Yeah, most benzos can be taken prn for anxiety, and I assume for sleep. I take Klonopin right now but find that jagermiester works better. I've also heard of (atypical) antipsychotics (specifically Zyprexa) being used prn. Ambien/Lunesta are alsoSUPPOSED to be taken prn for sleep. Most people end up abusing them, though.