Replacing seroquel with 5-htp - how can one go about this?

[clear_sky]

A friend of mine is on quite high doses of seroquel for sleep problems.
He is interested in quitting seroquel and I recommended 5-htp for sleep.
What would be the best way for him to switch?
Quit seroquel cold turkey and replace with 100mg 5-htp?
Taper off seroquel and add in small doses of 5-htp?

 

[i against i]

take the advice of a doctor and not a friend.