Drug Interaction Report

Using sildenafil together with sapropterin may lower your blood pressure and increase the risk of dizziness, weakness, headache, flushing, and fainting. These side effects are most likely to be seen at the beginning of treatment with sildenafil, following a dose increase, or when treatment is restarted after an interruption. Let your doctor know if you develop these symptoms and they do not go away after a few days or they become troublesome. Avoid driving or operating hazardous machinery until you know how the medication affects you, and use caution when getting up from a sitting or lying position. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

If you are receiving therapy with sildenafil you should avoid the regular consumption of large amounts of grapefruits and grapefruit juice. Grapefruit can raise the levels of sildenafil in your body and delay the time it takes for the medication to work. Do not increase or decrease the amount of grapefruit products in your diet without first talking to your doctor.

Food increases the absorption of sapropterin. Sapropterin should be administered with food, preferably at the same time each day. Sapropterin tablets should be dissolved in 4 to 8 ounces (120 to 240 mL) of water or apple juice and taken within 15 minutes of dissolution.