Sympathomimetics: Direct agonists
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Sympathomimetics: Direct agonists
Prerequisite basic sciences
Abdominal pain
Anatomy of the abdominal viscera: Esophagus and stomach
Anatomy of the abdominal viscera: Innervation of the abdominal viscera
Anatomy of the abdominal viscera: Kidneys, ureters and suprarenal glands
Anatomy of the abdominal viscera: Large intestine
Anatomy of the abdominal viscera: Liver, biliary ducts and gallbladder
Anatomy of the abdominal viscera: Pancreas and spleen
Anatomy of the abdominal viscera: Small intestine
Anatomy of the female reproductive organs of the pelvis
Anatomy of the gastrointestinal organs of the pelvis and perineum
Anatomy of the male reproductive organs of the pelvis
Anatomy of the peritoneum and peritoneal cavity
Anatomy of the urinary organs of the pelvis
Anatomy of the vessels of the posterior abdominal wall
Anatomy clinical correlates: Female pelvis and perineum
Anatomy clinical correlates: Male pelvis and perineum
Anatomy clinical correlates: Other abdominal organs
Anatomy clinical correlates: Peritoneum and diaphragm
Anatomy clinical correlates: Viscera of the gastrointestinal tract
Bile secretion and enterohepatic circulation
Gastrointestinal system anatomy and physiology
Liver anatomy and physiology
Pancreatic secretion
Appendicitis: Pathology review
Diverticular disease: Pathology review
Gallbladder disorders: Pathology review
GERD, peptic ulcers, gastritis, and stomach cancer: Pathology review
Pancreatitis: Pathology review
Endocrine diseases
Anatomy of the abdominal viscera: Kidneys, ureters and suprarenal glands
Anatomy of the thyroid and parathyroid glands
Anatomy clinical correlates: Vessels, nerves and lymphatics of the neck
Anatomy clinical correlates: Viscera of the neck
Adrenal gland histology
Thyroid and parathyroid gland histology
Calcitonin
Cortisol
Endocrine system anatomy and physiology
Estrogen and progesterone
Parathyroid hormone
Phosphate, calcium and magnesium homeostasis
Synthesis of adrenocortical hormones
Testosterone
Thyroid hormones
Vitamin D
Adrenal insufficiency: Pathology review
Adrenal masses: Pathology review
Cushing syndrome and Cushing disease: Pathology review
Hyperthyroidism: Pathology review
Hypothyroidism: Pathology review
Multiple endocrine neoplasia: Pathology review
Neuroendocrine tumors of the gastrointestinal system: Pathology review
Parathyroid disorders and calcium imbalance: Pathology review
Thyroid nodules and thyroid cancer: Pathology review
Fluids and electrolytes
Introduction to the lymphatic system
Body fluid compartments
Microcirculation and Starling forces
Movement of water between body compartments
Osmoregulation
Phosphate, calcium and magnesium homeostasis
Potassium homeostasis
Renin-angiotensin-aldosterone system
Sodium homeostasis
Cirrhosis: Pathology review
Deep vein thrombosis and pulmonary embolism: Pathology review
Diabetes insipidus and SIADH: Pathology review
Electrolyte disturbances: Pathology review
Heart failure: Pathology review
Hypothyroidism: Pathology review
Nephrotic syndromes: Pathology review
Parathyroid disorders and calcium imbalance: Pathology review
Renal failure: Pathology review
Gastrointestinal hemorrhage
Anatomy of the abdominal viscera: Blood supply of the foregut, midgut and hindgut
Anatomy of the abdominal viscera: Esophagus and stomach
Anatomy of the abdominal viscera: Large intestine
Anatomy of the abdominal viscera: Small intestine
Anatomy of the gastrointestinal organs of the pelvis and perineum
Anatomy clinical correlates: Viscera of the gastrointestinal tract
Enteric nervous system
Esophageal motility
Gastric motility
Gastrointestinal system anatomy and physiology
Gastrointestinal bleeding: Pathology review
Intra-abdominal and retroperitoneal masses
Anatomy of the abdominal viscera: Kidneys, ureters and suprarenal glands
Anatomy of the abdominal viscera: Liver, biliary ducts and gallbladder
Anatomy of the abdominal viscera: Pancreas and spleen
Anatomy of the peritoneum and peritoneal cavity
Anatomy clinical correlates: Other abdominal organs
Anatomy clinical correlates: Peritoneum and diaphragm
Neuroendocrine tumors of the gastrointestinal system: Pathology review
Pancreatitis: Pathology review
Viral hepatitis: Pathology review
Jaundice
Anatomy of the abdominal viscera: Liver, biliary ducts and gallbladder
Anatomy of the abdominal viscera: Pancreas and spleen
Anatomy clinical correlates: Other abdominal organs
Gallbladder histology
Liver histology
Bile secretion and enterohepatic circulation
Liver anatomy and physiology
Pancreatic secretion
Jaundice: Pathology review
Non-cardiac chest pain and shortness of breath
Anatomy of the abdominal viscera: Blood supply of the foregut, midgut and hindgut
Anatomy of the abdominal viscera: Esophagus and stomach
Anatomy of the abdominal viscera: Innervation of the abdominal viscera
Anatomy of the diaphragm
Anatomy of the inferior mediastinum
Anatomy of the larynx and trachea
Anatomy of the lungs and tracheobronchial tree
Anatomy of the pharynx and esophagus
Anatomy of the pleura
Anatomy of the superior mediastinum
Bones and joints of the thoracic wall
Muscles of the thoracic wall
Vessels and nerves of the thoracic wall
Anatomy clinical correlates: Mediastinum
Anatomy clinical correlates: Pleura and lungs
Anatomy clinical correlates: Thoracic wall
Bronchioles and alveoli histology
Esophagus histology
Trachea and bronchi histology
Alveolar surface tension and surfactant
Anatomic and physiologic dead space
Breathing cycle and regulation
Diffusion-limited and perfusion-limited gas exchange
Gas exchange in the lungs, blood and tissues
Lung volumes and capacities
Pulmonary shunts
Regulation of pulmonary blood flow
Respiratory system anatomy and physiology
Ventilation
Ventilation-perfusion ratios and V/Q mismatch
Zones of pulmonary blood flow
Chewing and swallowing
Enteric nervous system
Esophageal motility
Gastric motility
Gastrointestinal system anatomy and physiology
Aortic dissections and aneurysms: Pathology review
Deep vein thrombosis and pulmonary embolism: Pathology review
Pleural effusion, pneumothorax, hemothorax and atelectasis: Pathology review
Chest X-ray interpretation: Clinical sciences
ECG axis
ECG basics
ECG cardiac hypertrophy and enlargement
ECG cardiac infarction and ischemia
ECG intervals
ECG normal sinus rhythm
ECG QRS transition
ECG rate and rhythm
Perioperative care
Anatomy of the gastrointestinal organs of the pelvis and perineum
Anatomy of the perineum
Anatomy of the vertebral canal
Bones of the vertebral column
Joints of the vertebral column
Vessels and nerves of the vertebral column
Anatomy clinical correlates: Spinal cord pathways
Anatomy clinical correlates: Vertebral canal
Blood components
Clot retraction and fibrinolysis
Coagulation (secondary hemostasis)
Platelet plug formation (primary hemostasis)
Acetaminophen (Paracetamol)
General anesthetics
Local anesthetics
Neuromuscular blockers
Non-steroidal anti-inflammatory drugs
Opioid agonists, mixed agonist-antagonists and partial agonists
Postoperative care
Cardiovascular system anatomy and physiology
Cytokines
Gastrointestinal system anatomy and physiology
Inflammation
Innate immune system
Introduction to the immune system
Lymphatic system anatomy and physiology
Nervous system anatomy and physiology
Regulation of pulmonary blood flow
Renal system anatomy and physiology
Respiratory system anatomy and physiology
Ventilation
Wound healing
Zones of pulmonary blood flow
Shock
Blood pressure, blood flow, and resistance
Carbon dioxide transport in blood
Cardiac afterload
Cardiac contractility
Cardiac cycle
Cardiac preload
Cardiac work
Changes in pressure-volume loops
Compliance of blood vessels
Frank-Starling relationship
Free radicals and cellular injury
Hypoxia
Ischemia
Law of Laplace
Measuring cardiac output (Fick principle)
Microcirculation and Starling forces
Oxygen binding capacity and oxygen content
Oxygen-hemoglobin dissociation curve
Pressure-volume loops
Pressures in the cardiovascular system
Stroke volume, ejection fraction, and cardiac output
Acid-base map and compensatory mechanisms
Buffering and Henderson-Hasselbalch equation
Physiologic pH and buffers
The role of the kidney in acid-base balance
Shock: Pathology review
Sympathomimetics: Direct agonists
Trauma
Anatomy of the abdominal viscera: Blood supply of the foregut, midgut and hindgut
Anatomy of the axilla
Anatomy of the pelvic cavity
Anatomy of the urinary organs of the pelvis
Anatomy of the vessels of the posterior abdominal wall
Arteries and veins of the pelvis
Deep structures of the neck: Root of the neck
Fascia, vessels and nerves of the upper limb
Introduction to the cranial nerves
Superficial structures of the neck: Anterior triangle
Superficial structures of the neck: Posterior triangle
Vessels and nerves of the forearm
Vessels and nerves of the gluteal region and posterior thigh
Vessels and nerves of the thoracic wall
Vessels and nerves of the vertebral column
Anatomy clinical correlates: Arm, elbow and forearm
Anatomy clinical correlates: Axilla
Anatomy clinical correlates: Bones, fascia and muscles of the neck
Anatomy clinical correlates: Cerebral hemispheres
Anatomy clinical correlates: Clavicle and shoulder
Anatomy clinical correlates: Eye
Anatomy clinical correlates: Female pelvis and perineum
Anatomy clinical correlates: Heart
Anatomy clinical correlates: Hip, gluteal region and thigh
Anatomy clinical correlates: Male pelvis and perineum
Anatomy clinical correlates: Mediastinum
Anatomy clinical correlates: Pleura and lungs
Anatomy clinical correlates: Skull, face and scalp
Anatomy clinical correlates: Spinal cord pathways
Anatomy clinical correlates: Thoracic wall
Anatomy clinical correlates: Vertebral canal
Anatomy clinical correlates: Vessels, nerves and lymphatics of the neck
Anatomy clinical correlates: Viscera of the neck
Anatomy clinical correlates: Wrist and hand
Eye conditions: Inflammation, infections and trauma: Pathology review
Pleural effusion, pneumothorax, hemothorax and atelectasis: Pathology review
Spinal cord disorders: Pathology review
Traumatic brain injury: Pathology review
Vomiting, diarrhea, and constipation
Anatomy of the abdominal viscera: Esophagus and stomach
Anatomy of the abdominal viscera: Large intestine
Anatomy of the abdominal viscera: Small intestine
Anatomy of the gastrointestinal organs of the pelvis and perineum
Anatomy clinical correlates: Viscera of the gastrointestinal tract
Colon histology
Small intestine histology
Stomach histology
Development of the digestive system and body cavities
Development of the gastrointestinal system
Gastrointestinal system anatomy and physiology
Appendicitis: Pathology review
Colorectal polyps and cancer: Pathology review
Diverticular disease: Pathology review
Gallbladder disorders: Pathology review
GERD, peptic ulcers, gastritis, and stomach cancer: Pathology review
Jaundice: Pathology review
Pancreatitis: Pathology review
Viral hepatitis: Pathology review
Communication of bad news
How to deliver bad news
Assessments
Sympathomimetics: Direct agonists
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Sympathomimetics: Direct agonists
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External References
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Amphetamines p. 243
as noradrenergic drug p. 240
norepinephrine and p. 240
Cocaine p. 571
as noradrenergic drug p. 240
Depression
serotonin-norepinephrine reuptake inhibitors (SNRIs) for p. 599
Dopamine p. 243, 334
in noradrenergic drugs p. 240
Ephedrine p. 243
as noradrenergic drug p. 240
Generalized anxiety disorder (GAD) p. 585, 586
serotonin-norepinephrine reuptake inhibitors (SNRIs) for p. 599
Hypotension
norepinephrine for p. 243
Isoproterenol
norepinephrine vs p. 244
Noradrenergic drugs p. 240
Norepinephrine (NE)
adrenal medulla secretion p. 332
amphetamines and p. 240
bupropion effect on p. 600
changes with disease p. 512
circadian rhythm p. 513
direct sympathomimetic p. 243
isoproterenol vs p. 244
male sexual response p. 651
MAO inhibitor effects p. 599
in nervous system p. 237
opioid effect on p. 572
phenoxybenzamine and p. 231
pheochromocytoma secretion p. 345
REM sleep and p. 513
tramadol effects p. 572
tyrosine catabolism p. 81
vitamin B6 and p. 65
Phenoxybenzamine p. 245
norepinephrine and p. 231
Reserpine
as noradrenergic drug p. 240
Septic shock
norepinephrine for p. 243
Serotonin-norepinephrine reuptake inhibitors (SNRIs)
Shock p. 319
norepinephrine for p. 243
SNRIs (serotonin-norepinephrine reuptake inhibitors ) p. 599
Tricyclic antidepressants (TCAs) p. 599
as noradrenergic drug p. 240
Tyrosine
as noradrenergic drug p. 240
Transcript
Content Reviewers
Alpha agonists and beta agonists are two types of adrenergic medications that stimulate their respective receptors and mimic the effect of endogenous catecholamines, like norepinephrine and epinephrine.
The nervous system is divided into the central nervous system and the peripheral nervous system.
The peripheral nervous system can be further divided into the somatic nervous system, which controls voluntary movement of our skeletal muscles; and the autonomic nervous system, which controls the involuntary movement of the smooth muscles and glands of our organs; this system is then further divided into the sympathetic and parasympathetic nervous systems.
Now, the autonomic nervous system is made up of a relay that includes two neurons.
We’ll focus on just the sympathetic nervous system.
Signals for the autonomic nervous system start in the hypothalamus, at the base of the brain.
Hypothalamic neurons have really long axons that carry signals all the way down to the thoracic and lumbar spinal cord nuclei, where they synapse with preganglionic neuron cell bodies.
From there, the signal goes from the preganglionic neurons down its relatively short axon, exits the spinal cord, and reaches the nearby sympathetic ganglion, which is made up of lots of postganglionic neuron cell bodies.
The postganglionic neurons are also called adrenergic neurons, because they release the neurotransmitter norepinephrine, which is also called noradrenalin; and to a much lesser degree, epinephrine also known as adrenaline.
Summary
Sympathomimetics are drugs that act on the sympathetic nervous system to produce their effects. They include classes of drugs like alpha agonists and beta-agonists. Both alpha agonists and beta-agonists bind to receptors in the body and activate them.
Alpha agonists activate alpha receptors, which are found primarily in the smooth muscles of the blood vessels and lungs. Alpha agonists are divided into alpha-1 agonists, like phenylephrine and midodrine; and alpha-2 agonists, like clonidine. Phenylephrine is used to treat hypotension, but it can also be used as a decongestant to treat rhinitis, or as a topical agent to cause mydriasis. Midodrine is used to treat orthostatic hypotension; while intravenous and nasal administration of clonidine causes vasoconstriction.
On the other hand, beta-agonists activate beta receptors, which are found in the heart, lungs, and other organs. Beta-agonists are subdivided into non-selective beta agonists like isoproterenol; and selective beta-2 agonists, like albuterol, salmeterol, and terbutaline. Isoprenaline is used to stimulate the heart in individuals with bradycardia or heart block, while albuterol, salmeterol, and terbutaline are used in the treatment of asthma, chronic obstructive pulmonary disease, and hyperkalemia.
Sources
- "Katzung & Trevor's Pharmacology Examination and Board Review,12th Edition" McGraw-Hill Education / Medical (2018)
- "Rang and Dale's Pharmacology" Elsevier (2019)
- "Goodman and Gilman's The Pharmacological Basis of Therapeutics, 13th Edition" McGraw-Hill Education / Medical (2017)
- "Midodrine" Drugs & Aging (1998)
- "Conservative Treatment of Chronic Heart Block" BMJ (1969)
- "Mechanism of action of agents used in attention-deficit/hyperactivity disorder" J Clin Psychiatry (2006)
- "Pharmacological treatment of COPD – New evidence" Pulmonology (2019)
- "Nebulized Terbutaline and Ipratropium Bromide Versus Terbutaline Alone in Acute Exacerbation of Chronic Obstructive Pulmonary Disease Requiring Noninvasive Ventilation: A Randomized Double‐blind Controlled Trial" Academic Emergency Medicine (2018)
- "Terbutaline versus salbutamol for suppression of preterm labor: a randomized clinical trial" Ann Saudi Med (2010)
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