Drugs Affecting Adrenergic Function Autonomic Nervous System Involuntary system responsible for control of smooth muscles Bronchi Blood vessels GI tract Cardiac muscles Exocrine (gastric, sweat, and salivary) SNS and PSNS Effects on the Body Medication function Pharmacological drugs work on the receptors by either:  Increase (Agonist) Decrease (Antagonists)(anti) Neurotransmitters of ANS Acetylcholine DopamineNorepinephrine Epinephrine Adrenergic Agonists These drugs mimic the action of the sympathetic nervous system 2 groups Catecholamineo Short duration actiono Cannot be given orallyo They do not cross the blood brain barrier Non-catecholamine Classified according to their selectivity Nonselective-acting Selective-acting Adrenergic Receptors Alpha 1 Alpha 2 Beta 1 Beta 2Fight or Flight System Adrenergic Receptors Alpha 1:  Arteries/Veins Bladder  Eyes Male Sex Organs Alpha 2:  Inhibits Norepinephrine Release  Adrenergic Receptors Beta 1:  Heart & Kidney Beta 2:  Bronchi  Skeletal Muscle Arterioles Uterus Dopamine:  Kidneys Non-Selective Prototype Epinephrine:  Pharmacotherapeutics:  Wide variety of indications-- asthma, shock, anaphylactic reaction, ventricular fibrillation.  Pharmacokinetics:  Adminstered—parenterally, topically, or by inhalation. Metabolized in the liver and excreted through the kidneys.  Pharmacodynamics:  It stimulates all adrenergic receptors except dopaminergic and causes the greatest adverse effects in the cardiovascular system and CNS.  Epinephrine  Contraindications and precautions Absolute contraindications to epinephrine include hypersensitivity, sulfite sensitivity, closed-angle glaucoma, and its use during labor. Adverse effectshypertensive crisis cardiac arrhythmias angina elevated serum glucose cerebral hemorrhage J Drug interactions Beta blockers Selective-adrenergic agonists Nonselective-acting Activate both alpha and beta receptors Selective- acting Alpha 1 Arteries- veins, bladder, eyes, Male sex organ Alpha-2 Inhibits norepinephrine release Beta-1 Heart & Kidney Beta-2 Arterioles, Bronchi, liver, skeletal muscles Uterus Dopamine-1 Dopamine-2 Epinephrine Maximizing therapeutic effects/Minimizing adverse effects Requires close monitoring of vital signs and careful monitoring for adverse effects. Take as prescribed. When treating anaphylactic shock, monitor blood pressure. Assisting the patient with menu planning may help to promote appetite and counteract the anorectic influence of epinephrine. Alpha-1 Adrenergic Agonist Prototype: Phenylephrine  (Allerest, Sudafed PE, Neo-Synephrine, Preparation H) Remember where Alpha 1 receptors are located???? Phenylephrine Pharmacotherapeutics Used parenterally for vascular failure in shock. Used topically and orally to shrink tissues for relief of nasal mucosal congestion, hemorrhoids. Pharmacokinetics Administered: parenterally or topically because of poor absorption from GI tract Metabolized by liver Excreted in urine. Phenylephrine  Pharmacodynamics A powerful alpha-1 adrenergic agonist Very little activity on beta receptors Vasoconstrictor Predominant actions are in vascular system Phenylephrine  Contraindications Hypersensitivity, severe hypertension, ventricular tachycardia, closed angle glaucoma, sulfite sensitivity Use Cautiously with: Hyperthyroidism, pregnancy, asthma, myocardial disease, arteriosclerosis, diabetes, asthma Phenylephrine Adverse Effects Headache,  Restlessness,  Excitability, Reflex bradycardia (following increase in B/P) Rebound congestion Drug interactions Antihypertensive Meds,  Antidepressants (MAOI/Tricyclic) Oxytocics Phenylephrine Maximizing Therapeutic Effects/Minimizing Adverse Effects Correct blood loss/fluid deficits Proper technique for administration Use as prescribed Phenylephrine Minimizing Adverse Effects/Maximizing Adverse Effects Administer through large vein Frequent IV site assessment Avoid driving at night  Good sleep hygiene Watch for drug-drug interactions Safety Watch for rebound congestion Alpha 2 Agonist Prototype: clonidine (catapres) Remember alpha 2 receptors??  Clonidine  Pharmacotherapeutics Antihypertensive Symptoms of withdrawal ADHD Pain Pharmacokinetics Administered: parenterally, topically, or orally. Clonidine  Pharmocodynamics: Inhibits release of norepinephrine- opposite effect- vasodilation Clonidine Contraindications and precautions Coronary insufficiency Recent MI  Recent CVA Adverse effects  Clonidine Maximizing Therapeutic Effects/Minimizing Adverse Effects Monitor B/P Safety Client education Avoid abrupt discontinuationdry mouth sedationdizziness constipation Beta-Adrenergic Agonists Beta-adrenergic agonists Stimulates beta receptors  Selective versus non-selective Mimic action of the SNS Terms you should know: Inotropic: strength of contraction Chronotropic: increased heart rate Beta-Adrenergic Agonists Prototype: Dopamine (Intropin) Stimulation of beta-1 receptors Increased HR Increased force of contraction Increased cardiac output Dopamine PharmacotherapeuticsUsed to correct the hemodynamic imbalances present in shock. Also used at low dose to improve renal function PharmacokineticsIV only- Onset: 5 minutes. Duration: 10 minutes.Metabolized: Liver, kidneys, & plasmaExcreted in the urinePharmacodynamics Has the capability to stimulate all adrenergic receptors Strong beta-1 stimulation Dopamine  Contraindications and precautions Uncorrected tachyarrhythmias, Ventricular fibrillation Adverse effectsEctopic beats dyspneanausea and vomiting headachetachycardia hypotensionangina vasoconstrictionpalpitation DopamineMaximizing Therapeutic Effects/Minimizing Adverse Effects Administer IV dopamine via infusion pump Start at low doses Monitor B/P, UOP, CO, PWP Monitor IV