Pronunciation: trem fye´ ah
Generic name: guselkumab [ GUE-sel-KOO-mab ]
Dosage forms: 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 Sep 24, 2025.

What is Tremfya?

Tremfya (guselkumab) is an interleukin-23 antagonist used to treat plaque psoriasis, psoriatic arthritis, Crohn’s disease, and ulcerative colitis in certain adult patients. Tremfya injection works by blocking a protein in your body called IL-23 (interleukin-23), which is involved in the autoimmune response and inflammation, in these conditions. By blocking IL-23, Tremyfa helps reduce inflammation, pain, swelling, and symptoms in the skin, joints, and gastrointestinal tract. 

Tremfya belongs to the class of medicines known as interleukin inhibitors and may also be called a human monoclonal antibody.

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

Subcutaneous injection is used for: 

• Induction and maintenance doses for plaque psoriasis, psoriatic arthritis, Crohn’s disease, and ulcerative colitis.

Intravenous infusion can be used for:

• Induction doses for ulcerative colitis and Crohn’s disease.

What is Tremfya used for?

Tremfya's FDA-approved indications are to treat adults with:

• Plaque psoriasis that is moderate-to-severe, in patients who may benefit from taking injections or pills (systemic therapy) or phototherapy (treatment using ultraviolet or UV light)
• Psoriatic arthritis that is active
• Ulcerative colitis that is moderately to severely active
• Crohn’s disease that is moderately to severely active

How does Tremfya work?

Tremfya is an interleukin-23 antagonist. Tremfya's 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, Tremfya helps to regulate the immune system and control inflammation so that symptoms of these conditions improve.

Tremfya also binds to CD64, a receptor on cells that produce IL-23, but the clinical significance of this effect is unknown.

Tremfya side effects

Common Tremfya side effects may include:

• headache, joint pain;
• diarrhea, stomach pain;
• cold symptoms such as stuffy nose, sneezing, sore throat;
• cough, feeling short of breath;
• skin infections; or
• pain, itching, swelling, redness, or bruising where the medicine was injected.

Serious side effects

Allergic reactions: Get emergency medical help if you have signs of an allergic reaction to Tremfya: hives, rash, itching; chest tightness, difficult 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.

Liver problems. With the treatment of Crohn’s disease or ulcerative colitis, your healthcare provider will do blood tests to check your liver before and during treatment with this medicine. You may stop treatment with this medicine if you develop liver problems. Tell your healthcare provider right away if you notice any of the following symptoms:

• unexplained rash
• nausea
• vomiting
• stomach pain (abdominal)
• tiredness (fatigue)
•  loss of appetite
• yellowing of the skin or the whites of your eyes
• dark urine

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

Warnings before taking this medicine

Do not use Tremfya if you are allergic to the active ingredient guselkumab, polysorbate 80, or any of the inactive ingredients in this medication

Infections

This medicine may lower the ability of your immune system to fight infections and may increase your risk of infections. Your healthcare provider should check you for infections and tuberculosis (TB) before starting treatment with Tremfya and may treat you for TB before you begin treatment with Tremfya if you have a history of TB or have active TB. Your healthcare provider should watch you closely for signs and symptoms of TB during and after treatment with Tremfya.

Tell your healthcare provider right away if you have an infection or have symptoms of an infection, including:

• fever, sweats, or chills
• muscle aches
• weight loss
• cough 
• warm, red, or painful skin or sores on your body different from your psoriasis
• diarrhea or stomach pain
• shortness of breath
• blood in your phlegm (mucus)
• burning when you urinate or
• urinating more often than normal

Vaccines

Make sure you are current on all vaccines before you start treatment with this medicine. Avoid 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 Tremfya 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 by 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 Tremfya?

Tremfya subcutaneous injection is used for initial (induction) doses and maintenance doses for all four conditions. Patients with Crohn’s disease or ulcerative colitis may be given the option of receiving their induction doses as an intravenous infusion in a healthcare facility by a healthcare provider or as a subcutaneous injection.

This medicine should be used under the guidance and supervision of a healthcare professional. Tremfya subcutaneous injection may be administered by a healthcare professional, a patient, or a caregiver after proper training on correct subcutaneous injection technique.

Tremfya  injection

Use Tremfya injection exactly as prescribed by your doctor. Follow all directions on your prescription label. Do not use this medicine in larger or smaller amounts or for longer than recommended.

Tremfya is injected under the skin. You will be shown how to use injections at home. Do not give yourself this medicine if you do not understand how to use the injection and properly dispose of used needles and syringes.

The first two injections are usually given 4 weeks apart (induction treatment), then for maintenance treatment every 4 or every 8 weeks, depending on the condition being treated and the dose you receive. Your doctor will determine how often to have this treatment and how long to treat you.

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you do not understand all the instructions.

Store this medicine in the refrigerator. Protect from light and do not freeze.

Take the medicine out of the refrigerator and allow it to reach room temperature for 30 minutes before injecting your dose. Do not remove the needle cap until you are ready to give the injection.

Do not shake the prefilled syringe. Prepare your dose only when you are ready to give an injection.

Tremfya should appear clear to light yellow in color. Do not use the medicine if it looks cloudy or has particles in it. Call your pharmacist for a new medicine.

Do not inject Tremfya into an active psoriasis lesion. Avoid injecting into skin that is thick, scaly, bruised, red, or tender.

Each One-Press injector or prefilled syringe is for one use only. Throw it away after one use, even if there is still medicine left inside.

Use a needle and syringe only once and then place them in a puncture-proof "sharps" container. Follow state or local laws about how to dispose of this container. Keep it out of the reach of children and pets.

Tremfya dosing information

Usual Adult Dose of Tremfya 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 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 Tremfya for Crohn’s Disease or Ulcerative Colitis

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.

Use the lowest effective recommended dosage to maintain therapeutic response.

Tremfya formulations

Tremfya injections are available as:

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

Tremfya infusion is available as:

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

What happens if I miss a dose?

Use the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not use two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using this medicine?

Do not receive a "live" vaccine while using Tremfya. The vaccine may not work as well and may not fully protect you from the disease. 

What other drugs will affect this medicine?

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 Tremfya 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 Tremfya. You should refer to the prescribing information for Tremfya for a complete list of interactions or use the interactions checker below.

Tremfya Package Insert 

HCPs and patients often use the Tremfya Package Insert (PI) 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 Tremtya Prescribing Information (PI) or FDA label.

Tremfya J code

Tremfya J code is J1628.

J codes are used for medicines that are not taken orally and include injections, inhalations, and chemotherapies. 

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

Storage

• Store in the refrigerator between 36 °F to 46 °F (2 °C to 8 °C). 
• Keep  in the original carton to protect it from light until time of use. 
• Do not freeze.
• Do not shake.

Ingredients 

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.

Tremfya is not made with natural rubber latex

Manufacturer

Tremfya manufactured Janssen Biotech, Inc., Horsham, PA 19044, USA, 

Tremfya 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 Tremfya.

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Further information

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