There are several substances that, while useful for treating certain medical conditions, also have a high potential for addiction and abuse. Examples include stimulants, depressants and narcotic pain relievers. 

In the interest of allowing those who need them access to the drugs while preventing their misuse, the government imposes strict controls on them. It is illegal to obtain or possess such medications without a prescription from a physician. 

Even if it is legal for you to have a prescription medication now, it does not mean that that will always be the case. Here are some situations in which it is illegal for you to possess a prescription drug.

1. You receive the drug from someone other than a pharmacist

You may have a family member or friend who has a prescription for a medication with high abuse potential. It is illegal for this person to share the medication with you or anyone else. 

If authorities discover you in possession of a drug for which you do not have a prescription, they may arrest and charge you. Similarly, if you provide medications for which you have a prescription to someone who does not, you may face distribution charges.

2. Your prescription has expired

When a doctor gives a prescription for a controlled substance, the prescription is usually only valid for a certain period. If you still have medication left over after the prescription is no longer in effect, the law requires you to dispose of the remaining portion according to guidelines from the Food and Drug Administration.

3. You obtain prescriptions under false pretenses

This may mean altering otherwise valid prescriptions or calling in fraudulent refills. It may also involve doctor shopping, which is a practice of visiting multiple doctors and obtaining more than one prescription for the same or similar drugs. 

A conviction for a first offense of simple possession could carry penalties of a minimum $1,000 fine and/or imprisonment for up to a year.