Study Set Content:
It may increase risk of QT prolongation in susceptible individuals.
ALFUZOSIN
Resembles tamsulosin in blocking the a 1A receptor and is used in treatment of BPH.
SILODOSIN
another a 1-selective antagonist that also has efficacy as an antihypertensive. It is not available in the USA.
INDORAMIN
An a 1 antagonist (its primary effect) that also has weak a 2-agonist and 5- HT 1A-agonist actions and weak antagonist action at 3 1 receptors. It is used in Europe as an antihypertensive agent and for benign prostatic hyperplasia.
URAPIDIL
has both a 1 -selective and ß-antagonistic effects; Neuroleptic drugs such as chlorpromazine and haloperidol
Labetalol
Are potent dopamine receptor antagonists but are also antagonists at a receptors
Labetalol
Their antagonism of a receptors contributes to their adverse effects, particularly
hypotension
Antidepressant () has the capacity to block a 1 receptors.
trazodone
eg, ergotamine and dihydroergotamine, cause reversible a-receptor blockade, probably via a partial agonist action.
Ergot derivatives
An indole alkaloid, is an a 2 -selective antagonist
YOHIMBINE
An indole alkaloid,
Used in the treatment of orthostatic hypotension because it promotes norepinephrine release through blockade of a 2 receptors in both the central nervous system and the periphery.
YOHIMBINE
Used to treat male erectile dysfunction but has been superseded by phosphodiesterase-5 inhibitors like sildenafil
YOHIMBINE
Elevate blood pressure if administered to patients receiving norepinephrine transport blocking drugs
YOHIMBINE
Reverses the antihypertensive effects of a 2-adrenoceptor agonists such as
clonidine.
Is a tumor of the adrenal medulla or sympathetic ganglion cells. The tumor secretes catecholamines, especially norepinephrine and epinephrine
PHEOCHROMOCYTOMA
The diagnosis of pheochromocytoma is confirmed on the basis of elevated plasma or urinary levels of
catecholamines, metanephrine, and normetanephrine
Computed tomography and magnetic resonance imaging scans and scanning with radiomarkers such as
131 1-metalodobenzylguanidine (MIBG)
Symptoms and signs of catecholamine excess:
• Including intermittent or sustained hypertension, headaches, palpitations, and
increased sweating.
Release of stored catecholamines from pheochromocytomas may occur in response to
physical pressure, chemical stimulation, or spontaneously.
When it occurs during operative manipulation of pheochromocytoma, the resulting hypertension may be controlled with a-receptor blockade or
nitroprusside
