Signs and Symptoms of Fentanyl

| August 12, 2026

Individuals using drugs are usually skilled at covering up their drug dependence. They may deny drug use and cover their tracks carefully at first. But eventually, loved ones, co-workers, and employers may start to notice unusual behaviors that make them suspect drug use and dependence.

Knowing the signs and symptoms of fentanyl use is vital for the health and safety of drug-dependent individuals and those around them. Getting drug-dependent individuals the help they need to break their addictions will restore their physical, mental, and emotional health. Here are common symptoms of fentanyl use.

Physical Symptoms of Fentanyl Use

Fentanyl use can cause one or more of the following symptoms:

  • Small, pinpoint pupils
  • Shallow breathing
  • Lapses in consciousness
  • Drowsiness
  • Withdrawal symptoms, including fever, vomiting, or body aches
  • Persistent itching and scratching
  • Poor coordination
  • Gaining or losing weight

Behavioral Symptoms of Fentanyl Use

The physical symptoms of fentanyl use may be easy to cover up or excuse, but sudden or troublesome behavioral symptoms may be more difficult to conceal. Behavioral symptoms of fentanyl use include:

  • Noticeable euphoria
  • Isolating from friends and family
  • Changing friend groups
  • Mood swings

Other Indications of Fentanyl Use

While some physical or behavioral symptoms may be explainable, there are other indications someone is using fentanyl. They may suddenly experience financial problems, legal consequences, arrests, or begin visiting multiple doctors to obtain opioids.

What Should I Do if I Suspect Fentanyl Use?

Your next steps depend on your relationship to the user and your perception of their receptivity. Contacting the National Drug Helpline can help you know how to proceed.

Nationwide Drug Testing Services is one of the largest accredited drug testing networks in the U.S. We offer testing in every state, for affordable, same-day appointment drug testing and fast, accurate results. Call us today at 877.497.1002 or Order a Test Online!