Adrenergic Medications Overview

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Questions and Answers

Which adrenergic agonist is commonly used to treat anaphylaxis?

Dopamine

Dobutamine

Epinephrine (correct)

Norepinephrine

What type of adrenergic receptors does Norepinephrine primarily activate?

α (all types) and β2

Only β1

Only α1

α (all types) and β1 (correct)

Which of the following is an indirect acting adrenergic medication?

Propranolol

Phenylephrine

Salbutamol

Amphetamine (correct)

What type of drug is Pilocarpine classified as?

Direct acting cholinergic agonist Signup and view all the answers

Which adrenergic antagonist selectively blocks α1 receptors?

Prazosin Signup and view all the answers

Which adrenergic medication is specifically a β1 agonist?

Dobutamine Signup and view all the answers

What is the primary action of anticholinesterase drugs?

Inhibit acetylcholinesterase Signup and view all the answers

Which of the following medications is used to stimulate bladder emptying?

Bethanechol Signup and view all the answers

Which of the following conditions is NOT treated with reversible anticholinesterase agents?

Peripheral neuropathy Signup and view all the answers

What is the primary purpose of Atropine in clinical practice?

To induce mydriasis and cycloplegia Signup and view all the answers

What is a significant side effect of Atropine that affects bodily temperature regulation?

Inhibition of sweating Signup and view all the answers

Which drug is utilized primarily for its antispasmodic effects and also for treating motion sickness?

Scopolamine Signup and view all the answers

In a clinical setting, which neuromuscular blocker is classified as a depolarizing agent?

Succinylcholine Signup and view all the answers

What type of agent is used at autonomic ganglia to affect nicotinic receptors?

Ganglionic blocking agents Signup and view all the answers

Which of the following is NOT a side effect associated with Scopolamine?

CNS stimulation Signup and view all the answers

Which of the following conditions is Ipratropium most commonly used to treat?

Chronic obstructive pulmonary disease (COPD) Signup and view all the answers

Study Notes

Adrenergic Medications

Adrenergic medications are classified as:
- Direct-acting: stimulate adrenergic receptors directly
  - These are further divided into catecholamines and non-catecholamines
- Indirect-acting: affect adrenergic receptors indirectly by influencing the release or reuptake of neurotransmitters

Direct-Acting Adrenergic Agonists

Catecholamines
- Epinephrine:
  - α (all types) and β (all types) agonist
  - Used to treat anaphylaxis and as a local anesthetic
  - Side effects: hyperglycemia, arrhythmias, hypertension
- Norepinephrine:
  - α (all types) and β1 agonist
  - Used to treat neurogenic shock and as a last resort in shock patients
- Dopamine:
  - Stimulates D1, β1, and α1 receptors
- Dobutamine:
  - β1 agonist
Non-catecholamines
- α1 agonist: Phenylephrine
- α2 agonist: Clonidine
- β1 agonist: Only catecholamines are used
- β2 agonist: Salbutamol and Ritodrine

Indirect-Acting Adrenergic Agonists

Sympathomimetic
- These drugs cause:
  - Norepinephrine release from presynaptic terminals
  - Inhibition of norepinephrine uptake
- They enhance the effect of norepinephrine but do not directly stimulate post-synaptic receptors.
- Examples: Amphetamine, Ephedrine, and Pseudoephedrine

Adrenergic Antagonists (Sympatholytics)

These agents block adrenergic receptors.
Block both α and β receptors: Labetalol and Carvedilol
Non-selective α blockers: Phenoxybenzamine
Selective α1 blockers: Prazosin, Terazosin, Doxazosin, and Tamsulosin
Non-selective β antagonists:
- Block both types of β receptors
- Propranolol, Timolol, and Nadolol
Selective β1 antagonists:
- Acebutolol, Atenolol, and Metoprolol

Cholinergic Agonists

These medications stimulate cholinergic receptors.
Direct-acting:
- Acetylcholine:
  - Naturally occurring neurotransmitter
- Bethanechol:
  - Stimulates bladder emptying
- Carbachol:
  - Used for glaucoma
- Pilocarpine:
  - Used as eye drops to treat glaucoma
Indirect-acting:
- Reversible:
  - Neostigmine
  - Pyridostigmine
  - Physostigmine
  - Donepezil
- Irreversible:
  - These drugs irreversibly inhibit acetylcholinesterase and butyrylcholinesterase.
  - Pralidoxime can reverse the effects of these drugs in the peripheral system.

Uses of Cholinergic Agonists

Most muscarinic agonists are used clinically.
Pilocarpine is used to treat glaucoma by reducing intraocular pressure.
Bethanechol is used to stimulate bladder emptying.

Anticholinergic Antagonists

These medications block cholinergic receptors.
Atropine:
- Used for mydriasis and cycloplegia in ophthalmology
- Acts as an antispasmodic in the gastrointestinal tract
- Used to treat involuntary enuresis in children
- Helps treat heart block and dries secretions in the bronchi
- Acts as an antidote for cholinergic agonists.
- Side effects: CNS stimulation, increased body temperature, dry eyes, dry mouth, blurred vision, tachycardia, urinary retention, constipation.
Scopolamine (Hyoscine):
- Used as an antispasmodic and for motion sickness.
- Blocks short-term memory.
- Causes sedation and euphoria.
- Can be subject to abuse.
Ipratropium:
- Used as a bronchodilator in asthma patients.
- Acts locally in the lungs when administered by inhaler, minimizing systemic side effects.

Drugs Affecting Nicotinic Receptors

These drugs affect receptors at the neuromuscular junction (Nm) and autonomic ganglia (Nn).
Neuromuscular junction (Nm):
- Neuromuscular blocking drugs:
  - Block cholinergic transmission between motor nerve endings and nicotinic receptors at the neuromuscular junction.
  - Depolarizing:
    - Succinylcholine
  - Non-depolarizing:
    - Long-acting: Pancuronium
    - Intermediate-acting: Atracurium
    - Short-acting: Mivacurium
Autonomic ganglia (Nn):
- Ganglionic blocking agents:
  - Block transmission at autonomic ganglia.
- Ganglion stimulating agents:
  - Stimulate transmission at autonomic ganglia.

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Description

This quiz covers adrenergic medications, including their classifications into direct-acting and indirect-acting types. Learn about catecholamines and non-catecholamines, as well as specific drugs like epinephrine, norepinephrine, and phenylephrine. Test your knowledge on their uses, mechanisms, and side effects.