Tadalafil-Induced Generalized Bullous Fixed Drug Eruption: A Rare Side Effect of a Common Drug

Tadalafil is a phosphodiesterase-5 (PDE-5) inhibitor, an FDA-approved treatment for erectile dysfunction (ED), pulmonary arterial hypertension (PAH), benign prostate hyperplasia, etc. It is also widely used by otherwise healthy individuals for recreational purposes. Fixed drug eruption (FDE) is a distinctive type of adverse drug reaction in which every exposure to the offending medication leads to the appearance of lesions at the same 'fixed' sites. A sharply defined erythematous patch or plaque with a violaceous hue is typically seen. A clinical variant featuring classic FDE lesions along with blistering in at least three out of six anatomical sites or involving at least 10% of body surface area is known as generalized bullous fixed drug eruption (GBFDE). Tadalafil-induced FDE is in itself an uncommon phenomenon, with only a handful of documented cases, none of which seem to have reported GBFDE-type presentation post-tadalafil intake. Here, we present a case of GBFDE following tadalafil administration.