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Side Effects

How Pain Medicines Are Given

Pain medicines come in different forms and can be given in several ways. The way you take pain medicine depends on the type of pain, how bad it is, and where it is in your body.

By mouth (orally)

These medicines are either swallowed or put under your tongue or inside your cheek where they are absorbed.  Oral pain medicine can be given as a liquid, pill, capsule, or spray absorbed directly through the lining of the mouth.


Never crush, break, or open pills or capsules. Talk to your doctor if you have trouble swallowing your pain medicines. There are many ways to take them.


Skin patch

 A sticky patch is placed on the skin. It slowly releases medicine through the skin for 2 to 3 days.

Rectal suppositories

 Medicine that is inserted into the rectum and then is absorbed by the body.


Injections can be given several ways:

  • Just under the skin using a short, small needle (a subcutaneous or SC injection)
  • Deeper into a muscle (usually in the arm, leg, or buttocks) using a medium length needle (intramuscular or IM injection). This method is rarely used for pain medicines.
  • Right into a vein through a needle, port, or catheter (intravenous or IV injection).
  • Into the fluid around the spinal cord (intrathecal injection) or into the space around the spinal cord (epidural injection).

Pump or patient-controlled analgesia

A pump is connected to a small tube going into your body. The medicine might go into a vein, just under the skin, or into the area around the spine. When you need pain relief, you press a button on the pump to get a dose of pain medicine. (The pump carefully controls how much you can get at a time and how often, so you can’t get too much.)  

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.

National Cancer Care Center Network (NCCN). Adult Cancer Pain. Version 2.2023. Accessed November 16, 2023 at

National Cancer Institute (NCI). Cancer Pain (PDQ®) – Patient Version. 2023. Accessed November 20, 2023 at

Portenoy RK, Dhingra LK. Overview of cancer pain syndromes. In Abrahm J, ed. UpToDate, 2023. Accessed at Overview of cancer pain syndromes - UpToDate. 

Last Revised: March 29, 2024

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