Guselkumab

Pronunciation: GUE-sel-KOO-mab
Brand name: Tremfya
Dosage form: injection (Tremfya Pen, Prefilled syringe, One-Press Injector), infusion (single dose vial)
Drug class: Interleukin inhibitors

Medically reviewed by Melisa Puckey, BPharm. Last updated on Mar 24, 2025.

What is guselkumab?

Guselkumab (Tremfya) is an injectable medication used to treat inflammatory, autoimmune conditions plaque psoriasis, psoriatic arthritis, Crohn’s disease, and ulcerative colitis, in certain patients. Guselkumab helps reduce inflammation, pain, swelling, and skin, joint and gastric symptoms. 

Guselkumab works by blocking the action of interleukin-23 (IL-23) at its receptor. IL-23 is a naturally occurring small protein called a cytokine, which plays a role in your normal inflammatory and immune responses. Blocking the action of IL-23, guselkumab inhibits the release of small proteins called chemokines and cytokines that cause inflammation. Guselkumab is a biological drug from the drug class known as interleukin inhibitors, it is also called a human immunoglobulin G1 lambda (IgG1λ) monoclonal antibody

Guselkumab can be self-administered as an injection under the skin (subcutaneous injection) using pre-filled syringes or pens or may be given as an infusion by a healthcare professional, depending on your condition and stage of treatment. Guselkumab is given every 4 to 8 weeks as maintenance treatment, after initial doses.

Guselkumab was first approved by the US Food and Drug Administration (FDA) in 2017. It comes in the form of a prefilled syringe and a One-Press injector.

No biosimilars of guselkumab have been approved. Biosimilars are highly similar versions of a biological drug that are designed to work in the same was as the original version of the drug, but they are not identical.

What is guselkumab used for?

Guselkumab is an FDA-approved prescription medicine (indications) to treat:

• Plaque Psoriasis in adult patients with moderate-to-severe plaque psoriasis who may benefit from taking injections or pills (systemic therapy) or phototherapy (treatment using ultraviolet or UV light)
• Psoriatic Arthritis in adult patients with active psoriatic arthritis.
• Ulcerative Colitis in adult patients with moderately to severely active ulcerative colitis
• Crohn’s Disease in adult patients with moderately to severely active Crohn’s disease.

It is not known if guselkumab is safe and effective in children under 18 years of age.

How does guselkumab work?

Guselkumab mechanism of action (MOA) is by binding selectively to the p19 subunit of interleukin-23 (IL-23) which is a naturally occurring cytokine (protein). Cytokines are substances released by cells of the immune system that influence other cells and play a key role in promoting inflammation and immune response, in chronic immune-mediated diseases.

By blocking the effects of IL-23, guselkumab helps to regulate the immune system and control inflammation so that symptoms of these conditions improve.

Guselkumab is an interleukin-23 antagonist.

Guselkumab side effects

Common guselkumab side effects

The most common side effects of guselkumab include:

• Infections (23%)
• Upper respiratory tract infection (14.3%)
• Headache (4.6%)
• Injection site reaction including pain, itching, swelling, redness, or bruising where the medicine was injected (4.5%)
• Joint pain (2.7%)
• Elevated liver enzymes (2.6%)
• Diarrhea (1.6%)
• Gastroenteritis, inflammation of your stomach into your intestines, causing pain, vomiting, and diarrhea (1.3%)
• Fungal skin infections (1.1%)
• Herpes simplex infections (1.1%)

These common side effects occurred in 1% or more of plaque psoriasis patients being treated with Guselkumab for 16 weeks in clinical trials Ps01 and Ps02.

Serious side effects and warnings

Hypersensitivity reactions

Get emergency medical help if you have signs of an allergic reaction to guselkumab a: hives, rash, itching; chest tightness, difficulty breathing; feeling light-headed; swelling of your face, lips, tongue, or throat.

Infections

This medicine can weaken (suppress) your immune system, and you may get an infection more easily.

Call your doctor at once if you have signs of infection, such as:

• fever, chills, body aches, night sweats;
• weight loss, feeling very tired;
• cough (may contain blood or mucus), shortness of breath;
• pain or burning when you urinate;
• severe diarrhea or stomach cramps; or
• skin redness, tingling, blisters, oozing, or sores that look different from psoriasis.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Related/similar drugs

Before taking this medicine

Allergies

You should not use guselkumab if you are allergic to it, polysorbate 80, or any other of the inactive ingredients in this medication

Tuberculosis

Tell your doctor if you have ever had tuberculosis, or if anyone in your household has tuberculosis. Also, tell your doctor if you have recently traveled. Tuberculosis and some fungal infections are more common in certain parts of the world, and you may have been exposed during travel.

Before starting treatment with guselkumab, your doctor may perform tests to make sure you do not have tuberculosis or other infections.

To make sure guselkumab is safe for you, tell your doctor if you have:

• an active or chronic infection;

• active tuberculosis infection that is not being treated; or

• if you have recently received or are scheduled to receive any vaccine.

Vaccines

Make sure you are current on all vaccines before you start treatment with guselkumab.

Avoid the use of live vaccines while being treated with this medicine.

Hepatotoxicity

Medicine-induced liver injury has been reported with this medicine. When being treated for Crohn’s disease or ulcerative colitis your liver enzymes and bilirubin levels will be monitored at baseline, and for at least 16 weeks of treatment, and periodically thereafter according to routine patient management. If drug-induced liver injury is suspected your treatment will be paused until this diagnosis is excluded.

Pregnancy

It is not known whether guselkumab will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

If you are pregnant, your name may be listed on a pregnancy registry called MotherTOBaby to track the effects of guselkumab on the baby. You can enroll in this registry by visiting www.mothertobaby.org/ongoing-study/tremfya-guselkumab, by calling 1-877-311-8972, or emailing MotherToBaby@health.ucsd.edu. Breastfeeding

Breastfeeding

It is not known whether guselkumab passes into breast milk or if it could affect the nursing baby. Tell your doctor if you are breastfeeding.

How should I use guselkumab?

Patients with plaque psoriasis or psoriatic arthritis will receive guselkumab as an injection under the skin (subcutaneous injection). 

Patients with ulcerative colitis will receive their initial (induction) doses through a vein in the arm (intravenous infusion) in a healthcare facility by a healthcare provider. After completing the induction doses, patients will receive maintenance treatments as a subcutaneous injection which may be self-administered.

Patients with Crohn’s disease may receive their beginning (induction) doses as a subcutaneous injection or an intravenous infusion in a healthcare facility by a healthcare provider. After completing the induction doses, patients will receive maintenance treatments as a subcutaneous injection (subcutaneous injection) which may be self-administered or given by a carer.

Guselkumab injection

• Use guselkumab exactly as your healthcare provider tells you to use it.
• See the detailed "Instructions for Use" that comes with guselkumab for information on how to prepare and inject a dose of guselkumab, and how to properly throw away (dispose of) used guselkumab prefilled syringes or One-Press injectors.
• Prepare for your injection
• Remove your guselkumab prefilled syringe or One-Press injector carton from the refrigerator.
• Keep the prefilled syringe or One-Press injector in the carton and let it sit on a flat surface at room temperature for at least 30 minutes before use.
• Do not warm the prefilled syringe or One-Press injector any other way.
• Check the expiration date ('EXP') on the back panel of the carton.
• Do not use your prefilled syringe or One-Press injector if the expiration date has passed.
• Do not inject guselkumab if the perforations on the carton are broken. Call your healthcare provider or pharmacist for a refill.
• Choose injection site
• Select from the following areas for your injection:
• Front of thighs (recommended)
• Lower stomach area (lower abdomen), except for a 2-inch area right around your navel (belly-button)
• Back of upper arms (only if someone else is giving you the injection)
  Do not inject into skin that is tender, bruised, red, hard, thick, scaly or affected by psoriasis.
• Clean injection site
• Wash your hands well with soap and warm water.
• Wipe your chosen injection site with an alcohol swab and allow it to dry.
• Do not touch, fan, or blow on the injection site after you have cleaned it.
• Inspect liquid
• Take your guselkumab prefilled syringe or One-Press injector out of the carton.
• Check the guselkumab prefilled syringe or One-Press injector liquid in the viewing window. It should be clear to slightly yellow and may contain tiny white or clear particles. You may also see one or more air bubbles. This is normal.
• Do not inject if the liquid is cloudy or discolored, or has large particles. Call your healthcare provider or pharmacist for a refill.
• Inject. guselkumab
• Using prefilled syringe
• Remove needle cover.
• Hold your prefilled syringe by the body and pull needle cover straight off. It is normal to see a drop of liquid.
• Inject guselkumab within 5 minutes of removing the needle cover.
• Do not put needle cover back on, as this may damage the needle or cause a needle stick injury.
• Do not touch needle or let it touch any surface.
• Do not use a guselkumab prefilled syringe if it is dropped. Call your healthcare provider or pharmacist for a refill.
• Position fingers and insert needle.
• Place your thumb, index and middle fingers directly under the finger flange, as shown.
• Do not touch plunger or area above finger flange as this may cause the needle safety device to activate.
• Use your other hand to pinch skin at the injection site. Position syringe at about a 45 degree angle to the skin.
• It is important to pinch enough skin to inject under the skin and not into the muscle.
• Insert needle with a quick, dart-like motion.
• Release pinch and reposition hand
• Use your free hand to grasp the body of the prefilled syringe.
• Press plunger
• Place thumb from the opposite hand on the plunger and press the plunger all the way down until it stops.
• Release pressure from plunger
• The safety guard will cover the needle and lock into place, removing the needle from your skin.
• Using a One-Press injector
• Twist and pull off bottom cap
• Keep hands away from the needle guard after the cap is removed.
• Inject guselkumab within 5 minutes of removing the cap.
• Do not put the cap back on, this could damage the needle.
• Do not use a One-Press injector if it is dropped after removing the cap. Call your healthcare provider or pharmacist for a new One-Press injector.
• Place on skin
• Position the One-Press injector straight onto the skin (about 90 degrees relative to injection site).
• Push handle straight down
• Medication injects as you push. Do this at a speed that is comfortable for you.
• Do not lift the One-Press injector during the injection. The needle guard will lock and the full dose will not be delivered.
• Complete injection
• Injection is complete when the handle is pushed all the way down, you hear a click, and the teal body is no longer visible.
• Lift straight up
• The yellow band indicates that the needle guard is locked.

• After your injection
• Dispose of your prefilled syringe or One-Press injector
• Put your used guselkumab prefilled syringe or One-Press injector in an FDA-cleared sharps disposal container right away after use.
• Do not throw away (dispose of) your guselkumab prefilled syringe or One-Press injector in your household trash.
• Do not recycle your used sharps disposal container.
• For more information, see "How should I dispose of the used prefilled syringe or One-Press injector? under Storage below.
• Check injection site
• There may be a small amount of blood or liquid at the injection site. Hold pressure over your skin with a cotton ball or gauze pad until any bleeding stops.
• Do not rub the injection site.
• If needed, cover injection site with a bandage.

Guselkumab dosing information

Usual Adult Dose of Guselkumab for Psoriatic Arthritis:

Induction dose and Maintenance dose: 100 mg subcutaneously at Week 0, Week 4, and every 8 weeks thereafter.

Comment: This drug may be administered alone or in combination with a conventional disease-modifying antirheumatic drug (cDMARD) (e.g., methotrexate)

Usual Adult Dose of Guselkumab for Plaque Psoriasis:

Induction dose and Maintenance dose: 100 mg subcutaneously at Week 0, Week 4, and every 8 weeks thereafter.

Usual Adult Dose of Guselkumab for Crohn’s Disease

Induction dose: 

• 200 mg administered by intravenous infusion over at least one hour at Week 0, Week 4, and Week 8, or
• 400 mg administered by subcutaneous injection at Week 0, Week 4, and Week 8

Maintenance dose:

• 100 mg administered by subcutaneous injection at Week 16, and every 8 weeks thereafter, or
• 200 mg administered by subcutaneous injection at Week 12, and every 4 weeks thereafter.

Usual Adult Dose of Guselkumab for Ulcerative Colitis

Induction dose: 200 mg administered by intravenous infusion over at least one hour at Weeks 0, 4, and 8.

Maintenance dose: 

• 100 mg administered by subcutaneous injection at Week 16, and every 8 weeks thereafter, or
• 200 mg administered by subcutaneous injection at Week 12, and every 4 weeks thereafter.

Guselkumab formulations

Guselkumab (Tremfya) injections are available as:

• One-Press patient-controlled injector single-dose 100 mg/mL Injection:
• Tremfya Pen single-dose prefilled pen 200 mg/2 mL
• Prefilled syringe single-dose 100 mg/mL 
• Prefilled syringe single-dose 200 mg/2 mL (100 mg/mL)

Guselkumab infusion is available as:

• Single-dose vial  200 mg/20 mL (10 mg/mL) 

What happens if I miss a dose?

If you miss your guselkumab dose, inject a dose as soon as you remember. Then, take your next dose at your regular scheduled time. Call your healthcare provider if you are not sure what to do.

What happens if I overdose?

If you inject more guselkumab than prescribed, call your healthcare provider right away.

Interactions

Other drugs may interact with guselkumab, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

CYP450 substrates. When starting guselkumab in patients who are currently on CYP450 substrates, particularly those with a narrow therapeutic index, your healthcare provider will monitor the therapeutic effect or drug concentration and consider dosage adjustment as needed.

This list is not all-inclusive and other medications may interact with guselkumab. You should refer to the prescribing information for Tremfya for a complete list of interactions or use the interactions checker below.

Guselkumab Package Insert 

HCPs and patients often use the Guselkumab Package Insert (Tremfya) for more detailed information about this medicine. The Tremfya Package Insert contains more comprehensive information on Indications and Usage, Dosage and Administration, Clinical Pharmacology, Clinical Studies, Drug Interaction, and more. Discuss any medical questions you have with your HCP (health care professional). This is not all the information you need to know about this medicine for safe and effective use, and it does not take the place of talking to your doctor about your treatment.

The Package Insert is sometimes called Prescribing Information (PI) or FDA label.

Guselkumab J code

Guselkumab J code is J1628.

J codes are used for medicines that are not taken orally and include injections, inhalations, and chemotherapies. J codes are important for accurate and consistent coding for billing and reimbursement purposes.

Your physician will need guselkumab J code when filling out forms for your treatment.

Storage

• Store guselkumab in refrigerator at 36° to 46°F (2° to 8°C).
• Do not freeze guselkumab prefilled syringes or One-Press injector.
• Do not shake your guselkumab prefilled syringe or One-Press injector.
• Keep guselkumab prefilled syringe or One-Press injector in the original carton to protect from light and physical damage.

Keep guselkumab prefilled syringe or One-Press injector and all medicines out of reach of children.

How should I dispose of the used prefilled syringe or One-Press injector?

If you do not have an FDA-cleared sharps disposal container, you may use a household container that is:

• made of a heavy-duty plastic
• can be closed with a tight-fitting, puncture-resistant lid, without sharps being able to come out
• upright and stable during use
• leak-resistant
• properly labeled to warn of hazardous waste inside the container

When your sharps disposal container is almost full, you will need to follow your community guidelines for the right way to dispose of your sharps disposal container. There may be state or local laws about how you should throw away used needles and syringes.

For more information about safe sharps disposal, and for specific information about sharps disposal in the state that you live in, go to the FDA's website at: www.fda.gov/safesharpsdisposal

What are the ingredients in guselkumab?

Active ingredient: guselkumab

Inactive ingredients: 

• Single-dose prefilled syringe, single-dose One-Press patient-controlled injector, single-dose prefilled pen for subcutaneous use (TREMFYA PEN): L-histidine, L-histidine monohydrochloride monohydrate, polysorbate 80, sucrose and water for injection.
• Single-dose vial for intravenous infusion: EDTA disodium dihydrate, L-histidine, L-histidine monohydrochloride monohydrate, L-methionine, polysorbate 80, sucrose and water for injection.

Not made with natural rubber latex.

Company

Guselkumab is manufactured under the brand name Tremfya by Janssen Biotech, Inc., Horsham, PA 19044, U.S.

Guselkumab Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There is 1 for guselkumab.

Popular FAQ

More FAQ

• What are the new drugs for plaque psoriasis?
• How does Tremfya work?

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer