Tonic-clonic seizures in patients taking sildenafil

Sildenafil citrate (Viagra) is a specific phosphodiesterase type V inhibitor with a selective inhibitory effect on cyclic guanosine monophosphate (cGMP). Its enhancement of nitric oxide release leads to an increase in cGMP concentrations, which is responsible for its main clinical effect—relaxation of the smooth muscle in the corpus cavernosum. The increase in blood flow into the penis helps to alleviate problems of erectile dysfunction.1

Minor side effects—such as headache, flushing, nasal congestion, and defects in colour vision—and serious cardiovascular and cerebrovascular effects, have been described.1 Convulsive seizures have been an unknown neurological …