Adrenergic Agonists And Antagonists 2 Flashcards
Low dose of epinephrine mainly causes ______
Vasodilation due to β2 activation;
High doses: both α1 and β2 activated but vasoconstriction due to α1 > β2
Changes in _______ will produce a secondary homeostatic response that tends to compensate for any changes
MAP
What are the 5 classes of drugs that are adrenergic agonists?
- α antagonists: non selective and α1
- β antagonists: non selective and β1
- α1 and β antagonists
- partial agonists
- drugs that act presynaptically
Drugs that are non selective α adrenergic blockers
- phenoxybenzamine
- phentolamine
Phenoxybenzamine and phentolamien are _________
NON selective α adrenergic blockers
MOA of phenoxybenzamine and what is it used for?
Irreversible antagonist and is unsuccessful for treating hypertension
USED IN PHEOCHROMOCYTOMA
What drug would you give to treat pheochromocytoma
Phenoxybenzamine; give it prior to surgical removal of the tumor or if the tumor is inoperable
Phentolamine ______________ blocks __________
Reversibly; α1 and α2 receptors
What are some uses for phentolamine?
- control of HTN during preoperatirve preparing and surgical excision in pheochromocytoma
- used to DIAGNOSE pheochromocytoma via the phentolamine blocking test
- prevention of dermal necrosis due to NE
- solve hypertensive crisis due to stimulant drug overdose
______________ ↓ in response to epinephrine that is given in the presence of phenoxybenzamine
Systemic BP because the α1 action is blocked but NOT the β2 action → vasodilation
What is the clinical implication of someone taking α blockers and then they have a allergic reaction?
Would have to administer epinephrine but instead of ↑ their BP it would ↓ their BP because the β2 would be more activated because all the α receptors are blocked
List the 4 α1 selective adrenergic blockers
- prazosin
- terazosin
- doxazosin
- tamsulosin
What is important about when giving someone α1 blockers for the first time?
The first dose produces an exaggerated hypotensive response so the first dose should be 1/3 or 1/4 of the normal dose
α1 blockers are the drugs of choice for ______
Symptom relief of benign prostatic hyperplasia : relaxes smooth muscle in genitourinary tract improving urinary flow
__________ and __________ of the α1 blockers have longer half life
Terazosin; doxazosin
__________ is the α receptor subtype that is found predominant in the GU smooth muscle and _______ is selective for them
α1A; tamulosin
What are the benefits of using tamulosin?
Treat BPH with less effect on BP and less chance to cause orthostatic HTN because it acts specifically on α1A receptor
What are the non selective β blockers?
- propranolol
- nadolol
- Timolol
Non selective β blockers are contraindicated in _______
Patients with asthma
Metabolic effects of non selective β blockers:
↓ glycogenolysis
↓ glucagon secretion
what are the β1 selective adrenergic antagonists
- atenolol
- metoprolol
- esmolol
What kind of drugs would you give hypertensive patients with impaired pulmonary function
Β1 selective antagonists such as: atenolol and metoprolol
What would you give diabetic hypertensive patients who are using insulin to treat their hypertension
Β1 selective antagonists: atenolol and metoprolol
Esmolol is a _______________ drug and is given via _________ for ___________
Β1 selective antagonist; IV; rapid control of ventricular rate in patients with atrial fibrillation or atrial flutter
What is esmolol given to treat?
Control ventricular rate in patients with atrial fibrillation / atrial flutter
What drugs are the α1 and β blockers
Labetalol and carvedilol
Labetalol is a more potent as a ___________ antagonist than a ________ antagonist
β; α
What are some clinical uses of carvedilol
- HTN
- CHF
Has antioxidant properties
What kind of drug is pindolol and to whom would you give it?
Partial β agonist; to people with diminished cardiac reserve or a propensity to bradycardia
β blockers, particularly ________ are effective in diminishing intraocular pressure in treating glaucoma
Timolol
Conditions that β blockers can be used to treat:
- HTN
- glaucoma
- migraines (prophylaxis)
- hyperthyroidism
- angina pectoris: they ↓ O2 requirement of the heart muscle
- atrial fibrillation: esmolol
- MI: protects myocardium to ↓ cardiac remodeling
- performance anxiety
- essential tremor
β blockers are useful ______ management of stable angina
Chronic
________ blockers are used to treat essential tremors
Β
What are some adverse effects of β blockers
- bronchoconstrction
- impairs recovering from hypoglycemia because of blocking the β2 receptors in the liver AND the tachycardia associated with hypoglycemia is masked
What is the risk fo taking β blockers in someone who is diabetic?
The β blocker can mask the tachycardia that comes with hypoglycemia so they must monitor sugar levels closely
Lipid levees are relatively unaffected by ______ and_______
Labetalol & pindolol
In terms of lipid metabolism, both non selective and β1 selective blockers ↑ ______ and ↓ ______
TG; HDL
β blockers should be gradually tapered off to avoid ______________ and these adverse effects are due to ______
Tachycardia, HTN, and/or ischemia;
Up regulation of β receptors so if you remove the β blockers immediately, they will have an exaggerated sympathetic response
What kind of drug is α methyltyrosine (metyrosine)
Inhibitor of NE synthesis
What is the MOA of metyrosine and what is it used for?
MOA: competitive inhibitor of tyrosine hydroxylase
- used for: management of malignant pheochromocytoma
Metyrosine is a ____________ inhibitor of _________which converts _________ to ________
Competitive; tyrosine hydroxylase;
Dopamine → NE
Resperine is a reversibly / irreversibly blocks ________ causing ________
Reversibly;
VMAT (vesicles cannot store NE or dopamine)
Depletion of NE because they are in the cytoplasm which is where MAO is too
What is the drug that is a reversible inhibitor of VMAT?
Tetrabenazine
What drug is given for the treatment of chorea associated with Huntington’s Disease
Tetrabenazine
What receptor is associated with the ciliary epithelium and activation of it produces aqueous humour?
β2
Where are M3 receptors found on in the eye?
- pupillary constrictor muscle
- ciliary muscle (contract facilitates OUTFLOW of aqueous humor and thus ↓ intraocular pressure)
___________ receptors on the ciliary epithelium inhibit/facilitate secretion of aqueous humor
β2; facilitate
________ antagonist can be used to ↓ intraocular pressure by ↓ secretion of aqueous humor
β2 antagonist
