Knee and Hip Replacement Pain: A New Approach to Pain Management

Patients undergoing knee or hip replacements recover more quickly when treated with targeted pain-blocking medications that may eliminate the need for general anesthesia during surgery and intravenous narcotics drugs after surgery.

A decade ago, patients undergoing hip or knee replacements were almost exclusively given general anesthesia during surgery and intravenous narcotic pain medications afterward. This approach works for most people and still is commonly practiced. But both general anesthesia and intravenous narcotic drugs can cause nausea, vomiting, grogginess, decreased bowel function and other side effects.

In the early 2000s, Mayo Clinic anesthesiologists began developing new anesthesia protocols for joint replacement surgery that used known anesthetic and pain relief techniques in new combinations. Their goal was to eliminate the need for general anesthesia and intravenous narcotics and the resulting side effects.

The new procedures may vary but typically involve:

A choice: Even with the new protocols, patients may choose regional anesthesia, where the lower half of the body is numbed, or general anesthesia.

Oral pain medications early on: A combination of oral narcotic pain medications are given prior to surgery. Oral narcotics have fewer side effects than narcotics given intravenously. This technique is helpful for recovery whether general or regional anesthesia is used.

Sedation: Sedative drugs given before surgery help patients using regional anesthesia nap during the procedure, but not lose consciousness.

Nerve blocks: Through a catheter, a continuous infusion of numbing medicine is pumped near the surgery site for 48 hours. Nerve blocks are performed in conjunction with general or regional anesthesia.

Oral pain medications after surgery: For more than 95 percent of patients, pain that occurs after the nerve blocks are removed can be managed with oral pain medications such as acetaminophen (Tylenol, others), tramadol (Ultram, others) or oxycodone. Intravenous narcotic medications are used as a last resort.

Patients who receive regional anesthesia report significantly less pain after surgery than those receiving general anesthesia and intravenous narcotics. These patients are out of bed sooner, begin physical therapy sooner and leave the hospital one to two days before patients who were given general anesthesia and intravenous narcotics. With the newer protocols, patients may still experience typical side effects including nausea and vomiting, but to a lesser degree than with the older anesthesia methods.

Another benefit is that regional anesthesia protocols make surgery an option for older adults with more complicated conditions. A decade ago, older adults often were not considered candidates for surgery because they would have fared poorly with older anesthesia techniques.

Doctors report few downsides to these newer pain management approaches. Nerve injury is a rare potential complication. For most people, the regional anesthesia protocols are a change for the better, resulting in less pain, fewer complications and a quicker recovery.

Source: Mayo Clinic (2/10/2010)

One Quarter of All Americans Experience Daily Pain

More than a quarter of the entire population in the United States experiences some form of pain every day. Americans spent between $2 and $6 billion on non prescription painkillers in 2007, while the cost of productivity loss attributable to pain-related conditions is estimated at $60 billion a year.

"Although much is known about the pain experienced by those with chronic illnesses, until now relatively little was known about pain in the entire U.S. population," says Arthur A. Stone, Ph.D., a Professor in the Department of Psychiatry and Behavioral Science at Stony Brook University.

"Our assessment approach allowed us to get accurate information about pain at several carefully selected times from the previous day," explains Dr. Stone, which enabled the researchers to address several new questions about pain, daily activities, and respondents’ personal characteristics.

Ten thousand people were contacted via random-digit dialing, and a total of 3,982 people were actually interviewed. To make the study results representative of the U.S. population, the data were adjusted with sample weights developed by the Gallup Organization. 29% of men and 27% of women said they experienced pain at sampled times.

The researchers also found a correlation between pain and lower income and less education: "Those with lower income or less education spent a higher proportion of time in pain and reported higher average pain than did those with higher income or more education," they wrote.

Additionally, the report found that the average pain rating increased with age, although it reached a plateau between ages of about 45 years and 75 years, with little difference between men and women.

According to Dr. Stone, "The study results expand our understanding of pain in the United States and supplement more traditional assessment approaches with a very detailed perspective on the pain people experience on a daily basis. This suggests new avenues of research that may ultimately lead to improved treatment of pain."

Study authors: Arthur A. Stone, Ph.D., Distinguished Professor and Vice Chair, Department of Psychiatry and Behavioral Science at Stony Brook University, and Alan Krueger, Ph.D., Professor, Department of Economics and the Woodrow Wilson School at Princeton University

Source: The Lancet, May 3, 2008

Lidocaine Derivative (QX-314) with Capasicin Key to Pain-Specific Local Anesthesia Technique

Researchers from Massachusetts General Hospital and Harvard Medical School have found a way to target only pain-sensing neurons when injecting a local anesthetic. The technique blocks pain without affecting motor function or sensitivity to non-pain stimulus.

While current local and general anesthetics work well for controlling pain, since they work by interfering with the excitability of all neurons and not just pain-sensing neurons, they produce dramatic side effects—loss of consciousness for general anesthetics, and loss of motor function for local anesthetics.

The experimental results were achieved in rats by combining a normally inactive lidocaine derivative (QX-314) with capasicin, the "hot" ingredient in chili peppers.

According to the researchers, the results of their new technique were achieved by taking advantage of a membrane-spanning protein called TRPV1, which is unique to pain-sensing neurons. TRPV1 forms a large channel, where molecules can enter and exit the cell. But a "gate" typically blocks this opening. In this case, that gate is opened when the cells are exposed to the heat of the capsaicin. Non-pain sensing neurons are unaffected because they do not possess TRPV1.

The lidocaine derivative QX-314 is not used clinically because it can’t penetrate cell membranes to block the excitability of the cell, so it typically remains outside the neurons. In this case, that property is a benefit to the new pain management technique. When pain-sensing neurons are exposed to capsaicin, however, QX-314 can enter the cells and shut them down. But the drug remains outside other types of neurons that do not contain these channels so they retain their ability to send and receive signals.

"We’re optimistic that this method will eventually be applied to humans and change our experience during procedures ranging from knee surgery to tooth extractions," says the study’s senior author, Professor Clifford Woolf of Massachusetts General Hospital. "Eventually this method could completely transform surgical and post-surgical analgesia, allowing patients to remain fully alert without experiencing pain or paralysis."

The study appears in the October 4, 2007 issue of Nature.

Source: Harvard Medical School

Deaths Linked to Cephalon’s Cancer Pain Drug, Fentora

After receiving reports of deaths and other serious side effects, FDA is alerting consumers and health care professionals to concerns about the use of Fentora (fentanyl buccal) tablets, a potent opioid pain medication.

Fentora is used only for treating breakthrough pain in cancer patients receiving opioid treatment and who have become tolerant to it—those who take a regular, daily, around-the-clock narcotic pain medicine. Breakthrough pain is intense increases in pain that occur rapidly, even when opioid pain-control medication is being used.

People who develop tolerance to narcotic pain medicines are more resistant to the dangerous side effects of these medications than those who take narcotic pain medication less frequently.

The deaths reported indicate that some cancer patients

  • should not have been prescribed this medicine
  • were prescribed the wrong Fentora dose
  • took too many Fentora doses
  • received Fentora as a substitute for another fentanyl-containing product that is not equal to Fentora

Important Safety Information

  • Ask your doctor if you are opioid-tolerant before taking Fentora. The drug should only be used for breakthrough pain in opioid-tolerant patients with cancer.
  • Fentora should not be used to treat any type of short-term pain, including headaches or migraines, pain after an operation, or pain due to injury.
  • People who only take narcotic pain medications occasionally should not use Fentora.
  • Do not substitute Fentora for other fentanyl medicines, including Actiq. The dosage strength of fentanyl in Fentora is NOT equal to the same dosage strength of fentanyl in other fentanyl-containing products. Using the same dose can result in a fatal overdose.
  • Read the Medication Guide that comes with Fentora,and follow the directions exactly.

Watch For These Signs

Get medical attention right away if you have any of these signs:

  • trouble breathing or shallow breathing
  • tiredness, extreme sleepiness, or sedation
  • inability to think, talk, or walk normally
  • feeling faint, dizzy, or confused

FDA Actions

  • requested the manufacturer, Cephalon Inc., strengthen warnings and improve the dosing instructions in the drug’s product labeling and Medication Guide for patients
  • requested the company improve their education plan for prescribers and pharmacists
  • published a Public Health Advisory and Health Care Professional Sheet warning health care professionals that it is critical to follow Fentora’s product labeling
  • monitoring the Fentora issue closely and reviewing available information, including adverse events
  • working with the manufacturer to ensure the safest use of the medicine
  • providing updates as new information is available

Adverse events related to Fentora should be reported to MedWatch, the FDA’s voluntary reporting program.

Source: FDA

Electronic Device to Eliminate Migraine Pain

A new type of electronic device is designed to provide relief for migraine pain. The device is called TMS, which has been designed to stop migraine pain even before it begins.

According to a recent study, TMS has been found to be effective in treating the pain when used at the onset of migraine.
Earlier, it was assumed that migraines were caused by vascular constriction that resultant in aura—commonly known as electrical storms in the brain, followed by vascular dilation that resulted in severe pain.

However, in the late 1990s, studies revealed that migraine pain is caused by to neuronal electrical hyperexcitability. TMS is based on this new understating of the migraine mechanism and works by interrupting the aura phase of the migraine.

Most Pain Patients Don’t Obey Doctor’s Orders

According to a recently-concluded study, out of 240,000 long-term patients suffering from chronic pain, 77 percent did not follow the instructions of their physician.

The study, by Texas-based Ameritox, revealed that 75 percent of the patients were either taking excessive medication, inadequate medication, no medication or some other medications that were not originally prescribed to them. These extra medicines were illegal or were not recommended by the doctor.

According to the study, even the consumption of legitimate drugs might inflict a sort of addiction or substance abuse. More than 90 per cent of cases related to the misuse of prescribed drugs are not revealed until the patient discloses it.

Ameritox performs urine analysis for physicians’ patients in order to provide better information about what medications patients are taking.