(4)     Treatment options

The mainstay of pain management is as needed (PRN) dosing.  However, there are two reasons why PRN dosing regimens for acute pain may fail.  First, patients usually expect pain relief to be delivered immediately upon request.  PRN dosing can frequently contribute to a failure in this process.  This occurs because either the patient waits too long to request more pain medication or, the staff cannot immediately administer the drug.  Second, blood concentrations fluctuate between 4 hour dosing intervals (e.g., meperidine 50-75 mg IM q 4 hours PRN pain) such that the MEAC is maintained only 35 percent of the time, or patients are in pain 65 percent of the time.  Drugs used in the treatment of acute pain must be viewed as agents that need to be titrated on a frequent basis rather than being administered on a set dosing regimen determined by the average patient.

(5)   Stepcare Approach

Like the approach to the treatment of hypertension, acute pain management uses a stepcare system of drug administration.

• Step 1 - In patients tolerating oral (PO) medications, nonsteroidal anti-inflammatory drugs (NSAIDs) are the first line of therapy.

• Step 2 - In patients not controlled by NSAIDs or in whom they are contraindicated, add or initiate a weak narcotic analgesic.

• Step 3 - In patients not controlled by step 1 or 2, reassess the cause of pain and then replace the weak narcotic with a potent narcotic.

• Step 4 - If the patient is still not controlled or is not a candidate for oral treatment, initiate IM or IV therapy.

Remember intramuscular (IM) narcotic therapy results in large swings in concentrations, is uncomfortable for the patient, and provides analgesia for less than 50 percent of the every 4-hour dosing regimen.  However in some cases, IM narcotic therapy may be the best available option (e.g. for a patient being transported without direct physician supervision).  For intravenous therapy, initiate treatment with small aliquots of narcotic (e. g. morphine sulfate 2 to 4 mg every 5-10 minutes).  Adjust the dose depending on the patient’s age and physical condition.  After 2 to 3 hours, an average hourly requirement can be determined.

(5)   Complications

It is imperative to anticipate the adverse effects of narcotic use. Constipation, sedation, nausea, and vomiting are expected adverse effects.  Providing stool softeners, careful monitoring, and antiemetics prophylactically will prevent many of these problems.

(6)     Respiratory depression

Respiratory depression is probably the best example of a serious adverse pharmacological effect that is only rarely encountered clinically but generates concern sufficient to cause undertreatment. The occurrence of respiratory depression is extremely uncommon in patients who undergo gradually escalating doses.  Narcotic induced respiratory depression, if not caused by a massive overdose, is always heralded by the gradual onset of obtundation and slowed respiratory rate: signs that signal an impending problem that needs to be managed appropriately.  Monitoring drug effects by assessing the level of consciousness and respiratory rate can greatly diminish the risk of serious respiratory depression.