Patient education: How to use a pen injector (The Basics)

What is a pen injector? — This is a device to give medicines as an "injection," or shot.

A pen injector looks like a writing pen. It is reusable and has a cartridge that is filled with medicine. You place a new needle on the pen for each shot. You turn a knob or dial to choose the amount of medicine for each shot. You insert the needle into your skin and push a button to inject the medicine.

Some medicines given by injection come in other devices. These include a needle and syringe or an "autoinjector" that contains 1 dose. An autoinjector might look similar to a pen injector, but the steps for how to use them are different.

This information is about pen injectors only. Make sure that you know which type of injection device you have, and read the instructions that come with it. Check with your doctor, nurse, or pharmacist if you have any questions about your device or how to use it.

What medicines can be given with a pen injector? — Many different medicines can be given with a pen injector. Examples include medicines to treat conditions like:

●Obesity

●Diabetes

●Infertility

●Multiple sclerosis

●Osteoporosis

●Growth hormone deficiency

●Parkinson disease

What are the parts of a pen injector? — There are many types of pen injectors. Look at the instructions that come with your pen. Most reusable pen injectors have these parts (figure 1):

●A disposable pen needle with a large outer cap and a small inner cap. (Pen needles come in different sizes.) You use a new pen needle for each injection. If needles are not included with your pen injector, your doctor will prescribe them separately.

●A cartridge filled with medicine with a rubber stopper at the end

●A pen cap to cover the rubber stopper between uses

●A window or area to view the dose

●A dial or knob to select the dose

●A button to give the shot

Some pen injectors can be refilled and reused. To do this, place a new cartridge of medicine in the pen.

Where do I inject the medicine? — This depends on your medicine and the type of injection device you have. In most cases, you can give the shot in your belly, upper arms, or thighs (figure 2). Change where you give yourself the shot each time. This helps avoid soreness, skin thickening, and fat deposits.

Do not inject medicine into moles, scars, or stretch marks. Avoid areas that are open, bruised, red, hard, or tender. Do not inject medicine within 2 inches of your belly button.

How do I use a pen injector? — Ask your doctor, nurse, or pharmacist if you have any questions about your medicine. In general, these are the steps to using a pen injector.

●Check the medicine:

•Read the label to make sure that you have the correct medicine and the correct dose. Make sure that you are using the correct concentration.

•Check that the medicine is not expired.

•Know how long you are supposed to use the medicine and how to use it.

•Know how to store the medicine. Some medicines must be stored in the refrigerator until the first use. Some medicines are always stored in the refrigerator.

●Wash your hands with warm, soapy water before you begin and after you are finished.

●Gather your supplies. This includes the pen injector, cartridge of medicine, pen needle, and alcohol wipes. Many pen injectors come prefilled with the cartridge of medicine. If your medicine is stored in a refrigerator, you might need to let the cartridge or pen sit at room temperature for 15 to 45 minutes before using it.

●Get the pen injector ready:

•Remove the pen cap, and save it. If needed, put the medicine cartridge in the pen. To do this, follow the instructions included with the pen injector.

•Clean the rubber stopper with an alcohol swab.

•Pull the paper tab back on a new pen needle, and attach it over the rubber stopper on the pen. Push it straight on the pen with the needle cap on. Turn it to the right until it won't turn anymore. The needle should be on straight.

•Take off the outer needle cap. Do not throw it away. You might need it to re-cap the needle later.

•Take off the small inner cap that covers the pen needle. If you do not take off the small inner cap, you won't be injecting the medicine into your body.

•For some medicines, you need to get the air out of the pen needle. This is sometimes called "priming the pen," a "flow check," or an "air shot." You might need to do this before each injection or only before using the pen or cartridge for the first time. Check with your doctor, nurse, or pharmacist if you are not sure if you need to do this.

If you need to get the air out of the needle (figure 3):

-Turn the dial or knob to set the dose according to the device instructions. Some pens have a "priming" or "flow check" symbol for this setting. Point the pen with the needle straight up in the air. You might be told to tap lightly on the cartridge to move any air bubbles to the top. Press the injection button.

-You should see a drop of medicine at the tip of the needle. Repeat the above step if you don't see the drop.

-The number in the viewing area should reset or return to "0." This tells you that the priming dose of medicine has been pushed out of the pen.

•Turn the dial or knob, and set the number to the dose of medicine you need (figure 1). Do not prepare the dose by counting the clicks. Doing this could lead to giving the wrong dose.

•Look at the viewing area to make sure that the dose is correct.

●Give the shot (figure 4):

•Clean the skin where you plan to give the shot with an alcohol wipe. Let the skin dry fully. The alcohol helps to prevent infection.

•In some cases, you need to pinch the skin where the medicine is injected, especially if you are thin. This keeps the medicine from going into your muscle, where it is more slowly absorbed. To do this, pinch 1 to 2 inches (2.5 to 5 cm) of skin between your fingers and thumb on 1 hand. Make sure that you know whether or not you need to pinch the skin.

•Grip the pen in your fist with your thumb on the injection button. Insert the pen needle straight into your skin. Children and people with less fatty tissue might need to inject the medicine at a 45 degree angle.

•Use your thumb to press the button all the way down until it stops. Hold the button down and keep the needle in the skin for as long as it says in the instructions for your device. This is usually 5 to 10 seconds.

•Release the button. Let go of the skin, and pull the needle straight out. If you see blood or clear fluid when you remove the needle, press on the area for about 5 seconds. Do not rub.

•Carefully remove the needle from the pen, and throw it away in a "sharps container." This is a special container made of thick plastic. You might be told to put the outer needle cap back on the needle before removing it. Check with your doctor, nurse, or pharmacist if you are not sure how to remove the needle.

•Replace the pen cap. Do not store the pen injector with a needle attached to it. This could let medicine leak out or air enter the cartridge.

What are the risks of using a pen injector? — Your doctor, nurse, or pharmacist will talk to you about all of the possible risks, and answer your questions. Possible risks include:

●Pain

●Infection

●Not getting the correct dose of medicine

What else should I know?

●If you have trouble seeing or hearing, you might need help to use your injection device.

●Use a new needle each time you give yourself medicine. Do not share your pen injector with other people, even if the needle has been changed.

●When using a pen injector, always remove the inner needle cap before giving the shot. If you forget, the medicine will not be injected into your body.

●Some types of medicine are clear and colorless or clear, pale yellow in color. Others are cloudy. Make sure that you know what your medicine should look like before using it. If your medicine does not look the way it should, do not use it.

●Keep the needle in your skin for the full time the instructions say. If the needle "leaks" after giving the injection, you might be pulling it out too soon. This could mean that you are not getting the full dose of medicine.

●If you set the wrong dose, follow the instructions included with your pen to correct it. Sometimes, you can turn the knob to the correct dose. Other times, you must follow certain steps to change the dose. Never turn the dial or knob to change the dose with the pen needle in your skin. You could receive the wrong dose.

●Do not move medicine from a pen cartridge to a syringe or vial.

●Know how long your medicine can be used for. Some pen injectors can only be used for a certain amount of time after first use, like 30 days, even if there is still medicine left.

●Know how to throw away your pen needles and pen injector. You should usually use a sharps container. If you don't have one, you can use a heavy-duty plastic household container with a tight-fitting lid, such as a laundry detergent container, instead. Always follow local rules for disposing of the sharps container when it is full.

●If you do not have enough medicine left in your pen for a full dose, do not split the dose between 2 pens or cartridges unless your doctor, nurse, or pharmacist tells you to.

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