Combined administration of opioids with selected drugs to manage pain and other cancer symptoms: initial safety screening for compatibility.

Cancer patients suffer multiple symptoms and require numerous drug therapies. Parenteral administration of multiple medications from a single container can simplify drug regimens for patient self-administration. This simplification reduces drug preparation costs and risk of infection. Therapeutic options are limited by the lack of published information on the compatibility of opioids and adjuvant drugs. We report the results of a study evaluating the physical compatibility of injectable opioids with selected drugs for pain and symptom management. Fentanyl citrate, hydromorphone hydrochloride, methadone hydrochloride, and morphine sulfate solutions were physically compatible with 14 of 15 supportive care drugs tested through visual examination using a high intensity light beam and through measured examination using a turbidimeter over a range of times up to 48 hr. Phenytoin sodium was the only drug found to be incompatible with all opioid solutions tested. This compatibility information will assist clinicians in selecting the most efficient, safe, and cost-effective supportive care drug regimen.