Podcast
Questions and Answers
Phenoxybenzamine has a plasma half-life of approximately how many hours?
Phenoxybenzamine has a plasma half-life of approximately how many hours?
- 12 hours
- 36 hours
- 24 hours (correct)
- 48 hours
Which route of administration is NOT suitable for all α-blockers except phentolamine?
Which route of administration is NOT suitable for all α-blockers except phentolamine?
- Oral (correct)
- Intravenous
- Parenteral
- Intramuscular
Phenoxybenzamine binds covalently to which receptors?
Phenoxybenzamine binds covalently to which receptors?
- Muscarinic M1 & M2 receptors
- Dopamine D1 & D2 receptors
- β-1 & β-2 receptors
- α-1 & α-2 receptors (correct)
In addition to pheochromocytoma, phenoxybenzamine can also be used to control episodes of which symptoms?
In addition to pheochromocytoma, phenoxybenzamine can also be used to control episodes of which symptoms?
Which route of administration is phenoxybenzamine active by?
Which route of administration is phenoxybenzamine active by?
What is the duration of action of phenoxybenzamine after a single dose?
What is the duration of action of phenoxybenzamine after a single dose?
What effect does phenoxybenzamine have on parasympathetic nerves?
What effect does phenoxybenzamine have on parasympathetic nerves?
Besides pheochromocytoma, what else can phenoxybenzamine be used to control?
Besides pheochromocytoma, what else can phenoxybenzamine be used to control?
Study Notes
Phenoxybenzamine Overview
- Plasma half-life is approximately 24 hours.
- Not suitable for intravenous administration for all α-blockers, except phentolamine.
- Binds covalently to α-adrenergic receptors, leading to a prolonged effect.
Clinical Uses
- Primarily used to manage symptoms of pheochromocytoma, a tumor causing excess catecholamines.
- Additionally effective in controlling episodes of hypertension and tachycardia due to catecholamine release.
Administration and Dosage
- Active when administered orally, providing a convenient route for patients.
- Duration of action following a single dose can extend beyond 24 hours, due to its irreversible binding mechanism.
Physiological Effects
- Phenoxybenzamine has minimal effect on parasympathetic nerves, focusing its action on sympathetic adrenergic systems.
- Also useful in managing symptoms related to Raynaud's phenomenon and essential hypertension.
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Description
Test your knowledge on the pharmacokinetics and mechanisms of action of henoxybenzamine. Learn about its oral and parenteral routes of administration, plasma half-life, duration of action, and its binding to α-1 and α receptors.
