Drugs that mimic the action of endogenous catecholamines like noradrenaline and adrenaline are called adrenergic agonists or sympathomimetics. Based on their mechanism of action, sympathomimetics can be classified as direct-, indirect-, or mixed-acting sympathomimetics. Direct-acting adrenergic agonists activate adrenoceptors without affecting presynaptic neurons, making them independent of neuronal catecholamine-depleting agents like reserpine and guanethidine.

These agents can be classified based on their selectivity to specific adrenoceptor types. Non-selective agents, like oxymetazoline, have diverse effects. Selective direct-acting agonists target specific adrenoceptors, avoiding unwanted side effects. Examples include α1-selective agents (e.g., phenylephrine) that enhance cardiovascular function, α2-selective agents that inhibit it, ꞵ1-selective agents (e.g., dobutamine) that increase heart rate and cardiac output, and ꞵ2-selective agents (e.g., salbutamol, terbutaline) that act as bronchodilators and uterine relaxants. Additionally, ꞵ3-selective agents like mirabegron are used to treat urinary incontinence by acting on the detrusor muscle of the bladder.

From Chapter 6:

article

Now Playing

6.5 : Adrenergic Agonists: Direct-Acting Agents

Drugs Acting on Autonomic Nervous System: Adrenergic Agonists and Antagonists Agents

1.2K Views

article

6.1 : Adrenergic Neurons: Neurotransmission

Drugs Acting on Autonomic Nervous System: Adrenergic Agonists and Antagonists Agents

3.2K Views

article

6.2 : Adrenergic Receptors (Adrenoceptors): Classification

Drugs Acting on Autonomic Nervous System: Adrenergic Agonists and Antagonists Agents

2.0K Views

article

6.3 : Adrenergic Receptors: ɑ Subtype

Drugs Acting on Autonomic Nervous System: Adrenergic Agonists and Antagonists Agents

1.3K Views

article

6.4 : Adrenergic Receptors: β Subtype

Drugs Acting on Autonomic Nervous System: Adrenergic Agonists and Antagonists Agents

1.4K Views

article

6.6 : Adrenergic Agonists: Indirect-Acting Agents

Drugs Acting on Autonomic Nervous System: Adrenergic Agonists and Antagonists Agents

1.4K Views

article

6.7 : Adrenergic Agonists: Mixed-Action Agents

Drugs Acting on Autonomic Nervous System: Adrenergic Agonists and Antagonists Agents

605 Views

article

6.8 : Adrenergic Agonists: Chemistry and Structure-Activity Relationship

Drugs Acting on Autonomic Nervous System: Adrenergic Agonists and Antagonists Agents

2.4K Views

article

6.9 : Adrenergic Agonists: Therapeutic Classification

Drugs Acting on Autonomic Nervous System: Adrenergic Agonists and Antagonists Agents

606 Views

article

6.10 : Adrenergic Agonists: Therapeutic Uses

Drugs Acting on Autonomic Nervous System: Adrenergic Agonists and Antagonists Agents

670 Views

article

6.11 : Adrenergic Antagonists: Chemistry and Classification of ɑ-Receptor Blockers

Drugs Acting on Autonomic Nervous System: Adrenergic Agonists and Antagonists Agents

726 Views

article

6.12 : Adrenergic Antagonists: Pharmacological Actions of ɑ-Receptor Blockers

Drugs Acting on Autonomic Nervous System: Adrenergic Agonists and Antagonists Agents

497 Views

article

6.13 : Adrenergic Antagonists: Chemistry and Classification of β-Receptor Blockers

Drugs Acting on Autonomic Nervous System: Adrenergic Agonists and Antagonists Agents

433 Views

article

6.14 : Adrenergic Antagonists: Pharmacological Actions of β-Receptor Blockers

Drugs Acting on Autonomic Nervous System: Adrenergic Agonists and Antagonists Agents

468 Views

article

6.15 : Adrenergic Antagonists: ɑ and β-Receptor Blockers

Drugs Acting on Autonomic Nervous System: Adrenergic Agonists and Antagonists Agents

373 Views

See More

We use cookies to enhance your experience on our website.

By continuing to use our website or clicking “Continue”, you are agreeing to accept our cookies.

Learn More