There are street drugs that are sold, illegally as Xanax "The deaths caused by fentanyl pills disguised as Xanax provide a harrowing look into the real danger of purchasing prescription drugs on the street."

Benzodiazepines, such as Xanax, Klonopin, Valium, etc. They each have different half lifes, the amount of time that the drug still exists in the blood at half of a steady state value. Xanax is the shortest, about 10 hours, Klonopin is about 35 hours, and Valium is nearly 100 hours.

But, as we age, the elimination time of medication is increased, i.e. in senior years, it will take longer for the drug to drop to half it's steady state value, so the therapeutic action of shorter half life medications will last longer. Some people may benefit by a longer half-life medication. The short half life of Xanax is believed to contribute to it's addictive properties:

"Generally speaking, benzodiazepines with a shorter half life (such as Xanax) are harder to stop than those with a longer half life (such as Valium). Both drugs readily enter brain tissue which reinforces drug taking and is generally associated with more severe withdrawal symptoms."

I take Klonopin, due to other meds I take, a slight dose seems to provide significant, for me at least, effect. November 2018 I went into afib, and still am in afib, and for months I took a small dose every night. I was able to stop without side effects and without tapering. I have taken a Benzodiazepine, in one form or another, for 30 years now. I've learned to live with tension, so I don't take them often, but they are nice to have for troubled times. Those on higher doses need to consult their doctor about tapering, one should not stop, if that time comes, cold turkey.