There may be a few important reasons why you might see some weight changes if you are using Humira. The manufacturer of Humira (adalimumab) does not list weight gain or weight loss as a possible direct side effect in the product labeling for Humira. However, other conditions, symptoms, or medications may affect your weight while you are using this medication. Clinical studies have also shown weight gain with Humira.

Humira is a biologic Tumor Necrosis Factor (TNF) alpha inhibitor given by injection to treat many different autoimmune diseases where inflammation leads to symptoms. Common uses include rheumatoid arthritis, Crohn's disease, plaque psoriasis, adult and pediatric ulcerative colitis, ankylosing spondylitis, and psoriatic arthritis.

Weight gain

You may have inflammation and pain, not feel well, and your appetite could be decreased when you do not feel well. This may occur when you are having symptoms from rheumatoid arthritis, Crohn's disease, ulcerative colitis, ankylosing spondylitis or other conditions.

After your inflammation and pain are controlled with Humira, you may feel better and your appetite may return, leading to weight gain. This typically would happen slowly over time. To combat any weight gain due to a better appetite, talk to your doctor about an effective and safe exercise regimen and how to maintain a healthy diet. You may also be able to exercise more easily due to improved health.

You might use Humira with other medications to help control your symptoms. For example, you might use corticosteroid (steroid) medications like prednisone, or nonsteroidal antiinflammatory (NSAID) medications like naproxen or ibuprofen. These medications can also lead to fluid retention and weight gain. Corticosteroids are particularly linked to weight gain.

Humira may lead to weight gain in other ways. For example, cases of congestive heart failure (CHF) have been reported with the use of Humira. CHF can lead to weight gain, often due to fluid (water) retention. If you experience swelling (also called edema) in your legs, ankles or feet, a rapid weight gain, shortness of breath, or swelling in your stomach, be sure to contact your doctor as soon as possible. These may be signs of new or worsening heart failure.

Clinical studies of weight gain with Humira

Clinical trials published after the FDA approved Humira have investigated weight gain with this drug and other Tumor Necrosis Factor (TNF) alpha inhibitors.

• One observational study looked at the effect of TNF blocker therapy on the weight of patients with rheumatoid arthritis (RA).
• Patients in the study were using adalimumab (Humira, 44 patients), etanercept (Enbrel, 27 patients), or methotrexate (40 patients) as a single treatment for at least 24 months and had no previous use of other biologic therapy.
• At the start of the study (baseline), and at 12 and 24 months, each patient completed a questionnaire about physical activity, smoking, alcohol, and food habits.
• After 24 months of therapy, there was an increase of weight only in patients treated with the TNF blockers. Patients on etanercept and adalimumab therapy showed a risk of weight gain that was 6 times greater compared to those on methotrexate therapy.
• The authors conclude that a more careful evaluation of weight changes needs to be considered in RA patients under TNF blocker treatment.

In a long-term retrospective study, 168 patients with rheumatoid arthritis (RA) had received a TNF blocker for the first time, and were evaluated over a 24-month period.

• The mean weight change after 12 months of treatment was a 1.58 kg (3.5 lb) gain and after 24 months was a 1.80 kg (4 lb) gain. After 24 months, 64.3% of participants had gained weight.
• There was no statistically significant association between weight gain at 12 or 24 months and age, sex, steroid use at baseline, anti-TNF drug or baseline disease score (DAS28).
• Baseline body mass index (BMI) had a statistically significant negative association with weight gain at 12 and 24 months. RA patients with lower BMIs tended to gain weight with anti-TNF therapy.

Another retrospective analysis investigated the effect of TNF blockers on weight gain and body mass index (BMI) in patients with psoriasis. Patient’s body weight and BMI were compared at baseline and at weeks 12, 24 and 48.

• Out of 286 treatment courses, 178 courses were with a TNF blocker (54 on adalimumab [Humira], 61 on etanercept [Enbrel] and 63 on infliximab [Remicade]).
• Adalimumab and infliximab resulted in weight gain from week 12 until week 48. At week 12 the infliximab group gained 1.7 ± 4.7 kg (3.7 ± 10.3 lb) and the adalimumab group gained 1.5k ± 4.5 kg (3.3 ± 9.9 lb). This effect persisted until the end of the study.
• The authors conclude that adalimumab (Humira) and infliximab (Remicade) are associated with a significant increase in body weight and BMI.

These study designs cannot prove a direct cause and effect relationship of weight gain with Humira, but may offer some evidence of an association.

Weight loss

Humira has not been reported by the manufacturer to lead to weight loss, but there may also be reasons why weight loss can occur due to medicine-related factors.

Because TNF blockers affect the immune system, they can lower the ability to fight infections. These infections could lead to a loss of appetite and weight loss. Humira can increase your risk for certain infections, such as tuberculosis (TB) or hepatitis B virus. Other fungal, bacterial, or viral infections may occur, so be sure to notify your doctor of any weight loss or loss of body fat and muscle. Your doctor will monitor you closely for any infections while you are using Humira. Notify your doctor immediately if you think you have an infection.

Some gastrointestinal side effects reported to occur with Humira might lead to weight loss in the short-term: these include nausea, vomiting and abdominal (stomach) pain. Cancers, such as lymphomas, have also been reported with TNF blockers. Lymphoma can lead to weight loss. Lymphomas are a type of blood cancer that occurs in the infection-fighting white blood cells. Be sure to tell your doctor if you’ve ever had lymphoma.

Liver problems can also happen in people who use TNF-blocker medicines like Humira and might affect your weight. These problems can be serious and may lead to liver failure and death. Call your doctor right away if you have any of these symptoms:

• feel very tired
• poor appetite or vomiting
• skin or eyes look yellow
• pain on the right side of your stomach (abdomen)

This is not all the information you need to know about Humira for safe and effective use and does not take the place of talking to your doctor about your treatment. Review the full Humira (adalimumab) information here, and discuss this information and any questions you have with your doctor or other health care provider.