Podcast
Questions and Answers
Which of the following represents a common adverse effect associated with Silodosin?
Which of the following represents a common adverse effect associated with Silodosin?
Silodosin is primarily indicated for the treatment of which condition?
Silodosin is primarily indicated for the treatment of which condition?
What is a contraindication for the use of Silodosin?
What is a contraindication for the use of Silodosin?
Which condition is Silodosin less likely to exacerbate when compared to other medications?
Which condition is Silodosin less likely to exacerbate when compared to other medications?
Signup and view all the answers
What effect might result from the use of Silodosin in patients with specific contraindications?
What effect might result from the use of Silodosin in patients with specific contraindications?
Signup and view all the answers
The 'first dose effect' of Silodosin is characterized by what?
The 'first dose effect' of Silodosin is characterized by what?
Signup and view all the answers
What is the most common undesirable effect of methyldopa at the onset of treatment?
What is the most common undesirable effect of methyldopa at the onset of treatment?
Signup and view all the answers
Which group of patients should methyldopa be given with caution?
Which group of patients should methyldopa be given with caution?
Signup and view all the answers
What is the primary therapeutic use of methyldopa?
What is the primary therapeutic use of methyldopa?
Signup and view all the answers
What effect can long-term treatment with methyldopa lead to?
What effect can long-term treatment with methyldopa lead to?
Signup and view all the answers
What type of drug is Guanfacine categorized as?
What type of drug is Guanfacine categorized as?
Signup and view all the answers
What physiological response can occur after the abrupt cessation of methyldopa?
What physiological response can occur after the abrupt cessation of methyldopa?
Signup and view all the answers
Which of the following is a common side effect associated with both methyldopa and clonidine?
Which of the following is a common side effect associated with both methyldopa and clonidine?
Signup and view all the answers
In which age group is methyldopa most effective when used for ADHD?
In which age group is methyldopa most effective when used for ADHD?
Signup and view all the answers
What is a possible side effect of methyldopa related to salivation?
What is a possible side effect of methyldopa related to salivation?
Signup and view all the answers
What is the effect of α1 receptor blockers on smooth muscle tone in the prostate?
What is the effect of α1 receptor blockers on smooth muscle tone in the prostate?
Signup and view all the answers
What occurs as a result of presynaptic α2 receptor blockade?
What occurs as a result of presynaptic α2 receptor blockade?
Signup and view all the answers
Which receptors aid in the facilitation of insulin release when α2 receptors are blocked?
Which receptors aid in the facilitation of insulin release when α2 receptors are blocked?
Signup and view all the answers
What is the main result of α1 receptor blockade on urine outflow?
What is the main result of α1 receptor blockade on urine outflow?
Signup and view all the answers
What impact do catecholamines have on glucose output from the liver?
What impact do catecholamines have on glucose output from the liver?
Signup and view all the answers
What effect does α1 receptor blockade have on radiating smooth muscles?
What effect does α1 receptor blockade have on radiating smooth muscles?
Signup and view all the answers
What is one of the consequences of α2 receptor blockade in the pancreas?
What is one of the consequences of α2 receptor blockade in the pancreas?
Signup and view all the answers
How does presynaptic α2 receptor blockade influence the baroreceptor reflex?
How does presynaptic α2 receptor blockade influence the baroreceptor reflex?
Signup and view all the answers
What is a consequence of α1 receptor blockade on nasal mucous membranes?
What is a consequence of α1 receptor blockade on nasal mucous membranes?
Signup and view all the answers
What is the primary mechanism of action of guanfacine?
What is the primary mechanism of action of guanfacine?
Signup and view all the answers
Which of the following is an occasional adverse effect of guanfacine?
Which of the following is an occasional adverse effect of guanfacine?
Signup and view all the answers
What metabolic process is guanfacine primarily subjected to?
What metabolic process is guanfacine primarily subjected to?
Signup and view all the answers
What is one consequence of prolonged use of guanfacine?
What is one consequence of prolonged use of guanfacine?
Signup and view all the answers
Which adverse effect can guanfacine lead to due to inhibition of dopaminergic mechanisms?
Which adverse effect can guanfacine lead to due to inhibition of dopaminergic mechanisms?
Signup and view all the answers
What type of drug is methyldopa considered when treating hypertension?
What type of drug is methyldopa considered when treating hypertension?
Signup and view all the answers
Which condition may require dose adjustment for guanfacine?
Which condition may require dose adjustment for guanfacine?
Signup and view all the answers
What is a common adverse effect associated with the use of guanfacine?
What is a common adverse effect associated with the use of guanfacine?
Signup and view all the answers
What is a potential consequence of discontinuing guanfacine?
What is a potential consequence of discontinuing guanfacine?
Signup and view all the answers
What are EPS observed with guanfacine attributed to?
What are EPS observed with guanfacine attributed to?
Signup and view all the answers
Which medication is a selective α1A receptor blocker primarily used for lower urinary tract symptoms?
Which medication is a selective α1A receptor blocker primarily used for lower urinary tract symptoms?
Signup and view all the answers
What is the primary mechanism of action of prazosin in relation to blood pressure?
What is the primary mechanism of action of prazosin in relation to blood pressure?
Signup and view all the answers
What is the first dose effect associated with α1 receptor blockers?
What is the first dose effect associated with α1 receptor blockers?
Signup and view all the answers
Which of the following treatments involves the use of non-selective α1ABD receptor blockers?
Which of the following treatments involves the use of non-selective α1ABD receptor blockers?
Signup and view all the answers
Which of the following is an adverse effect of alfuzosin?
Which of the following is an adverse effect of alfuzosin?
Signup and view all the answers
What is the effect of quinazolines on lipid profiles?
What is the effect of quinazolines on lipid profiles?
Signup and view all the answers
What characteristic is true for selective α1A receptor blockers compared to non-selective blockers?
What characteristic is true for selective α1A receptor blockers compared to non-selective blockers?
Signup and view all the answers
Which mechanism contributes to a decrease in blood pressure with α1 receptor blockade?
Which mechanism contributes to a decrease in blood pressure with α1 receptor blockade?
Signup and view all the answers
What should be limited when starting the administration of prazosin to minimize side effects?
What should be limited when starting the administration of prazosin to minimize side effects?
Signup and view all the answers
Which pharmacological agent is used for short term treatment of congestive heart failure?
Which pharmacological agent is used for short term treatment of congestive heart failure?
Signup and view all the answers
Study Notes
Mechanism of Action
- Blockade of α1 adrenoceptors provides relief for benign prostatic hypertrophy (BPH) symptoms.
- Presynaptic α2 receptor blockade leads to increased norepinephrine release from sympathetic nerves.
- Increased norepinephrine stimulates cardiac β1 receptors and activates baroreceptor reflex, resulting in elevated heart rate (HR).
Effects of α1 Receptor Blockade
- α1A receptors are abundant in prostate and lower urinary tract tissue.
- Administration of α1 receptor blockers reduces smooth muscle tone and relaxes muscle in the prostate and bladder neck, facilitating urine flow.
- Blockade results in mydriasis (pupillary dilation) and nasal congestion.
α2 Receptor Blockade Effects
- Promotes unopposed insulin release from pancreatic β islet cells.
- Inhibits glucose release from the liver, as catecholamines usually increase liver glucose output via β and some α receptors.
- Stimulation of GI smooth muscle occurs, leading to increased gastric acid secretion.
Adverse Effects of Methyldopa
- Common side effects include sedation, dry mouth, and mental lassitude, especially at treatment onset.
- Serious effects include mental depression and impaired concentration, necessitating caution in patients with a history of depression.
- Positive Coombs test in 10-20% of patients due to autoantibodies; may include rare cases of hemolytic anemia and hepatotoxicity.
Therapeutic Uses of Methyldopa
- Considered the preferred antihypertensive for pregnant women due to its safety and efficacy profile for both mother and fetus.
- Not a first-line choice for hypertension treatment in the general population.
Chemistry and Pharmacokinetics
- Metyrosine inhibits tyrosine hydroxylase to treat excessive sympathetic stimulation.
- Prazosin, doxazosin, and terazosin are notable selective α1 receptor blockers.
- Selective α1A blockers include tamsulosin, silodosin, and alfuzosin, primarily for BPH management.
First Dose Effect
- Significant postural hypotension and syncope can occur with initial doses of α1 receptor blockers, typically within 30-90 minutes after administration.
- Risk factors include rapid dose increases and concurrent antihypertensive medications.
Cardiovascular Effects
- α1 receptor antagonism leads to vasodilation, decreasing blood pressure by reducing total peripheral resistance (PVR) and venous return.
- Quinazolines may improve lipid profiles and glucose metabolism in hypertensive patients.
Common Considerations and Precautions
- Monitor patients for sedation and drowsiness; dose adjustments may be required in those with hepatic impairment.
- Guanfacine and clonidine are alternative medications with similar mechanisms but differing side effect profiles.
- Contraindications may include concurrent use with CYP3A4 inhibitors, risking intraoperative floppy iris syndrome and QT interval prolongation.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz explores the mechanisms and effects of α1 and α2 receptor blockade in pharmacology. Understand how these actions relate to conditions like benign prostatic hypertrophy (BPH) and their broader physiological impacts. Test your knowledge on how these receptors affect various bodily systems.