Vasoconstriction is a common side effect
wherein the small blood vessels (usually arteries) becoming increasingly tight. "Vascular tone" is a term that describes the amount of tightness within the arterial walls. All arteries have vascular tone. Vascular tone is decreased when the vessel walls are relaxed. Vascular tone is increased in vasoconstriction.
What drugs cause vasoconstriction?
For purposes of this site, most CNS stimulants
, epinephrine, nor-epinephrine and others all generate increased vascular tone / vasoconstriction. Also, nasal inhalers (Vick's, Afrin, levamphetamine, etc.) work by causing vasoconstriction in the nasal turbinates---causing shrinkage of the tissues lining the airway.
What are the dangers associated with vasoconstrictive side effects?
1. Generalized vasoconstriction leads to increased blood pressure--the blood volume stays the same while the 'container' (blood vessels) tightens-up and becomes smaller, causing pressure to rise. Blood pressures can be monitored using an automatic cuff. It's a good idea for everyone to check their blood pressure at rest to determine your own 'normal' blood pressure. If resting pressures are high, you need to see your doctor for treatment, and also AVOID CNS stimulants (speed, amps, meth, cocaine, etc). For specifics on high blood pressure
, click here.
2. Regional Necrosis/Tissue Death. Occasionally, i will hear someone tell about an IV-meth user who accidentally injected amphetamines into an artery. When this happens, the injected drug
travels DOWN THE ARM/LEG instead of traveling up toward the heart. Meth happens to be such a powerful local vasoconstrictor that as the drug approaches the tiniest arterioles and capillaries, those tiny vessels will squeeze off the incoming blood supply, causing local ischemia, tissue death, black/green/dry gangrene in the fingers or toes. Expect the affected fingertips or even whole fingers and toes to slough off within a week. This is a totally irreversible loss of functional anatomy... it is a very good reason to avoid IV use of amphetamines altogether. If someone insists on injecting speed despite the risks, then please study up on injection technique, how to find veins, and never EVER EVER push against resistance (high pressure=typical of arteries), and ALWAYS pull-back on the plunger before injecting...If the needle is in a vein, then you should see a flash of DARK BLOOD (blue/black/brown/etc).
NEVER push the drug if you see bright-red blood!! Bright Red blood is full of oxygen and signifies ARTERY not vein. Pull out and reassess.
Symptoms of Dangerous Generalized Vasoconstriciton.
high blood pressure, headache, double-vision, sudden onset of slurred speech, sudden onset of clumsiness/imbalance, immediate difficulty performing routine tasks/muscular paralysis/loss of muscle control. All these are associated with stroke--the number 1 danger from extreme vasoconstriction and high blood pressure. Go to Emergency Room Immediately.
Examples of vasoconstriction.