Pain Tolerance and Addiction

by Food and Drug Administration (FDA)

(Page 2 of 3)

Because doctors are afraid patients may become dependent on opiate drugs, they sometimes hold back on the amount or number of doses, even if this means the patient doesn't get sufficient pain relief.

Ronald Dubner, D.D.S., chief of the Neurobiology and Anesthesiology Branch of the National Institute of Dental Research, says those fears are unfounded. But, he explains, "One needs to be very clear about making the distinction between tolerance and addiction." Tolerance occurs when the body no longer responds as well to the opiate's pain-relieving properties at the current dose. For example, some cancer patients with severe pain may need increasing amounts of morphine to maintain the same level of pain relief.

Addiction, on the other hand, is an overwhelming compulsion to continue use of the drug even when pain relief is no longer needed. While some of the addiction is physical, it is mainly considered a psychological dependence that has a detrimental effect not only on the individual, but also on society, because the addicted individual may have to obtain the drug illegally.

Addiction is "really a red herring in the field of pain control," says Dubner. The fear that giving patients opiates will turn them into addicts craving the drugs long after the pain has ended is unfounded, says Dubner.

"People who are truly seeking help for their pain and who are in good hands do not have addiction problems," he explains.

In any case, Dubner says, it is very rare for a patient to reach a point where no amount of an opiate will relieve pain and that should never be used as a reason for not increasing the drug's dose.

Anesthesiologist Francis Balestrieri agrees. "There's no reason to hold back the drug dose for people in acute pain," says Balestrieri, who is the director of the Woodburn Surgery Center at Fairfax Hospital in Falls Church, Va.

However, FDA's Curtis Wright, M.D., warns that the pain relief from higher doses of opiates must be weighed against the side effects these drugs can cause.

"It's a balancing act," says Wright, who is a medical review officer for the agency's center for drug evaluation and research. "The amount of pain relief must be weighed against the effects of adverse reactions such as agitation, nausea, confusion, and potentially lethal respiratory depression."

Patients in Control

Frequently, however, the doses of narcotics physicians prescribe are too low, not too high, and the time between doses is too long, according to a book by Barry Stimmel, M.D., Pain, Analgesia, and Addiction: The Pharmacologic Treatment of Pain. Stimmel writes that, "Analgesic medications should be prescribed regularly around the clock in the presence of acute pain. The intervals between administration should be sufficiently close together to avoid swings in pain levels. Both laboratory and clinical studies have shown that the presence of anxiety will result in an increased need for narcotics, thus setting up a vicious cycle whereby escalating doses of analgesics are needed, without adequate pain relief being obtained."

The use of analgesics provides more benefits to the patient than just relieving pain.

"Evidence from laboratory experiments has begun to accumulate showing that pain can accelerate the growth of tumors and increase mortality after tumor challenge," writes John C. Liebeskind in an editorial in the January 1991 issue of Pain. "It appears that the dictum 'pain does not kill,' sometimes invoked to justify ignoring pain complaints, may be dangerously wrong."

Dubner agrees. "Pain is not a passive symptom. We consider pain, in many instances, an aggressive disease in itself. Therefore it becomes very, very critical to control pain as rapidly and as completely as possible."

One solution to inadequate doses of pain relievers is patient-controlled intravenous analgesia (PCA), which is usually used in hospitals for acute pain following surgery. In PCA, the patient is connected to a machine called a PCA pump. When the patient pushes a control button, the machine delivers a dose of narcotic or other pain reliever intravenously. The doses are smaller than what would be given by injection, but because the drug goes directly into the bloodstream, relief can occur within seconds. A patient receiving traditional administration with an injection in the muscle or under the skin, may have to wait anywhere from 5 to 30 minutes for pain relief.

Although the pain relief with PCA's small doses may only last for 10 to 15 minutes, the patient can get another dose the second pain begins to return. Injections, on the other hand, may last up to two hours, but since the usual dosage schedule is three to four hours, the pain returns long before the nurse does.

About the Author

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