Bosentan Pharmacology


About Bosentan
Endothelin Receptor Antagonist, highly substituted pyrimidine derivatives.
Mechanism of Action of Bosentan
Bosentan is a competitive antagonist of endothelin-1 at the endothelin-A (ET-A) and endothelin-B (ET-B) receptors. Under normal conditions, endothelin-1 binding of ET-A or ET-B receptors causes pulmonary vasoconstriction. By blocking this interaction, bosentan decreases pulmonary vascular resistance. Bosentan has a slightly higher affinity for ET-A than ET-B.
Pharmacokinets of Bosentan
Distribution:Protein binding >98%
Metabolism: Hepatic
Elimination: Biliary excretion; less than 3% is recovered in urine.
Onset of Action for Bosentan
Duration of Action for Bosentan
Half Life of Bosentan
5 hours
Side Effects of Bosentan
4.Runny nose, sore throat, and other cold symptoms
Contra-indications of Bosentan
2.Coadministration of cyclosporine or glyburide
Special Precautions while taking Bosentan
1.Due to potential hepatotoxicity, the FDA requires monthly monitoring of liver function tests while taking Bosentan.
2.Bosentan use requires hematocrit monitoring due to potential onset of anemia.
3.Hormone-based contraception is not possible in women taking Bosentan, due to a pharmacokinetic a interaction.
4.This drug may make you dizzy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such
Pregnancy Related Information
Contraindicated because of its teratogenicity
Old Age Related Information
Select dose with caution, reflecting greater frequency of decreased hepatic, renal, or cardiac function, and comorbidity.
Breast Feeding Related Information
Children Related Information
Indications for Bosentan
Pulmonary hypertension
Interactions for Bosentan
1.Clarithromycin :The risk of bosentan hepatotoxicity may be increased.
2.Cyclosporine :Bosentan trough concentrations may be increased, while cyclosporine plasma levels may be decreased; coadministration is contraindicated.
3.Glyburide :Plasma concentrations of both glyburide and bosentan may be decreased; coadministration is contraindicated.
4.HMG-CoA reductase inhibitors (eg, atorvastatin, lovastatin, simvastatin) :Plasma concentrations of simvastatin and its metabolite may be decreased when coadministered with bosentan. Bosentan is also expected to reduce plasma concentrations of other HMG-CoA reductase inhibitors metabolized by CYP3A4 (ie, atorvastatin, lovastatin). Monitor cholesterol levels and adjust the HMG-CoA reductase inhibitor dose accordingly.
5.Hormonal contraceptives:Plasma concentrations may be reduced by bosentan, decreasing the effectiveness. Women should not rely on hormonal contraception alone when taking bosentan.
6.Ketoconazole :Plasma concentrations of bosentan may be increased. No dosage adjustment is necessary
7.Phosphodiesterase type 5 inhibitors (eg, sildenafil) :Coadministration may elevate bosentan plasma concentrations, increasing the pharmacologic effects and risk of toxicity. Phosphodiesterase type 5 inhibitor concentrations may be reduced, decreasing the pharmacologic effects. Coadminister these agents with caution
8.Rifampin :Coadministration may increase bosentan trough concentrations after the first concomitant dose and decrease bosentan trough concentrations at steady state
9.Ritonavir-containing regimens :Coadministration may increase bosentan trough concentrations. In patients receiving ritonavir for at least 10 days, start bosentan at 62.5 mg once daily or every other day based on tolerability. In patients receiving bosentan, stop bosentan at least 36 h before starting ritonavir. At least 10 days after starting ritonavir, resume bosentan at 62.5 mg once daily or every other day based upon tolerability.
10.Warfarin :Warfarin plasma concentrations may be decreased by bosentan. Because warfarin has a narrow therapeutic index, monitor coagulation parameters and adjust the warfarin dose as needed

Typical Dosage for Bosentan
PO 62.5 mg twice daily for 4 wk, then increase to maintenance dosage of 125 mg twice daily. In patients with a body weight less than 40 kg, the recommended maintenance dosage is 62.5 mg twice daily.
Dosage adjustments are necessary in patients developing aminotransferase abnormalities
Schedule of Bosentan
Storage Requirements for Bosentan
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat.
Effects of Missed Dosage of Bosentan
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
Effects of Overdose of Bosentan
In case of overdose, call your local poison control center
Symptoms of overdose may include:
2.Upset stomach
4.Fast heartbeat
7.Blurred vision

Home Delivery for Bosentan in Your City

Medicine India is just a publishing medium for medicine related information and does not provide services or sales of medicines including bosentan.

However, we do publish a comprehensive directory of Pharmacies, Chemists and Druggists in cities all over India. You can use this directory to find the medicine stores in your city (or area) that provide home delivery services for bosentan and other medicines and health products. Home delivery services for bosentan may be free or they may cost you depending on the pharmacy and the minimum order requirements. It would be best to get this clarified while placing the order.

Please be aware that you should take bosentan only if a doctor has recommended or prescribed it. Some or all pharmacies who provide a home delivery service for medicines might insist on a prescription for bosentan before they complete the sale. You can get this information while placing the order for bosentan with the pharmacy.

Bosentan is a generic medicine name and there are several brands available for it. Some of the brands for bosentan might be better known than bosentan itself. If the pharmacy that's willing to deliver medicines to your home doesn't have bosentan in stock, you can ask for one of the branded alternatives for bosentan.