phenoxybenzamine
Fuentes regulatorias consultadas
Indicaciones aprobadas
- Tratamiento del feocromocitoma para controlar episodios de hipertensión y sudoración. Si la taquicardia es excesiva, puede requerirse un betabloqueante concomitante.
Contraindicaciones
Absolutas
- Situaciones en las que una caída de la presión arterial sea indeseable.
- Hipersensibilidad a fenoxibenzamina o a cualquier componente de la cápsula.
Advertencias clínicas
- Advertencia mayor · El bloqueo alfa deja receptores beta sin oposición; los fármacos que estimulan receptores alfa y beta pueden causar respuesta hipotensora exagerada y taquicardia. — DailyMed setid 48a047c0-f409-420b-990a-2cab953a96cd
- Advertencia mayor · Administrar con precaución en arteriosclerosis cerebral o coronaria marcada y en lesión renal; el bloqueo adrenérgico puede agravar síntomas de infecciones respiratorias. — openFDA set_id 0be6a394-cd10-42fc-97cf-ad53d81d8d93
- Advertencia mayor · No se recomienda el uso prolongado: existen casos de carcinoma en humanos y señales mutagénicas o carcinogénicas preclínicas, sin causalidad demostrada; ponderar cuidadosamente beneficio y riesgo. — openFDA set_id 0be6a394-cd10-42fc-97cf-ad53d81d8d93
- Las reacciones observadas tienen frecuencia no estimable: hipotensión postural, taquicardia, inhibición de la eyaculación, congestión nasal, miosis, irritación gastrointestinal, somnolencia y fatiga. — DailyMed setid 48a047c0-f409-420b-990a-2cab953a96cd
- Advertencia mayor · En hipotensión grave causada por fenoxibenzamina, la noradrenalina intravenosa puede utilizarse como medida de rescate bajo monitorización intensiva; la epinefrina está contraindicada porque puede agravar la caída de presión. — openFDA set_id 0be6a394-cd10-42fc-97cf-ad53d81d8d93
Interacciones medicamentosas
- SeveraEpinefrina y otros agonistas alfa y betaC01CA24
Mecanismo: Con receptores alfa bloqueados, predomina la estimulación beta y puede aparecer vasodilatación con hipotensión exagerada y taquicardia.
Recomendación: Evitar epinefrina; vigilar estrechamente cualquier agonista mixto alfa y beta.
DailyMed setid 48a047c0-f409-420b-990a-2cab953a96cd
Embarazo y lactancia
Durante el embarazo, usar solo si es claramente necesario. Se desconoce si se excreta en leche humana; por el potencial de reacciones graves, decidir entre interrumpir la lactancia o suspender fenoxibenzamina según su importancia para la madre.
Bibliografía reciente (PubMed)
Surgical removal is the standard of care for adrenal tumors greater than 2.0 cm diameter. For tumors smaller than 2.0 cm, imaging techniques evaluating patterns of contrast washout may offer a promising avenue for early identification of adrenal malignancy. Pretreatment of pheochromocytoma with phenoxybenzamine is associated with reduced surgical mortality risk. Surgical technique can be laparoscopic or open, depending on tumor anatomy and the experience of the surgeon. Vascular invasion is a contraindication for a laparoscopic technique. This review provides a summary of minimally invasive and open adrenalectomy techniques, including a discussion of management of vascular invasion and partial cavectomy. FH tumor predisposition syndrome is characterized by cutaneous leiomyomata, uterine leiomyomata (fibroids), and/or renal tumors. Pheochromocytoma and paraganglioma have also been described in affected individuals from a small number of families with specific FH pathogenic variants. Cutaneous leiomyomata appear as skin-colored to light brown papules or nodules distributed across the trunk and extremities and occasionally on the face, and are usually noted in the second to fourth decades of life, increasing in size and number with age. Uterine leiomyomata tend to be numerous and large; mean age at diagnosis is ~30 years, with most females experiencing irregular or heavy menstruation and pelvic pain. Renal tumors are usually unilateral, solitary, and aggressive. They are associated with poor survival due to clinical aggressiveness and propensity to metastasize despite small primary tumor size. The median age of detection is approximately 40 years. Diagnosis of FH tumor predisposition syndrome is established in a proband with a heterozygous pathogenic variant in FH identified by molecular genetic testing. Treatment of manifestations: Treatment of cutaneous leiomyomas can include surgical excision, carbon dioxide laser, cryotherapy, or electrodessication. Medications for
Although oral phosphodiesterase 5 inhibitors represent a first choice and long-term option for about half of all patients with erectile dysfunction (ED), self-injection therapy with vasoactive drugs remains a viable alternative for all those who are not reacting or cannot tolerate oral drug therapy. This current injection therapy has an interesting history beginning in 1982. To provide a comprehensive history of self-injection therapy from the very beginnings in 1982 by contemporary witnesses and some members of the International Society for Sexual Medicine's History Committee, a complete history of injection therapy is prepared from eyewitness accounts and review of the published literature on the subject, as well as an update of the current status of self-injection therapy. Published data on injection therapy, as a diagnostic and therapeutic tool for ED, were reviewed thoroughly by PubMed and Medline research from 1982 until June 2023. Early pioneers and witnesses added firsthand details to this historical review. Therapeutic reports of injection therapy were reviewed, and results of side effects and complications were thoroughly reviewed. The pioneers of the first hours were Ronal Virag (1982) for papaverine, Giles Brindley (1983) for cavernosal alpha-blockade (phentolamine and phenoxybenzamine), Adrian Zorgniotti (1985) for papaverine/phentolamine, and Ganesan Adaikan and N. Ishii (1986) for prostaglandin E1. Moxisylyte (thymoxamine) was originally marketed but later withdrawn. The most common side effect is priapism, with the greatest risk of this from papaverine, which has modified its use for therapy. Currently, prostaglandin E1 and trimixes continue to be the agents of choice for diagnostic and therapeutic use in ED. A recent agent is a mixture of a vasoactive intestinal polypeptide (aviptadil) and phentolamine. After 40 years, self-injection therapy represents the medication with the highest efficacy and reliability rates and remains a viable option for man
The incidence of post-operative urinary retention (POUR) following inguinal hernia repair (IHR) is approximately 0.4% - 22.0%. POUR may lead to patient discomfort and catheter-related complications including urinary tract infection, urethral trauma, bladder overdistension and subsequent permanent bladder dysfunction. We aimed to perform a systematic review and meta-analysis of randomised control trials (RCT) evaluating the impact of administration of perioperative alpha-blockade to reduce the incidence of acute POUR following IHR. A systematic review was performed as per PRISMA guidelines. The incidence of POUR in the alpha-blocker and control groups were expressed as dichotomous outcomes, reported as odds ratios (ORs) expressed with 95% confidence intervals (CIs) following estimation using the Mantel-Haenszel method. Eight RCTs with a combined total of 918 patients were included. Of these, 53.7% (493/918) received alpha-blockers while 46.3% (425/918) did not. Five studies used tamsulosin, two used prazosin and one used phenoxybenzamine. Overall, the prescription of prophylactic alpha-blockers in the preoperative setting significantly reduced POUR compared to the control group (7.9% (39/493) vs 21.2% (90/425), OR: 0.31, 95% CI: 0.12-0.80, P = 0.020). Preoperative prescription of alpha-blockers reduced the incidence of POUR following inguinal hernia repair. The next generation of prospective randomised trials may identify which patients should be prescribed this medication prior to surgery.
Partial flap necrosis is a common complication after surgery. McFarlane flap model has been used for assessment of various agents' effects on random flap survival. The aim of this study was to review the methodology of studies using this flap model and reveal the most successful agents. PubMed, Scopus, and Web of Science databases were screened for words "McFarlane flap," "flap survival," and ("flap" and "rat") by using time limits between 1965 and 2019. A total of 71 original articles were reviewed. Dimensions and base (cranial/caudal) of the flap, treatment protocol, follow-up period, and survival rates were extracted. Modified survival rates were calculated. Coefficients of variation of cranial/caudally based control group flaps and most commonly used flap models were calculated to assess interstudy variability. A total of 165 different treatment regimens were studied. One-hundred twelve regimens (67.9%) were found to increase flap survival. Most common flap dimensions were 9 cm × 3 cm, followed by 10 cm × 3 cm, 8 cm × 2 cm and 6 cm × 2 cm. Studies using caudally based flaps showed less interstudy variability, but survival rates were similar. Pentoxifylline, sildenafil, chlorpromazine, phenoxybenzamine, and phentolamine were reported to be successful in multiple studies. There are numerous agents found to be effective for treatment of partial flap necrosis, but further clinical research is needed. To overcome standardization problems, use of commonly used flap dimensions with a caudal base and interpretation of results after 7 days of follow-up seems appropriate.