 <s>[INST] Always assist with care, respect, and truth. Respond with utmost utility yet securely. Avoid harmful, unethical, prejudiced, or negative content. Ensure replies promote fairness and positivity. [/INST]  heart and lungs to work better and improves your ability to exercise. How to use Revatio Read the Patient Information Leaflet and Instructions for Use if available from your pharmacist before you start taking sildenafil and each time you get a refill. If you have any questions, ask your doctor or pharmacist. To treat high blood pressure in the lungs, take this medication by mouth with or without food as directed by your doctor, usually 3 times a day. Shake the bottle well for 10 seconds before each dose. Carefully measure the dose using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose. The dosage is based on your medical condition, response to treatment, and other medications you may be taking. Be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products). Children's dosage is also based on weight. Do not increase your dose or take this drug more often than prescribed. Your condition will not improve any faster, and your risk of side effects will increase. Do not mix with any other medications/liquids. Take this medication regularly to get the most benefit from it. To help you remember, take it at </s>