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American Journal of Health-system... Sep 1997The stability of phenoxybenzamine hydrochloride in various oral liquids was studied. Phenoxybenzamine hydrochloride powder or capsules were combined with various...
The stability of phenoxybenzamine hydrochloride in various oral liquids was studied. Phenoxybenzamine hydrochloride powder or capsules were combined with various vehicles to prepare 10-mL formulations with a drug concentration of 2 mg/mL and a 20-mL stock solution containing 10 mg/mL. All formulations were prepared in triplicate and stored at 4 degrees C. A 1.0-mL sample of each of the 2-mg/mL formulations was withdrawn on days 0, 1, 2, 3, and 4, and samples of selected formulations were taken on days 7 and 10. Samples of the stock solution were withdrawn on days 0, 2, 4, 7, 10, 14, and 30. All samples were analyzed by high-performance liquid chromatography. Phenoxybenzamine hydrochloride 2 mg/mL was stable for a longer time in 1% propylene glycol, 0.15% citric acid, and water than in a similar vehicle in which syrup was used in place of water. The concentrations of the drug in both the 10-mg/mL stock solution and stock solutions diluted to 2 mg/mL were > 90% of the initial drug concentration for 30 days. Phenoxybenzamine hydrochloride 2 mg/mL in 1% propylene glycol and 0.15% citric acid in distilled water was stable for 7 days at 4 degrees C. A stock solution of phenoxybenzamine hydrochloride 10 mg/mL in propylene glycol was stable for 30 days at 4 degrees C and, after dilution with 66.7% sucrose in distilled water to a concentration of 2 mg/mL, for up to one hour at 4 degrees C.
Topics: Chromatography, High Pressure Liquid; Drug Compounding; Drug Stability; Pharmaceutical Vehicles; Phenoxybenzamine; Time Factors
PubMed: 9377206
DOI: 10.1093/ajhp/54.18.2073 -
The Journal of Physiology Jan 1971
Topics: Animals; Body Temperature; Cats; Cerebral Ventricles; Hypothalamus; Injections; Norepinephrine; Phenoxybenzamine; Propranolol; Rabbits; Reserpine; Sensory Receptor Cells
PubMed: 5548004
DOI: No ID Found -
Archives of Surgery (Chicago, Ill. :... Oct 1988
Topics: Humans; Hypotension, Orthostatic; Phenoxybenzamine
PubMed: 3178477
DOI: 10.1001/archsurg.1988.01400340113025 -
Surgery, Gynecology & Obstetrics Oct 1969
Topics: Cardiac Output; Humans; Norepinephrine; Phenoxybenzamine; Shock; Vascular Resistance
PubMed: 5821998
DOI: No ID Found -
Journal of Neurosurgery Jun 1984Forty consecutive cases of causalgia treated during a 7-year period are presented. The patients ranged in age between 17 and 55 years, and all patients were males who...
Forty consecutive cases of causalgia treated during a 7-year period are presented. The patients ranged in age between 17 and 55 years, and all patients were males who received their nerve injuries from missile or shrapnel wounds. The greater occipital nerve was involved in two cases, median nerve in 10, sciatic nerve in 12, brachial plexus in seven, cauda equina in five, and multiple nerves in four cases. Each patient was treated with phenoxybenzamine, a postsynaptic alpha 1-blocker and presynaptic alpha 2-blocking agent. The drug was given orally in gradually increasing increments until a maximum daily dose of 40 to 120 mg was reached. Duration of treatment was usually 6 to 8 weeks. Total resolution of pain was achieved in all cases. The follow-up period ranged between 6 months and 6 years. Side effects of phenoxybenzamine were minimal and transient, consisting primarily of mild orthostatic hypotension and ejaculatory problems. We conclude that oral phenoxybenzamine is a simple, safe, and effective treatment of causalgia.
Topics: Adolescent; Adult; Causalgia; Drug Evaluation; Ejaculation; Humans; Hypotension, Orthostatic; Male; Middle Aged; Neuralgia; Phenoxybenzamine; Wounds, Gunshot
PubMed: 6726371
DOI: 10.3171/jns.1984.60.6.1263 -
Stroke 1972
Topics: Adrenergic alpha-Antagonists; Animals; Basilar Artery; Blood Pressure; Cats; Electrocardiography; Ischemic Attack, Transient; Norepinephrine; Phenoxybenzamine; Phentolamine; Subarachnoid Hemorrhage
PubMed: 4403117
DOI: 10.1161/01.str.3.4.421 -
Journal of Cardiothoracic and Vascular... Feb 2018
Review
Topics: Angiotensin-Converting Enzyme Inhibitors; Cardiac Surgical Procedures; Cardiopulmonary Bypass; Child; Chlorpromazine; Humans; Natriuretic Peptide, Brain; Phenoxybenzamine; Vasodilator Agents
PubMed: 29249581
DOI: 10.1053/j.jvca.2017.07.007 -
Annals of Internal Medicine Jul 1987
Topics: Aged; Diagnosis, Differential; Humans; Hyponatremia; Inappropriate ADH Syndrome; Male; Phenoxybenzamine; Water
PubMed: 3592437
DOI: 10.7326/0003-4819-107-1-119 -
Endocrine Practice : Official Journal... Sep 2022Phenoxybenzamine (nonselective, noncompetitive alpha-blocker) is the preferred drug for preoperative treatment of pheochromocytoma, but doxazosin (selective, competitive...
OBJECTIVE
Phenoxybenzamine (nonselective, noncompetitive alpha-blocker) is the preferred drug for preoperative treatment of pheochromocytoma, but doxazosin (selective, competitive alpha-blocker) may be equally effective. We compared the efficacy of doxazosin vs phenoxybenzamine.
METHODS
We conducted a prospective study of patients undergoing pheochromocytoma or paraganglioma resection by randomizing pretreatment with phenoxybenzamine or doxazosin at a single tertiary referral center. The high cost of phenoxybenzamine led to high crossover to doxazosin. Randomization was halted, and a consecutive historical cohort of phenoxybenzamine patients was included for a case-control study design. The efficacy of alpha-blockade was assessed with preinduction infusion of incremental doses of phenylephrine. The primary outcomes were mortality, cardiovascular complications, and intensive care unit admission. The secondary outcomes were hemodynamic instability index (proportion of operation outside of hemodynamic goals), adequacy of blockade by the phenylephrine titration test, and drug costs.
RESULTS
Twenty-four patients were prospectively enrolled (doxazosin, n = 20; phenoxybenzamine, n = 4), and 15 historical patients treated with phenoxybenzamine were added (total phenoxybenzamine, n = 19). No major cardiovascular complications occurred in either group. The phenylephrine dose-response curves showed less blood pressure rise in the phenoxybenzamine than in the doxazosin group (linear regression coefficient = 0.008 vs 0.018, P = .01), suggesting better alpha-blockade in the phenoxybenzamine group. The median hemodynamic instability index was 14% vs 13% in the phenoxybenzamine and doxazosin groups, respectively (P = .56). The median highest daily cost of phenoxybenzamine was $442.20 compared to $5.06 for doxazosin.
CONCLUSION
Phenoxybenzamine may blunt intraoperative hypertension better than doxazosin, but this difference did not translate to fewer cardiovascular complications and is offset by a considerably increased cost.
Topics: Adrenal Gland Neoplasms; Adrenergic alpha-Antagonists; Case-Control Studies; Doxazosin; Humans; Phenoxybenzamine; Phenylephrine; Pheochromocytoma; Prospective Studies
PubMed: 35809774
DOI: 10.1016/j.eprac.2022.06.013 -
The Surgical Clinics of North America Jun 1966
Topics: Adult; Female; Humans; Hypertension; Phenoxybenzamine; Phentolamine; Pheochromocytoma
PubMed: 5931812
DOI: 10.1016/s0039-6109(16)37890-2