The contents of this page are provided for information purposes only. It should not be construed as a substitute for a professional medical advice and should not be relied upon in that regard. Consult your physician and other healthcare providers before taking prescription medicines found in this page.
Availability
Alu-alu blister pack x 10 tablets per strip, box of 30 tablets

Storage
Store at temperatures not exceeding 30°C. Protect from sunlight and moisture.

Caution
Foods, Drugs, Devices, and Cosmetics Act prohibits dispensing without prescription

For suspected averse drug reaction, report to FDA: www.fda.gov.ph. Seek medical attention immediately at the first sign of any adverse drug reaction.

SAFEBO

Bosentan
125 mg film-coated tablet
Endothelin Receptor Antagonist

What is Safebo?

Bosentan is an endothelin receptor antagonist indicated for the treatment of pulmonary arterial hypertension (PAH). It is absorbed from the gastrointestinal tract with an absolute bioavailability of about 50%. Peak plasma concentrations occur about 3 to 5 hours after an oral dose. It is more than 98% bound to plasma proteins, mainly to albumin. Bosentan is metabolised in the liver by the cytochrome P450 isoenzymes CYP2C9 and CYP3A4 and is an inducer of these enzymes and possibly also of CTP2C19; after multiple dosing, plasma concentrations of bosentan decrease gradually to 50 to 65% of those seen after a single dose. Bosentan has three metabolites, one of which is active. Bosentan is excreted almost entirely as metabolites in the bile; less than 3% of oral dose is excreted in the urine. The terminal elimination half-life is about 5 hours.

 

What is the medicine used for?

For the treatment of pulmonary arterial hypertension (PAH) to improve exercise ability and to decrease clinical worsening.

 

How should the medicine be taken?

In pulmonary hypertension, patients over 12 years of age may be given bosentan orally in an initial dose of 62.5 mb twice daily, increased after 4 weeks to a maintenance dose of 125 mg twice daily. In those with low body weight (below 40 kg) both the initial and maintenance doses are 62.5 mg twice. In systemic sclerosis with ongoing digital ulcer disease, bosentan is given in the same doses as for pulmonary hypertension; there are no data on safety or efficacy in patients under 18 years of age. Or as prescribed by the physician.

 

What adverse effects should I look out for?

Adverse effects reported with bosentan include headache, nasopharyngitis, flushing, oedema, hypotension, dizziness, palpitations, gastrointestinal disturbances, pruritus, skin rashes, fatigue, muscle cramps, and anaemia. Anaphylaxis and andioedema have been reported rarely. Dose-related increases in liver aminotransferases may also occur, and hepatic cirrhosis and liver failure.

 

PRECAUTIONS

General Precautions

Bosentan is contra-indicated in patients with moderate to severe hepatic impairment (Child-Pugh Class B or C). Liver-aminotransferase concentrations should be measured starting therapy, at monthly intervals during therapy, and 2 weeks after any increase in dose.

  • Bosentan therapy should not be started in patients with concentrations more than 3 times the upper limit of normal.
  • If concentrations increase to between 3 and 5 times the upper limit of normal during treatment, Bosentan should be stopped or the dose reduced and concentrations should be monitored every 2 weeks until they are below the pretreatment value; therapy may then be continued or reintroduced, but aminotransferase concentrations should be checked after 3 ays, after a further of 2 weeks, and then monthly.
  • If concentrations rise to more than 5 times the upper limit of normal, Bosentan should be stopped; reintroduction may be reconsidered when concentrations return to below the pre-treatment value.

 

Drug Interactions

Bosentan is metabolised by the cytochrome P450 isoenzymes CYP2C9 and CYP3A4 and is also an inducer of the same isoenzymes. It may also possibly include CYP2C19. Interactions may therefore occur with the other drugs that are either metabolised by, or inhibit, these isoenzymes. Use with ciclosporin is contraindicated since plasma concentrations of Bosentan are significantly increased. There is an increased risk of hepatotoxicity if Bosentan is given with glibenclamide and such use should be avoided; the hypoglycemic effect of glibenclamide may also be reduced. Bosentan has reduced the plasma concentrations of some hormonal contraceptives and additional; contraceptive measures are advised.

 

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