a prescription-only medication that should only be used under the supervision of a qualified physician. It is typically prescribed and managed by an endocrinologist, endocrine surgeon, or urologist who is coordinating the patient's pheochromocytoma diagnosis and surgical preparation. Because it is not a controlled substance, refills are handled through standard prescription renewal processes without the additional restrictions that apply to scheduled medications.
The most frequently reported side effects of phenoxybenzamine are:
Orthostatic hypotension (dizziness or lightheadedness upon standing)
Reflex tachycardia (fast heart rate)
Nasal congestion (stuffy nose)
Miosis (small pupils)
Fatigue and drowsiness
Inhibition of ejaculation or retrograde ejaculation (in males, reversible)
Syncope (fainting) from severe orthostatic hypotension
Severe postural hypotension (standing systolic BP <90 mmHg)
Tachycardia precipitating angina or CHF in patients with underlying coronary or cardiac disease
Shock from overdose (sympathetic nervous system blockade)
Potential carcinogenicity with long-term use (FDA warning; not a concern for standard short-term preoperative use)
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Doxazosin (Cardura)
Selective alpha-1 blocker; most commonly used alternative for pheochromocytoma preop prep; comparable outcomes to phenoxybenzamine in RCTs; once-daily dosing; widely available; approximately 100x less expensive
Prazosin (Minipress)
Selective alpha-1 blocker; multiple studies show comparable hemodynamics to phenoxybenzamine; requires BID-TID dosing; widely available at standard pharmacies
Terazosin (Hytrin)
Selective alpha-1 blocker with once-daily dosing convenience; acceptable alternative for pheochromocytoma prep; widely available
Metyrosine (Demser)
Tyrosine hydroxylase inhibitor; reduces catecholamine synthesis; used as adjunct to (not replacement for) alpha-blockers; reserved for refractory hypertension or large tumors
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Vardenafil (Levitra)
majorContraindicated: severe hypotension risk from combined vasodilation
Epinephrine (EpiPen)
majorParadoxical hypotension: alpha-blockade causes beta-mediated vasodilation to dominate, reversing expected vasopressor effect
Lofexidine (Lucemyra)
majorAdditive blood pressure and heart rate reduction; risk of bradycardia and severe hypotension
Sildenafil (Viagra) >25mg
majorAdditive hypotension; separate by at least 4 hours; avoid doses above 25 mg
Norepinephrine (Levophed)
majorReduced vasopressor effectiveness due to alpha-receptor blockade
Beta-blockers (propranolol, atenolol)
moderateMust always start phenoxybenzamine before beta-blocker; initiating beta-blocker first causes unopposed alpha vasoconstriction and hypertensive crisis
Other antihypertensives
moderateAdditive hypotension; monitor blood pressure closely
NSAIDs (ibuprofen, naproxen)
moderateReduced antihypertensive effect via prostaglandin synthesis inhibition
Alpha-blockers (tamsulosin, doxazosin)
majorAdditive vasodilation; severe hypotension risk with concurrent use
Alcohol
minorWorsens dizziness, drowsiness, and orthostatic hypotension
Phenoxybenzamine remains an important, if niche, medication — the only FDA-approved drug specifically indicated for pheochromocytoma management. Its irreversible alpha-receptor blockade provides unmatched protection against intraoperative catecholamine surges, and for the right patient, it is still the preferred preoperative agent at many high-volume endocrine surgery centers.
The challenges — extreme difficulty finding it at a retail pharmacy, very high cost, significant side effect burden — have driven increasing adoption of selective alpha-1 blockers like doxazosin as first-line alternatives in many centers. Clinical trial data support this shift for most patients. But when phenoxybenzamine is the right choice, finding it promptly matters enormously for surgical safety.
If you have been prescribed phenoxybenzamine and need help locating it at a pharmacy near you, medfinder calls pharmacies on your behalf, identifies which ones have it in stock, and texts you the results. Act quickly — your surgical timeline depends on starting this medication promptly.
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