Hi, I understand your concern. This drug Alprazolam(Zanax) although is sometimes prescribed for occasional anxiety related symptoms,but has great habituation potential and can give rise to withdrawal symptoms if continued for prolonged period although it does not have major drug interactions with transplant immunosuppressive drugs. My advice for you will be to have him evaluated in detail by a Psychiatrist for this condition and its management. It would then be prudent for him to be on a safer drug if drug treatment is required and condition can t be managed with counselling alone.