It is important to understand how substances, including prescribed medications, can interact with each other and other substances. Mixing medications-- whether the medication is prescribed by a doctor, available over-the-counter, or otherwise-- can be dangerous both in the long and the short-term. Make sure to consult with your prescribing doctor when you have any questions about what medications you are taking and how they may interact with other substances you may be using. It is also important to know what your medications are being prescribed to treat, and to be honest when your doctor ask what medications or supplements you are taking so they can better understand what may interact negatively with each other.
It is important to note that mixing 2 or more substances significantly increases the risk of dangerous or fatal effects. For example, a study done in Florida found that over 90% of opioid overdose deaths in the state included other, non-opioid drugs with an average of 2–3 drugs other than the opioids found at autopsy. (1)