Probably as reliable as Amazon reviews.
Biased towards negative, will have some useful info, people blaming non-drug related problems on the pills they are taking (à la vaccine-autism relationship), etc.
But it could be useful if patients use it properly. Like "Dr, you prescribed X. I'm concerned because I saw online that X can lead to Z and Y complications." Then the dr could dispel the concerns or discuss other options, etc. The site is only bad if patients take what is written at face-value and chooses not to take a prescribed drug without discussing it with their dr
