Flashcards in Hypertension Deck (17)
Methyldopa: mechanism of action?
Acts centrally by stimulating central alpha-2 receptor via its active metabolite alpha-methylnorepinephrine.
It might act as a peripheral alpha-2 blocker by acting as a false neurotransmitter.
Reduces SVR without causing change in CO, renal bloodflow is maintained.
Clonidine: mechanism of action?
Alpha-2 adrenoreceptor stimulant.
CO is unchanged or increased, renal bloodflow (RBF) is unchanged.
Prazosin: mechanism of action?
Selective alpha-1 post-synaptic blocker
Reduces both SBP and DBP.
Vasodilates both resistance and capacitance vessels reducing both preload and afterload without affecting RBF.
Calcium channel blockers: mechanism of action?
Inhibit transmembrane calcium influx, blocking smooth muscle contraction.
Cause vasodilation and reduction in peripheral resistance.
No effect on cardiac output or RBF.
ACE inhibitors: mechanism of action?
Inhibits enzyme that converts AgI to AgII causing vasodilation.
Increase vasodilating PGs and inhibit release of bradykinin.
No effect on CO or RBF.
Hydralazine: mechanism of action?
Direct peripheral vasodilator which acts on vascular smooth muscle.
CO is increased, RBF is unchanged or increased.
Labetalol: mechanism of action?
Mixed alpha and beta adrenergic blocker.
CO and RBF unchanged.
Metoprolol: mechanism of action?
Selective beta-1 adrenergic blocker
Thiazide diuretics: mechanism of action?
Followed by a long-term decrease in PVR (related to decreased intracellular Na in smooth muscle).
How can you qualify for the diagosis of superimposed preeclampsia?
New onset proteinuria >300mg (without proteinuria) OR A sudden increase in proteinuria or hypertension OR Platelets Increased AST or ALT >70
What's the proper way to assess BP?
Cuff 1.5x upper arm circumference with bladder that encircles >80% of the arm Arm at the level of the woman's heart Patient seated, at rest ÌâåÊ
Maximum dose of Labetalol (current first line therapy for HTN in pregnancy)
Max dose of Nifedipine?
What very rare reaction has been reported when Ca-channel blockers and magnesium are combined, and how is it reversed?
Neuromuscular blockade (reversed with calcium gluconate)
Conditions associated with previable HELLP
partial mole/triploidytrisomy 13antiphospholipid syndromeautoantibodies to angiotensin AT(1)- receptorsevere preterm preeclampsia with Ì¢‰âÂÒmirrorÌ¢‰âÂå syndrome
Benefits of magnesium for preeclampsia, compared to placebo
59% reduction in the risk of eclampsia (number needed to treat for an additional beneficial outcome: 100) 36% reduction in abruption, and nonstatistically significant but clinically important 46% reduction in maternal death.