HOUSTON--Opioid solutions appear to be physically compatible with
a number of adjuvant agents used in supportive care, researchers
from M.D. Anderson Cancer Center report. They evaluated the physical
compatibility of four injectable opioids--fentanyl, hydro-morphone,
methadone, and morphine--with 14 drugs used for pain and symptom
management (see table) for 48 hours.
Data on compatibility of opioids and adjuvant drugs have been
lacking, and the studies that are available tested compatibility
for only 1 to 4 hours, says Sonja W. Chandler, PharmD, of the
Division of Pharmacy. Yet, for patients with multiple cancer symptoms,
the ability to combine drugs in a single medication container
could improve the efficiency of drug delivery, reducing hospital
drug preparation costs and limiting the need for frequent venous
A 5-mL sample of each opioid dilution was combined with a 5-mL
sample of each of the supportive care drug solutions individually
in colorless culture tubes. Each combination was prepared twice
so that the order of mixing for each two agents could be reversed.
Samples were examined visually immediately and at 1, 4, 24, and
48 hours. Those samples that appeared clear were further examined
with a high-intensity directional light source.
Since some drug products appear hazy by nature, samples were also
evaluated with a turbidimeter, which allows measurement of the
haze and assessment of any changes. "A decrease in the expected
haze may also be evidence of a physical incompatibility,"
Dr. Chandler said. Samples with evidence of suspected incompatibility
were further evaluated by a HIAC-Royce particle sizer and counter.
The results showed that all four opioid solutions appeared to
be compatible for at least 48 hours with all of the supportive
care drugs tested except pheny-toin sodium (J Pain Symptom Manage
Dr. Chandler and her colleagues, Lawrence Trissel, FASHP, and
Sharon Weinstein, MD, say that the results may aid the clinician
in treating the inpatient with limited venous access or the outpatient
with multiple treatment needs.