Read the Medication Guide provided by your pharmacist before you start using bosentan and each time you get a refill. If you have any questions, consult your doctor or pharmacist.

Take this medication by mouth with or without food as directed by your doctor, usually twice daily (in the morning and evening).

The dosage is based on your medical condition, weight, 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). Your doctor may start you on a lower dose of this medication and then increase the dose after several weeks.

Use this medication regularly to get the most benefit from it. To help you remember, take it at the same times each day.

Do not stop taking this medication without consulting your doctor. Some conditions may become worse when the drug is suddenly stopped. Your dose may need to be gradually decreased.

Since this drug can be absorbed through the skin and lungs and may harm an unborn baby, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets. Do not crush the tablets because doing so will increase exposure to the dust.

Tell your doctor if your condition lasts or gets worse.