Other Health Conditions

Tremfya (Guselkumab): A Biologic Treatment for Psoriasis

Man suffering from psoriasis

Tremfya (guselkumab) is a prescription medication used to treat certain types of psoriasis, an autoimmune disease that affects the skin. An autoimmune disease is when your body’s immune system attacks its own healthy cells and tissues by mistake, causing inflammation and pain in adults. Tremfya is typically recommended in cases where people will benefit more from undergoing systemic treatment (e.g., taking injections or pills) or phototherapy (treatment via UV light) rather than another treatment option. 

Tremfya is classified as a biological medication, which means it is a protein-based medication made from living cells. Tremfya works by targeting a specific protein in the body that is believed to contribute to the development of psoriasis. 

Clinical trials have demonstrated the effectiveness of Tremfya in lowering the symptoms of psoriasis, including skin lesions and itching. Nonetheless, like any other medication, Tremfya can cause some side effects and should only be used under the guidance of a healthcare professional. Possible adverse reactions will be discussed in depth later.

How Does Tremfya Work?

Tremfya is known as a monoclonal antibody. It binds to the p19 subunit of IL-23, a cytokine (protein) that plays a key role in the immune system’s response to infection and inflammation. People with plaque psoriasis or psoriatic arthritis have too much IL-23 in their bodies. This leads to excessive growth and activity of skin cells that characterize the disease.

When Tremfya binds to IL-23, it blocks its ability to bind to its receptor and trigger an inflammatory response. By inhibiting IL-23, Tremfya lowers inflammation throughout the body. It also helps to normalize the growth and activity of skin cells. 

What Is Tremfya Used To Treat?

In July 2017, the Food and Drug Administration (FDA) approved Tremfya for the treatment of plaque psoriasis. In 2020, Tremfya also became approved for the treatment of psoriatic arthritis in adults.

Plaque psoriasis is the most common type of psoriasis. It’s an autoimmune skin problem that causes red, scaly patches to form on the skin. Due to the skin’s appearance, there is also discomfort and emotional distress in people with plaque psoriasis. Tremfya can help improve the quality of life of those suffering from plaque psoriasis.

Psoriatic arthritis is an autoimmune problem that causes inflammation in not only the skin, but also in the joints, spine, and tendons, which can lead to pain. 

Dosage and Administration of Tremfya


The recommended dose for both plaque psoriasis and psoriatic arthritis is 100 mg injected under the skin (subcutaneously) at week 0, week 4, and then every 8 weeks thereafter. For psoriatic arthritis, Tremfya can be used alone or with other medications known as disease-modifyng antirheumatic drug (DMARD), such as methotrexate.


  • Tremfya should be administered by a healthcare professional or self-administered by a patient after receiving training on how to properly give the injections. 
  • The medication comes as a single-dose prefilled syringe or as a single-dose One-Press prefilled pen, which should be stored in the refrigerator between 2°C to 8°C (36°F to 46°F).
  • Before administering, the syringe or pen should be allowed to reach room temperature for 30 minutes. Don’t try to warm up the syringe or pen any other way, or you might damage the medication.
  • Clean the injection site with an alcohol swab, and administer the injection subcutaneously in the stomach, thigh, or upper arm.
  • The injection site should be rotated to a different location with each injection to minimize the risk of injection site reactions. Don’t inject into skin that’s tender, bruised, red, hard, thick, scaly, or affected by psoriasis.

Make sure to follow the dosage and administration instructions provided by your healthcare provider or pharmacist to avoid any complications. Only change your dosage or administration after asking your healthcare provider.

Side Effects

Woman suffering from Tremfya side effects

Common side effects of Tremfya include:

  • Upper respiratory infections (such as the common cold) (14%)
  • Injection site reactions, such as pain, redness, or swelling (5%)
  • Headache (5%)
  • Muscle or joint pain (3%)
  • Diarrhea (2%)
  • Herpes or tinea (fungal) infections (1%)

Keep in mind that not all patients who take Tremfya will experience these side effects, and some individuals may experience other side effects not listed above. 

Some side effects may occur during or after your treatment, so it is important to tell your healthcare provider if any side effects occur or worsen. Some of these reactions may require immediate medical attention. If you have any concerns or questions about Tremfya, discuss them with your healthcare provider.


Tremfya has potentially serious side effects and precautions to consider before use. Examples include: 

  • Allergies: An allergic reaction can cause rash, hives, itching, swelling, difficulty breathing, and dizziness. If you are allergic to any of the ingredients in Tremfya, inform your doctor before taking the medication.
  • Infections: Tremfya can raise the risk of infections, especially if you have a history of latent tuberculosis (TB).  Your provider will test and treat you, if necessary, for certain infections before starting Tremfya. 
  • Vaccinations: Before starting Tremfya, ensure you are up-to-date on all your vaccinations. Live vaccines are not recommended while on Tremfya, and it is recommended to wait at least 2 weeks after receiving a non-live vaccine before starting Tremfya.
  • Immune system suppression: Tremfya can weaken your immune system, making it easier for you to get infections. If you have a weakened immune system, take medications that weaken your immune system, or have a history of recurrent infections, inform your doctor before taking Tremfya.
  • Pregnancy and breastfeeding: If you are pregnant or breastfeeding, talk to your provider before taking Tremfya. Pregnant females who use Tremfya should be enrolled in a pregnancy registry that monitors you and your baby. You can enroll by calling 1-877-311-8972.
  • Other medical conditions: If you have a history of cancer, liver disease, or any other medical condition, inform your doctor before taking Tremfya.

Always follow your provider’s instructions when taking Tremfya, and report any side effects or concerns immediately.


The cost of Tremfya can vary depending on a few factors, such as where you live, the dosage prescribed, and your insurance coverage. 

In the United States, the price for a 100 mg prefilled syringe of Tremfya is approximately $9,684. However, your actual price may be lower depending on your insurance coverage, copay assistance programs, and other factors. 

Outside of the United States, the cost of Tremfya can also vary depending on the country and the healthcare system. It’s best to consult with a local healthcare provider or pharmacist for specific pricing information.

This information is not a substitute for medical advice or treatment. Talk to your doctor or healthcare provider about your medical condition prior to starting any new treatment. AmeriPharma™ Specialty Care assumes no liability whatsoever for the information provided or for any diagnosis or treatment made as a result, nor is it responsible for the reliability of the content. AmeriPharma™ Specialty Care does not operate all the websites/organizations listed here, nor is it responsible for the availability or reliability of their content. These listings do not imply or constitute an endorsement, sponsorship, or recommendation by AmeriPharma™ Specialty Care. This webpage may contain references to brand-name prescription drugs that are trademarks or registered trademarks of pharmaceutical manufacturers not affiliated with AmeriPharma™ Specialty Care.

Dr. Robert Chad Hakim, PharmD, was born and raised in Northridge, CA. He received his pharmacy degree from the University of Wisconsin-Madison School of Pharmacy. The most rewarding part of his job is taking initiative to advance clinical programs that maximize impact on patient care. He has a board certification in critical care (BCCCP), and his areas of expertise are critical care, drug information, general medicine, and cardiology. In his free time, he enjoys traveling.