• Drugs of choice for severe cancer-related pain. Opioids do not have an analgesic ceiling effect, and therefore, dose can be titrated to achieve maximum pain relief.
• Constipation is an almost universal complication of opioid use, and all patients should receive prophylactic stimulant laxative therapy unless otherwise contraindicated (e.g., chronic diarrhea).
• Sedation is a frequent side effect of initial opioid use; however, tolerance develops soon in most patients.
• Respiratory depression rarely occurs except in opioid naive patients and those with significant pulmonary disease.
• True hypersensitivIty reactions to opioids are rare. If patients experience such reactions, it is often possible to administer an opioid from another subclass safely.

  The subclasses are: Phenanthrene derivatives: morphine, codeine, hydromorphone, oxycodone. Phenylpiperidine derivatives: meperidine, fentanyl. Diphenylheptane derivatives: methadone.

• The use of opioid antagonists such as naloxone causes immediate reversal of all opioid effects including analgesia. Such reversal results in acute withdrawal, which may be complicated by excruciating pain and seizure. Therefore, opioid antagonists are never recommended to reverse non-life-threatening effects such as confusion or sedation. If used to reverse life-threatening respiratory depression or hypotension, they should be administered cautiously.
• Oral is the preferred route of administration, except for patients who cannot take or tolerate oral medications. When given in appropriate doses, oral opioids are as efficacious as parenteral opioids.
• Rectal and transdermal dosage forms are available and effective, noninvasive alternatives when oral medication is not possible.

  Rectal suppositories are contraindicated if lesions of the rectum or anus are present.

• Repetitive intramuscular and subcutaneous (SC) injections should be avoided because they can be painful and absorption is inconsistent.
• Intravenous (IV) administration may be used when less invasive routes are ineffective or unavailable. IV opioids may be given by bolus or continuous administration (including PCA); however, they require careful monitoring during titration. Inappropriately excessive dosing may carry significant risk of respiratory depression, especially in opioid-naive patients and those with underlying pulmonary pathology.

  Rectal suppositories are contraindicated if lesions of the Low-volume continuous SC infusion may also be used if venous access is not established.

• IV or SC PCA provides a good steady level of analgesia. It is widely accepted by patients but requires special infusion pumps and staff education. May not be appropriate for patients with altered mental status or agitation.
• Epidural and intrathecal opioids provide good analgesia, when suitable. These routes have significant risk of respiratory depression, which may be delayed, necessitating careful monitoring. Special preservative-free drug formulations are necessary for these routes of administration.

Related Chunks

Intravenous or Subcutaneous

Intraspinal

Management of Side Effects

Sedation

Respiratory Depression

Intraspinal drug delivery systems

Drugs and routes of administration not recommended for treatment of cancer pain

Index