Expert Opinion Phosphodiesterase-5 Inhibitors and Migraine

CASE A 45-year-old man has a 10-year history of migraine without aura occurring about once a week relieved by an oral triptan. When he sought treatment for erectile dysfunction from a urologist, the side effect of triggering migraine was brought up. Now the patient and the urologist want my opinion about whether the patient should try an oral phosphodiesterase-5 inhibitor (PDE-5) and, if so, do I have a preference? Questions.—What is the risk of PDE-5 triggering migraines? Does the risk vary among the three medications, sildenafil (Viagra), vardenafil (Levitra), and tadalafil (Cialis)? Is the risk dose-related? What is the latency from taking the PDE-5 medication until onset of the headache? Would taking a migraine symptomatic medication along with the PDE-5 inhibitor prevent the migraine from occurring? Does the long-duration agent, tadalafil, cause long-duration migraines? Do PDE-5-triggered migraines respond to the patient’s usual acute migraine medications? Are preventative medications useful in reducing the risk of PDE-5-triggered migraines? How might PDE-5 inhibitors cause migraine?