Viagra and cluster headache.
Stein
M
M
D003027:Cluster Headache / Q000139:chemically induced*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010879:Piperazines / Q000009:adverse effects*; D011687:Purines / Q000009:adverse effects; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000009:adverse effects*; D014665:Vasodilator Agents / Q000009:adverse effects*
D010879:Piperazines; D011687:Purines; D013450:Sulfones; D014665:Vasodilator Agents; D000068677:Sildenafil Citrate