Prostaglandins and Leukotrienes 227
15-methyl-PGF2a is used to control
postpartum haemorrhage when
oxytocin and ergot alkaloids fail to
control the bleeding.- Peripheral vascular diseases: Infusion
or intraarterial injection of prostacyclin
(PGI 2 ) improves potency of blood
vessels in certain peripheral vascular
diseases. Infusion of PGI 2 can also
reduce the infarct size in immediate
postmyocardial infarction period. - Respiratory system: PGE 2 is a powerful
bronchodilator when given in aerosol
form, but due to its irritant action on
bronchial mucosa its clinical utility is
limited. - Renal system: PGE 1 , PGE 2 & PGI 2
increase glomerular filtration through
their vasodilatory effects and increase
water & sodium excretion. - Gastric ulcer: PGE 2 & PGI 2 has been
found to promote healing in gastric
ulcer. PGE’s are cytoprotective at low
doses and inhibit gastric acid secretion
at higher doses.
7. PGE 1 (Alprostadil) is being used as IV
infusion in infants with congenital
heart defects, to maintain the patency
of ductus arteriosus.
LEUKOTRIENES
The leukotrienes play a major role in the in-
flammatory response to injury and are
implicated in the pathogenesis of many
inflammatory diseases, most notably asthma,
allergic rhinitis, cystic fibrosis, glomerulone-
phritis, rheumatoid arthritis, psoriasis, and
inflammatory bowel disease. Several highly
effective cysteinyl leukotriene receptor antag-
onists and synthesis inhibitors are now in late
stage clinical development and are coming
in to the market for the treatment of asthma.
There are indications that these new com-
pounds are steroid sparing in their actions.
The development of leukotriene receptor an-
tagonists and synthesis inhibitors for the
treatment of other inflammatory conditions
is currently a highly active area of research.