Exam 3 Flashcards
Midodrine
Alpha 1 agonist
Used to treat orthostatic hypotension and urinary incontinance
Cocaine
Anesthetic
Prevents NE reuptake in the synapse
Affects DA receptors in the brain
Causes constriction of blood vessels when injected (good local anesthetic at mucosal sites).
Sometimes used during endotracheal intubation through the nose.
Pseudoephedrine
Stimulates NE release from sympathetic nerve endings independent of nerve action
Also directly stimulate on adrenergic receptors
Used to treat nasal/bronchial congestion and promote sinus drainage
Phenylephrine
Alpha 1 agonist
Used to raise BP
Greater reflex bradycardia effect due to no opposition from stimulated Beta 1 receptor
Used in neurogenic shock and to maintain BP during spinal anesthesia
Nasal decongestant, hemorrhoids, pupil dilator
Rarely used for supraventricular tachycardia.
8 Beta blockers
Acebutolol Atenolol Esmolol Metoprolol Nadolol Pindolol Propranolol Timolol
Timolol
Beta 2 inhibitor (also Beta 1)
Used topically to decrease intraoccular pressure in glaucoma.
Decreases aqueous humor production from the ciliary epithelium.
It is used because it doesn’t have a membrane stabilizing effect (local anesthetic action), which you don’t want in the eye.
Moderate lipid solubility makes it preferable to Nadolol, which otherwise has similar properties.
Esmolol
Beta 1 antagonist
Shortest half life due to rapid inactivation by esterases in the blood.
Only used in acute, critical cardiovascular conditions when you don’t want the effects to be long lasting.
Labetalol
Non selective Beta blocker plus specific alpha 1 blocker
Treats moderate to severe primary hypertension (oral) and in acute hypertensive crises (Intravenous).
Side effects include orthostatic hypotension (alpha blockade) and bronchoconstriction (beta blockade)
Less Raynaud’s aggravation than regular beta blockers and less tachycardia than regular alpha blockers.
Phenoxybenzamine
Non competitive inhibitor of alpha 1 and 2 receptors
Irreversible
Used to prevent severe hypertensive episode during surgical removal of a pheochromocytoma. Given prior to surgery.
Also can be used to treat chronic hypertension in patients with inoperable pheochromocytoma.
Phentolamine
Alpha 1 and 2 inhibitor
Used to diagnose pheochromocytoma. Small dose will drop BP a lot if hypertension is due to pheochromocytoma.
Used to prevent hypertension during pheochromocytoma surgery (given during surgery).
Also used to reverse hypertension caused by administration of too much alpha agonist.
Can stop spread of tissue necrosis caused by injection of alpha agonist into soft tissue.
Used to reverse oral soft tissue anesthesia in dentistry.
Prazosin
Selective alpha 1 antagonist
Treats mild to moderate primary hypertension
Treats BPH by relaxing bladder neck, prostatic urethra.
Can also treat Raynaud’s. Excessive response to cold/emotional stress.
Treats PTSD nightmares (inhibits central alpha 1 receptors)
Can see severe orthostatic hypotension during first dose.
Some extra cellular fluid retention.
Reflex tachycardia, but not as bad as non selective agents because presynaptic alpha 2s can still exert their feedback inhibition effect.
Doxazosin, terazosin
Selective alpha 1 inhibitors
Same effects as Prazosin, but they have longer halflives so they may be better for long term compliance in chronic hypertension
Tamsulosin, siludosin
Specific alpha 1 subtype A inhibitors
Subtype A receptors are found in smooth mm of bladder neck and prostate.
Used to treat BPH with few side effects
May cause abnormal ejaculation
Alfuzosin
Alpha 1 selective inhibitor
Used to treat BPH
Demonstrates uroselectivity because it accumulates in the prostate.
This makes it more specific than others.
Reserpine
Peripherally acting neuronal inhibitor
Decreases DA and NE uptake into storage vesicles
Decreases overall sympathetic tone
Treats hypertension by lowering cardiac output and peripheral resistance
Side effects: sedation, depression, postural hypotension, Bradycardia, fluid retention. Diarrhea and ulcers due to unopposed parasympathetic input to the gut.
Guanethidine
Like reserpine but without CNS effects
Antagonized by tricyclic antidepressants because it must get into nerve terminals via the reuptake pump, which they inhibit.
Mechanism of centrally acting adrenergic neuronal inhibitors
Act on centrally located alpha 2 receptors in vasomotor centers, causing feedback inhibition and decrease of sympathetic output.
They don’t have much impact on reflex mediated sympathetic output (for example, they don’t often cause significant postural hypertension).
Alpha-methyldopa
Centrally acting alpha 2 agonist in vasomotor centers.
Must be converted to alpha-methylnorepinephrine to become active (same enzymes as DOPA to NE).
Overall dampening of sympathetic output to CV tissues
Used to treat hypertension during pregnancy.
Side effects: fluid retention, dry mouth, sedation (like most alpha 2 agonists). Also autoimmune induction. Rarely causes liver necrosis or hemolytic anemia.
Clonidine
Direct alpha 2 agonist in the central vasomotor centers.
Treats hypertension
Available orally or through patch.
Can cause rebound hypertension if treatment is abruptly stopped (not seen in methyldopa).
Also used to treat addiction withdrawal, ADHD, PTSD, hot flashes, and migraine.
Analgesia with spinal injection.
Apraclonidine is used to reduce intraoccular pressure in post op patients.
Guanfacine
Centrally acting alpha 2 agonist
Used to treat ADHD
Also treats hypertension without the rebound hypertension and sedation seen with Clonidine.
Nicotine
Act on nicotinic receptors
Agonist at a low dose via depolarization of cell membrane
Antagonist at high dose via desensitization and persistent desensitization.
Acts in CNS, autonomic ganglia (CV and GI), and skeletal muscle.
Cromolyn sodium
Mast cell cell membrane stabilizer
Inhalation used as prophylaxis against as asthma attacks, not in acute situations.
Also useful for many allergies
Especially useful for asthma caused by specific allergens.
