Study Set Content:
is preferred because its effects can be more readily titrated and it has a shorter duration of action.
Nitroprusside
Alpha-receptor antagonists are most useful in the preoperative management of patients with
pheochromocytoma.
Administration of () in the preoperative period helps to control hypertension and tends to reverse chronic changes resulting from excessive catecholamine secretion such as plasma volume contraction, if present.
phenoxybenzamine
can be increased at intervals of several days until hypertension is controlled
Oral doses of 10 mg/d
Some physicians give phenoxybenzamine to patients with pheochromocytoma for
1-3 weeks before surgery
can be very useful in the chronic treatment of inoperable or metastatic pheochromocytoma
Phenoxybenzamine
PHEOCHROMOCYTOMA Is sometimes treated with () (a methyltyrosine), the amethyl analog of tyrosine.
metyrosine
This agent is a competitive inhibitor of tyrosine hydroxylase, the rate-limiting step in the synthesis of dopamine, norepinephrine, and epinephrine.
metyrosine
is especially useful in symptomatic patients with inoperable or metastatic pheochromocytoma,
Metyrosine
Metyrosine can cause extrapyramidal effects due to reduced
dopamine levels.
have limited application in the management of hypertensive emergencies, but labetalol has been used in this setting.
The a-adrenoceptor antagonist drugs
In theory, a-adrenoceptor antagonists are most useful when increased blood pressure reflects____ of a agonists,
excess circulating concentrations
family of a 1-selective antagonists are efficacious drugs in the treatment of mild to moderate systemic hypertension.
PRAZOSIN
• family of a
They are generally well tolerated, but they are not usually recommended as monotherapy for hypertension because other classes of antihypertensives are more effective in preventing heart failure.
PRAZOSIN
Their major adverse effect
• Orthostatic hypotension associated with
dizziness
Use of a-adrenoceptor antagonists such as prazosin has been found to be associated with either no changes in plasma lipids or increased concentrations of (), which could be a favorable alteration
high-density lipoproteins (HDL)
do not seem to be effective in the treatment of peripheral vascular occlusive disease characterized by morphologic changes that limit flow in the vessels.
Alpha-receptor-blocking drugs
Occasionally, individuals with____ involving excessive reversible vasospasm in the peripheral circulation do benefit from prazosin or phenoxybenzamine, although calcium channel blockers may be preferable for most patients
Raynaud's phenomenon
is common in elderly men. Various surgical treatments are effective in relieving the urinary symptoms of BPH, however, drug therapy is efficacious in many patients.
Benign prostatic hyperplasia
Mechanism of action in improving urine flow involves partial reversal of smooth muscle contraction in the enlarged () and in the
prostate, bladder
