Physiological effects
Dinoprostone has important effects in labor by inducing softening of the cervix and causing uterine contraction, and also stimulates osteoblasts to release factors that stimulate bone resorption by osteoclasts.Natural prostaglandins, including PGE1 and PGE2, are important in the structure and function of the ductus arteriosus in fetuses and newborns. They allow the ductus arteriosus to remain open, providing the necessary connection between the pulmonary artery and descending aorta that allows the blood to bypass the fetuss underdeveloped lungs and be transported to the placenta for oxygenation. The ductus arteriosus normally begins to close upon birth due to an increase of PGE2 metabolism, but in newborns with congenital heart disease, prostaglandins can be used to keep the ductus arteriosus open longer than normal to sustain healthy oxygen saturation levels in the blood. Although PGE1 is more commonly used in this setting, there has been a report of oral PGE2 being used to treat ductus-dependent congenital heart diseases in newborns to delay surgical treatment until the pulmonary arteries grew. In addition, PGE2 was used in another report to dilate the ductus arteriosus in newborns with various cardiovascular defects to allow for better perfusion of the lungs and kidneys.
Toxicity
When prostaglandin E2 (PGE2) is given in excess, hyper-stimulation of the uterus occurs and immediate discontinuation of the drug usually results in resolution of toxic effects. If symptoms continue a beta adrenergic drug (e.g. terbutaline) can be used.There are many different dosage forms of PGE2. The pharmacokinetic properties vary between dosage forms and should not be interchanged. A medication error was cited in the Institute for Safe Medication Practices where Prostin E2 was used in place of Cervidil. The hospital had run out of Cervidil which is a 10 mg endocervical insert and the provider decided to use half of a 20 mg Prostin E2 vaginal suppository. Cervidil delivers the drug at a constant rate and can be removed as necessary while Prostin E2 dissolves immediately and can not be removed. This error resulted in an emergency C-section since the fetuss heart rate dropped suddenly. Pharmacokinetics
The synthetic PGE2 dinoprostone has a plasma half-life of approximately 2.5–5 minutes, after vaginal administration, with most metabolites being excreted in the urine. History
Swedish physiologist Ulf von Euler and British physiologist M.W. Goldblatt, first discovered prostaglandins independently in 1935 as factors contained in human seminal fluid. Prostaglandins were noted for having blood pressure reducing effects and smooth muscle regulation effects. Prostaglandin E2 itself was identified in 1962 by Swedish biochemist Sune Bergström in the seminal fluid of sheep. The structure of prostaglandins is conserved in mammals, but it is also produced by marine organisms which allowed for more research into their biological roles.