Psoriasis Treatment: Medicine that Works throughout the Body

Psoriasis develops when faulty signals in the immune system cause new skin cells to form in days rather than weeks. Because this occurs inside the body, medicine that works inside the body is often needed to treat moderate to severe psoriasis. Your dermatologist may call this medication “systemic medication.” Systemic medication is either swallowed, injected, or infused. While effective, some of these medications can only be used for limited time and may be combined and rotated to minimize side effects and toxicity.

The systemic medications, excluding the biologics, approved by the U.S. Food and Drug (FDA) Administration for the treatment of psoriasis are:

Approved to treat severe psoriasis in adults, acitretin is a retinoid (vitamin A derivative) that patients take orally. Studies show acitretin is effective in treating erythrodermic and pustular types of psoriasis. It is effective in treating psoriasis on the palms of the hands and soles of the feet. Combining acitretin with phototherapy has proven effective, especially in treating severe plaque psoriasis, and allows for lower dosage. Since acitretin does not suppress the immune system, it may be considered for patients with severe psoriasis who are HIV-positive.

Dermatologists must closely monitor their patients taking acitretin as side effects may be experienced. Regular blood tests to check lipid (fat) levels are part of this monitoring. Side effects include raised lipid levels in the blood; severe headache; liver damage; hair loss; thinning of the nails; sticky feeling to the skin; dry skin; bone spurs; and aches in the muscles, joints or bone, especially during exercise.

Oral retinoids, including acitretin, should not be used by women who are pregnant or plan to become pregnant within 3 years of discontinuing therapy due to the possibility of severe birth defects.

How it works: Acitretin normalizes skin cells’ growth, which prevents the rapid growth of and piling up of cells on the skin’s surface.


  • Effective for severe psoriasis

  • Possible treatment for HIV-positive patients

  • May be used with phototherapy to lower the dosage of acitretin


  • Many side effects possible, some significant

  • Patients must be monitored during therapy

  • Cannot be prescribed to women who plan to become pregnant within 3 years

Cyclosporine is a potent immunosuppressive drug that benefits many with severe plaque psoriasis and psoriasis of the nails. It is taken in pill or liquid form. While it proves extremely effective in treating psoriasis, it is generally reserved for patients with severe cases whose condition has not responded to other therapies. Patients who respond typically show rapid improvement. Due to potential side effects, kidney function and blood pressure must be checked before the drug can be prescribed, and these need to be monitored regularly during therapy. Other side effects include increased risk of developing cancers, headache, tingling or burning sensations in the arms or legs, fatigue, abdominal upset, and musculoskeletal or joint pain.

Cyclosporine was first used to prevent rejection in organ-transplant recipients. Its effectiveness in treating psoriasis was discovered when an organ recipient who had psoriasis showed significant clearing after taking cyclosporine. This finding helped confirm that psoriasis is a dysfunction of the immune system.

The FDA recommends that cyclosporine not be used for more than one year. Patients must be carefully monitored, especially with long-term use. To help patients gain relief from the signs and symptoms of psoriasis, dermatologists may rotate cyclosporine with other systemic drugs such as methotrexate.

How it works: Cyclosporine inhibits T cell activity, which decreases the rapid growth of skin cells.


  • Highly effective in severe plaque psoriasis and psoriasis of the nails


  • Possibility of severe side effects, including kidney damage

  • Patient must be carefully monitored during therapy

One of the first chemotherapy drugs, methotrexate has been used for years to treat moderate to severe psoriasis and continues to be one of the most effective therapies for patients with erythrodermic and pustular psoriasis. Since methotrexate has potentially serious side effects, tests to check kidney and liver functions and blood are run before methotrexate is prescribed. If the tests show that the patient is a candidate for methotrexate, the patient must be carefully monitored during therapy. Patients take methotrexate either orally or by injection, usually once a week.

Patients who respond typically see an improvement within 4 to 6 weeks. After the initial clearing, the dose may be reduced or other therapies used to keep the psoriasis under control. Common side effects include nausea, fatigue, and headaches. Long-term side effects include liver damage, and patients must be closely monitored.

Methotrexate is known to cause birth defects, so pregnancy must be avoided while taking this medication. Methotrexate must not be taken during pregnancy or while trying to become pregnant. Due to multiple effects on the tissues, both men and women should stop taking methotrexate for at least 12 weeks before trying to conceive. This medication can be harmful to a nursing infant, so breast-feeding is not recommended during treatment.

Methotrexate also is not recommended for patients who have an active infection, liver disease, or a history of alcohol abuse.

How it works: Methotrexate blocks certain parts of the immune system, which decreases skin cell proliferation (rapid growth and multiplication) and suppresses inflammation.


  • Highly effective in severe psoriasis, especially erythrodermic and pustular psoriasis

  • Highly effective for psoriatic arthritis


  • Potentially serious side effects, including liver damage

  • Patients must be carefully monitored during therapy

Gribetz, C. et al. “Clearing Psoriasis: A New Era of Optimism.” Contemporary Dermatology 2003: Vol. 1, No. 1: 1-8.

All content solely developed by the American Academy of Dermatology


For an overview, visit the AAD pamphlet Psoriasis and Psoriatic Arthritis.


There are different types of psoriasis treatment:

Medicine Applied to the Skin

Lasers and Other Light Therapies


Medicine that Works throughout the Body

Other Medications





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Page last updated 2/17/10

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