A Non-Fatal Self-Poisoning Attempt with Sildenafil

The phosphodiesterase type 5 inhibitor, sildenafil, is not generally known for its use as a self-poisoning drug. However, intoxication cases with lethal outcome have been described. The case presented here is of a 56-year-old man who claimed to have undertaken an unsuccessful suicide attempt by mono-ingestion of 65 tablets of 100 mg sildenafil. He arrived at the emergency department 24 h after intake with severe vomiting and symptoms of blurred vision. Clinical examination revealed no priapism. Of note was a sinus tachycardia of 100 bpm without signs of hypotension. To quantify the sildenafil concentration in serum, an high-performance liquid chromatography photo-diode array method was developed and validated according to European Medicines Agency guidelines. The intoxicated patient had a serum concentration of 22.2 µg/mL sildenafil, at the time of presentation, which is far above the therapeutic peak concentration. The serum concentration further declined to 9.2 and 2.3 µg/mL, respectively, 5 and 14 h later, revealing a biological half-life of 4.2 h. To the best of our knowledge, this patient took the highest sildenafil dose, which resulted in the highest serum concentration, ever reported. In this subject, sildenafil showed good tolerability because few symptoms occurred and only moderate supportive therapy was needed for full recovery without sequelae.