Pharm Exam 1 – Adrenergic, Cholinergic, Cholinergic-Blocking & Diuretic Drugs – Questions & Answers Study Guide

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Exam #1


Adrenergic Drugs
(Sympathetic Nervous
System)
The neurotransmitters involved in adrenergic drugs are catecholamine’s (norepinephrine,
epinephrine, and dopamine). There are receptor sites for the catecholamine’s norepi and epi
throughout the body and are referred to as adrenergic receptors.

Adrenergic receptors

 Alpha-adrenergic
o Alpha1
 Located on postsynaptic effector cells (cell, muscle, or organ that nerve
stimulates)
o Alpha2
 Located on presynaptic nerve terminals (nerve that stimulates the effector
cells)
 Controls the release of neurotransmitters
o Alpha-Adrenergic Agonist
 Vasoconstriction
 CNS Stimulation

 Beta-adrenergic are all located on postsynaptic effector cells
o Beta1
 Located primarily in the heart
o Beta2
 Located in the smooth muscle of bronchioles, arterioles, and visceral
organs
o Beta-Adrenergic Agonist
 Bronchial, gastrointestinal, and uterine smooth muscle relaxation
 Glycogenolysis
 Cardiac stimulation

 Dopaminergic
o Causes dilation of the following blood vessels resulting in increased blood flow

Mechanism of action

 Direct-Acting
o Binds directly to the receptor and causes a physiologic response

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 Indirect-Acting
o Causes release of catecholamine from storage sites in nerve endings
o Catecholamine binds to receptors and causes a physiologic response

 Mixed-Acting
o Directly stimulates the receptor by binding to it and indirectly stimulates the
receptor by causing the release of stored catecholamine’s from the nerve endings

Stimulation of alpha-adrenergic receptors on smooth muscles results in:
 Vasoconstriction of blood vessels
 Relaxation of GI smooth muscles (decreases motility)
 Constriction of balder sphincter
 Contraction of uterus
 Male ejaculation
 Contraction of pupillary muscles of eye (dilated pupils)

Stimulation of beta1-adrenergic receptors on the myocardium, AV node, and SA node results in
cardiac stimulation
 Increased force of contraction (positive inotropic effect)
 Increased heart rate (positive chronotropic effect)
 Increased conduction through the AV node (positive dromotropic effect)

Stimulation of beta2-adrenergic receptors on the airways results in
 Bronchodilation (relaxation of the bronchi)
 Uterine relaxation
 Glycogenolysis the liver
 Increased renin secretion in the kidneys
 Relaxation of GI smooth muscles (decreased motility)

Indications

Respiratory Indications
 Beta2-adrenergic receptors and cause bronchodilation. Beta2 agonists are helpful in
treating conditions such as asthma and bronchitis.

Indications of Topical Nasal Decongestants
 Treatment for nasal congestion, stimulate alpha1-adrenergic receptors and have little or no
effect on beta-adrenergic receptors

Ophthalmic Indications
 Stimulate alpha-adrenergic receptors located on small arterioles in the eye and
temporarily relieve conjunctival congestion by causing arteriolar vasoconstriction.
 Temporary relief of conjunctival congestion
 Reduction of intraocular pressure and dilation of pupils

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Cardiovascular Indications
 Used to support the heart during cardiac failure or shock



Contraindications

 Drug allergy
 Severe hypertension

Adverse Effects

 Alpha-Adrenergic
o CNS
 Headache, restlessness, excitement, insomnia, euphoria
o Cardiovascular
 Palpitations, tachycardia, hypertension
o Other
 Loss of appetite, dry mouth, N/V

 Beta-Adrenergic
o CNS
 Mild tremors, headache, nervousness, dizziness
o Cardiovascular
 Elevated heart rate, palpitations, fluctuations in blood pressure
o Other
 Sweating, N/V/, muscle cramps

Toxic Effects

Seizures, hypotension, hypertension, dysrhythmias, palpitations, nervousness, dizziness, fatigue,
malaise, insomnia, headache, tremor, dry mouth, nausea

Interactions
 Adrenergic antagonist (compete and limit therapeutic effect)
 Anesthetics (increases risk for cardiac dysrhythmias)
 MAOI (may cause hypertensive crisis b/c increase levels of norepi and dopamine)
 Antihistamines and thyroid preparations increase effects of adrenergic drugs

Lab interactions
 ↑ corticotrophin levels
 ↑ corticosteroids
 ↑ glucose

Dobutamine (Beta1-selectve vasoactive adrenergic drug)