To use the oral liquid: Shake the bottle well for at least 10 seconds before each use. Dosing The dose of this medicine will be different for different patients. Talk to your doctor if you take too much sildenafil and you’re worried about any of these side effects: headaches. Objectives: Explain the mechanism of action of sildenafil in the treatment of erectile dysfunction and pulmonary arterial hypertension. Do not press on the plunger of the syringe. Benjamin P. This includes prescription or nonprescription over-the-counter [OTC] medicines and herbal or vitamin supplements.Sildenafil is used to treat erectile dysfunction (ED) and to reduce blood pressure in pulmonary arterial hypertension (PAH). It is taken when needed for ED and daily for PAH. A headache, stomach upsets, and flushing are the main side effects, and it should not be taken within 24 hours of a nitrate. 5. Tips. · 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 a medication used in the management and treatment of erectile dysfunction and pulmonary arterial hypertension. It is in the phosphodiesterase-5 inhibitor (PDE5-I) class of medications. This activity describes the indications, actions, adverse effects, and contraindications of sildenafil as an agent in the clinical setting. Knowledge .