EEG abnormalities during treatment with tadalafil, a phosphodiesterase type 5 inhibitor

Tadalafil is a selective phosphodiesterase type 5 (PDE-5) inhibitor approved for the treatment of erectile dysfunction. Less is known about the electroencephalography (EEG) effects of PDE-5 inhibitors, and the present study, therefore, examined the risk of EEG abnormalities associated with tadalafil.

EEG recordings from 35 erectile dysfunction patients taking tadalafil (20 mg) were graded for severity of EEG abnormalities (at admission, 2 and 48 hours after tadalafil administration).

At admission, there were no EEG abnormalities. At second EEG, abnormalities occurred in 12 (34.3%) of the 35 patients. Eight (22.9%) patients had mild and four (11.4%) patients had moderate EEG abnormalities. At third EEG, one (2.9%) patient had mild and one (2.9%) patient had moderate EEG abnormalities.

PDE-5 inhibitors may produce EEG abnormalities. Although the exact role of PDE in altering susceptibility to seizure remains unclear, epileptic seizures may occur during treatment with PDE inhibitors.