Types of Opioids
There are several types of opioids. Morphine is the most commonly used opioid in cancer pain management. Other commonly used opioids include hydromorphone, oxycodone, oxymorphone, methadone, fentanyl, meperidine (Demerol), tapentadol, and tramadol. The availability of several different opioids allows the doctor flexibility in prescribing a medication regimen that will meet individual patient needs.
Guidelines for Giving Opioids
Most patients with cancer pain will need to receive pain medication on a fixed schedule to manage the pain and prevent it from getting worse. The doctor will prescribe a dose of the opioid medication that can be taken as needed along with the regular fixed-schedule opioid to control pain that occurs between the scheduled doses. The amount of time between doses depends on which opioid the doctor prescribes. The correct dose is the amount of opioid that controls pain with the fewest side effects. The goal is to achieve a good balance between pain relief and side effects by gradually adjusting the dose. If opioid tolerance does occur, it can be overcome by increasing the dose or changing to another opioid, especially if higher doses are needed.
Occasionally, doses may need to be decreased or stopped. This may occur when patients become pain free because of cancer treatments such as nerve blocks or radiation therapy. The doctor may also decrease the dose when the patient experiences opioid-related sedation along with good pain control, or when kidney failure develops or worsens.
Medications for pain may be given in several ways. When the patient has a working stomach and intestines, the preferred method is by mouth, since medications given orally are convenient and usually inexpensive. When patients cannot take medications by mouth, other less invasive methods may be used, such as rectally, through medication patches placed on the skin, or in the form of a nasal spray. Intravenous methods are used only when simpler, less demanding, and less costly methods are inappropriate, ineffective, or unacceptable to the patient. Patient-controlled analgesia (PCA) pumps may be used to determine the opioid dose when starting opioid therapy. Once the pain is controlled, the doctor may prescribe regular opioid doses based on the amount the patient required when using the PCA pump. Intraspinal administration of opioids combined with a local anesthetic may be helpful for some patients who have uncontrollable pain.