Which Injections Can I Use to Treat My Psoriasis?

Medically reviewed by Debra Sullivan, PhD, RN, CNE, COI on June 10, 2016Written by Stephanie Watson on October 21, 2015

Understanding psoriasis

When you have psoriasis, your immune system causes skin cells to multiply too quickly. Dead skin cells build up and form itchy, red patches covered with silvery scales on your skin. You’re most likely to see these plaques on certain areas of your body, such as:

  • knees
  • elbows
  • scalp
  • lower back

Psoriasis stems from a problem with cells of the immune system. These cells are called T cells. Normally, they attack bacteria, viruses, and other foreign invaders. In psoriasis, a faulty immune response causes your body to make more skin cells than needed. It then causes those extra cells to slough off and build up. Thankfully, treatments can reduce redness, relieve itching, and improve your skin’s appearance.

If you have moderate to severe psoriasis that hasn’t cleared with topical treatments, your doctor might recommend an injectable drug. Drugs such as methotrexate (Otrexup, Rasuvo, and Trexall) and biologics can clear up plaques and reduce inflammation.

Biologic drugs

For moderate to severe psoriasis that covers more than 10 percent of the body, doctors recommend drugs called biologics. Biologics are man-made versions of proteins created from human cells. These drugs target specific parts of the immune system. Biologics can be injected under your skin or into a vein or muscle.

Biologics are some of the most effective psoriasis treatments. These drugs can also clear plaques and reduce joint damage in people with psoriatic arthritis. This is a condition related to psoriasis. Biologics work by blocking cytokines. These are substances that the immune system releases. They bring on the cell growth, overproduction, and inflammation in psoriasis.

Biologic drugs target your immune system, so they can increase your risk of infections. These drugs may increase cancer risk too, but this hasn’t been proven. Side effects from biologic drugs can include:

  • respiratory infections
  • headaches
  • stomach pain
  • swelling, itching, or a rash at the injection site

Two types of biologic drugs are approved to treat psoriasis: TNF-alpha inhibitors and interleukin inhibitors.

TNF-alpha inhibitors

These drugs block a type of cytokine called TNF-alpha. Examples include:

Interleukin inhibitors

These drugs block various forms of interleukin. This is another type of cytokine. Examples include:


Methotrexate (Otrexup, Rasuvo, and Trexall) was originally used to treat cancer. Now it’s been used to treat psoriasis for more than 30 years. Doctors once thought it worked by targeting rapidly growing cells, like it does to treat cancer. But now they think it helps psoriasis by suppressing the immune reaction.

Methotrexate is used for people with severe psoriasis. It can also treat psoriatic arthritis. You take this drug once per week. It comes as an oral tablet or a solution that you inject. The injection can be under your skin or in a vein or muscle. This drug typically clears plaques within three to six weeks after you start taking it.

This drug can cause the following side effects:

  • fatigue
  • nausea
  • vomiting
  • headache
  • trouble sleeping
  • lightheadedness
  • mouth sores
  • bruising
  • bleeding
  • diarrhea
  • chills

Taking folic acid can reduce some of these side effects. Ask your doctor how much to take.

Methotrexate has also been linked to liver damage. Your doctor will do blood tests every few months during treatment to check how well your liver works. You should not use methotrexate if you’re pregnant or could become pregnant. This drug can harm your growing baby.

The cost of injections

Biologic drugs are effective at treating psoriasis, but they come at a steep cost. A year of treatment with adalimumab (Humira) can be more than $39,000. Etanercept (Enbrel) is more than $46,000 per year, and ustekinumab (Stelara) costs over $53,000 each year, according to a 2014 study.

On the other hand, methotrexate only costs a fraction of what these treatments cost. It comes in at about $2,000 per year.

Under the Affordable Care Act, insurance companies must offer coverage for the treatment of chronic conditions like psoriasis. The percentage of the drug cost that your insurance company covers depends on your plan. Insurance companies often put expensive drugs like biologics in the top tiers of their covered prescription drugs. Drugs in the top tiers tend to cost people more money out of pocket.

Currently, there are no generic versions of biologic drugs available. Generic drugs usually cost less than brand-name versions. However, the Food and Drug Administration has approved a biosimilar drug to infliximab (Remicade). Unlike generic drugs, biosimilars are not exact replicas of biologic drugs. But they do work in the same way.

Other treatment options

For severe psoriasis, you may need injectable treatments. But for mild to moderate psoriasis, doctors often suggest topical drugs first. You rub topical drugs on your skin. They work to slow cell growth, remove scales, and relieve itching and inflammation. Examples of topical medications include:

  • Emollients: These moisturize your skin.
  • Steroid creams: These bring down swelling and redness.
  • Vitamin D analogues: These slow the production of skin cells and reduce inflammation.
  • Coal tar: This reduces scales, itching, and inflammation.

Phototherapy is another treatment for psoriasis. This treatment exposes your skin to ultraviolet light to slow cell growth. Sometimes you take a certain drug beforehand that makes your skin more sensitive to light.

Talk with your doctor

Your doctor will recommend a treatment for your psoriasis. If your psoriasis is moderate to severe and other treatments haven’t helped, your doctor may prescribe an injectable drug like methotrexate or a biologic. Talk with your doctor about the benefits and possible side effects of these drugs. You can use this article to help you ask questions. Don’t be afraid to work closely with your doctor to find a treatment that works for you.

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