Wikipedia reckons that nicotine raises blood pressure:
Nicotine has very powerful effects on arteries throughout the body. Nicotine is a stimulant, it raises blood pressure, and is a vasoconstrictor, making it harder for the heart to pump through the constricted arteries. It causes the body to release its stores of fat and cholesterol into the blood.[citation needed]
Mind you, the "citation needed" at the end of this paragraph and the comments immediately above it make you wonder.
I found an article at Harvard Health publications (yes that does seem to be the real Harvard) that says this
Nicotine stimulates the central nervous system. Whether you smoke a cigarette or absorb nicotine from a patch, your body responds by releasing a hormone called epinephrine (adrenaline). Its effects range from increased energy and awareness to high blood pressure, a rise in heart rate, and nervousness. High blood pressure with the use of a nicotine patch (or gum, inhaler, lozenge, or nasal spray) may mean you are taking too much nicotine.
High blood pressure by itself, or accompanied by nervous jitters and a fast heart rate, can be a sign of nicotine withdrawal. So the increase in your blood pressure could also mean you are not getting enough nicotine in the patch. For heavy smokers, a nicotine patch sometimes doesnt deliver enough nicotine to replace what they had been getting from their cigarettes.
So that second bit about nicotine withdrawal may explain the "nicotine lowers blood pressure" advice.
I don't think it's at all true to say "only the tar in cigarettes is harmful". Mom, you've been taking a powerful stimulant for several years. Like other stimulants (cocaine, ampetamines, caffeine?) it can stress your heart and your body generally. But when you come off it your system can bounce around before it settles to a new equilibrium. At least that's my take on it but you need to have a thorough talk about this with a good doctor.
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