How long does zyrtec 10mg stay in system? and how long should should i wait before taking a xanax (alprazolam)? half of 0.25mg.

8-10 hours: Zyrtec's half life is around 8-10 hours. It is supposed to be a non-sedating antihistamine. I do not believe there are any interactions between this and Xanax (alprazolam). You can take them together and at .125 mg dose, would not expect any interactions or side effects.

Zyrtec and Xanax (alprazolam): 1. No waiting is needed. No drug interactions. It is good idea to take Xanax (alprazolam) 1 hour before bed time. 2. Zyrtec is an antihistamine medication. The average elimination half-life is 8 hours. It takes approximately 6 half lives for a drug to be eliminated from your system. 8*6/24= 2 days. The Zyrtec will stay in your system for about 2 days. Hope it helps.