[Methylene blue: an effective therapeutic alternative for priapism induced by intracavernous injection of vasoactive agents].

OBJECTIVE

Priapism is defined as prolonged and persistent erection of the penis without sexual stimulation. Etiologies of this condition are numerous. Recent advances in the understanding of erectile physiology have improved the prompt diagnosis and treatment of priapism. Treatment of priapism varies from a conservative medical to a drastic surgical approach. Normally, priapism is effectively treated with intracavernous vasoconstrictive agents or surgical shunting. Recent findings indicate methylene blue (MB), a guanylate cyclase inhibitor, to be a potential inhibitor of endothelial-mediated cavernous relaxation. This prompted us to assess the feasibility, the use and the effectiveness of MB in the treatment of priapism.

METHODS

25 patients were treated for priapism. Etiologies were: 22 drug-mediated (PGE1 or papaverine/phentolamine mixture) after corpus cavernosum injection therapy (CCIT), 1 leukemia-induced and 2 idiopathic high-flow priapism. Patient ages ranged from 13 to 72 years. The average duration of priapism was 5 hours and 22 minutes after CCIT. MB was administered after blood aspiration of the corpora cavernosa. 5 ml of MB was injected intracavernously (i.c.) and left for 5 min. MB was then aspirated and the penis compressed for an additional 5 min.

RESULTS

All patients with CCIT-induced priapism were cured with MB alone. The 3 patients who did not respond to MB underwent i.c. phenylephrine administration and finally, if necessary, embolization of the pudendal artery. Etiology and duration of priapism were the strongest predictors for success with intracavernously administered MB. The primary side effects were a transient burning sensation and blue discoloration of the penis on injection of MB. The initial baseline erectile status was restored in all patients cured by MB.

CONCLUSIONS

These results confirm that MB is a safe and highly effective treatment agent for short-term pharmacologically-induced priapism. Furthermore, MB demonstrates distinct advantages over a-adrenergic agents for intracavernous use, such as lower costs, absence of systemic or local toxic side effects and shorter treatment time leading to faster detumescence. For this reason, MB is a suitable and safe substance for alternative routine intracavernous therapy in males with pharmacologically-induced priapism.