title: Viagra reacts with ritonavir.
mesh_terms: D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005060:Europe; D017320:HIV Protease Inhibitors / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D010726:Phosphodiesterase Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D010879:Piperazines / Q000008:administration & dosage* / Q000009:adverse effects; D011687:Purines; D018570:Risk Assessment; D019438:Ritonavir / Q000008:administration & dosage*; D000068677:Sildenafil Citrate; D013450:Sulfones; D013997:Time Factors
chemical_list: D017320:HIV Protease Inhibitors; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate; D019438:Ritonavir