Pulmoten

Indications

Bosentan is used to treat pulmonary arterial hypertension (PAH), a condition in which the blood vessels in the lungs become narrow and stiff, raising the pressure the heart has to pump against. It helps improve exercise ability and slow worsening of symptoms. It is also used in some patients with systemic sclerosis to reduce the number of new finger ulcers.

How It Works

The body makes a natural substance called endothelin that tightens blood vessels and makes their walls thicken. Bosentan blocks the receptors that endothelin acts on (it is an endothelin receptor antagonist), so the lung blood vessels relax and widen. This lowers the pressure in the lungs and eases the strain on the right side of the heart.

Dosage and Administration

Bosentan is started and supervised by a specialist. The dose is as prescribed, usually starting at a lower dose for the first weeks and then increased. Tablets are taken twice a day, morning and evening, with or without food. Do not stop suddenly unless your doctor advises it. Liver blood tests are done before starting and every month during treatment, and blood count (haemoglobin) is checked regularly.

Interactions

• Ciclosporin and Glibenclamide: should not be used together with Bosentan.
• Hormonal contraceptives (pills, injections, implants, patches): Bosentan makes them less reliable, so a second, non-hormonal method is needed.
• Strong enzyme blockers such as Ketoconazole, Fluconazole and Ritonavir: can raise Bosentan levels.
• Rifampicin, Simvastatin, Warfarin and Sildenafil: levels or effects may change.

Tell your doctor about all medicines and supplements you use.

Contraindications

Do not take Bosentan if you are pregnant or could become pregnant without reliable contraception, have moderate to severe liver disease or raised liver enzymes before starting, are taking Ciclosporin, or are allergic to it.

Side Effects

Common side effects include headache, flushing, swelling of the legs and ankles (fluid retention), stuffy nose, low blood pressure, indigestion and a fall in haemoglobin (anaemia). Raised liver enzymes are common and are the main reason for monthly blood tests.

Get urgent medical help if you notice yellowing of the skin or eyes, dark urine, nausea with vomiting, stomach pain, severe tiredness or fever (possible liver injury), sudden swelling with breathlessness or rapid weight gain, signs of an allergic reaction such as swelling of the face or difficulty breathing, or if you think you may be pregnant.

Pregnancy and Lactation

Bosentan can cause serious birth defects. A pregnancy test is needed before starting and every month during treatment, and reliable contraception (not hormonal methods alone) must be used during treatment and for some time afterwards as advised. Breastfeeding is not recommended while taking Bosentan.

Precautions and Warnings

Keep all appointments for liver tests and blood counts. Tell your doctor if you have heart failure, low blood pressure or liver problems. Men should know that Bosentan may lower sperm count. Report any new or worsening breathlessness or swelling.

Overdose

An overdose may cause severe headache, nausea, vomiting, dizziness, very low blood pressure and a fast heartbeat. Seek medical help straight away.

Therapeutic Class

Endothelin receptor antagonist for pulmonary arterial hypertension.

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.