Should we keep unfinished Liquid Medicine in the Refrigerator?

Most of us who have received liquid forms of medicine from the doctor (cough syrups etc) will probably be left with an unanswered question after we get well. Where do we store these medicine? Do we keep them in the fridge like unfinished food to keep them "fresher"?

The direct answer is to REFER TO STORAGE CONDITIONS ON THE BOTTLE. Unless it's some super heat sensitive medication, usually the storage conditions will say 25-30°C. Which means no, you do not store liquid medication in the fridge.

But Why Not? Usually stuff kept in the fridge tends to last longer.

We'll need some pictures to explain this to you.

Behold Exhibit A

When you buy a brand new liquid medicine like the one showed in the picture, the empty space in the bottle is either nitrogen purged, or at the very least be filled with clean air.

When we open and pour the contents of the bottle out, the nitrogen leaks out, and normal air fills the gap in the bottle. This air contains water vapor and also your usual mix of bacteria and fungi.

So when we recap the medicine bottle, the empty space is now filled with air, plus the icky stuff. But if we let it sink down to the liquid portion, the preservatives added in the solution will take care of these intruders.

But when you keep the medicine bottle in the fridge, the water vapor condenses into water droplets at the top inner portion of the glass, due to colder temperatures. These water droplets are preservative-free, and microbes can grow readily. So instead of prolonging the shelf life of the product, you're actually increasing microbial load at a much faster pace. THIS MEANS THE MEDICINE GETS SPOILED FASTER, INSTEAD OF SLOWER.

So, the simplest and safest way, is to buy syrups in smaller containers, and store it in the recommended temperatures (that means out of the fridge! :) ). It's probably best not to keep opened syrup bottles too long after opening though. Nobody knows exactly how long they last after opening! :)