[Effects of doxazosin mosylate and phenoxybenzamine in preoperative volume expansion of pheochromocytoma: a comparative study in 38 cases].

OBJECTIVE

To compare the effects of doxazosin mosylate and phenoxybenzamine in preoperative volume expansion of pheochromocytoma.

METHODS

Phenoxybenzamine 30-240 mg/d was given orally to 38 patients of pheochromcytoma for 3 weeks. After the blood pressure was restored to the primary level before taking phenoxybenzamine, doxazosin mosylate 2-8 mg/d was given orally for three weeks. If the maximum dose of doxazosin mosylate (16 mg/d) still failed to achieve efficient blood volume expansion then phenoxybenzamine was added till completely efficient blood volume expansion was achieved. The effect in volume expansion and side effects were observed with the criteria including decrease of blood pressure to less than 120/80 mm Hg and restoration of the microcirculation imaging to normal.

RESULTS

All the patients got complete volume expansion after taking phenoxybenzamine with tachycardia occurring in 23 of them and postural hypotension in 13 patients. In the 25 cases mainly with increase of norepinephrine before medical treatment doxazosin mosylate was completely effective in 18 cases with their blood pressure < 180/140 mm Hg; and was partially effective in the other 7 cases with their blood pressure > 180/140 mm Hg of which 2 suffered from postural hypotension. Doxazosin mosylate was partially effective in the other 13 cases mainly with increase of both norepinephrine and epinephrine. The total efficiency rate of these two medicines was not significantly different (chi(2) = 18.05, P > 0.05). The side-effect rate of doxazosin mosylate was significantly lower than that of phenoxybenzamine (chi(2) = 324, P < 0.01).

CONCLUSIONS

Doxazosin mosylate has a lower complete volume expansion rate and side-effect rate as well for patients of pheochromocytoma. Pheochromocytomas with mild or moderate level of blood pressure are indicative of the use of doxazosin mosylate.