It can be difficult to predict medication supplies. The pharmaceutical industry must meet strict quality standards, and drug shortages can happen (e.g., if a batch is rejected for some reason).

Fortunately, the same medication is often made by many companies. If your medication is completely out of stock, your pharmacist can substitute it with an equivalent one. When making a substitution, your pharmacist will ensure that the new drug is in the same family as your prescribed medication. He or she will also tell you how to take it properly and notify your doctor of the new prescription.

Your pharmacist will follow up with you after a few days to check that the new medication is working for you. Once your regular medication is available again, your pharmacist will give you the option of going back to this drug or staying with your substitution.