why do some medications lose their potency when refrigerated?
In: 5
Moisture is bad. Moisture can lead to bacteria. Bacteria can lead to sickness. Sickness can lead to death.
These are great answers already but I will add that anything injectable (IV or IM) has a tolerable viscosity and temperature affects that considerably.
Interestingly many are manufactured to worth stand Refrigeration because so many people ignore the Label and fridge them