…and addiction

Helpful links

My at a glance emergency list:

Sodium Ascorbate

Charcoal

Naloxone (especially helpful in case of fentanyl–or any opiate–overdose)

No no’s:

Melatonin

grapefruit

Aspirin

Any kind of depressant

Cocaine info, via Drugs.com

Although drugs.com seems to go a modern route when it comes to treatments (which is okay if that is what you are looking for!), I have found drugs.com to be a very great resource for learning about a drug and it’s symptoms and side effects.

Or, Cocaine info via Recovery.org

Learn about causes, withdrawal, recovery.

Fentanyl

Info on Drugs.com

Gleaning

Fentanyl is a synthetic opioid and is up to 100 times stronger than other opioids like morphine, heroin or oxycodone. It is a narcotic analgesic. (drugs.com)

Naloxone is used to reverse an opioid overdose and help restore breathing by blocking or reversing the opioid effects. 
Learn how to use Naloxone before it is needed.