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How do you use the Plegridy pen and where do you inject?

Medically reviewed by Carmen Pope, BPharm. Last updated on Jan 26, 2024.

Official answer

  • Your doctor or nurse should teach you how to use the Plegridy pen before you attempt to self-administer it.
  • Self-administration is straightforward and most people who need it can be taught how to administer it themselves.
  • The Plegridy pen is injected subcutaneously (which means under the skin) into an area of your stomach, thigh, or the back of your arm
  • You can also choose to get Plegridy administered by intramuscular (IM) injection, but this needs to be done by a healthcare provider.

Plegridy is an interferon beta (peginterferon beta-1a) that is indicated for the treatment of relapsing forms of multiple sclerosis in adults who are 18 to 65 years old. This includes clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease.

Plegridy is administered by subcutaneous (SC) injection under the skin. It may also be administered intramuscularly (IM) by your healthcare provider.

How do you use the Plegridy SC pen?

Your doctor, nurse, or other health care professional should teach you how to use the SC pen before you attempt to self-administer it yourself. Do not remove the cap of the Plegridy pen until you are ready to inject. If you do accidentally remove the cap, do not put it back on as this may cause the pen to lock.

Plegridy pens should be stored in a refrigerator between 36°F and 46°F (2°C to 8°C). If no refrigerator is available, they may be kept out of a refrigerator at room temperature (less than 77°F [25°C]) for up to 30 days; however, they should not be put back in a refrigerator after this time. Discard them instead.

  1. Take your Plegridy pen out of the refrigerator and let it warm up naturally to room temperature for 30 minutes. Do not put it in the microwave or use hot water to heat it.
  2. Wash your hands with soap and water.
  3. Check the injection status on your Plegridy pen. You should see green stripes in the injection status window. Also check the expiry date located on the side of the pen.
  4. Check how the injection fluid looks through the viewing window. It should be clear and colorless. Do not use it if it is cloudy or has particles floating in it. Air bubbles are normal and will not affect your dose.
  5. Choose an injection site and wipe it with an alcohol wipe. Let it dry.
  6. Pull the Plegridy pen cap straight off. You will not see the needle as it is hidden.
  7. Place the pen on your chosen injection site at a 90° angle (straight up and down). Firmly press and hold down the Plegridy pen. This will insert the needle and start the injection. You will hear a clicking sound.
  8. Hold the pen down firmly until the clicking sound stops and you see a green check mark (tick) status where the green stripes used to be). After the clicking has stopped, remove your pen from the injection site. You should see a yellow plunger in the medicine viewing window.
  9. If there is blood at the injection site, hold a gauze over the site to stop the bleeding and wipe away the blood.
  10. Dispose of the used Plegridy pen in an approved sharps disposal container.

Each Plegridy pen is administered just one time only. Discard the empty pen in a sharps bin after use and never share your Plegridy pen with others.

Where do you administer a Plegridy SC pen?

Plegridy SC is administered just under the skin (subcutaneously).

The usual sites for self-administration are your stomach area (but at least 2 inches [5cm] away from your belly button), the back of your upper arm, or your upper thigh.

You should rotate sites for each injection (do not use the same site twice in a row) and you should not inject Plegridy where the skin is bruised, discolored, red, infected, or if there is a rash on the skin.

Plegridy is also available as an intramuscular (IM) injection, that can be administered by a healthcare provider into a muscle. IM administered Plegridy has a lower rate of injection site reactions.

How does Plegridy work?

Interferons are a group of proteins that are produced naturally by the body in response to viral infections.

Experts aren’t sure exactly how Plegridy works for multiple sclerosis but believe it helps control immune system activities, preventing the immune system from attacking the myelin sheath. Plegridy helps to inhibit inflammation that can cause MS flare-ups. Plegridy may also help slow the progression of physical disability associated with Multiple sclerosis (MS) and reduce the number of relapses.


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