16 Questions
What is the characteristic feature of alpha adrenergic receptor antagonists?
Lowering blood pressure through blocking of the α1-receptors
Why are selective α-receptor antagonists like Tamsulosin used?
To relax smooth muscle in the bladder neck and manage benign prostatic hyperplasia
Why is Prazocin no longer commonly used as an antihypertensive agent?
It is less effective than many other antihypertensive agents
What is the distinctive pharmacological action of α1A-receptor antagonists like Tamsulosin?
Relaxing smooth muscle in the bladder neck and prostate capsule
What is the main use of Tamsulosin?
Relaxing smooth muscle in the bladder neck and managing benign prostatic hyperplasia (BPH)
Which type of drug is used to prevent the excessive stimulation of α-receptors by endogenous catecholamines released by pheochromocytoma?
Irreversible non-selective α-receptor antagonist
Why are more selective agents on specific α-receptor subtypes more widely used?
Due to their distinctive pharmacological action on the bladder neck with less vascular effect
What is the characteristic adverse reaction of α-receptor antagonists?
Postural (orthostatic) hypotension
Which β-receptor antagonist is a non-selective agent and the prototype of this class of drugs?
Propranolol
What is the therapeutic benefit of β1-receptor blockade in clinical situations such as hypertension and ischemic heart disease?
Reduced peripheral resistance
Which characteristic distinguishes lipid-soluble β-blockers from water-soluble ones?
Hepatic first pass metabolism
Which type of β-receptor antagonist has α-blocking activity?
Carvedilol
What distinguishes short-acting β-blockers from long-acting ones?
Half-life and duration of action
What is the expected adverse effect of non-selective agents blocking both β1 and β2 receptors?
Tachycardia
Why should treatment with α-receptor antagonists be started with lower doses at bedtime and increased gradually to standard doses?
To minimize postural (orthostatic) hypotension
What is the primary therapeutic benefit of non-selective agents with α-blocking activity?
Reduced peripheral resistance and decreased blood pressure
This quiz covers the pharmacological actions, uses, and adverse effects of alpha adrenergic receptors antagonists, with a focus on their effect on lowering blood pressure through blocking of the α1-receptors. It also discusses why they are less likely to be used for this purpose except in selected cases.
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