Pain practice : the official journal of World Institute of Pain
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The nonselective alpha-adrenergic antagonist, phenoxybenzamine, has been used in the treatment of neuropathic pain syndromes, specifically, complex regional pain syndrome (CRPS) types I and II. This agent has also previously been used in intravenous regional peripheral blocks for treatment of CRPS I; however, an intravenous preparation of phenoxybenzamine is not currently available in the U. S. ⋯ We report an apparent clinical benefit in three of the four patients following oral administration. We postulate that this may be due to the noncompetitive (irreversible) blockade of alpha(1)- and alpha(2)-adrenergic receptors. We further hypothesize that this blockade could reduce stimulation of an increased population of adrenergic receptors in hyperalgesic skin, blunt the stimulation by norepinephrine of alpha(2)-adrenergic receptors on macrophages, and ultimately reduce the release of proinflammatory cytokines from cellular elements.
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Median arcuate ligament syndrome, which presents with intractable visceral pain, is difficult to both diagnose and treat. This case report describes the first use of an intrathecal morphine pump as an effective therapeutic intervention. ⋯ The use of an intrathecal narcotic pump should be considered for treatment of patients with intractable visceral pain secondary to median arcuate ligament syndrome.