Fundamentals of Nursing Q 421
Which route of administration is preferred if immediate analgesia and rapid titration are necessary?
A. Intraspinal
B. Patient-controlled analgesia (PCA)
C. Intravenous (IV)
D. Sublingual
Correct Answer: C. Intravenous (IV)
The IV route is preferred as the fastest and most amenable to titration. Medications may be given as repeated intermittent bolus doses or by continuous infusion. Intravenous provides almost immediate analgesia; subcutaneous may require up to 15 minutes for effect. Bolus IV dosing provides a shorter duration of action than other routes.
Option A: Intraspinal administration requires special catheter placement and there are more potential complications with this route. Intraspinal and intraventricular administration are options if maximal doses of opioids and adjuvants administered through other routes are ineffective or produce intolerable side effects {e.g., nausea/vomiting, excessive sedation, confusion}. Opioids can be administered via indwelling percutaneous or tunneled catheters into the epidural or intrathecal space.
Option B: A PCA bolus can be delivered; however, the pump will limit the dosage that can be delivered unless the parameters are changed. Patient-controlled analgesia (PCA) devices can be used to combine continuous infusion with intermittent bolus doses, allowing more flexible pain control. It is recommended that the hourly SQ volume limit not exceed 5 cc. Medications can be concentrated to maintain SQ volume limits; maximal concentrations: fentanyl 50 ug/ml, morphine 50 mgs/ml, hydromorphone 50 mgs/ml.
Option D: Sublingual is reasonably fast, but not a good route for titration, medication variety in this form is limited. An alkaline pH microenvironment that favors the unionized fraction of opioids increased sublingual drug absorption. Although absorption was found to be independent of drug concentration, it was contact time dependent for methadone and fentanyl but not for buprenorphine. These results indicate that although the sublingual absorption and apparent sublingual bioavailability of morphine are poor, the sublingual absorption of methadone, fentanyl, and buprenorphine under controlled conditions is relatively high.