Why is phenoxybenzamine given before surgery?
Compared to selective alpha-antagonists, preparation with phenoxybenzamine prior to surgery is associated with superior intraoperative hemodynamic stability, but also more post-operative hypotension, adverse drug effects, and longer treatment period.
How do you prepare pheochromocytoma for surgery?
A patient may require 5–15 days of preoperative preparation with optimal alpha blocking drugs, increased oral fluids and salt intake and/or intravenous fluids before being “accepted” for surgery.
Why is phenoxybenzamine used for pheochromocytoma?
Endocrine Pharmacology Phenoxybenzamine is a nonselective α-adrenergic receptor antagonist used in patients with pheochromocytoma or paraganglionoma. The drug blunts the effects of catecholamines released from the tumor and is usually administered preoperatively in preparation for pheochromocytoma resection.
Is phenoxybenzamine used for pheochromocytoma?
Preoperative alpha blockade is therefore critical to safely perform surgery to resect pheochromocytoma. Phenoxybenzamine, a non-selective alpha blocker, is the most common medication used to alpha block patients prior to pheochromocytoma resection.
Does Phenoxybenzamine increase blood pressure?
Phenoxybenzamine is a long-acting, adrenergic, alpha-receptor blocking agent which can produce and maintain “chemical sympathectomy” by oral administration. It increases blood flow to the skin, mucosa and abdominal viscera, and lowers both supine and erect blood pressures.
How quickly does Phenoxybenzamine work?
This medication should take effect within 1 to 2 days, and improvements in clinical signs should follow.
How does Phenoxybenzamine lower blood pressure?
This medication is used to treat high blood pressure and heavy sweating due to a certain tumor of the adrenal glands (pheochromocytoma). Phenoxybenzamine belongs to a class of drugs known as alpha blockers. It works by relaxing and widening blood vessels so that blood can flow more easily.
How does Phenoxybenzamine cause tachycardia?
Phenoxybenzamine can cause a reflex tachycardia by inhibition of presynaptic α2 adrenoceptors at postganglionic neurons, resulting in increased release of norepinephrine.
What does Phenoxybenzamine treat?
Phenoxybenzamine is used to treat episodes of high blood pressure and sweating related to pheochromocytoma. This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.
How long does it take for Phenoxybenzamine to work?
How is phenoxybenzamine used to treat pheochromocytoma?
The diagnosis of pheochromocytoma was confirmed, and the patient was put on preoperative α- and β-adrenoceptor blockade. Three weeks before surgery, the patient was started on phenoxybenzamine 10 mg per day by mouth, which was gradually titrated up to 30 mg three times a day.
Are there any preoperative alpha blockers for pheochromocytoma?
On the basis of the current evidence, there is no evidently superior alpha-blocker for the pretreatment of patients with pheochromocytoma. Perioperative haemodynamics seem to be slightly better controlled with phenoxybenzamine, at the cost of more pronounced postoperative hypotension. Side effects o …
When to start phenoxybenzamine before heart surgery?
Phenoxybenzamine is started 7-21 days before the surgery and once the alpha blockade is established beta receptor blockers (propanolol or atenolol) can be used to reduce the resultant tachycardia or for patients with tachyarrhythmias [21].
Can a patient with pheochromocytoma die during surgery?
Patients with pheochromocytoma may develop complicated and potentially lethal cardiovascular and other complications, especially in the setting of diagnostic or interventional procedures ( e. g. upon induction of anesthesia or during surgery).