Here's some advice we'd never heard. You shouldn't be storing medicine in your medicine cabinet. At least not long-term. Someone posted a list of five things you shouldn't keep in your bathroom, because of how the heat and humidity from your shower affects them . . .
1. Medicine. High humidity shortens the shelf life, and it can become less potent. So medicine cabinets aren't really the best place to keep medicine.
2. Makeup. No matter where you store it, bacteria from your face ends up in your makeup. But the heat and humidity from your shower can make it grow faster.
3. Spare razor blades. The humidity can cause rust, or dull the blades before you've even used them.
4. Teeth-whitening gel. The humidity doesn't matter, but the temperature does. The fridge is actually the best place to keep it.
5. Painted wood furniture. Heat and humidity cause the wood to expand. So eventually, the paint will start cracking and flaking off. (Lifehacker