ANGIOEDEMA AFTER SILDENAF/ ANGIOEDEMA AFTER SILDENAFIL EXPOSURE

Abstract

Introduction Sildenafil is a phosphodiesterase-5-inhibitor used to treat erectile dysfunction. Common adverse events include headache, vasodilation, and rhinitis. Rarely, allergic hypersensitivity reactions can occur. Case Description A 74-year-old male presented with tongue swelling. Two weeks prior, the patient was advised to start as needed sildenafil by his urologist. After his first dose, he developed tongue swelling within 15 minutes. Symptoms were associated with vomiting, cough, and abdominal pain. He has no prior personal or family history of swelling. The patient is not taking ACE inhibitors, aspirin, or NSAID's. He tried placing ice cubes on his tongue without relief. Ultimately, symptoms resolved within 24 hours, and he did not seek further care until today's visit. He has strictly avoided sildenafil, but was looking for an alternative medication. After a literature search did not provide information regarding cross-reactivity between phosphodiesterase-5-inhibitors, the patient was offered an office drug challenge to avanafil. An emergency plan for anaphylaxis was reviewed, and he was discharged with epinephrine. After 6 weeks, the patient returned without further angioedema or anaphylaxis episodes. The risks and benefits of the challenge were explained. The patient had a successful graded dose challenge to avanafil. He has not had any further hypersensitivity reactions. Discussion Sildenafil, a commonly prescribed medication, rarely causes allergic hypersensitivity reactions. Cross reactivity between phosphodiesterase-5-inhibitors has not previously been established. This is the first case to describe tolerance of avanfil after anaphylaxis with associated angioedema to sildenafil. Further, this case illustrates the importance of obtaining a thorough history and reporting adverse effects. Table 1: Avanafil oral drug challenge Table 1: The patient underwent a two-step oral challenge to avanafil with stable vital signs and no episodes of angioedema or anaphylaxis