Tremfya 100mg Injection (Guselkumab)

Tremfya is an FDA-approved biologic medication that blocks interleukin-23 (IL-23), a protein that drives inflammation in psoriasis, psoriatic arthritis, and inflammatory bowel disease. Manufactured by Janssen (Johnson & Johnson), it is delivered as a 100mg subcutaneous injection via prefilled syringe, One-Press injector, or Tremfya Pen, and is intended for use under physician supervision.

What Tremfya Is Used For

Tremfya is indicated for adults and children 6 years and older (weighing at least 40 kg) with moderate-to-severe plaque psoriasis, active psoriatic arthritis, Crohn’s disease, and ulcerative colitis.

• Plaque psoriasis: for patients who are candidates for systemic therapy or phototherapy
• Psoriatic arthritis: can be used alone or combined with a conventional DMARD such as methotrexate
• Crohn’s disease: for moderately to severely active disease, typically starting with an induction phase
• Ulcerative colitis: for moderately to severely active disease, following the same induction-then-maintenance approach

How Tremfya Works

Tremfya works by selectively blocking IL-23, a signaling protein that triggers the inflammatory cascade behind psoriasis and related autoimmune conditions. By neutralizing IL-23 specifically, it interrupts inflammation upstream, which is why it’s classified as an interleukin inhibitor rather than a broader immunosuppressant.

Dosage and Administration

The standard maintenance dose is 100mg by subcutaneous injection at Week 0, Week 4, and every 8 weeks thereafter.

• Plaque psoriasis / psoriatic arthritis: 100mg subcutaneous at Weeks 0, 4, then every 8 weeks
• Crohn’s disease / ulcerative colitis (induction): 200mg IV infusion at Weeks 0, 4, and 8, or a 400mg subcutaneous induction option
• Maintenance (Crohn’s/UC): 100mg subcutaneous every 8 weeks, or 200mg subcutaneous every 4 weeks
• Injection sites: front of thighs, lower abdomen (avoiding 2 inches around the navel), or back of the upper arm (administered by a healthcare professional or trained caregiver)
• Adults may self-inject after proper training; pediatric self-administration is not recommended

Before Starting Tremfya

Patients should be evaluated for tuberculosis and brought up to date on age-appropriate vaccinations before starting Tremfya, since it affects immune function.

• TB screening is required before treatment initiation
• Liver enzymes and bilirubin should be evaluated at baseline, particularly for Crohn’s/UC patients
• Inform your doctor of any current infections, recent travel, or household TB exposure
• Effective contraception is recommended during treatment, as Tremfya has not been studied in pregnancy

Side Effects

The most common side effects of Tremfya include upper respiratory infections, headache, injection site reactions, joint pain, and diarrhea.

• Upper respiratory infections
• Headache
• Injection site reactions (pain, redness, swelling)
• Arthralgia (joint pain)
• Diarrhea and gastroenteritis
• Tinea (fungal) infections and herpes simplex infections

Because Tremfya affects immune response, patients should contact their care team promptly if signs of infection, fever, or allergic reaction develop.

Frequently Asked Questions

How often is Tremfya injected?

For psoriasis and psoriatic arthritis, Tremfya is injected at Week 0, Week 4, and then every 8 weeks as ongoing maintenance. Crohn’s disease and ulcerative colitis follow a different induction schedule before settling into maintenance dosing.

Can I inject Tremfya myself at home?

Yes, adults can self-inject Tremfya using the prefilled syringe, One-Press injector, or Tremfya Pen after receiving proper training from a healthcare provider. Pediatric patients should have the injection administered by a healthcare professional or trained caregiver.

How long does it take for Tremfya to work?

Some patients notice improvement within a few weeks, but full effect can take several months. Response time varies by condition and individual patient factors.

Does Tremfya require any tests before starting?

Yes — tuberculosis screening is required before starting Tremfya, and liver enzyme testing is recommended, particularly for Crohn’s disease and ulcerative colitis patients.

What is the difference between Tremfya and other psoriasis biologics?

Tremfya selectively targets IL-23, distinguishing it from biologics that target TNF-alpha or IL-17, and it is the only IL-23 inhibitor approved with both subcutaneous and intravenous induction options for Crohn’s disease.

References

1. U.S. FDA — TREMFYA Prescribing Information
2. Drugs.com — Tremfya: Uses, Dosage, Side Effects & Warnings
3. American College of Rheumatology — Guselkumab (Tremfya) Patient Information

Medically reviewed. Last updated: [20/06/2026]. This content is for informational purposes and does not replace consultation with a licensed physician.