Iloprost


Iloprost is a drug used to treat pulmonary arterial hypertension, scleroderma, Raynaud's phenomenon and other diseases in which the blood vessels are constricted and blood can't flow to the tissues. This damages the tissues and causes high blood pressure. Iloprost works by opening the blood vessels to allow the blood to flow through again. It was developed by the pharmaceutical company Schering AG and is marketed by Bayer Schering Pharma AG in Europe and Actelion Pharmaceuticals in the USA.

Clinical pharmacology

Iloprost is a synthetic analogue of prostacyclin PGI2. Iloprost dilates systemic and pulmonary arterial vascular beds. It also affects platelet aggregation but the relevance of this effect to the treatment of pulmonary hypertension is unknown. The two diastereoisomers of iloprost differ in their potency in dilating blood vessels, with the 4S isomer substantially more potent than the 4R isomer. While Iloprost is an analog of PGI2 that activates PGI2's receptor, the Prostacyclin receptor, to stimulate vasodilation, it has little selectivity in that it binds to and activates all four receptors for prostaglandin E2 viz., Prostaglandin EP1 receptor, Prostaglandin EP2 receptor, Prostaglandin EP3 receptor, and Prostaglandin EP4 receptor. Activation of the EP2 and EP4 receptors cause vasodilation but activation of the EP3 receptor causes vasoconstriction.

Dosage and administration

Inhaled iloprost

In the U.S., iloprost is inhaled specifically using the I-Neb AAD or Prodose AAD delivery systems. In Europe iloprost has been approved for use with two compressed air nebulizers with AAD delivery systems as well as with two ultrasonic nebulizers Ventaneb and I-Neb.
Ventavis is supplied in 1 mL single-use glass ampules containing either 10 μg/mL or 20 μg/mL. The 20 μg/mL concentration is intended for patients who are maintained at the 5 μg dose and who have repeatedly experienced extended treatment times which could result in incomplete dosing. Transitioning patients to the 20 μg/mL concentration using the I-neb AAD System will decrease treatment times to help maintain patient compliance.
The approved dosing regimen for iloprost is 6 to 9 times daily during waking hours, according to individual need and tolerability. The significant clinical effects observed in the pivotal study of patients with PAH were achieved with a median dose of 30 μg per day, corresponding to 6 daily inhalations of 5 μg. The majority of patients in the pivotal study used this median dose or a higher dose with an excellent treatment compliance after 12 weeks.
The first inhaled dose of iloprost should be 2.5 μg. If this dose is well tolerated, dosing should be increased to 5 μg and maintained at that dose. Any patient who cannot tolerate the 5 μg dose should be maintained at 2.5 μg.
Each inhalation treatment requires one entire single-use ampule. Each single-use ampule delivers a concentration of 10 μg/mL to the medication chamber of either the I-Neb AAD or Prodose AAD System, and delivers a nominal dose of either 2.5 μg or 5.0 μg to the mouthpiece. After each inhalation session, any solution remaining in the medication chamber should be discarded. Use of the remaining solution, even if the reservoir is "topped off" with fresh medication, will result in unpredictable dosing. Patients should follow the manufacturer's instructions for cleaning the I-Neb AAD or Prodose AAD System components after each dose administration.
Complete information regarding use of iloprost in specific populations, drug interactions, and overdosage can be found in full prescribing information.

Intravenous iloprost

Iloprost is also available in an intravenous form, developed and marketed by Schering AG under the trade name Ilomedine.
IV iloprost is usually administered diluted, via a peripheral vein or central venous catheter. The diluted iloprost should be delivered by an accurate rate delivery system such as a syringe driver. Doses vary with individuals as side effects are better tolerated by some patients than others. The duration of the treatment is typically 3 days. This is usually repeated every 8 to 12 weeks

Important safety information

Contraindications:
Common side effects:
Serious adverse events reported with the use of inhaled iloprost include congestive heart failure, chest pain, supraventricular tachycardia, shortness of breath, peripheral edema, and kidney failure.
Warnings: