Pathological vasospasm and free radical production contribute to skin flap survival. This study was undertaken to determine if combination therapy with anti-free radical agent-allopurinol and the vasodilatoprostaglandin E₁results in the synergistic enhacement of skin flap survival in rats. Twenty Sprague-Dawley rats were divided into four groups. With five rats in each group, group I being the control, group II was given intravenous allopurinol, group III was given transdermal PGE₁, and group IV was given both intravenous allopurinol and transdermal PGE₁. Control group demonstrated 27.7±3.0% skin flap survival. Compared to the control group, the increase in survival rate in PGE₁ group was statistically significant with a p value of less than 0.01. The group of both PGE₁ and allopurinol were given, mean flap survival rate was significantly higher than control group (p<0.01), but statistically insignificant compared to the single agent administered group.
This study demonstrated combination therapy with the two agents-intravenous allopurinol and transd PGE₁-fails to confer additive benefit on flap survival in comparison with the groups given a single agent. This lack of additive effect may be due to a common final mechanism of action or to the presence of another pathological mechanisms of ischemic necrosis are present. Based upon this data, only single agent, transdermal PGE₁ is recommended for the pharmcological adjuvant of the compromising flap and further studies may be needed for the evaluation of the correct mechanisms of allopurinol in flap survival.