prescription change from lexapro to effexor

my mother (77yrs.of age) has been taking 10mg lexapro for general depression and body aches. Today, the physician said he wanted to give her something that would make her feel more "perky" and changed her script to 150mg Effexor. The instructions are to take 1 pill/day and to stop the lexapro. From my reading it seems that these meds should be weaned. Before she gets started, I was wondering if the physician's instructions seem reasonable or if there should be some type of weaning on/off schedule. It also seems to be a huge difference in dosage- or is that simply because of the nature of the drug itself? Mom is also saying that this is more expensive and I am worried she will just stop taking the Effexor when the time comes to renew. This is a scary thought having read several remarks regarding "coming off'" this med.  And no- I am not exactly sure why the doc wants to change meds. I am seriously interested and most appreciative of any comments/suggestions. thank-you.

[biop]

I have been on Effexor for eight years and the reason is the effexor is habit forming.  When you take a larger dose of the Effexor it makes you more hyper and I felt my heart needed it because if I missed a dose I could feel my heart rate almost miss a beat.  Some times my Doctor says you could be too hyper or carry out dangereous tasks.  But I like it and it feels great.  You can ask for the generic doseage and if she is not covered ask the doctor to fill a special form to send to the government or Trilliumn Drug Plan where it has to be covered, you can fax it in and the response is sent to your doctor.  A little persistance helps, I believe in Canada the form is called Form 52, anyway ask your pharmacy but still stay on it its worth it.
biop