I buy my cycle of dewormer (all the different types) in advanced. Am I supposed to store them in my refrigerator, or am I ok storing them in my tack trunk?

All medicaments have a tendency to keep for longer if you refrigerate them. Even so, the effectiveness of the medicine is only reduced by about 10% each year the expiry date rolls round. I'm not saying you should take those kinds of chances with dewormer - I never would! - but with things like sunscreen that's a very reliable and predictable factor.

My mother is a doctor and she keeps all ointments and salves (including sunscreen) in the fridge. It looks silly with two ice cream tubs of tubes in the door of the fridge, but it means we can always rely on them and to be honest, the xylocaine that I used last week for a burn, was just as good although the expiry date was something like 1998.

I would definitely refridgerate it, but it depends on how cooled your tack room is. I don't know how long you're planning to store it for, but the shorter the time, the less difference it'll make. If you're storing it for a long time (like six months), then def. refrigerator! If it says "store at room temperature" on the tube however, it won't make much difference if you're planning to store it for only a couple of days or weeks.

Tack trunks probably get to hot for them, store them at room temp, I store mine in a heated and air conditioned room.

I store mine in the tack room but living in the uk it's cold so I guess anywhere that is coolish- maybe the packaging gives a recommended storage temperature.

I personally store mine in the fridge just to be sure they are good when I want to use them.

10 yrs of dealing with horses.

I buy mine as I need them but what Ellie said is true- All medicines last longer in the refrigerator. Hope this helps! =)
-Fresh Paint-