Perfect Pain Control

The Hospitalist. 2007 March;2007(03):

March 1, 2007 | The Hospitalist

IV Short-Acting Opioids as First-Line Therapy for Pain

With 100% bioavailability and peak effect within 15-30 minutes after intravenous administration, short-acting opioids have become the preferred first-line therapy in the management of moderate to severe pain.1,2 No longer reserved for the end-stage cancer patient, IV opioids are now used to effect rapid pain relief for a variety of conditions often seen by hospitalists. Below, the some common conditions for which IV opioids may be indicated. (Pain management specialists indicate that IV opioids are now used for many causes of severe pain.)

Non-malignant pain:

Pancreatitis;
Intense back pain;
Sickle cell disease;
Small bowel obstruction; and
Perioperative pain.

Malignant pain:

Metastases to the bone;
New diagnosis of metastatic disease; and
Dyspnea and other discomfort at the end of life.

With proper training and experience, hospitalists can utilize short-acting opioids effectively to gain rapid control of patients’ pain. Because IV opioids reach their peak effect within 15-30 minutes, patients may initially be reassessed and then re-dosed at this interval until adequate pain control is achieved and an effective dose is determined. The patient may then be placed on scheduled- or as-needed doses every two to three hours, or, alternatively, on a PCA pump. Doses may then be titrated by 25% for mild pain, by 50% for moderate pain, and by 100% for severe pain.

Choice of drug and starting doses must be individualized to each patient, taking into account his or her prior drug exposure—is the patient opioid-naïve or opioid-tolerant?—prior response to previous doses, age, liver and renal function, pain severity, anticipated pain duration, and co-morbidities such as renal or pulmonary disease.3 —GH

References

Gordon DB, Stevenson KK, Griffie J, et al. Opioid equianalgesic calculations. J Palliat Med. 1999;2:209-218.
National Comprehensive Cancer Network Practice Guidelines in Oncology. Adult cancer pain. Available at: www.nccn.org/professionals/physician_gls/PDF/pain.pdf. Last accessed January 28, 2007.
Gordon DB. Fast fact and concept #70: PRN range analgesic orders. Available at: www.eperc.mcw.edu/fastFact/ff_70.htm. Last accessed January 28, 2007.

Skill Sets to Acquire

In addition to postgraduate and conference courses on pain control, another good first step in educating oneself about pain is to become familiar with equianalgesic doses of opioids. It is also mandatory to know not only how to convert between different opioids but between different routes of administration, Dr. Artz emphasizes. This step is crucial when patients have been stabilized and are ready for discharge. When conversions from IV opioids to equianalgesic doses of oral opioids are performed incorrectly, patients get the idea that the oral medication doesn’t work as well and that they need the IV pain medicine, “when, in reality, we didn’t give them an equivalent dose of oral pain medicine.”

Equianalgesic tables for use in converting 24-hour standing doses of an IV opioid to an oral formulation are readily available. Dr. Bookwalter offers a cautionary note about the use of conversion charts: “These charts are based on single-dose studies. The thing to remember is that these are ballpark numbers. Every place and every practitioner will use them in a slightly different way. The key thing is close monitoring to make sure the pain is relieved and that side effects are kept at a minimum.”

Familiarity with various pain intensity scales is also necessary. The Wong numerical rating scale—either written or verbal (0 = no pain and 10 = worst pain imaginable)—is the most commonly used. The Wong-Baker FACES Pain Rating Scale is helpful when assessing patients who are not English speakers or who have other impairments.3 Dr. Artz reminds hospitalists never to guess by just looking at their patients what their levels of pain are. Many patients have developed coping strategies to mask their pain.