My vet thinks that our 11 year old staffie has a thyroid problem which is causing him problems and we have to wait another 3 weeks to get a another blood test done. He said that it can be controlled by medication, but there were dangers to this. He didn't go into detail at all, and I was hoping someone could explain what 'dangers' mean when it comes to thyroid medication.

I posted about him a couple of weeks ago and did get some helpful advice.

Going on what you posted a couple of weeks ago I'm guessing that your staffy is diagnosed as HYPOthyroid (lacking in thyroid hormone) and that the recommended treatment is thyroid replacement, the only dangers I can think of is that the dosage must be given much lower to start with in the elderly (humans) and where there's a heart problem (which may be caused by the hypothyrioidism) perhaps this is what the vet is thinking about?  The actual treatment is very effective and has few side effects, most of which are dosage related (I take it myself)

there's more info here

http://www.vetmed.wsu.edu/ClientED/hypothroidism.asp

http://www.medinfo.co.uk/conditions/hypothyroidism.html

and here

http://www.medi-vet.com/Soloxine.aspx

Hope this helps