Thursday, September 15, 2011

Tapering of Opioid Analgesics

Tapering of Opioid Analgesics
18. How should T.J.'s opioid analgesics be tapered?
Most patients gradually decrease their activation of a PCA pump as soon as their acute pain begins to subside. In instances in which patients have not decreased their PCA pump use, the dose may safely be reduced by 15% to 20% each day without precipitating symptoms of abstinence. For T.J., the oral levorphanol regimen should be changed to an as-needed schedule once the pain has stabilized. For most patients, a scheduled opioid taper is not essential unless the total daily requirement is in excess of 160 mg of oral morphine (or its equivalent) or if opioid use is prolonged. T.J. should be able to be converted to acetaminophen 325 mg with codeine 30 mg (or an equivalent opioid preparation) once her oral levorphanol has been completely discontinued.
Pain Management in the Opioid-Dependent Patient
19. If T.J. had a history of heroin and cocaine abuse, how would her pain treatment be modified?
Pain management in an IV drug abuser is not difficult as long as the clinician does not judge the patient's behavior or interject personal values into the decision-making process. As with any patient, the goal is to provide as much comfort as possible. Concerns over opiate abuse or addiction are not relevant when treating acute pain, although the clinician must recognize the potential for physical tolerance of opioids and adjust medication doses accordingly.
The first step in the treatment of a patient with a history of substance abuse is to try to determine the amount of illicit drugs the patient has been using, being alert to the possible abuse of multiple drugs in varying quantities.85 Patients who have a history of opiate (heroin) and stimulant (cocaine) use are likely to demonstrate a much greater tolerance to opiates than a patient who has been using opiates alone. Some evidence indicates that cross-tolerance can occur between cocaine and some opiates, but not to methadone.86
The primary goal is to control the patient's pain. A combination of methadone titrated to prevent withdrawal and to provide background analgesia plus a short-acting opioid analgesic dosed adequately to prevent breakthrough pain can be used. If T.J. had a history of substance abuse, she could start with methadone 20 to 40 mg/day in four equally divided doses depending on how much heroin had been used (see Chapter 83, Drug Abuse). The methadone would prevent heroin withdrawal and possibly provide additional analgesia. Because her actual pain requirements are unknown, she also would be placed on a PCA with an agent such as morphine or hydromorphone. It is always important to reassess the patient 1 to 2 hours after starting the analgesic regimen for signs of withdrawal, clinical response, and toxicity, and then titrate the doses of both the methadone and hydromorphone accordingly, although it is best to adjust one medication at a time.87 The final amount required may be higher than doses typically used in opioid-naïve patients. Conversely, some patients may exaggerate their history of prior drug use and will be quite sensitive to the prescribed therapy. Long-term management should include offering the patient appropriate referrals to drug treatment centers, but the final responsibility should rest with the patient.
Use of Opioids in Recovering Addicts
20. Should opioid analgesics be prescribed to recovering opiate addicts?
Acute opioid use in the hospitalized setting is unlikely to cause opioid addiction; the rate of addiction from clinical opioid use is much less than 1%. Unless it is the patient's choice not to use opioids, no rational reason to avoid them exists. Often the patient's fear of addiction can be alleviated by thorough education. The clinician should have a therapeutic contract with the patient that includes pain management as well as opioid tapering on the resolution of the acute pain (see Chapter 83, Drug Abuse).

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