Managing pain

Pain management can involve drug therapy with opioid or nonopioid analgesics, including patient-controlled analgesia (PCA) and adjuvant analgesics; neurosurgery; transcutaneous electrical nerve stimulation (TENS); cognitive-behavioral strategies; and intrathecal drug delivery via a pain-control pump.

Pain management: Opioid analgesics

Opioid analgesics are prescribed to relieve moderate to severe pain. Opioids can be natural or synthetic. Natural opium alkaloids and their derivatives are called opiates. Morphine (Duramorph) is the prototype for both natural and synthetic opioid analgesics.

The agony and the ecstasy

Opioid analgesics are classified as full agonists, partial agonists, or mixed agonist-antagonists. Agonists are drugs that produce analgesia by binding to central nervous system (CNS) opiate receptors. These drugs are the drugs of choice for severe chronic pain. They include:

  • codeine
  • hydromorphone (Dilaudid)
  • hydrocodone
  • fentanyl transdermal system (Duragesic)
  • methadone (Dolophine)
  • morphine

Up the anti

Agonist-antagonists also produce analgesia by binding to CNS receptors. However, they’re of limited use for patients with chronic pain because many have a ceiling effect or upper dosing limit. As the dosage increases, they also can cause hallucinations and other psychotomimetic effects and, in opioid-dependent patients, can produce withdrawal symptoms. This class of drugs includes:

  • buprenorphine (Buprenex)
  • butorphanol (Stadol)
  • nalbuphine
  • pentazocine (Talwin)

Any route you choose

Opioid analgesics can be given by many routes, including oral, sublingual, buccal, intranasal, rectal, transdermal, I.M., I.V., epidural, intrathecal, and PCA device. For most patients, oral administration is preferred. I.M. administration, though effective, can result in erratic absorption, especially in debilitated patients.

For severe pain, such as the pain caused by an angina attack, I.V. administration may be preferred because it allows the drug to take effect quickly and permits precise dosage control. Be aware that sudden profound respiratory depression and hypotension can occur with this route. Continuous I.V. infusion using a PCA system allows lower dosing. (See Understanding patient-controlled analgesia.)

Caution is the key

Focus Topic: Pain management

Opioids can produce severe adverse effects; therefore, caution is the key. They’re contraindicated in patients with severe respiratory depression and should be used cautiously in patients with:

  • chronic obstructive pulmonary disease
  • hepatic or renal impairment because they’re metabolized by the liver and excreted by the kidneys
  • head injuries or any condition that raises intracranial pressure (ICP) because they increase ICP and can induce miosis (which can mask pupil dilation, an indicator of increased ICP).

But wait, there’s more…

Other possible adverse effects include drowsiness, dizziness, nausea, vomiting, itching, constipation, and urine retention. Prolonged use of opioids can cause physical dependency, an expected consequence of long-term opioid use that shouldn’t be confused with addiction.

I’ll pencil you in

Analgesic schedules are commonly used in managing chronic pain. This approach may call for a single medication (usually an opioid) or a combination of medications to be administered on a set schedule. If breakthrough or acute pain occurs, additional medications may be added.

Monitoring

Before giving an opioid analgesic, make sure the patient isn’t already taking a CNS depressant such as a barbiturate. Concurrent use of another CNS depressant enhances drowsiness, sedation, and disorientation.

 

Pain Management

 

During administration, check the patient’s vital signs and watch for respiratory depression. If his respiratory rate declines to 10 breaths/minute or less, call his name, touch him, and tell him to breathe deeply. If he can’t be aroused or if he’s confused or restless, notify the practitioner and prepare to administer oxygen. If ordered, administer an opioid antagonist such as naloxone.

Countering adverse effects

Opioids may have several adverse effects. To prevent or manage them, follow these recommendations:

  • If the patient experiences persistent nausea and vomiting during therapy, ask the practitioner about changing medications and give the patient an antiemetic, such as promethazine (Phenergan), as ordered.
  • To help prevent constipation, administer a stool softener together with a mild laxative. Also, provide a high-fiber diet, and encourage fluids, as ordered. Regular exercise may also promote motility.
  • Encourage the patient to practice coughing and deep-breathing. These exercises promote ventilation and prevent pooling of secretions, which can cause respiratory difficulty.
  • Because opioid analgesics can cause postural hypotension, take measures to avoid accidents. For example, keep the bed at the lowest level with its side rails raised. If the patient is able to move around, help him in and out of bed and walk with him to provide support if necessary.

Evaluate for effect

Focus Topic: Pain management

Evaluate the effectiveness of the drug. Is the patient experiencing relief? Does his dosage need to be increased because of persistent or worsening pain? Is he developing a tolerance to the drug? Remember that the patient should receive the smallest effective dose over the shortest period. At the same time, a dosage that’s too low to be effective is pointless. Opioid analgesics are safe and effective; they simply require close monitoring to ensure the most effective dosage. Physical and psychological dependence are rare. In fact, psychological dependence occurs in less than 1% of hospitalized patients.

 

Getting worse instead of better?

Focus Topic: Pain management

Not all patients develop a tolerance to opioids. If a patient has been taking an opioid long-term and suddenly doesn’t have pain relief, check for worsening of the patient’s condition. Don’t assume he has developed tolerance.

Patient teaching

Teach the patient about his drug therapy and ways to avoid or resolve adverse effects. Tell him to:

  • take the prescribed drug before the pain becomes intense to maximize its effectiveness and talk with the practitioner if the drug seems less effective over time
  • not increase the dose or frequency of administration and take a missed dose as soon as he remembers, while maintaining the interval between doses
  • skip the missed dose if it’s just about time for the next dose to avoid serious complications of a double dose
  • refrain from drinking alcohol while taking the drug to avoid pronounced CNS depression
  • talk with his practitioner if he decides to stop taking the drug because the practitioner can suggest an appropriate gradual dosage reduction to avoid withdrawal symptoms
  • avoid postural hypotension by getting up slowly when getting out of bed or a chair
  • eat a high-fiber diet, drink plenty of fluids, and take a stool softener, if prescribed

Watch out for O.D.

Focus Topic: Pain management

Teach the patient’s family the signs of overdose: cold, clammy skin; confusion; severe drowsiness or restlessness; slow or irregular breathing; pinpoint pupils; or unconsciousness. Tell them to notify the practitioner immediately if they notice these signs. Teach them how to maintain the patient’s respiration in an emergency until help arrives.

Avoiding addiction

Focus Topic: Pain management

A concern many health care workers have when caring for patients taking opioid analgesics is the risk of addiction. Discussing the possibility with at-risk patients can help reduce that risk. (See Addressing addiction fears.)

Addressing addiction fears

Pain management

 

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Pain management: Nonopioid analgesics

Nonopioid analgesics are prescribed to manage mild to moderate pain. When used with an opioid analgesic, they help relieve moderate to severe pain and also allow lower dosing of the opioid agent. These drugs include acetaminophen (Tylenol) and NSAIDs, such as aspirin, ibuprofen (Advil), indomethacin (Indocin), naproxen (Naprosyn), naproxen sodium (Aleve), and ketorolac.

Special effects

Focus Topic: Pain management

NSAIDs and acetaminophen produce antipyretic and analgesic effects. In addition, as their name suggests, NSAIDs have an anti-inflammatory effect. Because these drugs all differ in chemical structure, they vary in their onset of action, duration of effect, and method of metabolism and excretion.

In most cases, the analgesic regimen includes a nonopioid drug even if the patient’s pain is severe enough to warrant treatment with an opioid. They’re commonly used to treat postoperative and postpartum pain, headache, myalgia, arthralgia, dysmenorrhea, and cancer pain.

Not so special effects

The chief adverse effects of NSAIDs include:

  • inhibited platelet aggregation (rebounds when drug is stopped)
  • GI irritation
  • hepatotoxicity
  • nephrotoxicity
  • headache

NSAIDs shouldn’t be used in patients with aspirin sensitivity, especially those with allergies, asthma, and aspirin-induced nasal polyps, due to the increased risk of bronchoconstriction or anaphylaxis. Also, NSAIDs are contraindicated in patients with thrombocytopenia, and should be used cautiously in neutropenic patients because antipyretic activity may mask the only sign of infection. Some NSAIDs are contraindicated in patients with renal dysfunction, hypertension, GI inflammation, or ulcers.

Just call me in the morning

Focus Topic: Pain management

Aspirin increases prothrombin and bleeding times; consequently, it’s contraindicated in a patient with a bleeding disorder. Don’t administer aspirin with anticoagulants or ulcer-causing drugs such as corticosteroids. Avoid aspirin use in a patient scheduled for surgery within 1 week.

Acetaminophen may be used in place of aspirin and other NSAIDs in patients with peptic ulcer or a bleeding disorder. High doses of acetaminophen may lead to hepatic damage, however.

Monitoring

Before administering nonopioid analgesics, check the patient’s history for a previous hypersensitivity reaction, which may indicate hypersensitivity to a related drug in this group. If the patient is already taking an NSAID, ask him if he has experienced GI irritation. If he has, the practitioner may choose to reduce the dosage or discontinue the drug.

Always report any abnormalities in renal and liver function studies. Also, monitor hematologic studies and evaluate complaints of nausea or gastric burning. Watch for signs of iron deficiency anemia, such as pallor, unusual fatigue, and weakness.

Patient teaching

For a patient taking an NSAID, teach him the signs and symptoms of overdose, hypersensitivity, and GI bleeding, such as rash, dyspnea, confusion, blurred vision, nausea, bloody vomitus, and black, tarry stools. Tell him to report any of these signs to his practitioner immediately.

If the patient is taking acetaminophen, teach him that nausea, vomiting, abdominal cramps, or diarrhea may indicate an overdose and that he should notify his practitioner immediately.

Understanding adverse effects

Focus Topic: Pain management

To help the patient respond to adverse effects, teach him to:

  • take his medication with food or a full glass of water to minimize the GI upset
  • remain upright for 15 to 30 minutes after taking his medication if he experiences esophageal irritation
  • notify the practitioner if he experiences gastric burning or pain
  • take special care to avoid injury that could cause bleeding because NSAIDs can increase bleeding time
  • talk to the practitioner about persistent tinnitus (a reversible, dose-related adverse effect)
  • exercise caution when driving or using machinery when taking ibuprofen, naproxen, or sulindac (which may cause dizziness)
  • get periodic blood tests to detect nephritis or hepatotoxicity
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