It’s Topic Tuesday at Aortic Hope!! We welcome you all back to our weekly educational series, where today we will be wrapping up our monthly Medication theme with a final discussion of some “atypical” anti-hypertensive drugs that don’t really fit under any of the drug types we’ve discussed so far. But first, time for trivia!
If you recall from last week, we dicussed a very popular class of drugs called diuretics, whose main effects came through increasing your ability to urine. Do you remember which type of diuretic (thiazide, loop, potassium-sparing) could be used to help treat calcium kidney stones? Comment below!
This week, we share a nice review article from the American Heart Association https://www.heart.org/en/health-topics/high-blood-pressure/changes-you-can-make-to-manage-high-blood-pressure/types-of-blood-pressure-medications
Before discussing some of the drugs for this week, it may be helpful to do a quick review of something called the sympathetic nervous system, also called our “fight-or-flight response”. The body produces two main hormones for this called norepinephrine and epinephrine (also called adrenaline). These hormones can bind several different receptors mediating different effects in the body.
One effect they carry out is by binding alpha 1 receptors (pro-sympathetic) which acts by increasing smooth muscle contraction throughout the body.
Additionally, epinephrine can bind beta 1 receptors, which increases heart rate / pumping (Did you know that these are the receptors, beta-blockers block to fight high blood pressure!)
Our first atypical anti-hypertensive drug for today are the alpha-1 blocker drugs, which all end in “-zosin”
ie. doxazosin, prazosin
These drugs directly oppose alpha-1 mediated arterial contraction and therefore help oppose high blood pressure.
Some side effects include dizziness, faster heart beat, and weakness.
Our next drug are the alpha-2 agonists. If alpha-1 was pro-sympathetic, alpha-2 is its arch nemesis - the anti-sympathetic system receptor. Drugs in this class usually end in “-ine”
ie. clonidine, guanfacine, a-methyldopa (exception to the rule!)
These drugs ACTIVATE alpha-2 receptors which OPPOSES alpha-1 effects, causing a decrease in vasoconstriction.
Some side effects include dry mouth, fatigue, hunger, and sexual dysfunction.
Finally, we have direct vaso-dilators. Like the name implies they cause muscles vessel walls (especially arterioles) to widen and dilate, allowing more blood to flow through easier with less pressure. The two main drugs in this class include hydralazine and minoxidil
Side effects include headache, eye swelling, fluid retention (minoxidil) and joint pain (hydralazine)
And that a wrap on this session and month theme! We hope you enjoyed and will join us next week to kick off our new monthly series - Imaging! Come join us every week as we review different diagnostic imaging tests doctors may use to assess your heart and aorta, including ultrasound, CT, MRI TEE, and TEE! Until next time, remember to always Think Aorta.
Best,
Adham