The invention provides a method of treating comorbid premature ejaculation and erectile dysfunction. In particular, the method comprises administering an effective amount of a tramadol material and an effective amount of a phosphodiesterase inhibitor. The invention also provides a pharmaceutical composition comprising a pharmaceutically-acceptable carrier, a tramadol material and a phosphodiesterase inhibitor. The invention further provides a kit comprising a tramadol material and a phosphodiesterase inhibitor.