Does Suboxone® cause weight gain?

What to know about the chances of weight changes on a Suboxone® treatment program.

Ophelia team
Suboxone medication and measuring tape
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Fact checked by
Adam Bisaga, MD

It’s common to wonder what the side effects are of any medication, but especially something like Suboxone® (brand name for the generic buprenorphine/naloxone; important safety information), which is used as an FDA-approved long-term maintenance treatment for opioid use disorder (OUD). 

There are two main methods of taking Suboxone, and the side effects differ slightly per method. Below, they’re listed in order of most to least common.

Side effects for sublingual tablets:

  • Headaches
  • Opioid withdrawal syndrome
  • Pain
  • Increased sweating
  • Low blood pressure 
  • Vomiting

Side effects for sublingual films: 

  • Tongue pain
  • Decreased sensation/redness in the mouth
  • Headache
  • Nausea
  • Vomiting
  • Excessive sweating
  • Constipation
  • Opioid withdrawal syndrome
  • Sleeping difficulties
  • Chronic pain
  • Swelling of the extremities 

As you may notice, weight gain or weight loss isn’t listed as a known side effect of Suboxone treatment; however, some people in the early stages of treatment from OUD do report feelings of weight gain…so what’s the consensus? Is this a myth? An unacknowledged side effect? It’s complicated.

The impact of water retention

Although Suboxone doesn’t directly cause you to gain weight, it can cause water retention, which manifests as more-than-usual puffiness around the face, feet, and hands.  That, combined with the fact that constipation is a known side effect, means that it often may feel like you’re gaining weight when, in fact, you’re not. Temporary bloating may be the culprit. 

The impact of sugar cravings

Evidence from clinical trials (1) suggests that chronic opioid exposure is associated with increased sugar intake — but this is primarily among patients on methadone treatment. When assessed at the beginning of treatment, nine months in, and four years in, methadone patients demonstrated increased consumption of sugary foods, fewer complex carbohydrates, and less fruits, vegetables, and healthy fats. Studies also show that patients on methadone tend to consume larger quantities of calorically dense foods, (2) which is a contributing factor to weight gain.   

But the same results aren’t necessarily seen across the board. (1) While opioid agonists (e.g., methadone, fentanyl, morphine) supercharge the preference for high-sugar foods, opioid antagonists (e.g., naloxone and naltrexone) demonstrate the opposite: decreased preference for high-sugar foods and a decreased caloric intake — so much so that naltrexone in combination with a smoking cessation medication bupropion is actually approved as a weight loss medication. And then there’s partial opioid agonists (e.g., buprenorphine), which behave like an antagonist in the beginning (decreasing cravings of sweet foods) but not over time with chronic administration. 

Other research (3) shows that humans withdrawing from abused opioid dependence/opiate addiction to substances like heroin or oxycodone develop strong urges for sugar. However, if the value of the reward delivered by the sweet doesn’t meet the threshold expected from opioid stimulation, this “withdrawal” may snowball into more sugar cravings in an attempt to attain that same level of “reward.”  

The impact of appetite

Those who use heroin chronically may suffer from poor nutrition and appetite loss, which often results in profound weight loss. Once off heroin and on stable prescription drug medications, those individuals will start regaining an appetite and, as they become healthier overall, regain weight as a result…which is a good thing!  

The takeaway

While more studies need to be conducted on human subjects to confirm these findings, most evidence points to the fact that sweet cravings are indeed a side effect of long-term Suboxone use as maintenance treatment. So if you’re experiencing this, know you’re not alone. And when you receive treatment through Ophelia, your dedicated care team will be there to support you through the entire process with personalized medical advice and mental health support.

Know someone who struggles with substance use but not sure how to help? Check out our guide on how to help a loved one without the conventional rehab healthcare treatment option. 

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