Adrenergic Agonists Pharmacology Quiz

Definition: Adrenergic agonists are drugs that stimulate the activity of the sympathetic nervous system by binding to adrenergic receptors.
Mechanism of Action: They mimic the action of endogenous catecholamines (e.g., norepinephrine, epinephrine) by binding to α1, α2, β1, β2, and β3 receptors.
Effects:
- α1 receptor stimulation: vasoconstriction, increased blood pressure
- α2 receptor stimulation: decreased insulin secretion, increased glucagon secretion
- β1 receptor stimulation: increased heart rate, contractility, and automaticity
- β2 receptor stimulation: relaxation of smooth muscle, bronchodilation, and vasodilation
- β3 receptor stimulation: lipolysis
Examples:
- Phenylephrine (α1 agonist): used to treat hypotension, nasal congestion, and priapism
- Clonidine (α2 agonist): used to treat hypertension, attention deficit hyperactivity disorder (ADHD), and opioid withdrawal
- Dobutamine (β1 agonist): used to treat heart failure and cardiogenic shock
- Salbutamol (β2 agonist): used to treat asthma, chronic obstructive pulmonary disease (COPD), and bronchitis

Definition: Adrenergic antagonists are drugs that block the activity of the sympathetic nervous system by binding to adrenergic receptors.
Mechanism of Action: They counteract the effects of endogenous catecholamines by blocking α1, α2, β1, β2, and β3 receptors.
Effects:
- α1 receptor blockade: vasodilation, decreased blood pressure
- α2 receptor blockade: increased insulin secretion, decreased glucagon secretion
- β1 receptor blockade: decreased heart rate, contractility, and automaticity
- β2 receptor blockade: bronchospasm, increased smooth muscle tone
- β3 receptor blockade: decreased lipolysis
Examples:
- Prazosin (α1 antagonist): used to treat hypertension, benign prostatic hyperplasia (BPH), and post-traumatic stress disorder (PTSD)
- Yohimbine (α2 antagonist): used to treat erectile dysfunction and xerostomia
- Metoprolol (β1 antagonist): used to treat hypertension, angina pectoris, and heart failure
- Propranolol (non-selective β antagonist): used to treat hypertension, angina pectoris, and anxiety disorders

Adrenergic agonists stimulate the sympathetic nervous system by binding to adrenergic receptors.
They mimic the action of endogenous catecholamines (e.g., norepinephrine, epinephrine) by binding to α1, α2, β1, β2, and β3 receptors.

α1 receptor stimulation: vasoconstriction, increased blood pressure
α2 receptor stimulation: decreased insulin secretion, increased glucagon secretion
β1 receptor stimulation: increased heart rate, contractility, and automaticity
β2 receptor stimulation: relaxation of smooth muscle, bronchodilation, and vasodilation
β3 receptor stimulation: lipolysis

Phenylephrine (α1 agonist): used to treat hypotension, nasal congestion, and priapism
Clonidine (α2 agonist): used to treat hypertension, attention deficit hyperactivity disorder (ADHD), and opioid withdrawal
Dobutamine (β1 agonist): used to treat heart failure and cardiogenic shock
Salbutamol (β2 agonist): used to treat asthma, chronic obstructive pulmonary disease (COPD), and bronchitis

Adrenergic antagonists block the activity of the sympathetic nervous system by binding to adrenergic receptors.
They counteract the effects of endogenous catecholamines by blocking α1, α2, β1, β2, and β3 receptors.

Prazosin (α1 antagonist): used to treat hypertension, benign prostatic hyperplasia (BPH), and post-traumatic stress disorder (PTSD)
Yohimbine (α2 antagonist): used to treat erectile dysfunction and xerostomia
Metoprolol (β1 antagonist): used to treat hypertension, angina pectoris, and heart failure
Propranolol (non-selective β antagonist): used to treat hypertension, angina pectoris, and anxiety disorders

6 Questions