MS, Tysabri and interactions with my other meds

I have had remitting, recurring MS for over 25 years.  I was on Copaxone but started having muscle tremors after some of the injections.  Then I was put on Avonex, and this worked well for several years but over the past 2 years I have had several recurrences of the MS.  My doctor wants to put me on Tysabri after taking a month off of the Avonex.  Given the 2 most recent instances of PML I am concerned about whether Tysabri is still a reasonable option.  Would you still recommend the use of Tysabri?  
My other concern is the additional drugs I am taking and their interaction with Tysabri.  I am currently on:
Advair, 250/50 2X/day (contains a steroid)
Prevacid, 30mg 1X/day
Detrol, 2mg 1x/day
Ranitidine 150mg 1X/day
Lamotrigine 100mg 2X/day (this is being used experimentally for the nerve pain in my feet - I had been unable to walk due to the pain but this medication has given me back some limited mobility.  I can't find any information about how this drug would interact with Tysabri, which concerns me)
Would you recommend changing/discontinuing any of these medications before starting on Tysabri?
Thank you,
Michele

    

[dr_simran]

Hello Mickyvl,

Tysabri is unlikely to cause any drug interaction with your current ongoing therapies.
Refer: http://www.tysabri.com/tysbProject/tysb.portal for further details. Also no need o disconue the drug in light of the two recently reported cases of PML
Biogen Idec stated that it will not suspend sales of Tysabri (natalizumab) after the treatment, which it markets in partnership with Elan, was linked to two new cases of progressive multifocal leukoencephalopathy (PML) in patients with multiple sclerosis. Biogen Idec spokesperson Naomi Aoki said that the company had anticipated additional cases of the infection and noted that "withdrawing the drug is not under consideration.''
In a conference call, Biogen Idec emphasised that Tysabri's label had already been modified to warn patients about the potential risk of developing PML and that patients taking the product must sign a waiver stating they understand the drug's risks.
Refer http://www.drugs.com/ppa/natalizumab.html