Overview
DESCRIPTION Alprostadil injection, USP for intravascular infusion contains 500 micrograms alprostadil, more commonly known as prostaglandin E 1 , in 1 mL dehydrated alcohol. The chemical name for alprostadil is (1R,2R,3R)-3-Hydroxy-2-[(E)-(3S)-3-hydroxy-1-octenyl]-5-oxocyclopentane heptanoic acid, and the molecular weight is 354.49.
Mechanism of Action
CLINICAL PHARMACOLOGY Alprostadil (prostaglandin E 1 ) is one of a family of naturally occurring acidic lipids with various pharmacologic effects. Vasodilation, inhibition of platelet aggregation, and stimulation of intestinal and uterine smooth muscle are among the most notable of these effects. Intravenous doses of 1 to 10 micrograms of alprostadil per kilogram of body weight lower the blood pressure in mammals by decreasing peripheral resistance. Reflex increases in cardiac output and rate accompany the reduction in blood pressure. Smooth muscle of the ductus arteriosus is especially sensitive to alprostadil, and strips of lamb ductus markedly relax in the presence of the drug. In addition, administration of alprostadil reopened the closing ductus of new-born rats, rabbits, and lambs.
Indications
- INDICATIONS AND USAGE Alprostadil injection, USP is indicated for palliative, not definitive, therapy to temporarily maintain the patency of the ductus arteriosus until corrective or palliative surgery can be performed in neonates who have congenital heart defects and who depend upon the patent ductus for survival. Such congenital heart defects include pulmonary atresia, pulmonary stenosis, tricuspid atresia, tetralogy of Fallot, interruption of the aortic arch, coarctation of the aorta, or transposition of the great vessels with or without other defects.
Common Doses
- 1 mL
- 250 mL
- 100 mL
- 50 mL
Dosage
DOSAGE AND ADMINISTRATION The preferred route of administration for alprostadil injection is continuous intravenous infusion into a large vein. Alternatively, alprostadil injection may be administered through an umbilical artery catheter placed at the ductal opening. Increases in blood pO 2 (torr) have been the same in neonates who received the drug by either route of administration. Begin infusion with 0.05 to 0.1 micrograms alprostadil per kilogram of body weight per minute. A starting dose of 0.
Black Box Warning
WARNING Apnea is experienced by about 10 to 12% of neonates with congenital heart defects treated with alprostadil injection. Apnea is most often seen in neonates weighing less than 2 kg at birth and usually appears during the first hour of drug infusion. Therefore, respiratory status should be monitored throughout treatment, and alprostadil injection should be used where ventilatory assistance is immediately available.
Contraindications
- CONTRAINDICATIONS None.
Side Effects
- ADVERSE REACTIONS Central Nervous System Apnea has been reported in about 12% of the neonates treated (see WARNING box). Other common adverse reactions reported have been fever in about 14% of the patients treated and seizures in about 4%. The following reactions have been reported in less than 1% of the patients: cerebral bleeding, hyperextension of the neck, hyperirritability, hypothermia, jitteriness, lethargy, and stiffness.
Interactions
- Drug Interactions No drug interactions have been reported between alprostadil injection and the therapy standard in neonates with restricted pulmonary or systemic blood flow. Standard therapy includes antibiotics, such as penicillin and gentamicin; vasopressors, such as dopamine and isoproterenol; cardiac glycosides; and diuretics, such as furosemide.