What happens if an intramuscular injection is given subcutaneously

Overview

A subcutaneous injection is a method of administering medication. Subcutaneous means under the skin.

In this type of injection, a short needle is used to inject a drug into the tissue layer between the skin and the muscle. Medication given this way is usually absorbed more slowly than if injected into a vein, sometimes over a period of 24 hours.

This type of injection is used when other methods of administration might be less effective. For example, some medications can’t be given by mouth because acid and enzymes in the stomach would destroy them.

Other methods, like intravenous injection, can be difficult and costly. For small amounts of delicate drugs, a subcutaneous injection can be a useful, safe, and convenient method of getting a medication into your body.

Medications administered by subcutaneous injection include drugs that can be given in small volumes (usually less than 1 mL but up to 2 mL is safe). Insulin and some hormones are commonly administered as subcutaneous injections.

Other drugs that need to be given very quickly can also be administered via subcutaneous injection. Epinephrine comes in an automated injector form, called an EpiPen, that’s used to quickly treat severe allergic reactions. While it’s intended to be given intramuscularly, epinephrine will also work if given subcutaneously.

Some pain medications like morphine and hydromorphone (Dilaudid) can be given this way as well. Drugs that prevent nausea and vomiting like metoclopramide (Reglan) or dexamethasone (DexPak) can also be given via subcutaneous injection.

Some vaccines and allergy shots are administered as a subcutaneous injection. Many other vaccines are administered as an intramuscular injection — into muscle tissue rather than under the skin.

The location of injection is important for subcutaneous injections. The drug needs to be injected into the fatty tissue just below the skin. Some areas of the body have a more easily accessible layer of tissue, where a needle injected under the skin will not hit muscle, bone, or blood vessels.

The most common injection sites are:

• Abdomen: at or under the level of the belly button, about two inches away from the navel
• Arm: back or side of the upper arm
• Thigh: front of the thigh

Equipment used for subcutaneous injections includes:

1. Medication: Vials of liquid medication can be single-use or multiuse. Vials can also be filled with a powder to which liquid needs to be added.
2. Syringes: The needles are short, at 5/8 inches long. The thickness of the needle is usually 25 or 27 gauge. There may be other options for doses more than 1 mL or for children or people with visual impairments.
3. Auto-injector pen: Some medications are available in a “pen” with a short single-use needle screwed onto the end of a pen-shaped, multiuse vial. The amount of medication needed is then dialed in at the end. As mentioned earlier, emergency medications like epinephrine can also come in this form.

1. Wash your hands. Wash your hands with soap and warm water to prevent potential infection. Be sure to thoroughly scrub between fingers, on the backs of hands, and under fingernails. The Centers for Disease Control and Prevention (CDC) recommends lathering for 20 seconds — the time it takes to sing “Happy Birthday” twice.

2. Gather supplies. Assemble the following supplies:

• needle and syringe with medication or auto-injector pen
• alcohol pads
• gauze
• puncture-resistant container to discard the used needles and syringe (typically a red, plastic “sharp’s container”)
• bandages

3. Clean and inspect the injection site. Before injecting medication, inspect your skin to make sure there’s no bruising, burns, swelling, hardness, or irritation in the area. Alternate injection sites to prevent damage to an area with repeated injections. Then you should clean the skin with an alcohol swab. Let the alcohol dry thoroughly before doing the injection.

4. Prepare the syringe with medication. Before withdrawing medication from a vial and injecting yourself or someone else, make sure you’re using the correct medication, at the correct dose, at the correct time, and in the right manner. Use a new needle and syringe with every injection.

Preparing a syringe:

Remove the cap from the vial. If the vial is multidose, make a note about when the vial was first opened. The rubber stopper should be cleaned with an alcohol swab.

Draw air into the syringe. Draw back the plunger to fill the syringe with air up to the dose that you’ll be injecting. This is done because the vial is a vacuum, and you need to add an equal amount of air to regulate the pressure. This makes it easier to draw the medication into the syringe. Don’t worry, though — if you forget this step, you can still get the medication out of the vial.

Insert air into the vial. Remove the cap from the needle and push the needle through the rubber stopper at the top of the vial. Inject all the air into the vial. Be careful to not touch the needle to keep it clean.

Withdraw the medication. Turn the vial and syringe upside down so the needle points upward. Then pull back on the plunger to withdraw the correct amount of medication.

Remove any air bubbles. Tap the syringe to push any bubbles to the top and gently depress the plunger to push the air bubbles out.

Preparing an auto-injector:

• If you’re using a pen delivery system, attach the needle to the pen.
• The first time you use the pen, you’ll need to prime it to push out extra air in the delivery system.
• Dial a small dose (usually 2 units or 0.02 mL, or as indicated by the package instructions) and push the button to expel the primer.
• Dial the correct dose and prepare for your injection.

5. Inject the medication.

Pinch your skin. Take a big pinch of skin between your thumb and index finger and hold it. (Your thumb and forefinger should be about an inch and a half apart.) This pulls the fatty tissue away from the muscle and makes the injection easier.

Inject the needle. Inject the needle into the pinched skin at a 90-degree angle. You should do this quickly, but without great force. If you have very little fat on your body, you may need to inject the needle at a 45-degree angle to the skin.

Insert the medication. Slowly push the plunger to inject the medication. You should inject the entire amount of medication.

Withdraw the needle. Let go of the pinched skin and withdraw the needle. Discard the used needle in a puncture-resistant sharp’s container.

Apply pressure to the site. Use gauze to apply light pressure to the injection site. If there’s any bleeding, it should be very minor. You may notice a little bruising later. This is common and nothing to be concerned about.

If you’ll be doing this type of injection for more than one dose or for multiple days, you’ll need to rotate the injection sites. This means that you shouldn’t inject medicine into the same spot twice in a row.

For example, if you injected medicine into your left thigh this morning, use your right thigh this afternoon. Using the same injection site over and over again can cause discomfort and even tissue damage.

As with any injection procedure, infection at the site of injection is a possibility. Signs of infection at the injection site include:

• severe pain
• redness
• swelling
• warmth or drainage

These symptoms should be reported to your physician immediately.

A subcutaneous injection or shot is one into the fatty tissues just beneath the skin. These injections are shallower than those injected into muscle tissues.

Providers often use subcutaneous injections for medications that must be absorbed into the bloodstream slowly and steadily, such as insulin.

Subcutaneous injections are usually safe and do not require as much force as intramuscular injections into the muscle tissues.

Subcutaneous injection can be used to give many types of medications for various medical conditions.

There are fewer blood vessels in the fatty layer of connective tissue just beneath the skin than the muscle tissue.

Having fewer blood vessels means that medication injected subcutaneously is absorbed more slowly.

This makes it an ideal way to administer medications that the body must use slowly over time, such as insulin for the treatment of diabetes.

Medications given this way include:

Many drugs that must be taken daily, or injected at home, are designed for subcutaneous injection.

To give a subcutaneous injection, people should follow these steps:

1. Choose a fatty area of the body, such as the abdomen, back of the arm, or thigh: If you are giving several injections or have to do daily injections, rotate the sites to allow each area to heal between injections
2. Wash hands before cleaning the area with an alcohol pad: Wait for the area to completely dry before the next step.
3. Take the cap off the needle: Draw medication into the syringe, according to the directions on the vial. This usually means turning the vial upside down then pulling the plunger back to suck in the medication. Tap the syringe to get rid of air bubbles.
4. Pinch a fold of skin: Pinch the fatty area about 2-inches thick in between the thumb and a finger.
5. While holding the needle like a dart, slide it into the skin at an angle of 90 degrees: Needles used for subcutaneous injection are usually short and small and should go all the way into the skin.
6. Push the plunger all the way down quickly: Do not push forcefully.
7. Cover the needle: Dispose of the needle in a needle-safe container.

The best location for a subcutaneous injection depends on a person’s pain sensitivity and where they have some subcutaneous fat.

A few commonly chosen locations include:

• the backs or sides of the arms
• the fatty part of the stomach
• the front of the thighs
• the top of the buttocks, where there is more fat than muscle

Some subcutaneous injections come in the form of an auto-injector. An auto-injector is a self-contained device that does not require drawing the medication up first. People can follow the instructions on the package if they are using an auto-injector.

The needle used for subcutaneous injection is usually small and short and causes minimal discomfort.

The amount of pain a person feels depends on factors such as where they or another person administer the injection, their pain tolerance, and skin sensitivity.

The pain also depends on the medication they are injecting, as it may cause stinging, burning, or aching during or following the injection.

Subcutaneous injections tend to be less painful than intramuscular injections because the needles are smaller and do not have to push through as much tissue.

Children and people who fear needles may still have issues with these injections that can cause anxiety.

A few strategies can help with the pain and anxiety:

• Use a numbing cream on the area a few minutes before the injection. Many doctor’s offices have these available.
• Try putting ice on the area to numb it a few minutes before the injection.
• Allow nursing babies to breast-feed during injections.
• If a child needs restraining, hold them in a hugging way rather than holding them down or yelling at them.
• Give a baby a pacifier before an injection.
• Cough or blow before or during the injection.
• Take five deep breaths or encourage children to breathe deeply before the shot.
• Distract yourself with a movie, video game, or conversation. Sometimes looking at the shot makes it hurt more.

The most common complication of a subcutaneous injection is pain near the injection site for 1 to 2 days afterward.

Pain near the injection site can happen when inserting the needle at the wrong angle, or when it moves slightly during the injection. Some medications can cause a bruise or irritation at the injection site.

Other complications are much less frequent and include:

• Infection: Any puncture in the skin can allow bacteria to enter and cause an infection. Properly cleaning the area and always using a clean needle can reduce the risk of infection.
• Contaminated needle: Reusing needles or sharing needles can spread diseases from one person to another. Always dispose of used needles in an appropriate container.
• Injecting medication into a blood vessel: A person may have hit a blood vessel if there is blood in the syringe. Injecting medication into a blood vessel can change the way the drug is absorbed.

Injecting a blood vessel can cause serious complications in rare cases. However, the likelihood of hitting a blood vessel in the subcutaneous fat is extremely rare. More than likely, if there is blood, it is from slight bleeding after the injection.

A subcutaneous injection is a minor and very safe medical procedure when done correctly.

Mastering the technique of injecting at home can take some practice. People should ask for help from a medical provider and not shy away from asking questions about the benefits of treatment or how best to minimize pain.