Important Information for Your Healthcare Provider
You should talk with your healthcare provider prior to taking this medication if you have:
- Liver disease, such as hepatitis, cirrhosis, or liver failure
- Heart disease
- Swelling in the arms, hands, legs, ankles, or feet (edema)
- Any allergies, including to foods, dyes, or preservatives.
Also, let your healthcare provider know if you are:
- Pregnant or thinking of becoming pregnant (see Tracleer and Pregnancy)
- Breastfeeding (see Tracleer and Breastfeeding).
Make sure to tell your healthcare provider about all other medications you are taking, including prescription and nonprescription medicines, vitamins, and herbal supplements.
(Click Precautions and Warnings With Bosentan to learn more, including information on who should not take the drug.)
How Does It Work?
Bosentan is an endothelin receptor antagonist. Endothelins are proteins that have a variety of effects in the body, including on the heart, blood vessels, lungs, and kidneys. One of the things endothelins do is cause blood vessels to constrict (narrow).
People with PAH have higher-than-normal levels of endothelins in the body. Endothelin can bind to two receptors. Bosentan works by blocking both of those receptors, preventing endothelin from binding to them. This helps block the effects of the extra endothelin in people with PAH.
Clinical Effects of Bosentan
Clinical studies have shown that bosentan can improve exercise ability in people with PAH. For instance, in one study, people who took the drug for 16 weeks were able to walk 36 meters farther within six minutes, on average. In comparison, those who took a placebo (a "sugar pill" with no active ingredients) walked eight meters less in six minutes.
Bosentan was also shown to slow worsening of PAH in clinical trials. In these studies, people given the drug had less worsening of their condition, which meant they were less likely to have the following things happen:
- Go the hospital for PAH
- Stop treatment because their PAH got worse
- Need intravenous (IV) treatment