For example, rimonabant is a cannabinoid ligand and is used for treating obesity; fomepizole prevents alcohol dehydrogenase, celecoxib is a nonsteroidal anti-inflammatory drug (NSAID), specifically, a COX-2 inhibitor, which relieves pain and inflammation, and sildenafil is a PDE5 inhibitor used in the treatment of erectile dysfunction [39] (Figure 4). The gene discussed is PDE5A; the disease is erectile dysfunction.