Opioid Analgesics

 

Medication Names:

Short Acting: Propoxyphene, Codeine, Hydrocodone, Oxycodone, Morphine, Hydromorphone, Fentanyl* , Pentazocine*, Buprenophene*, Butorphanol*

Long Acting: Slow Release Morphine, Slow Release Oxycodone, Methadone, Fentanyl Skin Patch, Levorphanol**

*These should not be used routinely, as short acting Fentanyl is usually restricted for breakthrough pain for terminal patients and Pentazocine, Buprenophene and Butorphanol are mixed agonists and antagonists, causing significant problems with withdrawal with other opioids. Pentazocine has much more frequent psychotomimetic side effects.

**Levorphanol has run out of production for several months on four separate occasions in 1998 to 2001. This has caused serious hardship for patient's who have been taking this medications, especially those who did not tolerate other opioids well. We cannot recommend using this medication unless the pharmaceutical companies manufacturing it can guarantee a more reliable supply. For patients who selectively respond well to this medication and no other long acting opioids, a compounding pharmacist can make oral capsules.

On Label Use:

Analgesia

Pain Use:

Effective for all types of pain, but not as effective for neuropathic pain, except at higher doses. NMDA receptor stimulation causes wind-up pain and increased tolerance to opioids

Therapeutic Benefit:

These medications decrease acute and chronic pain and can help prevent acute pain from becoming chronic pain. For cases of chronic intractable pain it is best to use the long acting opioids.

Dose Range and Titration:

Combination pills with Acetaminophen, Ibuprofen, Aspirin are limited by these additives and their total daily safe dose. There are no upper limits in treating chronic pain with other opioids, but doses must be titrated versus side effects and brought up slowly. People can overdose and die on these medications, especially if they are relatively opioid naive.

Titrate up q week to two weeks, making sure that length of dose remains efficacious (MS Contin, no more than q 12 h, Methadone no greater than q 8 h) to effective pain relief, or intolerable side effects.

Of special note, MS Contin and other wax based slow release morphine pills are not AB equivalent with Oramorph a methylcellulose based slow release morphine. Oramorph should not be substituted for waxed based products as generics. The risk of variable MS blood levels with this substitution is quite high.

Side Effects:

Dry mouth, blurred vision, drowsiness, constipation, urinary retention, forgetfulness, confusion,excessive perspiration, peripheral vasodilation, peripheral edema, depressed testosterone levels, and depression are among the more common side effects. Respiratory depression is less common, but quite serious and needs to be taken seriously. Euphoria is a side effect that makes these medications high risk for abuse, by drug addicts. The rate of addiction in patients without a history of addictive behavior is small. Physiologic dependency develops with regular use. Overdose can cause respiratory failure, obtundation, circulatory collapse and death.

Despite this significant list, side effects with these medications are usually manageable and are often time limited.

Drug Interactions:

Problems are less with drug interactions than with toxicity from combination medications containing Acetaminophen, Aspirin, and Ibuprofen. Additive problems of drowsiness, forgetfulness and confusion may occur with other CNS active medications.

Methadone and Amitriptyline should not be used together, due to potential caardiac arrythmia problems.

Dependency or Abstinence Syndrome:

This is a significant issue with these medications. Even after a few weeks of regular use, these medications should be tapered off and not stopped abruptly. The first symptom of abstinence is increased pain. The next symptoms are goosebumps, chills, nausea, diarrhea, confusion, hallucinations and general feelings of flu-like symptoms. This can run from mild to severe and is generally not life threatening.

Dependency problems are a major issue, hence the schedule 2 nature of these medications. On the other hand these are the most useful medications in treating acute and chronic pain and as such should not be avoided because of fear of addiction in ones patients. If a physicians feel that their patient is an addict, but needs opioids, they should enlist the help of an Addictionologist in treating this group of patients. For other patients, physiologic dependency will develop with regular use of opioids, but this is easily managed by the treating physician.

Opioid informed consent forms should be instituted with all patients on long term opioid treatment. There is an excellent model on the American Academy of Pain Medicine Website.



 

 

 

Bay Area Pain Medical Associates provides the information as a guideline for physicians interested in up to date knowledge about the treatment of pain in their patients. We provide this as a public service without endorsing any specific treatment. Much of the medication used in managing pain is for "off label" use. Physicians using these medication are responsible for researching their efficacy, side effects, therapeutic benefits, interactions, titration and cessation, before deciding whether to use them in their practice. While we have provided information on these subjects, we do not feel this should serve as a substitute for looking up medications in standard texts and resources. When medications are left out of dosing, titration, drug interaction and side effect categories, it is because we do not think they should be used by anyone except for pain specialists.