... Palo Alto Labs is conducting this recall after being informed by representatives of the Food and Drug Administration (FDA) that lab analysis by FDA of Aspire36 and Aspire Lite samples found that the products contained Aildenafil in trace amounts and Dimethyl sildenafil thione (sulfoaildenafil) a purported analog of Sildenafil, an FDA-approved drug used as treatment for male Erectile Dysfunction (ED). Sulfoaildenafil is close in structure to Sildenafil and is expected to possess a similar pharmacological and adverse event profile. ...