When ‘type’ of injection is mentioned, ‘type’ usually refers to the body tissue or path by which a medication is injected. The ‘type’ of injection describes its route of administration.

The four most frequently used types of injection are:

1. Intravenous (IV) injections. An IV injection is the fastest way to inject a medication and involves using a syringe to inject a medication directly into a vein. When people talk about receiving medication via IV, however, they are usually talking about an IV infusion or drip, which involves using a pump or gravity to infuse the medication into a vein, rather than a syringe. IV infusions allow a set amount of medication to be administered in a controlled manner over a period of time.
2. Intramuscular (IM) injections. IM injections are given deep into a muscle where the medication is then absorbed quickly by surrounding blood vessels.
3. Subcutaneous (SC) injections. SC injections are injected into the innermost layer of the skin called the subcutis or hypodermis, which is made up of a network of fat and collagen cells. SC injections are also known as ‘subcut’ or ‘SQ’ injections. These injections work more slowly than an IV or IM injection because the area does not have such a rich blood supply.
4. Intradermal (ID) injections. ID injections are given directly into the middle layer of the skin called the dermis. This type of injection is absorbed more slowly again than IV, IM or SC injections.

Some medications can be injected in more than one way. EpiPens (epinephrine) used to treat severe allergic reactions can be given via IM or SC injection, for example. Epogen (epoetin alfa) on the other hand, which is used to treat anemia, can be given by IV or SC injection. Depending on the condition you are treating, Botox may be administered as an IM, ID or intradetrusor injection.

Other types of injections include:

• Intra-articular injections – into a joint
• Peri-articular injections – into the soft tissue close to a joint
• Intraosseous injections – into the bone marrow
• Intradetrusor injections – into the muscle in the wall of the bladder
• Intraocular (intravitreal) injection – into the jelly-like fluid in the eye
• Intraperitoneal injections – given within the abdominal cavity
• Intracardiac injections – into the muscle or ventricles of the heart
• Intracavernous injections – into the base of the penis