Here’s what you need to know about the heroin crisis unfolding here at home.

1. Hard numbers

Heroin is less prevalent. The number of heroin users in the United States is still relatively small: about 3 out of every 1,000 people, or 900,000 people total.

2. The bigger threat

Prescription drug misuse is much more common. In 2014, 15 million Americans aged 12 or older reported using prescription drugs non-medically in the past year. This includes misuse of opioid pain medication.

3. More to misuse

The sale of opioid pain medication nearly quadrupled from 1999 to 2010, as did the number of opioid overdose deaths.

4. Collateral damage

Other negative outcomes that can result from prescription drug misuse and abuse include falls and fractures in older adults and, for some, starting to use injection drugs, with resulting risk for infections such as hepatitis C and HIV.

5. Tolerance yields higher risk

While many people benefit from using these medications to manage pain, prescription drugs are frequently diverted for improper use. As people use opioids repeatedly, their tolerance increases and they may not be able to maintain the source for the drugs. This can cause them to turn to the black market for these drugs and even switch from prescription drugs to cheaper and more risky substitutes, like heroin.

6. The slippery slope

According to a 2014 survey by the Substance Abuse and Mental Health Services Administration, 12.7 percent of new illicit drug users began with prescription pain relievers.

7. Rules of thumb

If you take prescription medication, keep yourself safe:

Always follow the prescribed directions.

Be aware of potential interactions with other drugs.

Never stop or change a dosing regimen without first discussing it with a health care provider.

Always tell your health care provider about all the prescriptions, over-the-counter medicines and dietary and herbal supplements you are taking.

Never use another person's prescription.

8. Warning signs

Parents should discuss the risks of misusing or abusing prescription drugs with their children and be familiar with the warning signs, such as missing prescription drugs, changes in friends, increased secrecy, changes in school performance and frequent borrowing of money.

9. Take-back time

Each year, the Drug Enforcement Administration holds a National Take-Back Day. During Take-Back day, you can anonymously and safely discard your unused and expired medication at sites around the county at no cost.