This is a prostaglandin (PG), which is normally produced by human cells from dihomo-γ-linolenic acid (DGLA). DGLA is one of the ω − 6 fatty acids. Like any other prostaglandin, it is released as a paracrine-acting hormone with a short half-life.
Pharmacokinetics[edit | edit source]
Prostaglandin E1 (=PGE1) has a very short half life of around 10 seconds. 60-90% of it is metabolized in the lungs by the first pass effect.
Effects of PGE1[edit | edit source]
PGE1 generally causes vasodilation in the systemic and pulmonary circulation (at the level of arterioles and precapillary sphincters, or muscular arteries), it relaxes the smooth muscle of the corpus cavernosum, but stimulates (contractions) the uterus and small intestinal muscles.
Indications[edit | edit source]
PGE1 maintains the dilation of patent ductus arteriosus in newborns. This condition is undesirable because it leads to an increase in right ventricular pressure and pulmonary hypertension. However, in congenital heart defects that depend on the patent ductus arteriosus (otherwise the newborn will not survive), it is desirable to be kept open for the heart. These are the following heart defects:
- Cyanotic defects: transposition of large vessels, atresia of the tricuspid valve and stenosis of the tricuspid valve
- Acyanotic defects: hypoplastic left heart, aortic coarctation, aortic stenosis and broken aortic arch
The synthetic variant alprostadil is used for its vasodilatory effects in the following indications:
- Erectile dysfunction - injection of alprostadil directly into the corpora cavernosa penis, alternatively also transurethrally
- Critical limb ischemia - the vasodilatory effect of alprostadil is used to increase blood flow through peripheral vasodilation.
Another synthetic analogue, Misoprostol, can be used in the treatment of peptic ulcer, silent miscarriage and to induce labor or abortion.
Route of administration[edit | edit source]
Continuous intravenous infusion. See above for specific routes of administration.