If you forget to take it If you have pulmonary hypertension and you forget to take a dose of sildenafil, take it as soon as you remember unless it’s nearly time for your next dose. If you are taking sildenafil to treat erectile dysfunction, you should know that it does not cure erectile dysfunction or increase sexual desire. Do not start these medications while taking sildenafil without discussing it with your healthcare provider. Sildenafil usually should not be taken more than once every 24 hours. These include itraconazole Sporanox, Tolsura , ketoconazole Extina, Ketozole, others and ritonavir Norvir. How to take liquid If you or your child are taking sildenafil as a liquid, 1ml is usually the same as taking a 10mg tablet, but it’s important to always check the medicine label. Other contraindications include hypersensitivity to any component of the formulation, pulmonary veno-occlusion, left ventricular outflow obstruction, PAH associated with sickle cell anemia, and multiple system atrophy.Sildenafil Citrate Coupons, Prices, and Savings Card. Brand Names: Revatio, Viagra. Sildenafil is used to treat male sexual function problems (impotence or erectile . Last updated on Uses Warnings Before taking Dosage Side effects Interactions FAQ What is sildenafil? Sildenafil relaxes muscles of the blood vessels and increases Missing: cost. Viagra is available in a generic version. Read on to learn about Viagra and cost, as well as how to save money on prescriptions. If you’d like other information about .