In patients with vasoactive pulmonary arterial hypertension, vasodilation of the pulmonary artery leads to reduced resistance to blood flow, with subsequent reductions in mean pulmonary arterial pressure. Ask your healthcare professional how you should dispose of any medicine you do not use. Dose-related visual disturbances occurred more frequently at toxic levels, while blood pressure changes showed a low correlation. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine. Children—Use is not recommended. Remove the cap by pushing it down and twisting it counter-clockwise. · The effects may be increased because of slower removal of the medicine from the body. Leukemia (blood related cancer) or. Multiple myeloma (blood related cancer) or. Sickle-cell anemia (blood disorder)—Sildenafil should be used with caution in these patients as problems with prolonged erection of the penis may occur.  · Sildenafil is used to treat erectile dysfunction and pulmonary arterial hypertension. Includes sildenafil side effects, interactions and test1.rug: comprar. Sildenafilo (Viagra). Este medicamento funciona mejor cuando lo tomas con el estómago vacío una hora antes de tener relaciones sexuales. El cuerpo demora más en absorberlo después de ingerir una comida alta en grasas o de consumir alcohol. Sus efectos suelen durar entre 4 y 5 horas, o más si tienes disfunción eréctil de leve a .