seems like an easy fix, doesn't it. The problem with that is, your body is used to the current BP you're at, and it will adjust as needed, when you have a stark, immediate drop in BP (e.g. if you've ever jumped up after taking a long nap and gotten dizzy, this is essentially what is occuring) you will experience signs and symptoms of shock (hypotension-related) and that can be life-threatening if the BP drops too much too fast.
Fun fact, this is a problem for asthmatics. There have been times when I've been struggling to breathe, so I used my rescue inhaler. It delivers... let me check the canister... 180 micrograms of Albuterol per puff (albuterol being a potent beta-adrenergic agonist) which mimics Epinephrine at beta receptors. If inhaled, this has an immediate effect on bronchial tissue which causes it to expand rapidly. The drug itself reaches the nervous system slightly faster than Nicotine (according to studies); about 4 to 6 seconds after inhalation.
There have been times when I've had such a hard time breathing that I've used my inhaler and stood up the moment I used it (using gravity to propel more of the aerosol into my lungs). Problem with this is, a couple things. My body is already lower than normal in terms of Oxygen, and since albuterol is a vasodilator, it causes a huge, sudden drop in blood pressure. Not to mention the fact that the propellant for albuterol is tetrahydroethane which starves the body of oxygen.
There's one time in particular that I remember standing up at the same time I used my inhaler. You're supposed to hold your breath for as long as you can so more of the medication can be absorbed. And while holding my breath, I became really dizzy, and started to loose my vision. Everything became a kaleidoscope within about 10 seconds and the next thing I remember is opening my eyes on the floor. I felt a huge surge of pain hit me in my lower back and realized that I'd fallen straight backwards onto the brick of my fireplace.
I remember this so vivdly because I scraped the side of my head on the brick (ever so slightly). It took me about 80 seconds to really come to senses and realize what had just happened. When I did I instantly thought, "Holy shit... how the fuck didn't I slam my head into that brick?! I should be dead! I should be fucking dead!...."
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Anyways, just like any drug. Your body will become tolerant to the effects of propranolol and over time you will no longer experience the anti-hypertension effects of the drug. Tbh, this isn't sustainable anyways. Not to mention the fact that you'll be dead tired all the time.
Try to get to the root cause of your hypertension. Are you overweight? How much do you sleep at night? How much do you exercise? Do you smoke? Are you overworked? Are you exceedingly stressed? Are you taking a large amount of stimulant drugs? Are you drinking a lot of coffee or soda? Etc.
Ultimately fixing the problem in your lifestyle will be a much better solution to solving your hypertension.