Alpha Agonists And Antagonists Flashcards
List alpha1 antagonists selective
Prazosin
Terazosin
Kelu osin
Indoramib
Urapidil
Blockage of alpha1 will inhibit—–
Blockage of alpha2 will lead to—-
Vasoconstriction (decrease resistance and pressure)
Increase sympathetic outflow will lead to activation of alpha1 and B1 thus increasing blood pressure
Prazosin
Fam:
Effect:
Alpha1 antagonist
Decrease in vascular resistance and venous return
Decrease cardiac preload
Doxazosin (highly/low)—-selectivity for alpha1, (selective/nonselective)—- for a1 subtypes
Usage:
High
Nonselective
Treat hypertension adn BPH
Alfuzosin with (similar/different)—- affinity to a1 subtypes
Usage:
Similar
Extensively for PBH
Tamsulosin is with (high/low)—-selectivity for a1 found on SMC of prostate
Usages:
Adverse:
Some slectivity
BPH and little for BP
Abnormal ejaculation
Adverse of prazosin and its congeners
1-
2-
3
4
Postural hypotension
Headache
Dizziness
Asthenia
Alpha2 agonists
Usages
1-
2-
Names:
1-
2-
Systemic hypertension
Reduce inteaocular pressure (decreas production of aqueous humor)
1-clonidine
2-methyldopa
Clonidine:
Usages:
1-
2-
3-
4-
Adverse mama:
Tx of HTN
Resistant HTN for two or more drugs
Preoperative sedation and anxiolysis
Reducing flashes (transdermally)
Adverse
Rebound hypertension after withdrawal,dry mouth and sedation
Methyldopa:
Site of action:
Effects:
Use:
Adverse effect:
Contraindicated in pregnancy?
Centrally actinggggg
Metabolized to a-methylnor in brain yo diminish the adrenerguc outflow
Cardiac output not decreased and flow is not
Uses: HTN with renal insuff
Can be used in pregos
Adverse: dry mouth sedation and drowsiness
K+ channel openers:
Name:
Effect:
Minoxidillll
Dilation of the arterioles and the arterioles onlyyyyyyy
They open ATP sensitive K+ channels (la barraaaa) in smooth muscle which closes the calcium channel upon hyperpilarization
Usages of minoxidil:
1-
2-
3-
Severe hypertension (responds poorly to other meds)
Can be given with loop diuretics to avoid fluid retention
Guven with B antagonist to control reflex tachy
Andverse effects of minoxi:
1-
2-
Fluid retention leading to congestive HF
Hypertrichosissss (bser 3ndn da2en mesh mtl nes) face arm back legs
T or F
Minoxi can’t be used to treat male pattern baldness
False
Lesh laaa betale3 l sha3r
Solution 2-5% eza btheb tjebu
Hydralazine:
Mode of act:
Direct smooth muscle relaxant in arteties and arterioles
Lead to reflex stimulation in HR anf increased contraction and oxygen demand
Andverse effects of hydralazine
Angina pectoris
Myocardial infarct
Cardiac failure
Increase renin
Sodium and water retention
The best way to avoid all these adverse effects is by administring—–or —–
B blocker (propranolol metoprolol or atenolol ( to decrease reflex tachy))
Diuretics to avoid fluid retention
T or F
Hydralazine can’t be used in pregos
False it can
Adverse effrct of hydralazine
With high doses—-
Headache
Tachy
Nausea
Sweating
Arrythmia
Angina
Lupus like syndromeeeee with high doses but reversiblr upon withdrawal
