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Popular Brands: : Vivitrol, Trexan, Nalorex, Celupan, Naltrexone
Official FDA Reports5,956
Social Media Events2,575
Total Posts4,226
Avg. Review Score3.91/ 5
Active Ingredients
  • Naltrexone
Approved Uses *

* Extracted from Drug Label

  • Alkermes Inc

  This report is for all products sharing this active ingredient. For more details, please use our Workbench for research on individual brands like Vivitrol.

* Extracted from FDA Adverse Event Report


The quarterly trend chart illustrates changing levels of adverse events over time. Results from both the FDA Adverse Event Database (FAERS) and adverse events extracted from social media by Druginformer are plotted side-by-side for easy comparison.

The proportion of people completing user reviews who complained about a side effect.

The proportion of social media adverse event complaints for each adverse event type.

The proportion of FAERS (FDA) adverse event complaints for each adverse event type.

Naltrexone Side Effects

  Social Media
(Online Comments)
(Reports Submitted to FDA)
Side Effect On Drug
Reports % of
Alarm Reports % of

* DrugInformer calculates alarm using a proprietary algorithm. Alarm should not be taken as an ofiicial signal from the FDA or other regulatory entity.

User Voices

The following are comments from users that experienced side effects while taking Naltrexone


Was on pill form but made me very tired. Yesterday I got my first Vivitrol injection. Same thing-really tired. And injection site little sore , but so far so good.

Source: Naltrexone

View full report on Naltrexone related tenderness

Did the author experience tenderness while taking vivitrol?

What is this?


helps with pain fatigue and pain fog

Source: Naltrexone

View full report on Naltrexone related somnolence

Did the author experience somnolence while taking naltrexone?

What is this?


helps with pain fatigue and pain fog

Source: Naltrexone

View full report on Naltrexone related pain

Did the author experience pain while taking naltrexone?

What is this?

Tell us about your Experience with Naltrexone

Thank you for sharing your experience with us!

Share Your Experience

Druginformer Identified Side Effects: Drug ineffective

Posted By Sherri in fdb.rxlist.com on June 1, 2015 @ 12:00 am

I've used Vicodin on different occasions and, for me, it never works. I get more relief with OTC Tylenol.

Druginformer Identified Side Effects: None

Posted By triedeverymedoutthere in fdb.rxlist.com on May 21, 2015 @ 12:00 am

Only Medication I can function and have a normal life with MS, Fibro,Chronic back pain, It gives me a life and I can function daily and work 2 full time jobs, without it I am in bed full time!! But d...

Druginformer Identified Side Effects: None

Posted By Mike in fdb.rxlist.com on March 10, 2015 @ 12:00 am

I drink more on this than I did before

Druginformer Identified Side Effects: Hypersensitivity

Posted By Anonymous in fdb.rxlist.com on January 23, 2015 @ 12:00 am

Recently had bunion surgery, and Vicodin knocked out the pain and helped me sleep. I did have a mild allergic reaction to it, which was a rash on my stomach and hips, but did not affect me at all. The...

Druginformer Identified Side Effects: None

Posted By LibraryLady42 in fdb.rxlist.com on December 30, 2014 @ 12:00 am

I had to have major dental surgery and the medicine relieved all the pain for me.

Druginformer Identified Side Effects: Headache, Pain, Dry mouth, Migraine, Withdrawal syndrome

Posted By Eric m in fdb.rxlist.com on November 23, 2014 @ 12:00 am

... percocet or other people and drugs.. I tried to stop taking just to see if I got any bad withdrawal.. And the most that happened was I pooped alot and slight headache but Excedrin Migraine help.. Sid...

Druginformer Identified Side Effects: Abnormal dreams

Posted By Anonymous in askapatient.com on November 10, 2014 @ 12:00 am

Side Effects: None in particular. Having vivid, active dreams but not sure that is the medication because I've always had vivid dreams. Seems to subdue alcohol cravings. Will continue as ...

Druginformer Identified Side Effects: Constipation, Abdominal pain

Posted By Migraine Sufferer in fdb.rxlist.com on November 4, 2014 @ 12:00 am

... Folks, if you have pain, do not be shy about asking for help. Yes, you may attract some interesting attention on occasion. It happens. One bad side effect is constipation and resulting abdominal...

Druginformer Identified Side Effects: Drug ineffective

Posted By Lisann in fdb.rxlist.com on October 30, 2014 @ 12:00 am

... I've almost gone to the hospital 3 separate times when the pain got unbearable, then I remind myself they can't give me anything for the pain anyway......it wouldn't work! Pretty ironic! Not sure i...

Druginformer Identified Side Effects: None

Posted By Felicia Hill in fdb.rxlist.com on October 16, 2014 @ 12:00 am

Additional Drug Information

* Warning: The facts and figures contained in these reports are accurate to the best of our capability; however, our metrics are only meant to augment your medical knowledge, and should never be used as the sole basis for selecting a new medication. As with any medical decision, be sure to work with your doctor to ensure the best choices are made for your condition.

* About FAERS: The FDA Adverse Event Reporting System (FAERS) is used by FDA for activities such as looking for new safety concerns that might be related to a marketed product, evaluating a manufacturer's compliance to reporting regulations and responding to outside requests for information. Reporting of adverse events is a voluntary process, and not every report is sent to FDA and entered into FAERS. The FAERS database may contain duplicate reports, the report quality is variable, and many factors may influence reporting (e.g., media attention, length of time a drug is marketed, market share). For these reasons, FAERS case reports cannot be used to calculate incidence or estimates of risk for a particular product or compare risks between products.