Morphine bioavailability from a topical gel formulation in volunteers.

Although available therapies provide relief to many patients with cancer-related pain, swallowing difficulties or intestinal obstruction may preclude oral analgesic delivery in some. Topical morphine might provide an alternate delivery form but morphine bioavailability from a topical gel formulation has not been reported in humans. We conducted a randomized, placebo-controlled, double-blind, crossover study of five volunteers after they provided institutionally-approved, written, informed consent. They were admitted to the Northwestern University General Clinical Research Center twice, being randomly assigned to receive either 1mL of morphine compounded at 10mg/mL in pluronic lecithin organogel (PLO) base applied to the wrist and 1mL of normal saline administered subcutaneously, or 1mL of topical drug-free PLO base and 1mL of subcutaneous morphine, 3mg/mL, the first time and the opposite combination the second. Seventeen blood samples were collected from 5minutes to 10hours after dose administration for morphine concentration determination. Plasma samples were prepared by solid-phase extraction and morphine concentrations measured by a mass spectrometric technique with a linear range of 0.5-500ng/mL. Bioavailability of the topical formulation relative to the subcutaneous dose was to be estimated from doses and the plasma morphine concentration versus time relationships. Because morphine was seldom detected in plasma samples after topical administration and was unquantifiable when it was, the low bioavailability of topical morphine was unquantifiable. These results suggest that topical administration of morphine compounded in a PLO base for transdermal drug delivery is unlikely to provide relief of cancer-related pain.

Use of herbal therapies to relieve pain: a review of efficacy and adverse effects.

To find holistic treatment with effective pain relief and few side effects, Americans spend billions of dollars annually on complementary and alternative medicine, including herbal therapies. Despite extensive use, the lack of regulatory scrutiny of these herbal supplements contributes to the paucity of reliable clinical data assessing their efficacy and safety. This review summarizes the existing studies investigating the efficacy of herbal therapies as a treatment for pain. Possible side effects, potential drug-herb interactions, and information about common herbal therapies are also summarized. MEDLINE, AMED, and the Cochrane Library databases were searched for the period from January 1966 to June 2005. Uses, dosages, routes of administration, and side effects were summarized. Strength of empirical evidence also was evaluated. This review found few well-controlled clinical studies. Furthermore, these studies documented limited efficacy of herbal therapies to treat pain. The information presented here may be used to further educate nurses and patients on the use of herbal therapies as well as direct future research efforts.