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How It Works

Interferon can kill viruses and prevent them from reproducing. It also stimulates the body's immune system to fight viruses, including the human papillomavirus (HPV) that causes genital warts.

Interferon is given by injection just under the skin at the base of the wart. A common injection schedule is three injections a week for 3 weeks or two injections a week for 8 weeks, depending on the type of interferon. You are treated in your health professional's office or clinic.

Why It Is Used

Interferon will not be the medicine your health professional recommends first for genital warts. Interferon may be used when other treatments (medicine or surgery) have failed or are not possible.

Interferon should not be used during pregnancy because it may harm the fetus.

How Well It Works

Studies have shown that interferon injected into the base of a wart is an effective treatment.¹

Side Effects

Interferon injected into warts has more flu-like side effects such as:

• Fever and chills.
• Muscle aches.
• Pain at the injection site.
• Hives.
• A temporary decrease in white blood cells, which fight infection in the body.
• A decrease in the blood component that helps blood to clot (platelets).

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Interferon injected into a vein (systemic) has many side effects. But you are less likely to have side effects if the interferon is injected into the wart. It is not known if interferon given in a vein treats genital warts effectively.¹

Research studies are continuing to look at how interferon can be used together with other treatments.

Genital warts may go away on their own. Also, treating genital warts may not cure a human papillomavirus (HPV) infection. The virus may remain in the body in an inactive state after warts are removed. A person treated for genital warts may still be able to spread the infection. Condoms may help reduce the risk of HPV infection.

The benefits and effectiveness of each type of treatment need to be compared with the side effects and cost. Discuss this with your health professional.

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.

Citations

1. Buck HW (2005). Genital warts. Online version of Clinical Evidence (14): 1–13.

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