a quirky Dibenzyline Generic Name: Phenoxybenzamine Hydrochloride Class: Non-selective alpha-Adrenergic Blocking Agents VA Class: AU200 CAS Number: 63-92-3 Overview Side Effects Dosage Professional Interactions More Pregnancy Warnings User Reviews Drug Images Support Group Q & A Compare Alternatives Pricing & Coupons Introduction α-Adrenergic blocking agent; a haloalkylamine. a b Uses for Dibenzyline Pheochromocytoma Prevention or treatment of paroxysmal hypertension and sweating in patients with pheochromocytoma. a b Considered drug of choice for medical management of pheochromocytoma until surgery is performed and for prolonged treatment of hypertension caused by pheochromocytoma not amenable to surgery. a Used in conjunction with a β-adrenergic blocking agent (propranolol) to control symptoms from excessive β-receptor stimulation in patients with inoperable or metastatic pheochromocytoma or to control tachycardia prior to or during pheochromocytomectomy. a b (See General under Dosage and Administration.) Peripheral Vascular Diseases Has been used as adjunctive therapy in the treatment of peripheral vasospastic disorders associated with increased α-adrenergic activity (e.g., Raynaud s syndrome, acrocyanosis, and frostbite sequelae) but efficacy in the treatment of peripheral vascular disease is not established. a Phenoxybenzamine should not be used in diseases affecting large blood vessels. a Micturition Disorders and Urinary Retention Has been used in the treatment of micturition disorders resulting from neurogenic bladder, 100 functional outlet obstruction, 100 or partial prostatic obstruction. 100 101 102 103 Has been used for the prevention and treatment of acute postoperative urinary retention , 105 106 107 108 including that associated with the use of epidural morphine. 107 108 Slideshow The Ferocity of Chemotherapy - Does The End Justify The Means? Dibenzyline Dosage and Administration General Adjust dosage carefully according to individual requirements and response. a b Minimize adverse effects by starting with small doses and gradually increasing the dosage until the desired effect is obtained or adverse effects occur. a b If concomitant propranolol therapy is required, initiate phenoxybenzamine prior to use of propranolol and continue during propranolol therapy in order to prevent severe hypertension due to unopposed α-adrenergic stimulation. a Administration Oral Administration Administer orally in divided doses. a If GI irritation occurs, administer with milk. a Dosage Available as phenoxybenzamine hydrochloride; dosage expressed in terms of the salt. a Pediatric Patients Pheochromocytoma Oral Initially, 0.2 mg/kg or 6 mg/m 2 once daily; do not exceed 10 mg. a Increase dosage gradually until an adequate response is achieved (e.g., BP is controlled). a Usual maintenance dosage: 0.4 1.2 mg/kg or 12 36 mg/m 2 daily. a Adults Pheochromocytoma Oral Initially, 10 mg twice daily. a b Increase dosage gradually every other day until an adequate response is achieved (e.g., BP is controlled). a b Usual maintenance dosage: 20 40 mg 2 or 3 times daily; higher dosages may be required. a Peripheral Vascular Diseases Oral Initially, 10 mg twice daily. a Increase dosage gradually every other day until an adequate response is achieved. a Usual maintenance dosage: 20 40 mg 2 or 3 times daily; higher dosages may be required. a Prescribing Limits Pediatric Patients Pheochromocytoma Oral Initially, maximum 10 mg daily. a Special Populations No special population dosage recommendations at this time. b Cautions for Dibenzyline Contraindications Conditions where a decrease in BP is undesirable. a b Known hypersensitivity to phenoxybenzamine or any ingredient in the formulation. b Warnings/Precautions Warnings Cardiovascular Effects Phenoxybenzamine s α-adrenergic blocking effect leaves β-receptors unopposed; concomitant use with drugs that stimulate α- and β-adrenergic receptors (i.e., epinephrine) may cause an exaggerated hypotensive response and tachycardia. b (See Specific Drugs under Interactions.) Phenoxybenzamine-induced tachycardia may precipitate CHF and angina in patients with compensated CHF or CAD. a General Precautions Respiratory Effects May aggravate symptoms of respiratory infections. b Arteriosclerosis Use with caution in patients with marked cerebral or coronary arteriosclerosis. b Specific Populations Pregnancy Category C. b Lactation Not known whether phenoxybenzamine is distributed into milk. a b Caution if used in nursing women. a b Pediatric Use Safety and efficacy not established. b Renal Impairment Use with caution in patients with renal damage. b Common Adverse Effects Nasal congestion, a b miosis, a b postural hypotension, a dizziness, a tachycardia. a b Interactions for Dibenzyline Specific Drugs Drug Interaction Comments Epinephrine Possible exaggerated hypotensive response and tachycardia b (See Cardiovascular Effects under Cautions.) Do not use epinephrine for phenoxybenzamine-associated hypotension b Norepinephrine May interfere with hyperthermia production of norepinephrine b Reserpine May interfere with hypothermia production of reserpine b Dibenzyline Pharmacokinetics Absorption Bioavailability Variably absorbed from the GI tract; a 20 30% of an oral dose is absorbed. b Onset Following oral administration, onset of action is gradual over a period of several hours. a Duration α-Adrenergic blockade persists for 3 4 days following oral administration of a single dose; after administration of fixed daily doses, α-adrenergic blocking effects are cumulative for about 7 days. a Distribution Extent Highly lipid soluble; may accumulate in fat following administration of large doses. a Not known whether phenoxybenzamine crosses the placenta or is distributed into milk. a b Elimination Metabolism Dealkylated to form N -phenoxyisopropyl-benzylamine. a Elimination Route Excreted in urine and bile. a Half-life Approximately 24 hours. a b Stability Storage Oral Capsules 25 C (may be exposed to 15 30 C). b Actions Long-acting, α-adrenergic blocking agent that produces and maintains chemical sympathectomy. b Inhibits responses (primarily excitatory responses of smooth muscle and exocrine glands) to adrenergic stimuli by noncompetitively blocking α-adrenergic receptors; however, does not affect β-adrenergic receptors a or the parasympathetic system. b Exact mechanism of action not fully elucidated; appears to form a reactive ethylenimonium intermediate and a highly reactive carbonium ion that forms stable covalent bonds with sulfhydryl, phosphate, amino, and carboxyl groups of α-adrenergic receptors. a Blocks α-adrenergic responses to circulating epinephrine and/or norepinephrine and to norepinephrine released at the adrenergic nerve ending. a Acts on vascular smooth muscle to block epinephrine- and norepinephrine-induced vasoconstriction and causes peripheral vasodilation and reflex tachycardia. a Reverses the pressor effect of epinephrine ( epinephrine reversal ) and blocks, but does not reverse, the vasoconstrictor effects of norepinephrine. a Increases blood flow to the skin, mucosa, and abdominal viscera; lowers BP; b blocks pupillary dilation, lid retraction, and adrenergically mediated sweating; and decreases uterine motility. a Advice to Patients Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs, as well as any concomitant illnesses. a Importance of taking only as prescribed; do not increase dosage or duration of therapy unless otherwise instructed by a clinician. a Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed. a Importance of informing patients of other precautionary information. (See Cautions.) a Preparations Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details. Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations. Phenoxybenzamine Hydrochloride Routes Dosage Forms Strengths Brand Names Manufacturer Oral Capsules 10 mg Dibenzyline (with benzyl alcohol) WellSpring AHFS DI Essentials. Copyright 2017, Selected Revisions April 1, 2010. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814. Use is not currently included in the labeling approved by the US Food and Drug Administration. References 100. Fillmore AD, Latiolais CJ. Phenoxybenzamine for the treatment of micturition disorders. Hosp Formul . 1984; 19:593-5,598-600. 101. Caine M, Perlberg S, Shapiro A. Phenoxybenzamine for benign prostatic obstruction: review of 200 cases. Urology . 1981; 17:542-6. [PubMed 6166111] 102. Gerstenberg T, Blaaberg J, Nielsen ML. Phenoxybenzamine reduces bladder outlet obstruction in benign prostatic hyperplasia. Invest Urol . 1980; 18:29-31. [PubMed 6157651] 103. Anon. Phenoxybenzamine for symptoms of bladder neck obstruction. Drug Ther Bull . 1983; 21(4):15-6. [PubMed 6187524] 104. Leventhal A, Pfau A. Pharmacologic management of postoperative overdistention of the bladder. Surg Gynecol Obstet . 1978; 146:347-8. [PubMed 625669] 105. Eftaiha MS, Amshel AL, Shonberg IL. Comparison of two agents in prevention of urinary retention after benign anorectal surgery. Dis Colon Rectum . 1980; 23:470-2. [PubMed 7438948] 106. Livne PM, Kaplan B, Ovadia Y et al. Prevention of post-hysterectomy urinary retention by α-adrenergic blocker. Acta Obstet Gynecol Scand . 1983; 62:337-40. [PubMed 6138916] 107. Evron S, Magora F, Sadovsky E. Prevention of urinary retention with phenoxybenzamine during epidural morphine. BMJ . 1984; 288:190. [PubMed 6419851] 108. Evron S, Samueloff A, Sadovsky E et al. The effect of phenoxybenzamine on postoperative urinary complications during extradural morphine analgesia. Eur J Anaesthesiol . 1984; 1:45-54. [PubMed 6536506] 109. Aron NB. Phenoxybenzamine-induced hyponatremia simulating the syndrome of inappropriate antidiuretic hormone secretion. Ann Intern Med . 1987; 107:119-20. [PubMed 3592437] a. AHFS drug information 2007. McEvoy GK, ed. Phenoxybenzamine . Bethesda, MD: American Society of Health-System Pharmacists; 2007: pages [1361-1362]. b. WellSpring Pharmaceutical Corporation. Dibenzyline (phenoxybenzamine hydrochloride) capsule prescribing information. Bradenton, FL ; 2005 Oct. Next Interactions Print this page Add to My Med List More about Dibenzyline (phenoxybenzamine) Side Effects During Pregnancy Dosage Information Drug Images Drug Interactions Compare Alternatives Support Group Pricing & Coupons En Español 0 Reviews Add your own review/rating Generic Availability Drug class: miscellaneous cardiovascular agents Consumer resources Dibenzyline Dibenzyline (Advanced Reading) Professional resources Dibenzyline (FDA) Phenoxybenzamine Hydrochloride (AHFS Monograph) Related treatment guides Pheochromocytoma} FEATURED: CAR-T Cell Therapy Overview Mechanism of Action KTE-C19 Studies KTE-C19 Cancer Targets Adverse Events Manufacturing Drug Status Rx Availability Prescription only C Pregnancy Category Risk cannot be ruled out N/A CSA Schedule Not a controlled drug 10 + years Approval History FDA approved 1953 Manufacturer Concordia Pharmaceuticals Inc. Drug Class Miscellaneous cardiovascular agents Related Drugs Pheochromocytoma propranolol , labetalol , Inderal , Normodyne , Trandate , phentolamine , phenoxybenzamine , metyrosine , Demser , Regitine , More... Dibenzyline Rating No Reviews - Be the first! No Reviews - Be the first! Not Rated - Be the first! Dibenzyline Images Dibenzyline 10 mg (SKF E33 SKF E33) View larger images} } which in retrospect
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