Pain Management
Joshua Greenspan
Pain is an important phenomenon in many otolaryngologic disorders. During the last 10 years, treatment of these disorders has improved greatly through cooperative arrangements with physicians specializing in pain management—a discipline that has developed into a fellowship of anesthesiology with a rigorous board certification program. The management of pain may require administration of medications or use of procedural interventions.
OPIOIDS
Opioids are the mainstay in the pharmacologic management of pain. Regarding opioid medications, four important concepts to remember are summarized below.
Tolerance—Patient is resistant to analgesic effect of opioids and requires increasing doses. Tolerance can develop over days and the upper limits can be striking, requiring progressively increasing doses.
Habituation—Patient’s body becomes physically dependent on opioid blood level and sudden cessation of opioids results in withdrawal. The same phenomenon is seen with caffeine, antihypertensives, and hypoglycemics. This does not mean the patient is addicted.
Addiction—Patients are psychologically dependent on opioids and may lie in order to get more.
Pseudoaddiction—The patient has legitimate pain but the present dose of opioid is providing insufficient analgesia and the patient may ask for more or ask for it earlier. This creates the illusion of addiction. The healthcare provider labels the patient as “drug seeking,” becomes indignant, and refuses to “feed an addict their addiction.” This is a major obstacle for proper care.
There are two types of opioids: short acting and long acting. Short-acting opioids are used for breakthrough pain when a patient’s pain flares up. They can also be used prior to physical therapy sessions or other activities (e.g., dressing changes) that worsen pain. Many physicians wrongly believe short-acting opioids are less addicting than long-acting opioids. In fact, short-acting opioids are far more addicting than long-acting opioids because the patient is chasing the pain with pills. They are taking medication as a reflex to their pain, rather than taking medication by the clock and staying ahead of their pain. They are essentially being conditioned to take medication whenever they have pain.
Long-acting opioids are effective for delivering a basal blood level of analgesics. They deliver round-the-clock treatment of round-the-clock pain. With long-acting opioids, you get a constant blood level, much like that seen with an intravenous infusion, or by using a basal infusion rate on a PCA (patient-controlled analgesia)
pump. This method works well especially at night when a patient is sleeping so that they continue to have relief of pain without having to wake up and ask for more analgesic medication. Basal infusion rates are usually necessary in patients with chronic continuous pain or who exhibit tolerance.
pump. This method works well especially at night when a patient is sleeping so that they continue to have relief of pain without having to wake up and ask for more analgesic medication. Basal infusion rates are usually necessary in patients with chronic continuous pain or who exhibit tolerance.
What dose of long-acting opioid should you use? It is appropriate to have the long-acting opioid be equivalent to four doses of the short-acting opioid. In this way, if the patient takes four rescue doses of opioid in 1 day, they will be able to double the long-acting opioid dose. This works in both directions. If you already have a known dose of long-acting opioid and need to start a patient on rescue doses, choose a dose that is approximately one-fourth of the long-acting dose.
Various short-acting opioids have long-acting counterparts. Examples of these are listed below.
Morphine (MSIR) has MSContin and Kadian
Oxycodone (OXY-IR) has OxyContin (oxycodone is the opioid in Percocet)
Fentanyl has Fentanyl Patch (3-day delivery system of a shortacting analgesic)
The following short-acting opioids do not have long-acting counterparts.
Dilaudid (hydromorphone)—no active metabolites; good for renal-impaired patients
Codeine (found in Tylenol #3)—worst side effect profile among opioids
Demerol (meperidine)—has central nervous system excitatory effects and short half-life; very addicting
Vicodin (hydrocodone)
Pure long-acting opioids include methadone (dolophine), which has the longest half-life but carries a social stigma limiting its use. The long-acting opioids are given by the clock, not PRN. The dosing regimen for long-acting opioids is summarized below.
Methadone BID or TID
MSContin BID or TID
OxyContin BID or TID
Kadian QD
Fentanyl Patch Q72hours—takes a day to kick in and lingers for nearly a day after the patch is removed
Frequently, patients need to be switched from one opioid regimen to another. They may be on an intravenous regimen and need to be on an oral regimen to get ready for discharge from the hospital. Or the converse may be true: patients are already on a regimen prior to admission that cannot be continued because the hospital does not have their medication on formulary. Please refer to the included conversion table for such needs. Note that the Fentanyl patch corresponds to a range of oral or intravenous opioids at each strength of the patch (Table 50.1).
The major side effect of opioids is constipation from binding to the opioid receptors in the gastrointestinal tract. For constipation,
you can use Colace, Senekot, Lactulose, Miralax, and enemas. Other side effects such as sedation, pruritis (not actual allergic reactions), and nausea fade over several days.
you can use Colace, Senekot, Lactulose, Miralax, and enemas. Other side effects such as sedation, pruritis (not actual allergic reactions), and nausea fade over several days.
TABLE 50-1. Conversion table | ||||||||||||||||||||||||||||||||
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Nonsteroidal Antiinflammatory Drugs
Nonsteroidal antiinflammatory drugs (NSAIDs) play an integral role in treating pain. They reduce prostaglandin synthesis, which generates pain and inflammation. Prostaglandins are also needed for other functions, such as protecting the stomach, kidneys, and platelets. In 1998, a new breed of NSAID was born—the cyclooxygenase-2 enzyme-specific blocking agents (a.k.a. Cox-2s). The benefit of these drugs is that they block pain and inflammation without hurting the stomach or platelets. They do not offer improved renal protection compared to traditional NSAIDs.
Regarding their effect on the stomach, they are designed not to reduce the protective mucosal lining of the stomach. Nonetheless, there have been reports of gastrointestinal bleeding in patients taking these agents. The incidence is greatly reduced with these agents, which accounts for their increased use.
Regarding the platelet-sparing effect, these agents have been studied in perioperative use and research shows that they do not increase bleeding whatsoever. When used preoperatively, they block prostaglandin synthesis and reduce the amount of opioid used postoperatively by up to 40%. The idea of preemptive analgesia to reduce postoperative pain is catching on, especially in ambulatory surgical cases where the patient goes home the day of surgery.
There are currently three Cox-2s: Bextra (10-20 mg/day); Celebrex (200-400 mg/day); and Vioxx (25-50 mg/day).
Anticonvulsants
The more frequently a pain nerve fires, the more pain is perceived. Anticonvulsants “calm down” nerves and reduce the aberrant firing of pain nerves. There is a special type of pain called “neuropathic pain.” This is pain caused by an abnormality in a nerve itself, rather than from peripheral tissue damage. This pain is usually sharp, lancinating, and electrical. Patients often feel paresthesias or numbness in the area of their pain. The pain is usually constant and unrelenting. One of the signs of neuropathic pain is that it usually does not respond to opioids. The most opioids do is “take the edge off of the pain.” Ask the patient, “Does the pain medication (opioid) really help your pain, or does it just take the edge off?” They will stare at you in amazement and say, “You’re right! It does just take the edge off.” At that moment, think “neuropathic pain.”
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