Complex regional pain syndrome (reflex sympathetic dystrophy and causalgia): management with the calcium channel blocker nifedipine and/or the alpha-sympathetic blocker phenoxybenzamine in 59 patients.

Complex Regional Pain Syndrome (CRPS) is the new name for entities formerly known mostly as Reflex Sympathetic Dystrophy and Causalgia. Treatment of CRPS with either the calcium channel blocker nifedipine or the alpha-sympathetic blocker phenoxybenzamine was assessed in 59 patients, 12 with early stages of CRPS, 47 with chronic stage CRPS. In the early stage CRPS patients, 3 of 5 were cured with nifedipine and 8 of 9 (2 of whom had earlier received nifedipine) with phenoxybenzamine, for a cure rate of 92% (11 out of 12). In the chronic stage CRPS patients, 10 of 30 were cured with nifedipine; phenoxybenzamine cured 7 of 17 patients when administered as a first choice and another 2 of 7 patients who received nifedipine earlier, for a total late stage success rate of 40% (19 out of 47). The most common side effects necessitating discontinuing the drug were headaches for nifedipine and orthostatic dizziness, nausea and diarrhoea for phenoxybenzamine. All male patients on phenoxybenzamine experienced impotence, but this did not lead to discontinuing this agent and immediately disappeared after stopping the drug. These results once again stress the importance of early recognition of CRPS, and treatment with either of these drugs could be considered as a first choice for early CRPS, especially because in this series this treatment was not combined with physical therapy making it very cost-effective. In the chronic stage of CRPS, treatment with these drugs was much less successful (40%), even though it was always combined with physical therapy, but it can still be considered, either as a first choice or when other types of treatment have failed.