Role of the nitric oxide donor linsidomine chlorhydrate (SIN-1) in the diagnosis and treatment of erectile dysfunction.
OBJECTIVE
Recently, nitric oxide was shown to be a mediator of penile erection in men and the nitric oxide donor linsidomine chlorhydrate (SIN-1) was introduced as a novel treatment option in patients with erectile dysfunction. We now present our follow-up results with the intracavernous application of SIN-1.


METHODS
One hundred thirteen patients with erectile dysfunction of various etiologies and 10 normal control subjects underwent intracavernous pharmacotesting with 1 mg SIN-1. Of the 113 patients, 71 (62.8%) underwent additional pharmacotesting with a mixture of papaverine (15 mg/mL) and phentolamine (0.5 mg/mL) (P/P). Forty-eight responders to SIN-1 were enrolled in an autoinjection program with this substance.


RESULTS
All normal control subjects had full rigid erections lasting 40 to 70 minutes. Of 113 patients, 78 (69%) had responses sufficient for intercourse with SIN-1, and the other 35 patients (31%) demonstrated inadequate responses. All 44 responders to SIN-1 who also received P/P had erections sufficient for intercourse with P/P in doses of 0.25 to 2 mL (mean, 0.6 +/- 0.3 mL). Six patients (13.6%) had prolonged erections with minimal to moderate doses of P/P. From the total of 27 patients who had erections insufficient for intercourse with SIN-1, 20 (74.1%) had good responses with 0.25 to 2.0 mL P/P (mean, 1.5 +/- 0.5 mL). One patient (4%) had a prolonged erection with 1.0 mL P/P: After 10 to 150 injections/patient (total of 1160 injections; mean, 24.1 injections), no significant side effects were noted with SIN-1.


CONCLUSIONS
Our data suggest that intracavernous SIN-1 is safe and efficacious in the majority of patients with erectile dysfunction; however, it has a lower smooth muscle relaxing effect than a combination of P/P. The absence of severe side effects, including priapisms, may be explained by the use of a physiologic pathway for induction of the erectile response and the rapid intracavernous decomposition of SIN-1.
Truss
M C
MC
Department of Urology, Medizinische Hochschule Hannover, Germany.
Becker
A J
AJ
Djamilian
M H
MH
Stief
C G
CG
Jonas
U
U
D000328:Adult; D000368:Aged; D004359:Drug Therapy, Combination; D004576:Electromyography; D007172:Erectile Dysfunction / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D005500:Follow-Up Studies; D006801:Humans; D007267:Injections; D008297:Male; D008875:Middle Aged; D008981:Molsidomine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D010208:Papaverine / Q000494:pharmacology / Q000627:therapeutic use; D010410:Penile Erection / Q000187:drug effects; D010646:Phentolamine / Q000494:pharmacology / Q000627:therapeutic use; D012646:Self Administration; D014665:Vasodilator Agents / Q000494:pharmacology / Q000627:therapeutic use*
D014665:Vasodilator Agents; C002385:linsidomine; D008981:Molsidomine; D010208:Papaverine; D010646:Phentolamine