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 your knees, elbows, scalp, or lower back.
Psoriasis is an autoimmune disease, which means it stems from a problem with the immune system. With psoriasis, a faulty immune response causes your body to make more skin cells than needed. It then causes those extra cells to build up. Fortunately, 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. Injectable drugs such as methotrexate (Otrexup, Rasuvo, and Trexall) and biologics can help clear up plaques and reduce inflammation. Here’s what you need to know about injections for psoriasis.
For moderate to severe psoriasis that covers more than 5 to 10 percent of the body or is disabling, 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.
These drugs can also clear plaques and reduce joint damage in people with psoriatic arthritis. This is a condition related to psoriasis.
Biologics are some of the most effective psoriasis treatments. They work by blocking cytokines, which are substances that the immune system releases. Cytokines bring on the cell growth, overproduction, and inflammation in psoriasis.
Because biologic drugs target your immune system, they can increase your risk of infections. These drugs might increase cancer risk too, but this hasn’t been proven. Side effects from biologic drugs can include:
- respiratory infections
- stomach pain, nausea, or vomiting
- 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.
These drugs block a type of cytokine called TNF-alpha. Examples include:
- adalimumab (Humira)
- certolizumab pegol (Cimzia)
- etanercept (Enbrel, Erelzi)
- golimumab (Simponi, Simponi Aria)
- infliximab (Remicade, Inflectra, Renflexis)
These drugs block various forms of interleukin, which is another type of cytokine. Examples of these drugs include:
- brodalumab (Siliq)
- guselkumab (Tremfya)
- ixekizumab (Taltz)
- secukinumab (Cosentyx)
- ustekinumab (Stelara)
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 to treat psoriasis by targeting rapidly growing cells, as 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 comes as an oral tablet or a solution that you inject. The injection can be under your skin or in a vein or muscle.
You take methotrexate once per week, or one dose every 12 hours for a total of three doses per week. It typically clears plaques within three to six weeks after you start taking it.
Methotrexate can cause the following side effects:
- trouble sleeping
- mouth sores
- hair loss
- skin sensitivity to light
Taking folic acid can reduce some of these side effects. Your doctor can tell you how much folic acid you should 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 pregnancy.
The cost of injections depends on the type of drug used.
Costs of biologics and methotrexate
Biologic drugs are effective at treating psoriasis, but they come at a steep cost. According to a 2014 study, a year of treatment with adalimumab (Humira) can cost more than $39,000. Etanercept (Enbrel) can cost more than $46,000 per year, and ustekinumab (Stelara) can cost over $53,000 each year.
On the other hand, methotrexate costs only 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 such as 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.
Costs of biosimilars
Currently, there are no generic versions of biologic drugs available. Generic drugs usually cost less than brand-name versions. However, the U.S. Food and Drug Administration (FDA) has approved two biosimilar drugs based on infliximab (Remicade) called Inflectra and Renflexis. They’ve also approved a biosimilar based on etanercept (Enbrel) called Erelzi.
Unlike generic drugs, biosimilars are not exact replicas of biologic drugs. Also, they can’t be automatically substituted for the biologic drug. But like generics, biosimilars work in the same way as the biologic they’re based on, and they’re less expensive than that biologic. If you’re interested in trying a biosimilar drug, talk to your doctor.
Doctors typically prescribe injectable treatments for moderate to severe psoriasis or psoriasis that’s disabling. One other option is apremilast (Otezla), which comes as a pill. But if you can’t take any of these medications or they don’t work for you, there are other drugs that suppress the immune system and may help. Talk to your doctor about all possible options.
For mild to moderate psoriasis, doctors often suggest topical drugs first. Topical drugs are applied to 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.
Your doctor will recommend a treatment for your psoriasis. If your psoriasis is moderate to severe and other treatments haven’t helped, they may prescribe an injectable drug such as 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. Work closely with your doctor to find a treatment that works for you.