Can fentanyl cause hallucinations?

Possibly. However, more common psychological side effects, include confusion and anxiety. A brief review of fentanyl use, administration, and effects here.

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In some cases, yes. Fentanyl has been the cause of hallucinations.

This may be a sign that your dosage needs to be adjusted, or it could precede further complications. However, more common psychological side effects of fentanyl include confusion and anxiety.

More here on the uses, effects, and mechanism of fentanyl in the brain. Plus, what to do if you experience visual or auditory hallucinations while on fentanyl. Then, we invite your questions about fentanyl’s side effects at the end.

Main uses of fentanyl

Fentanyl is a strong opiate pain reliever, that is similar to but much more potent than morphine. It is typically used as a post-surgical pain reliever, or in situations of severe chronic pain. It is also commonly given to cancer patients who experience severe pain.

Fentanyl is classified by the Drug Enforcement Agency (DEA) as a Schedule II drug, meaning it has some medicinal value but high abuse potential.

Fentanyl actions in/on the brain

Fentanyl, like other opiate pain-relievers, attaches itself (or “binds”) to the opiate receptors in the brain. These receptors are highly concentrated in the parts of the brain responsible for pain and emotion. The drug works by blocking increasing the amount of dopamine in the brain, thus producing a “high” feeling of euphoria.

However, it also has an effect on the parts of the brain responsible for some autonomic functions such as breathing. The main deadly mechanism of any opiate drug is the depression of respiration. Essentially, an overdose can cause the user to stop breathing, which leads to brain damage and death if not reversed in time.

Common administration of fentanyl

The most common administration of fentanyl is via a transdermal patch. The underside of the patch is coated with fentanyl, which when worn, absorbs through the skin and into the bloodstream. This allows the medication to be released in a controlled manner over a longer period of time than via injection or oral administration. NOTE: Fentanyl patches can be addictive. It is also available, however, as a:

  • film
  • intravenous injection
  • lozenge
  • spray
  • tablet

Can fentanyl cause hallucinations?

The fentanyl transdermal patch has been reported to cause some psychological side effects, including confusion and anxiety. In more extreme cases, hallucinations have been listed as a possible side effect, meaning it may cause the user to see or hear things that aren’t actually there, or even a combination of the two. Other psychological side effects of fentanyl include:

  • confusion
  • depression
  • drowsiness
  • feeling cold
  • mood changes

The occurrence of hallucinations or other side effects likely varies as a function of fentanyl dose, as well as factors relating to the person taking the drug, including body weight, gender, age, drug history, and general physical health.

What are some other side effects of Fentanyl use?

Aside from psychological effects, Fentanyl use has been shown to produce a range of physical side effects which are concerning, including:

  • bloating/swelling of face or extremities
  • chest pains
  • decrease in the amount or frequency of urination
  • decreased motor coordination
  • difficulty speaking
  • fainting
  • fast or pounding heartbeat
  • rapid weight gain
  • spitting blood

What Should I Do if I Experience Hallucinations?

If you are taking fentanyl (or any other medication) and begin to experience hallucinations, let your doctor know immediately. This may be a sign that your dosage needs to be adjusted, or it could precede further complications. With any serious side effect like this it is important to keep your prescribing physician informed to avoid life-threatening complications.

Help for Fentanyl Addiction

If you or someone you know is abusing fentanyl, it is vital to seek professional Fentanyl addiction treatment help. The best chance at recovery, especially from opiates, is a minimum of 30 days in an inpatient treatment facility. Detox from any opiate, but particularly one as strong as fentanyl, can be extremely uncomfortable, and is best performed under close medical supervision,

References Sources: NIDA: Drugs of abuse: Fentanyl
Mayo Clinic: Fentanyl Side Effects
WebMD: Side effects fo transdermal fentanyl
About the author
Heather King, Ph.D., completed her graduate studies in preclinical substance abuse research in July of 2015. She has authored several peer-reviewed publications in scientific journals on the effects of drug abuse on the brain and behavior, and has personal experience in addiction and recovery. She currently works at Serenity Acres, a drug and alcohol treatment center outside of Annapolis, MD.
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