Humira (Adalimumab)

What Is Humira and What Is It Used For?

Humira (adalimumab) is a biologic medicine that works by blocking TNF-alpha, a key protein that drives inflammation in the body. It is used to treat a wide range of autoimmune and inflammatory diseases, including rheumatoid arthritis, Crohn's disease, ulcerative colitis, psoriasis, and several other conditions where the immune system attacks the body's own tissues.

Adalimumab is a fully human monoclonal antibody, meaning it was engineered to closely resemble antibodies naturally produced by the human immune system. It binds specifically to tumor necrosis factor alpha (TNF-alpha), a cytokine that plays a central role in the inflammatory cascade. In autoimmune diseases, the body produces excessive amounts of TNF-alpha, leading to chronic inflammation that damages joints, the digestive tract, skin, and other organs. By neutralizing TNF-alpha, adalimumab reduces this inflammatory response and helps control disease activity.

First approved by the U.S. Food and Drug Administration (FDA) in 2002 and by the European Medicines Agency (EMA) in 2003, Humira became one of the best-selling prescription drugs worldwide. Its patent exclusivity has since expired in many markets, and numerous biosimilar versions have been approved, increasing patient access and affordability. The original product is manufactured by AbbVie and is available as a pre-filled syringe or auto-injector pen for subcutaneous (under the skin) self-administration.

Humira has transformed the treatment of several chronic inflammatory conditions. Before biologic therapies became available, many patients with severe rheumatoid arthritis, Crohn's disease, or psoriasis had limited treatment options and often experienced significant disability. TNF inhibitors like adalimumab have made it possible to achieve disease remission or low disease activity in a substantial proportion of patients, fundamentally changing the long-term outlook for these conditions.

Approved indications

Humira is approved for the treatment of numerous inflammatory and autoimmune conditions across both adult and pediatric populations. The specific indications may vary slightly between regulatory agencies, but the following conditions are generally approved worldwide:

• Rheumatoid arthritis (RA) – Moderate to severe active RA in adults, often used in combination with methotrexate
• Psoriatic arthritis – Active psoriatic arthritis in adults when response to DMARDs has been inadequate
• Ankylosing spondylitis – Severe active ankylosing spondylitis in adults with inadequate response to conventional therapy
• Crohn's disease – Moderate to severe active Crohn's disease in adults and children (aged 6 years and older)
• Ulcerative colitis – Moderate to severe active ulcerative colitis in adults with inadequate response to conventional therapy
• Plaque psoriasis – Moderate to severe chronic plaque psoriasis in adults who are candidates for systemic therapy
• Hidradenitis suppurativa – Moderate to severe active hidradenitis suppurativa (acne inversa) in adults and adolescents
• Uveitis – Non-infectious intermediate, posterior, and panuveitis in adults and children (aged 2 years and older)
• Juvenile idiopathic arthritis – Active polyarticular juvenile idiopathic arthritis in children aged 2 years and older

How does adalimumab work?

Adalimumab works through a highly specific mechanism of action. It binds to both soluble and membrane-bound forms of TNF-alpha with high affinity, preventing TNF-alpha from interacting with its receptors (p55 and p75) on cell surfaces. This blockade interrupts the inflammatory signaling cascade at a critical point, reducing the production of other pro-inflammatory mediators such as interleukin-6 (IL-6), interleukin-1 (IL-1), and matrix metalloproteinases that contribute to tissue destruction.

In rheumatoid arthritis, blocking TNF-alpha reduces joint inflammation and slows the progression of structural damage to cartilage and bone. In inflammatory bowel diseases like Crohn's disease and ulcerative colitis, it helps heal the intestinal lining and reduce symptoms such as abdominal pain and diarrhea. In psoriasis, it decreases the overactive immune response in the skin that leads to the characteristic red, scaly plaques.

What Should You Know Before Taking Humira?

Before starting Humira, you must be screened for tuberculosis (TB) and hepatitis B, as adalimumab can reactivate these infections. You should not use Humira if you have active severe infections, moderate to severe heart failure, or a known hypersensitivity to adalimumab. Tell your doctor about all medications you are taking, your vaccination history, and whether you are pregnant or planning to become pregnant.

Starting treatment with a biologic medicine like Humira requires careful medical evaluation. Your doctor will assess your overall health, review your medical history, and perform specific tests before determining whether adalimumab is appropriate for you. This pre-treatment evaluation is essential to minimize the risk of serious side effects and to ensure the best possible outcome from therapy.

Contraindications

Humira must not be used in the following situations:

• Active tuberculosis or other severe infections – Including sepsis, opportunistic infections, and active hepatitis B. Treatment of the infection must be completed before starting adalimumab
• Moderate to severe heart failure (NYHA class III/IV) – TNF inhibitors may worsen heart failure and should be avoided in patients with significant cardiac impairment
• Hypersensitivity to adalimumab – Known allergy to adalimumab or any of the excipients in the formulation

Warnings and Precautions

Several important warnings and precautions apply when using Humira. Patients and prescribers should be aware of the following:

• Infections: Adalimumab suppresses the immune system, increasing the risk of serious infections including bacterial, viral, and fungal infections. Patients should be closely monitored for signs and symptoms of infection during and after treatment. Treatment should be interrupted if a serious infection develops
• Tuberculosis: All patients must be evaluated for latent and active TB before initiating therapy. Patients with latent TB should start treatment for TB before beginning adalimumab. TB has occurred in patients even after they tested negative for latent TB
• Hepatitis B reactivation: Carriers of the hepatitis B virus (HBV) may experience reactivation of the virus during TNF-blocker therapy. HBV testing should be performed before starting treatment
• Malignancies: Cases of lymphoma and other malignancies, some fatal, have been reported among patients treated with TNF inhibitors. The risk appears greatest in children and adolescents. Hepatosplenic T-cell lymphoma, a rare and aggressive form of lymphoma, has been reported primarily in adolescents and young adults with inflammatory bowel disease
• Demyelinating disorders: Rare cases of new onset or exacerbation of central nervous system demyelinating disorders (e.g., multiple sclerosis, optic neuritis) have been reported. Caution is advised in patients with pre-existing or recent-onset demyelinating conditions
• Blood disorders: Rare cases of pancytopenia, including aplastic anemia, have been reported. Patients should seek immediate medical attention if they develop signs of blood dyscrasias such as persistent fever, bruising, bleeding, or pallor
• Allergic reactions: Serious allergic reactions, including anaphylaxis, have been reported rarely. If a serious allergic reaction occurs, treatment should be discontinued immediately
• Surgery: Patients scheduled for surgery should inform their surgeon about their adalimumab treatment. The long half-life of the drug (approximately 2 weeks) should be considered when planning surgical procedures

Pregnancy and Breastfeeding

The use of Humira during pregnancy requires careful consideration of the benefits and risks. Adalimumab crosses the placenta, particularly during the second and third trimesters, which means the drug can be present in the newborn's circulation at birth. Based on available data from pregnancy registries and observational studies, adalimumab does not appear to increase the risk of major birth defects or miscarriage above background rates, but the data are limited.

If Humira is used during pregnancy, the newborn infant may have an increased risk of infection due to in utero exposure to the immunosuppressive effects of the drug. Live vaccines should not be administered to infants exposed to adalimumab in utero for at least 5 months after the mother's last injection during pregnancy. Non-live vaccines can be given according to the normal schedule.

Adalimumab is excreted in breast milk at very low concentrations (approximately 0.1-1% of serum levels). Since the drug is a large protein molecule, it is likely degraded in the infant's gastrointestinal tract and is not expected to be absorbed systemically. However, the decision to breastfeed while taking Humira should be made in consultation with the treating physician, weighing the benefits of breastfeeding and treatment against the potential risks.

How Does Humira Interact with Other Drugs?

Humira should not be combined with other biologic DMARDs (such as anakinra or abatacept) due to an increased risk of serious infections with no additional clinical benefit. Methotrexate may be used together with adalimumab and can help reduce the formation of anti-drug antibodies. Live vaccines must be avoided during treatment. Some immunosuppressants may increase the risk of infections when combined with Humira.

Drug interactions with adalimumab can affect both its efficacy and safety profile. Since Humira works by suppressing part of the immune system, combining it with other immunosuppressive agents can amplify the risk of infections and other immune-related complications. Your doctor will carefully evaluate all of your current medications before prescribing adalimumab.

Unlike many small-molecule drugs, adalimumab is a large protein (monoclonal antibody) that is not metabolized by cytochrome P450 (CYP) enzymes in the liver. This means it does not have the typical pharmacokinetic drug interactions seen with conventional medications. However, clinically significant pharmacodynamic interactions exist, particularly with other immunomodulatory drugs.

Major Interactions

Minor Interactions

What Is the Correct Dosage of Humira?

The standard adult dose of Humira is 40 mg administered by subcutaneous injection every other week. Some conditions may require an initial higher loading dose. The injection is given under the skin of the thigh or abdomen. After proper training, patients or caregivers can self-inject at home. Dosing varies by condition, age, and body weight.

The dosing regimen for Humira depends on the specific condition being treated, the patient's age, and their body weight (particularly in pediatric patients). Your prescribing physician will determine the most appropriate dose and schedule for your individual needs. It is important to follow the prescribed dosing schedule closely to maintain therapeutic drug levels and achieve the best treatment outcomes.

Adults

Children

Pediatric dosing of Humira is based on body weight and the specific condition being treated. The following are general guidelines for pediatric use:

Elderly

No dose adjustment is required for elderly patients. However, the frequency of serious infections is generally higher in elderly patients compared to younger adults, so careful monitoring for infections is particularly important in this population. Elderly patients may also have reduced renal and hepatic function and may be taking multiple medications, which should be considered in the overall treatment plan.

Missed Dose

If you miss a dose of Humira, inject it as soon as you remember. Then take your next dose at the regularly scheduled time. If it is almost time for your next scheduled dose, skip the missed dose and inject the next dose on your regular schedule. Do not inject a double dose to make up for a missed injection. If you are unsure about what to do, contact your prescribing physician or pharmacist for guidance.

Overdose

The maximum tolerated dose of adalimumab has not been established in humans. In clinical trials, doses up to 10 mg/kg have been administered without dose-limiting toxicity. In the event of an overdose, the patient should be monitored for signs and symptoms of adverse effects, and appropriate symptomatic treatment should be initiated. There is no specific antidote for adalimumab overdose. Given the long half-life of the drug (approximately 2 weeks), monitoring may need to continue for an extended period.

What Are the Side Effects of Humira?

The most common side effects of Humira are injection site reactions (pain, redness, swelling), upper respiratory infections, headache, rash, and nausea. Serious but less common side effects include serious infections (including TB reactivation), malignancies (particularly lymphoma), heart failure worsening, and liver injury. The frequency of side effects is categorized below by how commonly they occur.

Like all medicines, Humira can cause side effects, although not everybody experiences them. The side effects listed below are based on data from clinical trials involving thousands of patients as well as post-marketing surveillance reports. Understanding the potential side effects and their relative frequency can help you and your doctor make informed decisions about your treatment and recognize problems early if they arise.

It is important to distinguish between common, generally manageable side effects (such as injection site reactions) and rare but potentially serious complications (such as serious infections or lymphoma). Most patients tolerate adalimumab well, and the benefits of treatment typically outweigh the risks for the approved indications. However, ongoing monitoring is essential throughout treatment.

How Should You Use Humira?

Humira is given as a subcutaneous injection in the thigh or abdomen. After training from a healthcare professional, patients can self-inject at home. Remove the pen or syringe from the refrigerator 15-30 minutes before injection to let it reach room temperature. Rotate injection sites and avoid areas that are bruised, red, or tender.

Humira is available as a pre-filled pen (auto-injector) or pre-filled syringe, both designed for self-administration at home after appropriate training. Your healthcare provider or nurse will demonstrate the proper injection technique during your initial visits. It is important to follow the instructions carefully to ensure effective drug delivery and to minimize injection site reactions.

Step-by-step injection guide

1. Prepare: Remove the Humira pen or syringe from the refrigerator and allow it to reach room temperature for 15-30 minutes. Do not remove the cap during this time. Do not heat the product using any external heat source (e.g., microwave, hot water)
2. Inspect: Check the solution through the viewing window. It should be clear and colorless to slightly yellow. Do not use if the liquid is cloudy, discolored, or contains visible particles. Check the expiry date
3. Choose injection site: The recommended injection sites are the front of the thighs or the abdomen (at least 5 cm/2 inches away from the navel). Rotate injection sites with each dose. Do not inject into areas that are red, bruised, tender, or hard
4. Clean: Wash your hands thoroughly. Clean the chosen injection site with an alcohol swab using a circular motion. Allow the skin to dry completely before injecting
5. Inject: Remove the cap from the pen. Place the pen firmly against the skin at a 90-degree angle. Press the activation button. Hold the pen in place until the window turns completely yellow (approximately 10 seconds). You will hear a click when the injection starts and another click when it is complete
6. Dispose: After injection, the needle guard will automatically cover the needle. Place the used pen or syringe immediately in a sharps disposal container. Do not recap or reuse. Do not dispose of in household waste

How Should You Store Humira?

Store Humira in the refrigerator at 2-8°C (36-46°F) in the original carton to protect from light. Do not freeze. If necessary, a single pen or syringe can be stored at room temperature (up to 25°C / 77°F) for a maximum of 14 days, after which it must be used or discarded.

Proper storage of Humira is essential to maintain its effectiveness and safety. As a biologic medicine containing a protein (monoclonal antibody), adalimumab is sensitive to temperature extremes and light exposure. Improper storage can degrade the protein, reducing its effectiveness or potentially making it unsafe to use.

• Refrigeration: Store in a refrigerator at 2°C to 8°C (36°F to 46°F). This is the standard storage condition that maintains the drug's stability for the duration of its shelf life
• Light protection: Keep in the original carton until ready to use to protect the solution from light
• Do not freeze: Freezing can damage the protein structure of adalimumab. If accidentally frozen, do not use the product
• Room temperature storage: If needed (e.g., for travel), a single pen or syringe may be stored at room temperature (up to 25°C / 77°F) for a maximum of 14 days. Write the date removed from the refrigerator on the carton. It must be used within 14 days or discarded, even if returned to the refrigerator
• Travel: When traveling, use an insulated bag with cool packs to keep Humira refrigerated. Avoid exposing it to extreme heat or direct sunlight. Airlines generally allow biologic medicines in carry-on luggage with appropriate documentation
• Expiry date: Do not use Humira after the expiry date printed on the label and carton

Keep all medicines out of the sight and reach of children. Do not dispose of unused medicines via wastewater or household waste. Ask your pharmacist about how to dispose of medicines you no longer use.

What Does Humira Contain?

Humira contains the active ingredient adalimumab (40 mg per 0.8 mL). The inactive ingredients (excipients) include mannitol, citric acid monohydrate, sodium citrate, disodium hydrogen phosphate dihydrate, sodium dihydrogen phosphate dihydrate, sodium chloride, polysorbate 80, sodium hydroxide, and water for injections.

Understanding the full composition of Humira can be important for patients who have known allergies or sensitivities to specific excipients. The formulation has been carefully designed to maintain the stability of the adalimumab protein and to ensure comfortable subcutaneous injection.

Active ingredient

Each 0.8 mL pre-filled pen or syringe contains 40 mg of adalimumab. Adalimumab is a recombinant fully human immunoglobulin G1 (IgG1) monoclonal antibody produced in Chinese hamster ovary (CHO) cells using recombinant DNA technology. It has a molecular weight of approximately 148 kilodaltons.

Inactive ingredients (excipients)

• Mannitol
• Citric acid monohydrate
• Sodium citrate
• Disodium hydrogen phosphate dihydrate
• Sodium dihydrogen phosphate dihydrate
• Sodium chloride
• Polysorbate 80
• Sodium hydroxide (for pH adjustment)
• Water for injections

The solution does not contain preservatives. The product does not contain latex. The pH of the solution is approximately 5.8. Patients with known hypersensitivity to any of these excipients should discuss this with their prescribing physician before starting treatment.

Frequently Asked Questions About Humira