Bosentan: Treatment for Pulmonary Arterial Hypertension (PAH)
Bosentan is a specific non-selective endothelin receptor antagonist (types A and B). Endothelin-1 is a potent natural hormone in the body that causes significant vasoconstriction. In certain diseases, its levels rise, leading to dangerous narrowing of the lung arteries.
Bosentan blocks the action of endothelin, thereby dilating the vessels, reducing pulmonary artery pressure, and improving blood flow to the lungs. This significantly increases patients' physical endurance and slows down disease progression.
The drug requires strict medical supervision, especially regarding liver function, as it possesses potential hepatotoxicity.
Indications
- Pulmonary Arterial Hypertension (PAH): To improve exercise capacity and reduce symptoms in patients with functional class II–IV PAH.
- Systemic Sclerosis: To reduce the number of new digital ulcers in patients with systemic sclerosis and an ongoing risk of developing ulcerative processes.
Dosage and administration
Treatment with bosentan should only be initiated by a physician experienced in the management of pulmonary hypertension. The drug is available in 62.5 mg and 125 mg tablets.
- Initial phase: During the first 4 weeks, take 62.5 mg twice daily (morning and evening).
- Maintenance dose: After 4 weeks, the dose is usually increased to 125 mg twice daily.
- How to take: Tablets should be swallowed whole with water, regardless of food intake.
- Crucial monitoring: Liver enzyme levels (ALT/AST) must be checked before starting treatment and then monthly thereafter.
- Pregnancy: The drug is highly teratogenic (causes severe fetal malformations).
- Breastfeeding period.
- Moderate to severe hepatic impairment.
- Concomitant use with cyclosporine A or glibenclamide.
- Hypersensitivity to any components of the drug.
The most commonly reported side effects include:
- Liver: Increased liver transaminase activity (requires regular monitoring).
- Edema: Fluid retention, swelling of the lower extremities.
- Blood: Decreased hemoglobin levels (anemia).
- Vascular reactions: Flushing, headache.
- Gastrointestinal: Dyspepsia, diarrhea, nausea.
