Is valium an appropriate drug to take as needed for ptsd?

Possibly: It may be required for this condition. Depends upon how well other less addicting and potentially impairing medications work.

Not first, usually: Valium can calm anxiety and relax muscle tension which are common in ptsd. But this would not usually be the first step in treatment, nor would it be the only one. Psychotherapy is essential in ptsd -- medications alone are insufficient. Also, most psychiatrists would try non-habit-forming ones before valium. Benzos like valium are best used temporarily, in context of overall treatment.

Not really : Valium as well as all other medications of its category (benzos) are not the first choice indication for ptsd. Sertraline remains the first choice ssri indication for ptsd combined with ptsd therapy. However, low dose valium may be taken "as needed" the time sertraline is taking to become effective. Benzos r not ptsd 1st indication because of tolerance & memory impairment risks. Hope it helps.